Final Report for GNE10-002
The purpose of this study was to investigate the genetic and environmental interactions of crossbred Normande, and U.S. purebreds (primarily Holstein) on production, reproductive performance, and survivability as well as determine how crossbreeding affects partitioning of body energy during periods of high and low pasture availability. Body condition scores were assigned on 6 herds in the Northeastern United States that had Normande crossbred cattle. Production and pedigree information was collected for all animals from the 6 BCS herds, in addition to 1 herd in Minnesota that milked Normande crossbreds. Multiple trait mixed-models were used to analyze body condition score (BCS), milk yield, fat yield and percentage, protein yield and percentage, somatic cell score (SCS), and calving interval. Normande sired cattle had significantly higher BCS (3.08) than animals sired by Ayrshire (2.78), Holstein (2.59), and Jerseys (2.21). Holstein sired animals had significantly higher daily milk yield (27.95 kg) compared to animals sired by Normande (23.56 kg), Ayrshire (25.12 kg), and Jersey (22.05 kg). There were no significant differences in daily protein yield among animals sired by Ayrshire, Holstein, Jersey, and Normande. Normande sired cattle had a fat yield (0.93 kg) that was significantly lower than Holstein sired cattle (1.11 kg). Normande sired cattle also had the highest SCS (2.87), which was significantly higher than Holstein sired animals.
A significant season effect for BCS and yield traits was noted, with yield (particularly fat and protein) and BCS depressed during the summer months. Normande sired cattle were able to mobilize body reserves during the summer months when pasture growth was expected to be slow, and lost significantly less fat yield during the summer months compared to Holstein sired animals. However, limited record numbers did not allow for significant breed differences to be detected in other yield traits. The exception was cows sired by bulls of unknown or crossbred lineage which had significantly larger declines in milk, fat and protein yield during summer months. This reinforces the need to use high-quality sires, even in grazing systems that incorporate crossbreeding.
Historically, dairy production in the United States has benefited from a favorable ratio between feed and milk prices, allowing for the selection of cows to maximize milk output per cow (Muller and Fales, 1998). Feed has become increasingly expensive as grain prices have greatly increased in the past several years. Low input forage based systems have thus become an increasingly popular way to try and maximize profits on dairy farms. However, dairy animals have lower milk yields when consuming a high forage diet compared to their confinement counterparts (Kolver and Muller, 1998), which may be a result of lower DMI for cows on pasture (Leaver, 1985; Kolver and Muller, 1998). Even with lower milk production, the lower costs associated with grazing can offset the lost income from milk production to maintain or improve profit (Parker et al., 1992).
Genotype x environment interactions have been recognized for production traits when comparing confinement and grazing systems (Kearney et al., 2004). Interestingly, different feeding systems have shown a scaling effect regarding genetic potential for production traits with pasture based cows having a response rate of approximately 70% when compared to cows with high concentrate supplementation (Boettcher et al., 2003; Weigel et al., 1999; Veerkamp et al., 1994). This may indicate that high genetic merit cows may not obtain all of the nutritional resources required to meet their genetic potential for production traits in low input grazing systems (Kolver and Muller, 1998; Holden et al., 1995).
Dairy cattle of high genetic merit that have been selected in generous feeding systems may be impacted more severely by feed restrictions caused by poor pasture growth than dairy cattle that have been historically selected in grazing systems (Macdonald et al., 2007). Holsteins are more likely to direct all nutrients toward milk production during rapid pasture growth and then have few body energy reserves left to mobilize when pasture growth is limited, thus needing increased concentrate supplementation (Pryce et al., 2006). Even when feed supplementation occurs in pasture systems, it still may not prevent undesirable BCS loss in Holsteins (Macdonald et al., 2008). This undesirable BCS loss may lead to negative effects on reproduction and animal health. Reproductive performance is of increased importance in many pasture based herds and reproductive inefficiencies may hinder the potential of production in pasture based systems (Evans et al., 2006).
Selection of cattle in grazing systems versus selection in intensive commercial systems also seems to impact grazing behavior. Grazing behavior in New Zealand Holsteins (which have historically been raised on pasture) has been shown to be different than North American Holsteins suggesting that genetics impact grazing behavior and efficiency (Sheahan et al., 2011).
If a producer is going to take advantage of a low input grazing system, proper management of the system, including genetics, is essential for success. Breeding goals of low input grazing systems should differ from conventional breeding goals. For example, if a cow of high genetic merit cannot meet its nutrient demand for high milk production in a pasture based system, then it may be inappropriate to continue to select for increased milk production (Mayne, 1998). Other traits such as reproductive performance, feed efficiency, stature, and milk solids may play a more important role in selection.
Dairy producers face not only increasing input costs, but they also face the genetic limitations of the current dairy breeds. Purebred dairy cattle, particularly Holsteins, have been intensively selected for milk production traits because yield is the major source of income for dairy farms. This intense selection has improved milk production in dairy cattle, but has come with a decline in health and fertility traits in dairy cattle and an increase in inbreeding that can cause deleterious genetic effects (USDA-AIPL, 2012). Body condition score has also declined with increased selection for dairy traits due to a negative genetic correlation between milk yield and BCS (Dechow, 2001). However, BCS may be a good indicator trait for health and reproductive traits. Thus, selecting for increased BCS or crossbreeding for increased BCS could have a positive impact on important cattle traits that have suffered from unfavorable correlations to milk production traits.
Crossbreeding is not widely used in the United States dairy industry, mainly because it has been reported that crossbred dairy cattle may not be able to outperform their purebred herd mates in any one production trait (Mcdowell, 1982). However, crossbred dairy cattle may be able to provide a net economic merit greater than that of their purebred herd mates (McDowell, 1982; McAllister, 2002) after accounting for all the advantages that crossbred cattle present.
Normande cattle, which originate from France, present a unique genetic pool that could be utilized in the United States. Normande cattle can be considered a dual purpose breed and is marketed as the “French Cheese Breed” because of the high value cheeses made in the Normande region of France from Normande cattle. Milk from Normande is also thought to have improved characteristics for cheese making (Normande Genetics, 2012). The meat from Normande cattle is also considered to be of a high quality and is sold for a premium price in France. The Normande breed has historically been raised and selected on pasture, which may present some advantages for this breed’s genetics to be utilized in low input grazing systems.
Crossbreeding with Normande cattle is reported to provide several advantages, including improved reproduction, survival, and total economic merit when compared to purebreds in certain environments. The decline in fertility of purebred Holsteins is an important issue, but evidence suggests that NormandexHolstein crossbreds have improved fertility compared to their purebred Holstein counterparts (Heins et al., 2006, Walsh et al., 2008; Heins et al., 2012). NormandexHolstein crossbreds have been shown to have fewer days to first breeding (7 fewer days), fewer days open (52% bred before 99 days open, compared to only 38% for pure Holstein), higher pregnancy rates and also had an improved first service conception rate compared to purebred Holsteins (35% for Normande crossbreds, 22% for pure Holsteins) (Heins et al., 2006; Heins et al., 2012).
Survivability of dairy cattle is of economic importance to dairy producers since replacement animals are costly. NormandexHolstein may have improved herd survival (Heins, 2006; Walsh et al., 2008; Heins et al., 2012). NormandexHolstein first calf heifers had greater survival to 30, 150, and 305 days postpartum compared to Holsteins (Heins et al., 2006). NormandexHolstein crossbreds were also more likely to survive to subsequent calvings than Holsteins in all parities in a study done over five lactations (Heins et al., 2012). NormandexHolstein animals were 12.9% more likely to survive to parity 2, 22.3% more likely to survive to parity 3, and 23.9% more likely to survive to parity 4 (Heins et al., 2012).
Normande crossbreds may also have fewer calving problems compared to their purebred herd mates. NormandexHolstein heifers had significantly lower still birth rates (9.9%) compared to pure Holsteins (14.0%) (Heins et al., 2006). Additionally, NormandexHolstein crossbred cows had lower rates of calving difficulty (11.6%) compared to pure Holsteins (17.7%) (Heins et al., 2006).
Although the NormandexHolstein crossbreds had better reproductive performance and survivability, they produced fewer pounds of milk, fat, and protein compared to Holsteins, with no difference in somatic cell scores (Heins et al., 2012). Lifetime production estimates after the first four years from first calving favored the NormandexHolstein crossbreds in milk (+1,680 kg), fat (+108 kg), protein (+95 kg), fat plus protein (+203) and revenue from production (+ $1,105). However, these increases in production were seen with an increase in days of herd life for the NormandexHolstein crosses (+ 172 days), resulting in a profit per day was significantly less (- $0.28) (Heins et al., 2012). While NormandexHolstein crossbreds do not appear to be economical in high production systems, it has been suggested that utilizing NormandexHolstein crossbreds in low input pasture systems may improve profit due to excellent fertility and survival (Heins et al., 2012).
Several studies conducted in pasture based systems in Ireland have included Normande cattle in their analysis. Purebred Normande cattle were found to have lower values for peak milk flow (kg/min) and average milk flow (kg/min), while having a longer milking duration when compared to purebred Holsteins. However, Normandex;Holstein crossbreds had flow rates and milking durations similar to purebred Holsteins (Walsh et al., 2007). Purebred Normande and NormandexHolstein crossbreds were also found to have lower milk yield than purebred Holsteins in Ireland, which supports the work done in California dairy herds (Walsh et al., 2007; Heins et al., 2012; 2006).
Normande cattle were found to have higher BCS than Holsteins (Walsh et al., 2008). Body condition loss from weeks 2-8 of lactation was also found to be greater for Holsteins compared to purebred Normande or NormandexHolstein crossbreds (Walsh et al., 2008). This increased loss of body condition indicates that the Holsteins are directing more nutrients towards milk production than the Normande, and subsequently may be at risk of more health problems that are associated with an increased rate of body tissue mobilization.
Body condition score is a visual appraisal of an animal’s energy reserves. Evidence continues to accrue on the importance and dynamics of dairy cattle body condition. Problems can arise from a dairy animal that carries too much or too little body condition. Part of the dairy cow’s ability to produce milk is the ability of her to mobilize body reserves to provide for the neonate (Bauman et.al. 1980). In fact dairy cattle tend to lose a substantial amount of body condition postpartum for about 40 to 100 days before regenerating the lost condition later in lactation (Koenen et. al., 2001; Coffey et al., 2004). Genetic selection has impacted the body condition dynamics across breeds and within breeds of dairy cattle, including many physiological responses that increase the mobilization of body energy stores (McNamara et.al., 1986 &1991). It is because of this increasing knowledge of body condition that most animal and dairy scientists agree that managing body condition is an important factor that influences animal health, milk production, and reproduction (Domecq et al., 1997; Buckley et al., 2003).
This project recognizes that many dairy producers are shifting their production practices to stay economically stable in today’s market. Crossbreeding and moving to low input grazing systems are tools which are available to these producers that may help them in their goals. That is why this project investigates crossbreeding with Normande cattle in a variety of environments including grazing systems to determine if they might provide a source of alternative genetics that could help improve dairy farm efficiency and thus improve the economic stability of dairy producers.
1.Evaluate interactions of Normande, U.S. pure breeds, and Normande crossbred cattle with varying levels of grazing and concentrate supplementation on milk, fat, and protein yield, reproductive performance and survival in Northeast grazing herds.
•This objective was met except for the survival analysis.
•Limited record numbers did not allow for significant breed differences to be detected for several traits of interest (survival and fertility). The limited number of records was due to it being more difficult than anticipated to find herds that had both Normande crossbred cattle and production information in their herd.
2.Determine if crossbreeding with Normande affects partitioning of energy during periods of high and low pasture availability.
•This objective were met, however more research is needed to confirm the observations of this study.
Body condition scores were assigned on 1 herd in Massachusetts, 1 herd in New York, 2 herds in Pennsylvania, and 2 herds in Vermont. Herds were visited once during each of four seasons during 2011. The four seasons included winter (visit in January or February), spring (visit in late May or first week of June), summer (visit in middle of August), and fall (visit in October). The herds varied from herds with minimal confinement and high amounts of pasture utilization to herds with high confinement and minimal pasture allowance. The breed composition of the herds varied and was composed primarily of purebred Ayrshire (AY), Holstein (HO), and Jerseys (JE) in addition to Normande (NO) crossbreds and other crossbreds of varied and unknown lineage. Four herds where animals had access to pasture except during milking and that provided less than 7 kg of grain supplementation per day were grouped together as grazing herds. Herds that utilized little or no pasture were grouped as non-grazing herds. One of the non-grazing herds allowed no outdoor access for lactating cows, and two allowed access to a barnyard with minimal pasture growth for several hours per day,
Test day milk production from DHI was collected for 7 herds. The herds included the 6 herds that were visited for body condition scoring and an additional herd from Minnesota that provided milk production data. Six of the herds participated in DHI testing prior to the start of the trial. A seventh herd with a large number of Normande crossbreds (34) tested 4 times (once per season) during the trial. This herd was added to increase the number of records from Normande crossbred cows; however, total lactation yields were not available for this herd so the primary traits evaluated included test-day milk, fat (yield and percentage), protein (yield and percentage), and somatic cell score (SCS) as opposed to lactation totals. Calving interval (CINT) was calculated as the number of days between subsequent calving dates capped at 550 days) and was also included in the analysis.
For BCS, there were 4 seasons corresponding to the winter, spring, summer and fall herd visits. Season was derived on a bimonthly basis for yield traits and SCS (January and February = Season 1, March and April = Season 2, etc.). Days in milk (DIM) classes corresponding to 28-d intervals through 252 DIM were generated, after which DIM was grouped into 48-d intervals, and a final class of >348 days, resulting in 12 total DIM groups.
Pedigree information was limited for many of the cows. Of the 1240 cows in the data set sire identification was available for 1053 cows, dam breed for 1073 cows and maternal grand-sire for 309 cows. Dam breed was coded as crossbred with no known maternal grandsire for 391 cows, whereas sire breed was missing or coded as unknown for 195 cows. If the dam was a crossbred, not Holstein, Ayrshire, or Jersey, or was unknown it was defined as other (OT). If the sire breed was something other than Normande, Holstein, Ayrshire, or Jersey it was also categorized as OT. Breed combinations of animals sired by Ayrshire, Holstein, Jersey, Normande, other known breeds, crossbreds, or if sire breed was unknown are tabulated in Table 1.
Statistical models were run in ASREML that accounted for sire breed, herd, and lactation number to investigate the individual traits of milk (kg), fat (kg), protein (kg), BCS, SCS, and CINT . The statistical model was then modified to investigate difference between grazing and non-grazing environments. Herd was removed from the model and replaced with grazing class (1=grazing herd, 0=non-grazing), and an interaction between sire breed and grazing class was included.
In total, 1931 BCS were available for analysis (Table 2) with an approximately equal number of Normande sired cattle in herds that utilize large amounts of pasture and herds that utilized little or no pasture. Table 3 displays the breed combinations that were available for BCS analysis. In total there were 11,376 test day records available from all herds and breed combinations (Table 4). Holstein sired animals had the most test day records (5821); there were also 797 test day records for Normande sired animals, 1376 test day records for Ayrshire sired animals, 676 test day records for Jersey sired animals, and 2706 records for animals sired by OT. There were no test day or BCS observations of HolsteinxAyrshire animals or JerseyxAyrshire animals, and several other breed combinations had limited observations for test day records and BCS observations. Means for BCS, milk yield, fat yield, protein yield, SCS, and calving interval are reported in Table 5. Information about sire breeds, grazing, average milk yield, and average BCS for each herd is provided in Table 6.
Predicted means (PM) for milk yield, fat yield, fat %, protein yield, protein %, BCS, SCS, and CINT with standard errors are reported in Table 7.
Holstein sired animals had the highest for daily milk yield. Normande sired cows produced significantly less milk (23.56 kg) than Holstein sired cows (27.95 kg) and Ayrshire sired cows (25.12 kg), but produced more milk than Jersey sired cows (22.05 kg). Jersey sired cows had a significantly lower milk yield than animals sired by Ayrshires. Animals sired by OT had a daily milk yield estimate of 24.62, which was significantly different than animals sired by Holstein, Normande, and Jersey. Daily milk yield and other yield traits had significantly lower estimates in grazing herds compared to non-grazing herds (Table 8).
Predicted means for milk yield, fat yield, protein yield, and BCS for different breed combinations are reported in Table 9. There was minimal variation among breed combinations within sire breed groups (AY, HO, JE, NO, OT) for milk yield and protein yield PM. There was more variation observed for fat yield and BCS, but with large standard errors.
Normande sired cattle had a numerically lower daily fat yield (0.93 kg) estimate than cows sired by other breeds, but were only significantly different than Holsteins (1.11 kg). Normande sired cattle did not have daily protein yields that were significantly different than animals sired by other breeds. Normande sired cows had the highest SCS (2.87). Holstein cattle had a significantly lower SCS estimate (2.26) than cows sired by Jerseys (2.84), Ayrshires (2.85), and Normande. Animals sired by OT had a significantly lower CINT of 395 days compared to animals sired by Holstein, Jersey, and Normande. There were no significant differences among animals sired by Ayrshire, Holstein, Jersey, and Normande for CINT.
Normande sired cattle had a significantly higher BCS estimate (3.08) than animals sired by Holstein (2.59), Jersey (2.21), Ayrshire (2.78), and OT (2.69). Jersey sired cattle had a significantly lower BCS estimate than all other breeds. Animals sired by Holsteins, Ayrshires and OT were not significantly different from each other. Correlation of cow effects (representing genetic and permanent environment) showed that BCS tended (P<0.10) to be correlated with daily milk yield (-0.28), daily fat yield (-0.30), daily protein yield (-0.22), and SCS (0.15). Cattle that were on pasture did not have significantly different BCS than those in herds that were mainly confinement.
Daily milk yield (Figure 1), fat yield (Figure 2), and protein yield (Figure 3) were all influenced by season in herds that utilized large amounts of pasture. The seasonal effect was not as apparent for daily milk yield in non-grazing herds, but there appeared to be seasonal effect for daily fat yield and protein yield in non-grazing herds.
In grazing herds, daily milk yield peaked in the period of March through June before milk yield dropped in July and August and remained lower September through December.
Protein yield showed a decline from January through February until July through August where it appears to reach its nadir, then increased through November and December. Protein yield was at its highest predicted levels during January through February and November through December in both grazing and non-grazing herds.
Daily fat yield followed a similar seasonal pattern to that of daily protein yield for grazing herds. Fat yield was predicted to be greater during the winter months (November through February) with nadir daily fat yield occurring during the summer months (July through August). In similar fashion to grazing herds, fat yield in non-grazing herds appears to be higher March through June before dropping in July through August and then increasing September through December.
Normande sired cattle were found to carry more body condition than animals sired Ayrshires, Jerseys, and Holsteins. Ayrshire and Holstein cattle did not differ significantly in BCS. Jersey sired animals had a significantly lower BCS. This research supports findings by Walsh (2008) that found Normande cattle and crossbred Normande cattle to have higher BCS than Holsteins. BCS was also found to be negatively correlated with milk yield, protein yield, and fat yield which supports work done by Dechow (2001).
Previous work has shown Jersey animals to carry more body condition than Holsteins (Washburn et al., 2001; Prendiville et al., 2009), and no significant difference was found by Pryce and colleagues (2006). This study found that Jersey sired animals carried significantly less body condition compared to Holstein sired animals. The Normande is considered to be a dual purpose breed (Normande Genetics, 2012) and the use of Normande sires appears to greatly increase the BCS of the resulting offspring. This increase is seen even if the dam is of a dairy breed, such as Jersey, which was found to carry significantly less body condition.
No significant difference was found between breed BCS in grazing and non-grazing herds. This does not support research done by Washburn and colleagues (2001) which found animals that were in grazing herds had lower BCS. However, all of the grazing herds in this study provided concentrate supplementation during milking for all of their lactating cows, and the supplementation may have been at higher levels than the grazing herds previously studied. Another reason that no difference may have been found because the two herds that were considered non-grazing and had BCS observations fed rations that may have contained higher amounts of forage than is typical in a normal commercial dairy mixed ration. The average daily milk yield of Holsteins in the two non-grazing herds with BCS observations was 19.9 kg and 27.9 kg respectively. These two herds did not buy in large amounts of concentrate and depended heavily on stored forage that was produced on the farm. The commercial non-grazing herd from Minnesota had Holsteins with an average daily milk yield of 41.5 kg. These differences observed in the average daily milk yield between the non-grazing herds may reflect differences in the amount of concentrate feeding since milk production is expected to increase with increasing concentrate feeding (Roche et al., 2006). If the non-grazing herds that provided BCS observations in this study were not feeding high amounts of concentrate it may explain why no difference in BCS between animals in grazing and non-grazing herds was observed.
Normande sired cattle had the lowest daily fat yield and had a similar fat percent to that of Holstein sired animals. Jerseys had a relatively high fat yield when taking into account that they had the lowest daily milk yield, due to their higher milk fat percentage. Daily protein yield for Normande sired cattle was not significantly different than animals sired by Ayrshire, Holstein, and Jerseys. It has been suggested that Normande cattle are desirable for cheese making due to an increase proportion of Normande sires that are homozygous for the B kappa casein haplotype, which is thought to improve cheese yields (Normande Genetics, 2012; Keating et al., 2007).
Normande sired cattle had the highest SCS, but was only significantly higher than Holstein sired cattle. Heins (2012) found that NormandexHolsteins had a higher SCS in their second lactation than pure Holsteins, but SCS between the Holsteins and Normande crossbreds did not differ significantly in lactations 1, 3, and 4.
The reproductive data available for analysis was limited to CINT for this study, and there were no significant differences among animals sired by Ayrshire, Holstein, Jersey and Normande for CINT. This may reflect the lower heritability for reproductive related traits (Weigel and Rekaya, 2000) coupled with relatively few observations because first lactation cows do not have a CINT. Animals sired by other breeds did have a CINT that was significantly lower than animals sired by Holstein, Jersey, and Normande.
With a greater BCS estimate, Normande crossbred cattle may have more body reserves to mobilize during periods when pasture growth slows. It has been previously reported that Holsteins have a propensity to direct all nutrients toward milk production during periods where their energy needs are met with the available pasture and, thus, have few body resources to mobilize during periods when pasture growth cannot meet their energy requirements (Pryce et al., 2006). Breeds with low BCS might require larger amounts of concentrate supplementation during these periods to maintain production.
For grazing herds in this study, it was expected that cows would be able to harvest more energy from pasture during the spring season (May through June), and that cows would not be able to harvest as much energy from pasture during the summer months of July through August. During the spring months pasture would be expected to be growing more rapidly in the Northeastern United States, and it would also be expected that pasture growth would slow during the hotter and dryer summer months. However, animals in grazing systems are usually provided with stored forage if there is inadequate pasture available during the summer months.
Dry matter intake has been suggested to be a limiting factor for pasture based dairy herds (Kolver and Muller, 1998), and even if the cattle are being supplemented with stored forage in the summer months there are several factors during the summer season which could decrease DMI in grazing herds. For example, it has been noted that hot and humid weather associate with the summer season can decrease DMI (West et al., 2003). Due to the expected drop in DMI during the summer it is often recommended that the energy density of the ration provided be increased for cattle during the summer. The effect of heat and humidity may be even more significant in grazing herds compared to their conventional counterparts because it may be more difficult for grazing herds to provide common cooling methods such as shade, fans, and misters while the cows are on pasture during the day.
Thus, it would be expected that animals would have increased milk production and be able to maintain their body condition during the spring and early summer. Milk yield and BCS were greater during the winter and spring visits before decreasing during the summer months for cows sired by all breeds. Changes in yield traits (difference between July through August and the average of November through April) and BCS (difference between the summer visit and the average of the winter and spring visits) are reported in Table 10.
However, while Normande sired cows had a larger decline in BCS from the average of the winter and spring visits to summer (0.27) than Holsteins (0.17) and a smaller decline in milk yield from the average of spring and winter seasons to the summer season when compared with Holstein (0.04 kg and 0.52 kg, respectively) the differences were not significant (P=0.27 for BCS and 0.32 for milk yield).
Animals in non-grazing herds also tended have decreased fat and protein yield during the summer months, indicating that not all of the differences observed in the grazing herds can be explained by poorer pasture growth. Hot, humid weather associated with the summer season can cause cows to reduce DMI (West et al., 2003), thus the drop in BCS and yield may reflect reduced DMI associated with hot weather in non-grazing herds.
Daily milk yield for all breeds in grazing herds were lowest during the summer months and highest during the late fall and winter months. This supports previous research that found milk production in dairy cattle was depressed during the hot summer months (Lee et al., 1976; Ray et al., 1992). However, the trend for daily milk yield to decrease in the summer season was not as apparent in non-grazing herds. This suggests that effects other than temperature were affecting dairy animals that were in grazing herds. It may be that pasture quantity or quality was reduced during the summer months and thus milk production was depressed, or it could be that management factors to keep the animals cool were different between grazing and non-grazing herds.
Daily fat and protein yield were depressed during the summer months in grazing herds, as were fat and protein percentages. Across breeds, there was a 9.4% drop in fat and 7.2% drop in protein yield compared to average yields of November through April. Animals in non-grazing herds appeared to follow a similar trend, but changes were less pronounced.
Education & Outreach Activities and Participation Summary
Several opportunities to share the information found from this project were utilized. In July 2011 a poster was presented at the Joint Annual Meeting of the American Dairy Science Association and the American Society of Animal Science displaying our findings that Normande sired cattle had higher body condition scores compared to their purebred herd mates. Also, in the fall of 2011 a presentation and question and answer session was held at a field day at Thistle Creek Farms (Tyrone, Pa) to area farmers interested in cattle genetics and grazing systems about the our findings about Normande sired cattle.
In 2012 at the end of January a poster was presented at the New York Northeast Organic farming association’s winter conference. In July 2012 a seminar was held at Penn State University on the complete research findings of this project and the findings were also published in a thesis at Penn State. We are also planning on submitting an article based on this study to the Journal of Animal breeding for publication.
Cows sired by bulls of unknown origin, crossbred sires, or breeds other than Ayrshire, Holstein, Jersey or Normande; were found to mobilize less body condition and had significantly larger declines in milk, fat and protein yield during summer months than cows of other sire breeds. These results indicate that dairy producers in the Northeast should use sires of high genetic merit to maximize production on their farms regardless of their production system. This maximized production within the producer’s desired production system could lead to increased net farm income.
Seasonal trends for production and body condition were also found in this study which may help farmers plan the number of animals they wish to have freshen or dry at certain times of the year to increase production yields and efficiency. However, this may not be as applicable in some grazing based dairies that require their calving season to align with peak pasture growth that usually occurs during the spring season.
This study also provides information to farmers that are investigating the potential of different sire breeds for their cross breeding program or low input grazing system. For example when using economic values for lifetime net merit (NM$) and cheese merit (CM$) it does not appear that Normande sired animals are economically competitive from a production standpoint –based on milk, fat, and protein yield only (Table 11). However, this does not take into account other potential benefits that may be obtained from crossbreeding with Normande such as beef price, fertility, and cheese yields.
Normande genetics may be able to improve net farm income through the marketing of value added cheese and beef as is done in France. In fact, Normande are considered the “French cheese breed,” since Normandes have higher incidences of beta and cappa caseins as well as a more favorable calcium/phosphorous ratio for cheese making than most other dairy breeds (Normande Genetics, 2012). This may allow farmers to market homestead cheese to increase net farm income. The sale of beef from Normande crossbreds may also increase net farm income. Studies have shown that steers with Normande genetics also perform similarly to conventional beef breeds because Normande steers have the potential to provide a carcass with similar muscle conformation, adequate marbling , with decreased deposition of back fat (Lehmkuhler, 2008). However, increasing net farm income from such products were beyond the scope of this project.
There were many opportunities to interact with dairy farmers that had experiences with crossbred Normande cattle as well as dairy producers who had no experience with the breed. Some of the farmers that were using Normande crossbreds seemed to be moving away from the breed due to concerns about their overall milk production, compared to other purebred dairy animals. Several of the farmers also seemed to be concerned with the udder quality of the Normande crossbreds and cited that as another reason to discontinue the use of Normande genetics.
However, there were also several farmers that seemed to appreciate the increased body condition that the Normande crossbreds brought to their herd and were planning on continuing the use of the Normande crossbreds. There was also interest from farmers in the perceived potential of Normande crossbreds commanding a higher cull value due to their increased body condition score and the strong beef market prices.
Areas needing additional study
We did not have enough data to compare individual sires. There has been some shift in the types of Normande sires imported over time, with initially the Normande sires being more of a beef type animal now shifting to the importation of Normande sires with improved dairy qualities. We had hoped to see if there were notable differences in performance between these individual sires and their types. We only compared breeds for traditional dairy production traits. Some of the Normande breeds potential strengths (cull value, cheese making properties) were beyond the scope of our research.
There was evidence that Normande cows used the energy from the additional body condition mobilization to maintain yield levels during periods of lower pasture growth. Normande sired cows had a more stable level of production across seasons than cows of other breeds; however, more research is needed to confirm this observation.
Research into specific crosses between Normande and other pure breds would be useful in future research. Normande and Jerseys may be better breed compliments for grazing herds than NormandexHolstein crossbreds. The NormandexJersey crosses could potentially have a more moderate body size and weight since Jerseys are small and body weight and body size are considered to be highly heritable traits (Bourdon, 1997). Genetics from the Jersey may also improve the daily fat yield in the crosses because the heritability of fat percent protein percent is high (Bourdon, 1997). Normande would provide additional BCS in such a system for potential mobilization during periods of slow pasture growth.
Another breed that may be of interest in future crossbreeding studies may be the Ayrshire which tended to carry more body condition than Holstein and Jersey sired animals in this study. There is little literature available on Ayrshire, which may make further investigations into utilization of this breed intriguing.