Unraveling challenges and opportunities of kelp meal supplementation in Northeast organic dairies

Final report for LNE16-346

Project Type: Research and Education
Funds awarded in 2016: $199,820.00
Projected End Date: 10/31/2020
Grant Recipient: University of New Hampshire
Region: Northeast
State: New Hampshire
Project Leader:
Dr. Andre Brito
University of New Hampshire
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Project Information

Summary:

We learned through surveys that 59% of organic dairy farmers in the Northeast feed kelp meal. We hypothesize that the antimicrobial and antioxidant properties of kelp improve animal health, and that kelp’s iodine is promptly transferred to milk resulting in concentration of iodine above recommended for human consumption, particularly young children. High iodine intake can lead to poor thyroid health including goiter in humans and animals. These hypotheses were tested by 2 mechanisms: (i) Improve animal health and farm profitability by fine-tuning kelp supplementation, and (ii) An industry-scale survey of the iodine content in organic retail milk in the Northeast. Our overarching goal is to increase farmers’ knowledge about the challenges and opportunities of kelp supplementation and its potential benefits on improving animal health, as well as kelp cost effectiveness and impacts on milk iodine levels. Farmers will be confident on how to fine-tune the amount of kelp fed to their milking cows, and how this adjustment may affect profitability and milk iodine levels.

A core group of 5 organic dairy farmers in collaboration with our team guided the implementation of this project by feeding kelp meal to their dairy herds. Feeding trials conducted at the University of New Hampshire, aimed at investigating different strategies of kelp meal supplementation provide insights about the profitability of kelp use as well as cow health, production, and methane emissions. Dairy Herd Improvement (DHI) records of participant dairies were used to assess the efficacy of kelp meal on improving milk somatic cell count (SCC). High milk SCC reduces milk quality and milk pay prices in addition to be associated with mastitis and poor mammary gland health, which can further decrease farm profitability. Based on project overall research, we do not recommend feeding more than 2 oz of kelp meal/day to milking cows due to kelp high costs and no additional benefits on milk production and milk SCC. Our team also delivered surveys, workshops, webinars, and field days to educate farmers in the region and beyond about kelp meal supplementation.

Performance Target:

Performance target:

Sixty organic dairy farmers managing 3,500 cows with milk iodine of 1,370 micrograms/L and annual kelp meal costs of $8,891/farm ($0.07/oz of kelp × 58 cows/farm × 365 days) reduce milk iodine to 800 micrograms/L and annual kelp costs to $4,446/farm after fine-tuning kelp supplementation from 6 to 3 oz/cow/day.

Introduction:

PROBLEM OR OPPORTUNITY DESCRIPTION

Kelp meal is known to contain a wide spectrum of nutritional compounds, including minerals (particularly iodine), polyunsaturated fatty acids, bioactive peptides, and vitamins. Kelp meal is also rich in antioxidants with potential animal health benefits and phlorotannins with antimicrobial properties. A 2013 survey (Northeast-SARE award# G12-049) conducted by our team prior to the implementation of the current project revealed that 59% of organic dairies in the Northeast feed kelp meal seasonally or year-round (245 total survey respondents). Specifically, our survey showed that 131 or 92% farmers (142 respondents) feed kelp meal to their milking cows, while 116 or 82% (142 respondents) feed it to dry cows and heifers, and 84 or 60% (140 respondents) to calves. Farmers feed kelp meal because (i) it improves body condition and overall animal appearance, (ii) it decreases somatic cell count (SCC) and the incidence of pinkeye and reproductive problems, and (iii) it helps to control nuisance flies. Although these anecdotal claims seem to justify the use of kelp meal, there is limited scientific evidence to support its remarkable popularity among northeastern organic dairies. Collective results from the current project obtained via University and on-farm research showed little or no benefits of feeding kelp meal above 2 oz/cow daily due to kelp high costs and lack of effects on reducing milk SCC even when it was fed to large number of cows (~1,000) over 2 years during the grazing season. For instance, while production of milk increased (+1.5 lb) with feeding kelp meal in one of 2 studies conducted at the University of New Hampshire (UNH) as part of this project, no further changes in the production of milk fat abd milk protein, milk SCC, and enteric methane emissions were observed.     

It is well known that kelp meal has high concentration of iodine with values ranging from 300 to 1,000 ppm, and excess iodine intake is a growing public health concern. Research conducted at the University of New Hampshire prior to the current project revealed that milk iodine increased linearly with feeding incremental amounts of kelp meal (0, 2, 4, or 6 oz/day) to organic-certified dairy cows. American children 1 to 3 year-old should consume 2 cups of low-fat or fat-free milk daily as part of a healthy diet. This recommendation would result in excess iodine intake of 85, 342, and 448 μg daily if drinking milk from cows fed 2, 4, or 6 oz/day of kelp meal, respectively, based on the tolerable upper intake limit of 200 μg/day of iodine consumption recommended to 1 to 3 year-old children. Chronic consumption of excess iodine increases the risk of thyroiditis, hyperthyroidism, hypothyroidism, and goiter. As part of the current project, we conducted a comprehensive evaluation of the content of iodine in conventional and organic retail milk by purchasing milk from grocery stores across the Northeast. It was surprising to find that despite the high prevalence of kelp meal in organic dairy herds in the Northeast, the difference in iodine concentration between retail conventional and organic milk available in grocery stores across the region was small, but influenced by season. In general, iodine concentration was lower in retail organic than conventional milk during the summer possibly because a minimum of 30% of the total dietary intake of organic cows should come from pasture. Forage species like white clover are known to contain goitrogenic compounds that bind to iodine making it less available to be absorbed by mammary tissues. In addition, our results showed that organic milk is as safe as conventional milk to humans’ consumption considering that, on average, iodine levels remained below the recommended 500-μg/L threshold despite high use of kelp meal in organic dairies. As organic farmers feed more forages than conventional farmers, it is conceivable that forage goitrogenic compounds may offset iodine supplied by kelp meal. Our data also showed that is possible to reduce milk iodine concentration in cows supplemented with kelp meal by simultaneously feeding canola meal, which has goitrogenic compounds (i.e., glucosinolates).   

Our team engaged northeastern organic dairy farmers in a research and educational program focused on fine-tuning kelp meal supplementation for improving farm profitability and animal health, while comprehensively assessing the concentration of iodine in organic retail milk for the first time in the US. Our educational and research components addressed top concerns about kelp meal use including its cost effectiveness and impact on milk SCC, and the amount of kelp to be fed. Specifically, we delivered several educational products including  workshops, field days, webinars, popular-press articles, and peer-reviewed publications. 

Cooperators

Click linked name(s) to expand
  • Dr. Leanne Dillard (Educator and Researcher)
  • Dr. Michal Lunak (Educator)
  • Dr. Kathy Soder
  • Dr. Dorn Cox (Researcher)

Research

Hypothesis:

We hypothesize that the antimicrobial and antioxidant properties of kelp meal improve animal health, and that kelp’s iodine is transferred to milk resulting in concentration of iodine above the recommended level for human consumption, particularly children. These hypotheses will be tested by 2 mechanisms:  

Mechanism 1: Improve animal health and farm profitability by fine-tuning kelp meal supplementation.

Mechanism 2: Measure milk iodine concentration through an industry-scale survey of retail samples of organic milk in the Northeast.

Materials and methods:

Mechanism 1 (Fine-tuning kelp meal supplementation – University Research) – Study 1:

A 84-day long feeding trial was conducted at the University of New Hampshire-Organic Dairy Research Farm (UNH-ODRF) from February to May, 2017. Twenty milking cows received diets containing soybean meal or canola meal as the sole protein sources supplemented or not with kelp meal in a factorial replicated 4 x 4 Latin square design (4 treatments and 4 periods) with 14 days for diet adaptation and 7 days for data and sample collection. Dietary treatments were fed as total mixed rations (TMR) and consisted (dry matter basis) of 55% grass-legume mix baleage, 2.5% liquid molasses, 2% roasted soybean meal, 2% mineral-vitamin premix, and one of the following energy-protein mix: (1) 28.5% ground corn, 10% soybean meal, and 0 oz kelp meal, (2) 28.5% ground corn, 10% soybean meal, and 113 g of kelp meal, (3) 26% ground corn, 12.5% canola meal, and 0 oz kelp meal, and (4) 26% ground corn, 12.5% canola meal, and 113 g of kelp meal. In the 2 diets without kelp meal, ethylenediamine dihydroiodide (EDDI) was fed to keep rations with similar concentrations of iodine. Our rationale is that canola meal contains goitrogenic compounds that reduce the transfer of iodine into milk, whereas soybean meal is deprived of such metabolites. If kelp meal is economical to feed or positively impacts animal health, canola meal may allow farmers to continue feed kelp without producing milk with excess iodine.

Individual intake and milk production were measured daily throughout the trial. Milk samples were collected and analyzed for fat, protein, lactose, urea nitrogen (MUN), somatic cells count (SCC), and iodine. Feeds and TMR were collected in each period and analyzed for dry matter, crude protein, neutral and acid detergent fiber, ash, and minerals. Blood samples were collected and analyzed for thyroid hormones and cortisol. Data were analyzed using the MIXED procedure of SAS according to a Latin square design with a 2 x 2 factorial arrangement of treatments.

Mechanism 1 (Fine-tuning kelp meal supplementation – University Research) – Study 2:

A 63-d long experiment was conducted at the UNH-ODRF from February to May 1, 2018. Following a 2-wk covariate period, 20 multiparous organically-certified lactating Jersey cows were used. Cows averaged (mean ± standard deviation) 102 ± 52 days in milk, 467 ± 60 kg of body weight, and 23.8 ± 3.45 kg/d of milk at the beginning of the study. Cows were assigned to 2 groups in a completely randomized block design. Animals were paired (n = 10 pairs) and each pair balanced by parity, days in milk, or milk yield. Within pairs, cows were randomly assigned to 1 out of 2 treatments. Each experimental period lasted 21 d, with the first 2 weeks used for diets adaptation. Samples were collected on weeks 3, 6, and 9. The basal diet was fed as a component feeding system (i.e., alfalfa hay allocated to each cow first followed by concentrate top-dressed to hay). The forage-to-concentrate ratio averaged (% of the diet dry matter) 60:40. The 2 experimental diets fed in the first period (d 1-21) consisted of (1) basal diet (control) or (2) basal diet plus 400 g/d of kelp meal (dry matter basis). In period 2 (d 22-42; step-down phase) cows were fed: (1) control diet or (2) 0.5% kelp meal (100 g/d, dry matter basis). In period 3 (d 43-63; withdraw phase), kelp meal supplementation was discontinued, and all cows received the control diet. The GreenFeed system (C-Lock Inc.; automated head chamber apparatus shown in the picture below) was used to measure gaseous emissions, including methane (CH4) and carbon dioxide (CO2). All 20 cows had access to the GreenFeed system and visited the unit regularly during the study. To analyze the effects of kelp meal withdrawal on milk iodine concentration, milk samples were collected at the end of period 2 and at 24, 48, 72, 96, and 168 h after kelp feeding was discontinued. The rationale behind this study was that previous in vitro trials showed that high levels of kelp meal (up to 5% of the diet dry matter) decreased methane emissions possibly as a result of the antimicrobial properties of phlorotannins present in kelp, thus inhibiting the growth of methanogenic microorganisms in the rumen. However, inclusion of 5% of kelp meal in dairy diets is not practically feasible because of the high iodine intake, which may result in negative effects on animal and human health. We fed 2% of kelp meal in the diet dry matter (i.e., 400 g/d). 

Individual intake and milk production were measured daily throughout the trial. Milk, feed, and blood samples were collected and analyzed as reported above. Data were analyzed using the MIXED procedure of SAS with repeated measures over time. Data sets from Feeding Trials 1 and 2, as well from previous studies done at UNH funded by Northeast SARE were used to conduct a sensitivity analysis about milk consumption and iodine requirement in pregnant women as they are one of the population groups known to be deficient in iodine. Iodine deficiency can impair fetal development and child cognitive functions in addition to different thyroid disorders.   

The Greenfeed device, manufactured by C-Lock of Rapid City, South Dakota, measures methane production from respiration in a cow’s breath and monitors the environmental conditions. This is being used to measure greenhouse gas emissions from various diets with a goal of formulating rations that have less impact on the environment.

 

Mechanism 1 (Fine-tuning kelp meal supplementation – On-farm Research):

Approximately 600 milking dairy cows/year from 4 organic dairy farms (2 in Maine and 2 in Pennsylvania) were used in the summer of 2018 and 2019 in a study to investigate the effects of kelp meal on milk iodine and SCC. Baseline data (milk and feeds) were collected prior to the beginning and analyzed as reported above. Cows were fed 57 g/d of kelp meal for 3-5 months in each farm. During the kelp meal feeding period, farms were visited monthly for collection of feeds and milk. Feed and milk samples were analyzed as reported above. Milk SCC from the baseline, kelp meal-feeding period, and post-feeding period were evaluated using Dairy Herd Improvement (DHI) records from individual farms.

Mechanism 2 (Milk iodine industry-scale survey)

A survey was conducted during 4 different times across 2 years (spring, summer, fall, and winter) to evaluate the potential differences in milk iodine concentration across seasons and management systems (organic vs. conventional). Organically-certified dairy cows must graze during the grazing season (usually from April to November in the Northeast) to comply with federally-mandate rules, while conventional cows are generally raised in confinement systems. Therefore, we are expecting to see differences in the concentration of iodine in milk from organic versus conventional sources. All states of the Northeast region (i.e., CT, DE, NH, MA, MD, ME, NJ, NY, PA, VT, RI) and Washington D.C. were visited for purchasing milk from selected grocery stores. We visited the most populated cities in each state with population greater than 100,000 people. In ME, VT, and DE, no cities met the 100,000-population threshold, so milk was purchased from the most populated city in each of these 3 states. The number of grocery stores selected to be visited in each city was proportional to the population size. Surveys were done as follows: 1) End of may-June 2017 to represent early grazing season (summer); 2) October 2017 to represent the end of the grazing season and transition to winter feeding (fall), 3) January 2020 to represent feeding practices that do not include pastures in the diet covering the earlier part of the season(winter), and 4) March-April 2018 to represent feeding practices that generally do not include pasture in dairy diets in the Northeast, but covers the later part of the season (spring). Milk from all northeastern states and Washington D.C. was purchased during the summer and spring, while fall and winter milk were purchased from the New England states only (i.e., CT, NH, MA, ME, RI, VT) The fall season survey was done to capture differences in feeding practices and changes in pasture botanical composition compared with the early pasture season survey. In our surveys, 22 cities and 100+ popular grocery stores were visited and over 400 milk samples were bought including all different types of milk, packages, and brands. Milk with 2% fat concentration was purchased (organic and conventional) because reduced reduced fat milk is recommended by the US dietary guidelines.

Research results and discussion:

Mechanism 1 (Fine-tuning kelp meal supplementation – University Research) – Study 1:

The nutritional profile of kelp meal is presented in Table 1 (see attachment below), and the ingredient and nutritional composition of the basal diets are shown in Table 2 (see attachment below). As expected, kelp meal has high concentration of iodine [mean = 700 mg/kg of dry matter (DM)] and diets had similar crude protein content as formulated.

Effects of diets on DM intake, and milk yield and composition are presented in Table 3 (see attachment below). Cows fed diets containing soybean meal and kelp meal produced more milk than those fed canola meal and EDDI. Improved milk production with kelp meal may be related to its minerals and vitamins better matching the basal diet compared with EDDI. Dry matter intake increased by 1.2 kg/d in cows fed canola meal compared with those fed soybean meal without differences between both iodine sources (kelp meal vs. EDDI). Concentrations of milk fat, protein, lactose, and total solids decreased, while milk non-fat content tended to decrease in cows fed soybean meal vs. canola meal. These results may be explained by a dilution effect caused by increased milk volume with feeding soybean meal rather than canola meal. Yields of milk lactose and solids non-fat were greater in diets containing soybean meal than canola meal and followed milk production. Likewise, cows fed kelp meal showed increased milk lactose yield in comparison to those fed EDDI. The concentration of milk urea N (MUN) was greater when feeding soybean meal vs. canola meal likely because protein from soybean meal is more degraded in the rumen than that from canola meal. No treatment effects were observed for yields of milk fat and protein and milk SCC.

Effects of diets on iodine intake, milk, blood, and urinary iodine concentration, and blood hormones are presented in Table 4 (see attachment below). Milk iodine concentration decreased in cows fed kelp meal and canola meal suggesting that goitrogenic compounds (i.e., glucosinolates) present in canola were effective in binding to iodine, thus preventing its transfer to milk. In fact, milk iodine, as a proportion of iodine intake, was lower with feeding canola meal than soybean further indicating that glucosinolates present in canola meal reduced the transfer of feed iodine to milk. It is important to emphasize that only the canola meal plus kelp meal diet resulted in milk iodine concentration that was below the 500 μg/L threshold recommended for human consumption by the European Food Society Authority. Feeding canola meal increased the concentrations of iodine in blood and urine compared with soybean meal, indicating that less uptake of iodine by the mammary gland. We also observed an iodine source effect, with cows fed EDDI showing greater blood iodine concentration than those offered kelp meal, suggesting that iodine from EDDI appears to be more bioavailable relative to iodine from kelp meal. In contrast, no diet effects were observed for the serum concentrations of thyroid hormones and cortisol except that the serum concentration of thyroid stimulating hormone was lower in cows fed canola meal, which may be linked to glucosinolates present in canola. The serum concentration of urea-N followed that of MUN and increased in cows fed canola meal vs. soybean meal without an effect of iodine source (kelp vs. EDDI). As discussed earlier, canola meal is less degradable in the rumen than soybean meal resulting in lower ammonia formation and urea synthesis in the liver. Therefore, canola meal reduces circulating urea and transfer of urea to milk, indicating improved N use efficiency.

Nitrogen intake and urinary excretion of nitrogenous metabolites are presented in Table 5 (see attachment below). As expected, N intake followed DM intake and was greater in cows fed canola meal than soybean meal. Urinary N excretion, expressed in g/d or as a proportion of N intake, decreased with feeding canola meal versus soybean meal. Likewise, urinary excretion of urea N (g/d, % of total urinary N excretion, % of N intake) decreased with feeding canola meal compared with soybean meal diets. The urinary excretion of uric acid increased with feeding kelp meal rather than EDDI. However, neither urinary excretion of allantoin nor total purine derivatives was affected by iodine source. Purine derivatives (i.e., uric acid plus allantoin) are used as internal markers to estimate microbial protein synthesis in the rumen. Microbial protein has a balance profile of essential amino acids, and previous research demonstrated that increased microbial protein synthesis in the rumen is associated with improved milk production and milk protein. Overall, cows fed canola meal showed better N use efficiency with reduced MUN, blood urea N, and urinary excretion of N and urea N than those fed soybean meal.

Tables 1-5

Mechanism 1 (Fine-tuning kelp meal supplementation – University Research) – Study 2:

The nutritional profile of feedstuffs, including kelp meal used in Study 2 is presented in Table 6 (see attachment below), and the ingredient and nutritional composition of the basal diet are shown in Table 7 (see attachment below). Kelp meal showed high concentration of iodine, which averaged 611 mg/kg of DM.

Effects of diets on DM intake, and milk yield and composition are presented in Table 8 (see attachment below). Diets did not affect DM intake (mean = 20.4 kg/d), feed efficiency, and yields of milk and energy-corrected milk (mean = 24 and 28.3 kg/d, respectively). Concentrations and yields of milk fat, protein, lactose, solids non-fat, and total solids were not affected by diets. Similarly, MUN concentration and milk SCC did not change when feeding diets different levels of kelp meal. Phase effects (i.e., elevated, reduced, withdraw) were observed for several variables (e.g., DM intake, energy-corrected milk, milk fat content) indicating changes in feed intake and milk composition over time.

Effects of diets on iodine intake, milk, blood, and urinary iodine concentrations, and blood hormones are presented in Table 9 (see attachment below). Significant diet by phase interactions were observed for iodine intake, and milk, urinary, and blood iodine concentrations. Specifically, iodine intake and concentrations of iodine in milk, urine, and blood decreased from the elevated to the reduced phase, and returned to baseline in the last 21 days of the study (i.e., withdraw phase). Iodine concentrations in milk samples collected at 24, 48, 72, 96, and 168 h after kelp meal feeding was discontinued averaged 588, 402, 261, 234, and 184 μg/L, respectively. The slope of milk iodine concentration decline over time was calculated as 0.76%/h according to the equation Y = 6.26 (±0.13) – 0.0076x (±0.0013). It should be noted that the milk iodine concentrations during the elevated and reduced phases in cows fed kelp meal averaged 854 and 578 μg/L, respectively, and were greater than the 500-μg/L recommended for human consumption. In addition, iodine intake averaged 260 and 75.5 mg/d during the elevated and reduced phases, respectively. The mean iodine requirement of cows used in our study was calculated as 7.08 mg/d (i.e., 1.5 mg/100 kg of body weight; mean body weight = 472 kg). Therefore, the amount of iodine consumed daily by cows used in the present study was approximately 3,570% and 966% greater than required for animals fed kelp meal during the elevated and reduced phases, respectively. The maximal tolerable concentration of iodine in the diet, as far as cow health is concerned, is reported to be 50 mg/kg of diet DM, which translates to about 1,000 mg/d for cows consuming 20 kg of DM as those used in this study. Even though the amount of iodine consumed was far below 1,000 mg/d, there are reports of iodine toxicity with 500 to 600 mg/d in dairy cows. However, diets did not affect the blood concentrations of thyroid hormones (Table 9), as well as white and red blood cells count (data not shown in Table 9), which averaged 7.60 × 103 and 5.86 × 106 cells/µL, respectively. Despite high levels of kelp meal supplementation (100-400 g/d) and iodine intake, it appears that animal health was not negatively affected as thyroid hormones and white and red blood cells count were not changed.  

The effects of diets on rumen fermentation profile and gaseous emissions are presented in Table 10 (see attachment below). Diets did not not affect the rumen concentration of total volatile fatty acids, as well the rumen molar proportions of three major volatile fatty acids acetic, propionic, and butyric. These results indicate that kelp meal had no negative effects on rumen fermentation profile. In addition, diets did not affect CH4 and CO2 emissions. Specifically, CH4 production averaged 389 g/d (elevated phase), 394 g/d (reduced phase), and 380 g/d (withdraw phase). Similarly, CH4 yield (mean = 19.2 g/kg of DM intake) and CH4 intensity (mean = 13.9 g/kg of energy-corrected milk) did not differ between diets. Overall, dietary inclusion of 2% kelp meal in the diet DM (elevated phase) had no effect on enteric CH4 production, thus suggesting that greater amounts of kelp meal may be required to depress methanogenesis. However, chronic intake of high levels of iodine may cause toxicity and impair thyroid function.

Tables 6-10

Mechanism 1 (Fine-tuning kelp meal supplementation – On-farm Research):

We conducted 4 on-farm studies to evaluate whether kelp meal supplementation reduces milk SCC. Specifically, milk SCC from cows supplemented with 57 g/d (2 oz) of kelp meal was compared against milk SCC prior and after the kelp feeding period. DHI records from these 4 organic dairies were used in the analyses. Overall, kelp supplementation did not change milk SCC across farms. It should be noted that there are some challenges when conducting longitudinal studies (i.e., period of kelp supplementation vs. no supplementation) because results may be confounded by stage of lactation. However, it was not possible to conduct the studies with a control (no kelp) diet vs. a diet supplemented with kelp meal because this would require farmers to split the milking herd in two and feed cows individually like we did at UNH. We needed to use herds with large number of cows to detect difference in milk SCC, but the compromise was to run longitudinal studies rather dividing the herds in control vs. kelp, which was logistically difficult to farmers collaborating with our team.

Mechanism 1 (Sensitivity analysis using Feeding Trials data set):

A sensitivity analysis was conducted to gain insights regarding how different milk iodine intake affects the iodine status of pregnant women relative to the United States Institute of Medicine (US IOM) recommended dietary allowance (RDA; 220 μg/d) and the World Health Organization (WHO) recommended nutrient intake (RNI; 250 μg/d) for iodine. Four studies, included those from the current project, in which dairy cows received various amounts of kelp meal generated the milk iodine data set used in the sensitivity analysis. The annual per capita consumption of 2% reduced-fat milk in the United States, converted to daily intake (i.e., 0.26 cup; 1 cup = 236.6 mL), was used as the actual milk intake in the simulations. Five additional milk intake scenarios (2, 3, 4, and 5 times the actual per capita milk consumption and the 3 cups-equivalent recommended by the 2015–2020 Dietary Guidelines for American were also included in the sensitivity analysis with varying milk iodine concentrations (180, 765, and 483 μg/L). The 180, 765, and 483 μg/L values are milk iodine concentrations derived from cows not receiving kelp meal or fed various amounts of kelp in the diet or a single level (113 g/d) during the grazing season, respectively. With the actual United States milk per capita consumption of 0.26 cup/d and milk iodine concentrations of 180, 765, and 483 μg/L, 5.09, 21.7, and 13.6% of the RDA for iodine for pregnant women were met based on the US IOM, respectively. Similarly, 4.48, 19, and 12% of the RNI for iodine advised by the WHO was achieved with intake of 0.26 cup/d of milk containing iodine concentrations of 180, 765, and 483 μg/L, respectively. When 3 cups/d was included in the simulations, 58.2, 247, and 156% (US IOM), and 51.2, 217, and 137% (WHO) of the RDA or RNI for iodine required by gestating women was satisfied with milk iodine concentrations of 180, 765, and 483 μg/L, respectively. A regression analysis between iodine intake and milk iodine concentration revealed that 103 g/d of kelp in the diet of dairy cows reached the maximum 500 μg/L threshold of iodine in milk recommended by the European Food Society Authority. Overall, milk from dairy cows fed kelp can prevent iodine deficiency in pregnant women, but the amount of kelp fed to cows needs to be fine-tuned to avoid excess iodine in milk. Further research is required to better understand the interactions between goitrogenic compounds from forages and concentrates and milk iodine concentration in cows fed kelp. Details of this sensitivity analysis were published and can be found in the attachment (Brito 2020).  

Mechanism 2 (Milk iodine industry-scale survey)

Survey results reporting milk iodine concentrations from retail conventional and organic milk are presented in Tables 11, 12, and 13, and Figures 1 and 2 (see attachment below). A total of 444, 2%-reduced fat conventional (n=277) and organic (n=167) milk was purchased in grocery stores (n = 100+) between June 2017 and January 2020 across the Northeast. Table 11 shows the milk iodine concentration in retail milk samples available in grocery stores from 11 Northeastern states and Washington D.C. bought in June 2017 (summer) and end of March and beginning of April 2018 (spring). Therefore, these milk samples represent milk available in the Northeast from processing samples located within and outside the region. Processing plant codes stamped on milk containers allowed our team to determine milk processing origin. Overall, there was no difference in milk iodine concentration comparing conventional vs. organic milk, which averaged 425 and 410 μg/L, respectively. Similarly, milk processing method did not affect milk iodine concentration, with values averaging 415 and 420 μg/L for pasteurized and ultra-high temperature (UHT), respectively. In contrast, a seasonal effect was found, with milk iodine concentration being greater during the spring (mean = 479 μg/L) than summer (mean = 375 μg/L). We also observed a significant interaction between milk labeling (i.e., organic, conventional) and season (i.e., summer, spring), with milk iodine concentration being lower for organic milk during the summer, but greater during the spring compared with the conventional counterpart (Figure 1). These results indicate that milk iodine concentration appears to be influenced by different feeding strategies between the summer and winter. Notably, increased intake of goitrogenic compounds present in pasture species like withe clover during the grazing season is possibly responsible for reduced milk iodine concentration observed in organic than conventional milk. It is well known that goitrogenic metabolites bind to iodine and prevent iodine transfer into milk. Interestingly, the concentration of iodine in organic milk went from 310 μg/L in the summer to 510 μg/L in the spring, an increase of 65%. In addition, organic milk iodine concentration was 14% greater than that found in conventional milk during the spring season, suggesting feeding practices with increased iodine levels in diets fed to organic dairy cows, including kelp meal. In fact, data from our surveys showed that up to 80% of organic dairies feed kelp meal.

Table 12 shows the milk iodine concentration in retail milk samples from processing plants located in New England (see attachment below). Milk was bought from grocery stores located in all New England states during the summer (June 2017), fall (October 2017), winter (January 2020), and spring (March-April 2018). Processing plant codes stamped on milk containers were used to determine milk processing origin. Overall, while no difference in milk iodine concentration was observed between conventional and organic milk, a seasonal effect was found, with summer resulting in lower milk iodine content than winter. We also observed a significant interaction between labeling (i.e., conventional, organic) and season (i.e., summer, fall, spring, and winter) as shown in Figure 2 (see attachment below). Specifically, while no difference in milk iodine concentration was observed between conventional and organic milk during the spring and winter months, milk iodine content was lower in organic milk during the summer and tended to be lower in the fall compared with the conventional counterpart. As discussed above, goitrogenic compounds present in pasture forage species prevent the transfer of iodine to milk, thus lowering iodine content in milk during the summer season. Even though organic cows graze during the fall, some herds may have transitioned to winter feeding or are receiving less pasture in the diet. This may explain the lack of difference in iodine concentration between conventional and organic milk during the fall season.         

Table 13 shows milk iodine concentration in retail milk samples from processing plants located in New England and outside New England states (see attachment below). Milk was bought from grocery stores located in all New England states during the summer (June 2017), fall (October 2017), winter (January 2020), and spring (March-April 2018). Processing plant codes stamped on milk containers were used to determine milk processing origin. This data set also showed no difference in milk iodine concentration between conventional and organic milk, which averaged 380 and 386 μg/L. Similar to what was reported above, a seasonal effect was observed for milk iodine concentration. The concentration of iodine in milk was, on average, 45% greater in the winter and spring months compared with the summer and fall counterparts. We also observed that milk originated from processing plants outside New England had greater iodine concentration (405 μg/L) than that (362 μg/L) originated from plants located in the New England states. Increased (+12%) milk iodine concentration suggests that milk processed outside New England may have originated from herds with more iodine supplementation or less pasture in the diet.

Tables 11-13

Figures 1-2

Research conclusions:

Our overall research in the last 7-8 years funded by Northeast SARE revealed that production of milk and milk components were not changed in dairy cows supplemented with kelp meal. Specific to the current project, milk production increased statistically by 0.6 kg/d (1.3 lb) in cows fed kelp meal (113 g/d) compared with those receiving another iodine source (i.e., EDDI) during Feeding Trial 1. However, practically speaking, this 0.6 kg/d increase in milk production is not large enough to justify the use of kelp meal to booster yields due to kelp’s high costs. In addition, cows fed up to 400 g/d of kelp meal during Feeding Trial 2 did not show improvements in milk production and composition (i.e., butterfat, protein) relative to cows not supplemented with kelp meal. Published research from our group further demonstrated that kelp meal did not improve milk production and composition when fed during the winter (Antaya et al., 2015; see attachment; Antaya-et-al-2015) and grazing (Antaya et al., 2019; see attachment; Antaya-et-al-2019) seasons. It should be noted that, based on our surveys, 58% organic dairies feed kelp meal in the Northeast. We also surveyed grass-fed organic dairy producers in the region and nationally and results revealed that 73% feed kelp meal to their milking cows. Moreover, surveys done in Wisconsin and Minnesota showed that up 83% of Midwestern organic dairies feed kelp meal. Therefore, there is no doubt that kelp meal is popular among organic dairy farmers. However, collective research done at the University of New Hampshire showed modest effects of kelp meal on improving animal heath. In 2 studies (Antaya et al., 2015; Brito, unpublished), we observed reduction in the stress hormone cortisol, while in Antaya et al. (2019) milk SCC decreased suggesting improvement in milk quality. However, milk SCC obtained from DHI records of our 4 collaborating dairies did not corroborate our earlier findings (i.e., Antaya et al., 2019). Because kelp meal is an expensive supplement, farmers need to make judicious decisions when feeding it as our research showed few improvements in production and animal health. Diets with balanced supply of trace minerals may be more profitable than feeding kelp meal. Chronic high intake of iodine from kelp meal can also impair thyroid function and compromise health of dairy animals, and farmers should pay close attention of signs of iodine toxicity such as excessive nasal and ocular discharge, salivation, decreased milk production, coughing, and dry, scaly coats. Nevertheless, further research is needed to specifically address how kelp meal can positively impact animal health due to kelp’s high concentration of bioactive compounds and antioxidant and antimicrobial properties.   

Kelp meal is a rich iodine source, with substantial proportion of iodine being transferred from kelp to milk. Results from the current project and our earlier research showed that feeding as low as 57 g/d (2 oz) resulted in milk iodine concentrations above the 500 μg/L threshold considered for human consumption. Feeding canola meal together with kelp meal did reduce the iodine transfer from kelp to milk due to the present of glucosinolates in canola, which are known to bind iodine and reduce its uptake by the mammary gland. Therefore, feeding kelp meal with feedstuffs like canola meal or forage brassicas appears to be an attractive strategy to reduce iodine concentration in milk while benefiting of the potential positive effects of kelp on animal health.

It was surprising to find that despite the high prevalence of kelp meal in organic dairy herds in the Northeast, the difference in iodine concentration between retail conventional and organic milk available in grocery stores across the region was small, but influenced by season. In general, iodine concentration was lower in retail organic than conventional milk during the summer because at least 30% of the total dietary intake should come from pasture in organic herds, which can reduce the transfer of iodine from feed to milk as pastures species like white clover are known to contain goitrogenic compounds that bind to iodine making it less available. Alternatively, less kelp meal may be fed to organic dairies during the summer. Overall, our results showed that organic milk is as safe as conventional milk regarding levels of iodine relative to human health (<500 μg/L) and the high prevalence of kelp meal supplementation in the Northeast does not seem to be a concern. As organic farmers feed more forages than conventional farmers, it is conceivable that forage goitrogenic compounds may offset iodine supplied by kelp meal. We also showed that kelp meal supplementation to dairy cows may be used as an strategy to enrich milk with iodine and meet iodine requirements of population groups such as pregnant and nursing women known to be iodine-deficient in the United States.

Participation Summary
5 Farmers participating in research

Education

Educational approach:

We originally surveyed over 1,000 organic dairy farmers (n = 245 respondents) in the Northeast in collaboration with the Northeast Organic Dairy Producers Alliance (NODPA) to learn about kelp meal supplementation practices in the region. This survey revealed that 59% of northeastern organic dairies feed kelp meal seasonally or year-round. Specifically, our survey showed that 131 farmers feed kelp meal to their milking cows (n = 142 respondents), 116 feed it to dry cows and heifers (n = 142 respondents), and 84 to calves (n = 140 respondents). Farmers feed kelp meal because (1) it improves body condition and overall animal appearance, (2) it decreases milk SCC and the incidence of pinkeye and reproductive problems, and (3) it helps to control nuisance flies. Our team used this survey to recruit farmers to participate in our educational program in partnership with the Wolfe’s Neck Center for Agriculture and the Environment in Freeport, ME (https://www.wolfesneck.org/) and deliver research-based information to fine-tune kelp meal supplementation in the region and beyond. For instance, we collaborated with the University of Vermont on a national survey focused on organic grass-fed producers and learned that, on average, 73% of the respondents feed kelp meal to their milking herds. This information was incorporated in our educational program to specifically advise organic grass-fed dairy farmers on how to best use kelp meal supplementation.  

Our project combined a comprehensive educational and research program to fine-tune kelp meal supplementation, while surveying the iodine concentration of conventional and organic retail milk. Project results and educational materials were delivered via regional farmer-oriented conferences and workshops [Vermont Organic Dairy Producers Conference, Northeast Organic Farming Association (NOFA)-NY Annual Winter Conference, NOFA-VT Annual Winter Conference, NODPA Annual Field Days and Conference, and Northeast Pasture Consortium Annual Meeting], national conferences (American Dairy Science Association Annual Meeting), international symposiums and invited presentations, field days (University of New Hampshire and Wolfe’s Neck Center for Agriculture and the Environment), and social media (YouTube). Specifically, knowledge gained from University and on-farm research was used to educate farmers in the region on how to fine-tune kelp supplementation including impacts on farm profitability (measured as income over feeds costs) and animal production and health. We also educated milk processors and the general public during our workshops about the relationship between kelp meal supplementation and milk iodine, and incorporated their perspectives and feedback to our integrated research and educational program.

Milestones

Milestone #1 (click to expand/collapse)
What beneficiaries do and learn:

1,000 Northeastern organic dairy farmers learn about kelp meal supplementation educational opportunities and receive an online survey to gauge their interest in participating in project activities. (September 2016)

Proposed number of farmer beneficiaries who will participate:
1000
Actual number of farmer beneficiaries who participated:
245
Actual number of agriculture service provider beneficiaries who participated:
10
Proposed Completion Date:
September 30, 2016
Status:
Completed
Date Completed:
December 1, 2016
Accomplishments:

We conducted a survey with the support of the Northeast Organic Dairy Producers Alliance (NODPA) that helped our team to initially identify farmers who are feeding kelp meal in the region, how much is being fed, and which class of animals receive kelp. A list of organic dairies feeding kelp meal was produced from our original survey and farmers were invited to participate in on-farm research and educational activities.

Milestone #2 (click to expand/collapse)
What beneficiaries do and learn:

200 farmers return the survey; 150 farmers agree to participate in our educational program; 6 farmers agree to conduct kelp meal feeding trials and become peer-leaders helping disseminate project results. (December 2016)

Proposed number of farmer beneficiaries who will participate:
6
Proposed number of agriculture service provider beneficiaries who will participate:
8
Actual number of farmer beneficiaries who participated:
5
Actual number of agriculture service provider beneficiaries who participated:
6
Proposed Completion Date:
December 31, 2016
Status:
Completed
Date Completed:
October 31, 2019
Accomplishments:

Four organic dairy farms (2 from ME and 2 from PA) agreed to conduct on farm-research by feeding kelp meal to their milking cows. An organic dairy farmer from VT who has been consistently feeding for last 5 years also agreed to participate and provide DHI data. The on-farm feeding trials were completed in October, 2019.

Milestone #3 (click to expand/collapse)
What beneficiaries do and learn:

100 farmers attend three, 2-hour workshops in New England and Pennsylvania that explain performance target, known benefits and challenges about kelp meal supplementation, ongoing kelp research, on-farm feeding trials, and The Kelp Profitability Calculator; 40 of these farmers agree to provide access to dairy herd improvement
(DHI) records. (January to March 2017)

Proposed number of farmer beneficiaries who will participate:
40
Proposed number of agriculture service provider beneficiaries who will participate:
8
Actual number of farmer beneficiaries who participated:
20
Actual number of agriculture service provider beneficiaries who participated:
6
Proposed Completion Date:
March 31, 2017
Status:
Completed
Date Completed:
December 31, 2017
Accomplishments:

We found difficult to obtain DHI data according to project objectives from organic dairy farmers feeding kelp meal as many farmers do not feed kelp year-round. Therefore, we decided to work closely with 5 organic dairy farmers who agreed to consistently feed kelp meal during the on-farm feeding trials, so that we could obtain DHI data in line with project goals. Project information and background regarding kelp meal profitability, supplementation level, benefits and challenges have been disseminated to farmers, veterinarians, nutritionists, milk processors personnel, students, and researchers at project events such as field days, workshops, and webinars.

A presentation titled “Why consumers should be concerned about the iodine content of milk and milk alternative beverages?” delivered at the UNH Department of Agriculture, Nutrition, and Food Systems Seminar Series on November 17, 2017 (Durham campus) and engaged students, faculty, extension educators, and farmers (see attachment; Why consumers should be concerned about the iodine content of milk and milk-alternative beverages). Approximately 50 participants.

Milestone #4 (click to expand/collapse)
What beneficiaries do and learn:

80 farmers attend field days at University of New Hampshire (UNH) and lead dairies about fine-tuning kelp supplementation and its cost effectiveness. (June 2017)

Proposed number of farmer beneficiaries who will participate:
80
Proposed number of agriculture service provider beneficiaries who will participate:
12
Actual number of farmer beneficiaries who participated:
25
Actual number of agriculture service provider beneficiaries who participated:
10
Proposed Completion Date:
June 30, 2017
Status:
Completed
Date Completed:
October 31, 2017
Accomplishments:

The UNH Agriculture Experiment Station organizes annual field days highlighting the research conducted at the UNH farms including both dairy herds (conventional and organic). Our team has been actively participating in such events presenting project results and information about kelp meal supplementation and other dairy nutrition related materials to farmers, students, faculty, extension educators, and industry personnel. Field days were also conducted at Wolfe’s Neck Center for Agriculture and the Environment (Freeport, ME) to enhance our educational program. We hosted approximately 25 dairy farmers in addition to 20+ extension educators, students, and industry personnel during project field days in partnership with Wolfe’s Neck (2017 and 2018). It should be noted that Wolfe’s Neck hosts thousands of visitors per year including farmers, dairy industry personnel (veterinarians, nutritionists, milk processors), and extension educators. Wolfe’s Neck also participated in the on-farm kelp meal feeding trial and shared data and information with visitors about seaweed supplementation to dairy cows.

Milestone #5 (click to expand/collapse)
What beneficiaries do and learn:

On-farm feeding trials start in 6 lead dairies to investigate the effects of kelp meal on animal health, milk iodine, and farm profitability. (June to August 2017)

Proposed number of farmer beneficiaries who will participate:
6
Proposed number of agriculture service provider beneficiaries who will participate:
6
Actual number of farmer beneficiaries who participated:
5
Actual number of agriculture service provider beneficiaries who participated:
4
Proposed Completion Date:
August 31, 2017
Status:
Completed
Date Completed:
October 31, 2019
Accomplishments:

Four organic dairy farmers (2 in ME and 2 in PA) did feed kelp meal for approximately 4 months over 2 grazing seasons (2018, 2019). About 500 milking cows were supplemented with kelp meal during each summer. We also collected DHI records form an organic dairy farm in VT, which has been consistently fed kelp meal for the past 5 years. Overall, kelp meal supplementation did not consistently reduced milk SCC, suggesting minor effects of kelp on milk quality of organic dairy herds.

Milestone #6 (click to expand/collapse)
What beneficiaries do and learn:

Farmers consult with project team via email, phone calls, and Facebook about the impact of kelp meal on milk quality, animal health, and feed costs. (Ongoing)

Proposed number of farmer beneficiaries who will participate:
6
Proposed number of agriculture service provider beneficiaries who will participate:
8
Actual number of farmer beneficiaries who participated:
5
Actual number of agriculture service provider beneficiaries who participated:
4
Proposed Completion Date:
December 31, 2019
Status:
Completed
Date Completed:
December 31, 2020
Accomplishments:

Our team consistently communicated with organic dairy farmers, extension educators, and industry personnel regarding kelp meal supplementation through emails, phone calls, workshops, conferences, and field days and continue do so. Specifically, we presented project results at the following events:

1) NOFA-NY Annual Winter Conference held in Saratoga Springs, NY ( January 19, 2019); Workshop Title: “What’s in Your Milk?” (see attachment; Whats in your milk). Approximately 30 participants.

 

2) Granite State Graziers Annual Conference held in Concord, NH (February 16, 2019); Workshop Title: “Annual Forage Crops and Supplementation Strategies for Grazing Dairy Cows” (see attachment; Annual Forage Crops and Supplementation Strategies for Grazing Dairy Cows). Approximately 60 participants.

 

3) NOFA-VT Annual Winter Conference held in Burlington, VT (February 17, 2019); Workshop Title: “Opportunities for Strengthening Organic Dairy in the Northeast: From Kelp to Grass Fed to Human Health” (see attachment; Opportunities for Strengthening Organic Dairy in the Northeast From Kelp to Grass Fed to Human Health). Approximately 25 participants.

 

4) 2019 Vermont Organic Dairy Producers Conference held in Randolph Center, VT (March 14, 2019); Oral Presentation Title: “Highlights of Kelp Meal Research at UNH” (see attachment; Highlights of kelp meal research at UNH). Approximately 100 participants.

 

5) 2019 American Dairy Science Association Annual Meeting held in Cincinnati, OH (June 23-26, 2019). This conference attracted over 2,000 participants from the United States and overseas. The following conference papers presented as posters were published in the conference proceedings:

 

M. Ghelichkhan, D. Williams, L. H. P. Silva, and A. F. Brito. 2019. Interactions between iodine and protein sources: Effects on milk yield, milk components, and urinary N excretion in Jersey cows. J. Dairy Sci. 102:68 (Suppl. 1).

 

M. Ghelichkhan, D. Williams, L. H. P. Silva, and A. F. Brito. 2019. Interactions between iodine and protein sources: Effects on milk iodine and thyroid hormones in Jersey cows. J. Dairy Sci. 102:69 (Suppl. 1).

 

M. Ghelichkhan, R. C. R. Tinini, J. G. Dessbesell, H. A. Whitesel, Y. Zang, L. H. P. Silva, M. A. Zambom, and A. F. Brito. 2019. Effect of kelp meal on milk yield, methane emission, and thyroid hormones in Jersey cows. J. Dairy Sci. 102:376 (Suppl. 1).

 

6) VIII Brazilian Congress of Milk Quality held in Lages, Santa Catarina, Brazil (September 11-13, 2019). Oral Presentation Title: “Organic Milk Quality” (presentation done in Portuguese). Approximately 400 participants.

 

7) VII SIMLEITE International Symposium of Dairy Cattle held in Viçosa, Minas Gerais, Brazil (October 10-12, 2019). Oral Presentation Title: “Organic Milk Production (presentation done in Portuguese). Approximately 500 participants.

 

8) 2020 American Dairy Science Association Annual Meeting held virtually (June 22-24, 2020). This conference attracted over 2,000 participants from the United States and overseas. The following conference papers presented orally were published in the conference proceedings:

 

M. Ghelichkhan, L. H. P. Silva, R. C. R. Tinini, J. G. Dessbesell, M. A. Zambom, and A. F. Brito. 2020. Comparison of milk iodine concentration between retail conventional and organic milk in the United States. J. Dairy Sci. 103:222 (Suppl. 1).

 

M. A. Snider, S. E. Ziegler, H. M. Darby, K. J. Soder, A. F. Brito, B. Beidler, S. Flack, S. L. Greenwood, and M. T. Niles. 2020. Evaluation of research needs and management practices on organic, grass-fed dairy farms in the United States. J. Dairy Sci. 103:236 (Suppl. 1).

 

M. Ghelichkhan, L. H. P. Silva, R. C. R. Tinini, J. G. Dessbesell, M. A. Zambom, and A. F. Brito. 2020. Effect of different levels of Ascophyllum nodosum meal on iodine metabolism in Jersey cows. J. Dairy Sci. 103:248 (Suppl. 1).

 

L. H. P. Silva, A. T. O. Melo, S. F. Reis, B. P. Jackson, F. Evans, and A. F. Brito. 2020. Effects of Ascophyllum nodosum meal and monensin on ruminal fermentation and microbiota. J. Dairy Sci. 103:258 (Suppl. 1).

 

8) Articles featuring kelp meal research at UNH based on our webinar (see Milestone 9) was published by NODPA News and Progressive Dairy:

NODPA News (NODPA Article).

Progressive Dairy (https://www.progressivedairy.com/topics/feed-nutrition/keeping-kelp-in-front-of-cows-on-grass).

 

Milestone #7 (click to expand/collapse)
What beneficiaries do and learn:

90 farmers attend field days at UNH and lead dairies to learn about the results of the kelp meal feeding trials. (June to September 2018)

Proposed number of farmer beneficiaries who will participate:
90
Proposed number of agriculture service provider beneficiaries who will participate:
12
Actual number of farmer beneficiaries who participated:
30
Actual number of agriculture service provider beneficiaries who participated:
10
Proposed Completion Date:
September 30, 2018
Status:
Completed
Date Completed:
October 31, 2018
Accomplishments:

The UNH Agriculture Experiment Station organizes annual field days highlighting the research conducted at the UNH farms including both dairy herds (conventional and organic). Our team has been actively participating in such events presenting project results and information about kelp meal supplementation and other dairy nutrition related materials to farmers, students, faculty, extension educators, and industry personnel. Field days were also conducted at Wolfe’s Neck Center for Agriculture and the Environment (Freeport, ME) to enhance our educational program. We hosted approximately 25 dairy farmers in addition to 20+ extension educators, students, and industry personnel during project field days in partnership with Wolfe’s Neck (2017 and 2018). It should be noted that Wolfe’s Neck hosts thousands of visitors per year including farmers, dairy industry personnel (veterinarians, nutritionists, milk processors), and extension educators. Wolfe’s Neck also participated in the on-farm kelp meal feeding trial and shared data and information with visitors about seaweed supplementation to dairy cows.

Milestone #8 (click to expand/collapse)
What beneficiaries do and learn:

65 farmers who attended field days at UNH and lead dairies and participated in project surveys and educational program submit kelp meal supplementation strategies for project team to review. (October 2018)

Proposed number of farmer beneficiaries who will participate:
65
Proposed number of agriculture service provider beneficiaries who will participate:
4
Actual number of farmer beneficiaries who participated:
20
Actual number of agriculture service provider beneficiaries who participated:
2
Proposed Completion Date:
October 31, 2018
Status:
Completed
Date Completed:
October 31, 2019
Accomplishments:

We estimated that over 100 organic dairy farmers participated in our project educational program including field days, workshops, webinars, and conference presentations. Our team worked closely with 4 organic dairy farms that conducted on-farm feeding trials feeding kelp meal to the milking herd. We also worked with another organic dairy farmer who has been consistently feeding for the past 5 years. Overall, milk quality and udder health represented by milk SCC did not consistently improve in response to kelp meal supplementation based on farm DHI records. 

Milestone #9 (click to expand/collapse)
What beneficiaries do and learn:

Project team produces a video-clip to educate farmers, milk processors, and the general public about the relationships among kelp meal supplementation, milk iodine, and human health; video is disseminated via project Facebook and UNH websites. (March 2019)

Proposed number of farmer beneficiaries who will participate:
50
Proposed number of agriculture service provider beneficiaries who will participate:
4
Actual number of farmer beneficiaries who participated:
60
Actual number of agriculture service provider beneficiaries who participated:
4
Proposed Completion Date:
March 31, 2019
Status:
Completed
Date Completed:
December 31, 2018
Accomplishments:

We delivered a 60-min webinar regarding kelp meal supplementation to grazing dairy cows in partnership with the Pennsylvania State Extension in their featured Dairy Grazing Management webinar series. The webinar was titled “Kelp for Supplemental Feeding of Dairy Cows on Pasture” and done on December 19, 2018. The webinar power-point pdf presentation can be accessed in the attachment (Kelp for Supplemental Feeding of Dairy Cows on Pasture) and the link for the recorded webinar can be found here (https://psu.mediaspace.kaltura.com/media/1_0f5hiy6z).

Project personnel (Brito and Cox) and extension collaborator Rick Kersbergen (University of Maine) were invited by WMTW-ABC Chanel 8 News to share our insights about seaweed supplementation and greenhouse gas emissions in the dairy sector. This material was aired on May 24, 2017 and is available on YouTube (https://www.youtube.com/watch?v=yimKVVCjqVk). It has over 1,800 views and we were able to educate the general population about seaweeds and methane emissions.

Our education program about kelp meal supplementation is an ongoing enterprise and our team will deliver additional webinars, publications, and workshops in the near future.   

Milestone #10 (click to expand/collapse)
What beneficiaries do and learn:

60 farmers fine-tune kelp meal supplementation to reduce feed costs, thus improving the economic sustainability of organic dairying in the region. (June to September 2019).

Proposed number of farmer beneficiaries who will participate:
60
Proposed number of agriculture service provider beneficiaries who will participate:
8
Actual number of farmer beneficiaries who participated:
5
Actual number of agriculture service provider beneficiaries who participated:
6
Proposed Completion Date:
September 30, 2019
Status:
Completed
Date Completed:
December 31, 2020
Accomplishments:

We worked closely with 5 organic dairies and discussed strategies to fine-tune kelp meal supplementation to their milking herds. In addition, we estimated that over 100 organic farmers participated in project educational activities including webinars, workshops, field days, and conference presentations. Based on the collective work done at UNH with a total of 5 feeding trials in which cows received varies levels of kelp (from 57 to 400 g/d or 2 to 14 oz), production of milk and milk components, MUN, and milk SCC were not changed. Data from the on-farm feeding trials also showed no effects kelp meal (57 g/d or 2 oz/d) on milk SCC. The Kelp Meal Profitability calculator (see attachment; The Kelp Meal Profitability Calculator) revealed that income over feed costs (IOFC) dropped by 12% and 44% in the summer and winter, respectively, in cows supplemented with 2 oz of kelp meal vs. no kelp in the diet. Feeding higher levels of kelp meal during the winter (i.e., 6 oz/cow/day) decreased IOFC even further (-23% relative to 0 oz of kelp in the diet; see The Kelp Meal Profitability Calculator attachment). Therefore, our overall recommendation to organic dairy farmers in the Northeast is to not feed more than 2 oz of kelp meal per day to milking cows, which can minimize losses in IOFC and capitalize on potential health benefits reported by farmers and captured on project surveys. However, farmers should be diligent on collecting health records of the milking herd and young stock and make decisions accordingly. Our team does not recommend kelp meal supplementation as a source of minerals because of the excessive concentration of iodine found in kelp in addition to be more costly than typical mineral-vitamin premix available in the market. In summary, organic dairy farmers should feed kelp only if they are able to document health benefits such as lower incidence of pinkeye and reproductive issues, and improved milk quality (i.e., reduced bulk tank milk SCC).   

Milestone Activities and Participation Summary

35 Consultations
2 Curricula, factsheets or educational tools
3 Journal articles
4 On-farm demonstrations
1 Online trainings
1 Published press articles, newsletters
12 Tours
20 Webinars / talks / presentations
6 Workshop field days
3 4H educational events done at the UNH Fairchild Dairy Teaching and Research Center and UNH Organic Dairy Research Farm to educate the young generation about dairy production and types of feeding strategies including the use of seaweeds in dairy diets.

Participation Summary

100 Farmers
10 Number of agricultural educator or service providers reached through education and outreach activities

Learning Outcomes

25 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
8 Service providers reported changes in knowledge, attitudes, skills and/or awareness as a result of project outreach
8 Agricultural service providers reported changes in knowledge, skills, and/or attitudes as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

Key areas in which our team verified change in knowledge include kelp supplementation strategies, animal health, milk iodine, and human health. We were able to verify these changes from farmers, extension personnel, nutritionists, and veterinary practitioners via phone calls, emails, and mostly face-to-face consultations during project events. Specifically, farmers who attended our events indicated that they left the workshops and field days more knowledgeable about the benefits and challenges of kelp meal supplementation and were willing to revise kelp feeding practices in their own farms.  In addition, our team worked with 5 operating organic dairies and provided information regarding ways to fine-tune kelp meal supplementation and, thus, empowering them to become peer experts in the dairy farming community.  We also verified change in knowledge about milk iodine and human health from our interactions with non-technical audience who attended project workshops delivered during NOFA events in Vermont and New York, as well in academic settings. Project data on milk iodine from cows fed kelp meal, combined with milk iodine results from the Northeast retail survey, provide, to the best of our knowledge, the most comprehensive data set about milk iodine supply to humans currently available in the United States. This data will not only help farmers but also milk processors and industry personnel to make scientific-based decisions to optimize human and animal health as impacted by iodine intake. 

Our team has generated significant amount of data showing that kelp does not improve milk production and composition when cows are receiving diets with balanced supply of trace minerals. However, kelp meal is extremely popular among organic dairy farmers based on surveys done in the Northeast, Midwest, and nationally. We will continue to deliver educational materials regarding kelp meal supplementation in years to come to guide farmers on how to make best decisions about kelp meal supplementation. It is important to emphasize that that due to the remarkable popularity of kelp meal among organic dairy farmers, it is challenging to convince them to not use certain practices including feeding kelp free-choice. This type of concern is illustrated in one of interactions between the project leader and a veterinarian from New Hampshire. Feeding kelp free-choice to cows and heifers can result in negative interactions between minerals and excess iodine intake, which can both compromise animal health.                  

“Hello Dr. Brito,

I am a large animal veterinarian in Southern New Hampshire and have a significant amount of small organic dairies as clients. I have been consulting with them on their mineral programs and as you know many of these small farms supplement with kelp, oftentimes free choice kelp. I have read a decent amount of the literature on Kelp and have come to the conclusion myself that feeding between 50 and 100 g/cow/day gives the benefits of kelp and it’s unnecessary to provide it free choice and even increases the milk iodine levels when it’s free choice. This amount is based on the work you have done, so thank you for that! The farmers don’t always agree with me on this and feel as though the cows are “self medicating” with this supplement when they eat as much as they want. Recently one of my farmers saw on a listserv that the molybdenum content in Kelp would tie up copper, given that there is less copper than molybdenum in a bag of kelp. I thought that was an interesting point given that molybdenum affects the availability of copper. If they are only feeding that 50 grams, that doesn’t seem like an issue, but I was wondering if you knew the risk of decreasing copper availability by feeding free choice kelp. There are certainly high levels of Sulfur, which I know also affects copper. I am very interested in learning more about mineral supplementation for grass based organic dairies, so I appreciate any insight.”

Performance Target Outcomes

Target #1

Target: number of farmers:
60
Target: change/adoption:

Fine-tune kelp meal kelp meal supplementation reducing from 6 oz to 3 oz.

Target: amount of production affected:

Reduction of milk iodine concentration from 1,370 to 800 micrograms/L.

Target: quantified benefit(s):

Improve income over feed costs.

Actual: number of farmers:
5
Actual: change/adoption:

We are reporting the numbers of dairies that our team worked closely with monthly visits during the on-farm feeding trials in the summer and that we obtained DHI records. Farmers are feeding less kelp meal (approximately 2 oz) and two discontinued kelp due to costs.

Actual: amount of production affected:

Overall, milk production was not affected by reducing kelp meal supplementation while milk iodine concentration dropped, on average, 66% when kelp meal supplementation was reduced by 2-oz units based on project's data sets.

Actual: quantified benefit(s):

Based on project Kelp Meal Profitability Calculator, income over feed costs improved 43.5% ( from $0.69 to 0.99/head daily or from $10,350 to $14,850) during the grazing season (mean = 150 days) by reducing kelp meal supplementation from 2 oz to 0 oz using a herd size of 100 milking cows.

Performance Target Outcome Narrative:

Out team worked closely with 5 organic dairies that provide DHI records and access to their milking herds to be part of longitudinal feeding trials. In addition, we estimate that approximately 50 organic dairy farmers fine-tuned kelp supplementation practices based on our team exchanges with farmers during project events such field days, workshops, and conferences, and webinars, and publications. It should be noted that we also worked with veterinarians, nutritionists, and Extension educators in the region, so that the impact of the project likely exceeded 50 organic dairies. Our decision to work directly with 5 organic dairies rather a bigger pool of farmers was based on logistics and costs to conduct on-farm feeding trials and no additional benefits to assess DHI records from a larger number of farms. Based on our surveys and interactions with field nutritionists and veterinarians, kelp meal supplementation is not consistent across organic dairies with farmers feeding it free choice, top-dressed or mixed on a total mixed ration in various amounts year-round or seasonally as influenced by kelp costs and milk prices. Therefore, it was challenge to obtain a consistent feeding practice prompted us to work with a selective group of organic dairy farms. Nevertheless, kelp meal supplementation is prevalent among organic dairy farmers in the Northeast based on our original survey (n = 245 respondents; 55% feed kelp) and even more so among organic grass-fed farmers according to a more recent survey done in 2019 in collaboration with the University of Vermont where 73% feed kelp to lactating cows (n =167 respondents). We anticipate that further research is needed targeting the organic grass-fed sector and their specific research needs relative to kelp supplementation, as well as research investigating kelp bioactive compounds and effects on the health calves, heifers, and milking cows. In summary, we verified changes in kelp supplementation among organic dairy farmers in the region and delivered a comprehensive education plan that exponentially enhanced the project outreach to a community of organic dairy farmers and allied industry beyond the Northeast region.     

50 Farmers changed or adopted a practice

Additional Project Outcomes

6 Grants applied for that built upon this project
2 Grants received that built upon this project
$3,000,000.00 Dollar amount of grants received that built upon this project
20 New working collaborations
Additional Outcomes:

Northeast SARE funds were leveraged to secure grants amounting to $3 million dollars ($600,000 UNH portion) from a foundation interested in seaweed research. Project leader Brito is currently collaborating with Bigelow Laboratory for Ocean Sciences, University of Vermont, Wolfe’s Neck Center for Agriculture and the Environment, and Colby College to conduct feeding trials evaluating the impact of different seaweeds, including, kelp on methane emissions and cow health (check here UNH scope of work; UNH Today Article). We also submitted a $3-million dollars grant proposal to the USDA-NIFA-OREI program this past January looking at supplementation of local seaweed species to organic cows during the grazing season. In addition, our team was invited to submit a $10-million dollars grant proposal to the USDA-NIFA-SAS program this coming April looking at life cycle analysis and the use of macro- and microalgae in dairy diets. In all these proposals we used and, will continue to do so, data from our work funded by Northeast SARE.   

We were expecting to see a significant reduction in milk somatic cells count (SCC) as a result of kelp meal supplementation, which did not occur in the University and on-farm feeding trials. However, research done by other groups showed a beneficial effect of kelp on reducing milk SCC. Therefore, further research is needed to better understand discrepancies across studies. We were also expecting a greater iodine concentration in retail organic milk than retail conventional milk due to the high prevalence of kelp meal supplementation in organic dairies. The fact that only small differences in iodine concentrations were observed between conventional and organic milk suggest that the higher proportion of pasture and forages in organic versus conventional dairy diets, which can lead to increased intake of goitrogenic compounds may have offset iodine supplied by kelp. Alternatively, organic herds with larger number of cows not supplemented with kelp meal may dilute milk iodine from farms supplemented with kelp when milk from different sources get mixed at processing plants.    

 

Success stories:

“Lovely to have this conversation with you! It’s hard to find veterinarians who like to talk about mineral supplementation and mineral sources like kelp for pastured dairy cows.” (NH veterinarian).

“I leaned a lot in your workshop and information showing the health benefits of milk iodine compared to non-dairy alternatives should be share in our schools” (NY Extension educator).

“Kelp is getting really expensive, about twice more expensive than when I started to feed 10 years ago. I’m glad too see research that helps me too see the whole spectrum of the effects of kelp supplementation. Thanks!” (PA organic dairy farmer).  

“I was always curious to know if different sources of kelp (Thorvin vs. Acadian) change too much in trace minerals. I learned today that variation is not too bad other than iodine” (VT organic dairy farmer).

“We’ve been feeding kelp for 15 years. We stopped feeding for 3 months and SCC went way up started feeding again and went back down. We will always feed kelp” (NY organic dairy farmer).

Assessment of Project Approach and Areas of Further Study:

Our collaboration with organic dairy farmers who conducted the on-farm feeding trials, as well as the team network with the organic dairy sector in the Northeast were key for project success. The University of New Hampshire has been one the national leaders in organic dairy research and our team collaborates with institutions in New England (e.g., University of Vermont, University of Maine, Wolfe’s Neck Center for Agriculture, Bigelow Laboratory for Ocean Sciences), Northeast (e.g., USDA ARS Pasture Systems and Watershed Management Research), and Midwest (e.g., University of Minnesota) in various projects guided by farmers’ research and educational needs. This team approach has enhanced and leveraged Northeast SARE funds to a common goal to improve the economic, social, and environmental sustainability of organic dairy farming in the region and beyond.

Challenges faced by our team were to find a compromise on how to best conduct the on-farm feeding trials. It is difficult to conduct controlled studies on commercial dairy farms because the first priorities of an operating dairy are to ensure cow health, profitability, and daily management to run the farm. We worked with excellent farmers and selected three dairies with herds sizes (over 100 milking cows/farm) above the average 50-cow dairy in the region. The on-farm studies needed large number of cows to test the hypothesis that kelp meal supplementation would decrease milk SCC. However, it was not possible to conduct the studies with a control (no kelp) diet vs. a diet supplemented with kelp meal because this would require farmers to split the milking herd in two and feed cows individually like we did at UNH. The compromise approach was to run longitudinal studies meaning that all cows received kelp meal and results were compared against pre- and post-kelp meal feeding, resulting in confounding effects of stage of lactation.  Another challenge faced by our team and possibly by other researchers in the region is that farmers are “over-surveyed”. Our interactions with Extension educators and industry indicated that farmers are constantly asked to fill surveys from different groups and institutions. Therefore, we cut back on evaluation surveys and collaborated with the University of Vermont in a survey targeting organic-grass fed farmers in which we assessed the proportion of kelp meal fed in these dairies. 

Funding from Northeast SARE has allowed our team to advance the knowledge about kelp meal supplementation to organic dairy cows in the Northeast. Experiments were focused mostly on the effects of kelp on production of milk and milk components, milk iodine, methane emissions, and some health indicators such as measurements of the stress hormone cortisol. Our project also revealed key information regarding milk iodine concentration of conventional and retail organic milk, which is one of the most comprehensive picture of milk iodine content in the United States to date. However, there are still significant knowledge gaps related to kelp meal supplementation including how kelp impact health of dairy calves, heifers, and cows. We also believe that research on isolated compounds of kelp like iodine and phenols would help to shed light on the potential effects of kelp to reduce milk SCC observed in previous research.            

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.