Since the inception of the Organic Foods Production Act (OFPA) in 1990, the sale of organic foods has increased at double-digit rates every year (OTA, 2004). This trend for organic food sales has prompted a dramatic increase in the number of certified organic dairy farms in the U.S., especially over the last five years. One of the reasons for the recent surge is the greater and more stable milk price received by organic dairy farmers compared to the very volatile milk price received by non-organic dairy farmers. And, while this greater and more stable milk price (≈$27.50/cwt for dairy farmers in Lancaster County, PA) has in most cases increased farm income, there seems to be a decreasing trend for milk production per cow on organic dairy farms in southeastern Pennsylvania (Karreman, personal observation). If this perceived downward trend is true and continues, then organic dairy farmers in the region face a developing problem on how to sustain farm income and remain competitive in the dairy industry. As a result, there is an immediate need to determine the current trend for milk production per cow on organic dairy farms in southeastern Pennsylvania and identify the factors driving this trend. This problem is important because milk production per cow is directly related to dairy farm income and long-term profitability.
The overall goal of the proposed project is identification of viable organic dairy management practices that will sustain or enhance milk production per cow per year on certified organically-managed (OM) dairies in Southeastern Pennsylvania. The proposed project will achieve this goal by meeting the following objectives:
1.) Using DHIA records, determine the trend for milk production per cow per year for certified OM dairy farms in southeastern Pennsylvania.
2.) Using DHIA records, determine monthly trends or changes in milk production, milk components, milk quality, and reproductive performance parameters for certified OM dairy farms in southeastern Pennsylvania.
3.) Using DHIA records identify certified OM dairy farms that have significantly different trends or changes as compared to those determined in Objective 2, and determine what management practices were in place on those farms that may have caused those differences, positive or negative.
4.) Using DHIA records compare monthly trends or changes in milk production, milk components, milk quality, and reproductive performance parameters between certified OM dairy farms and CM dairy farms.
A total of 85 certified organically-managed dairy farms or farms transitioning to organic management were recruited for the study by Dr. Karreman. All farms interested in participating in the study were asked to sign a letter of commitment to complete a survey of their management practices and allow access to their DHIA records. Only 51 of the 85 farms returned a signed letter of participation.
Participating farms were provided with the six-page, 308 question survey. The survey was divided into six sections: basic farm information, youngstock, nutrition, reproduction, milk quality, and health. In order to facilitate completion of the survey, the majority of the questions were designed to be answered as yes or no. Surveys were distributed in the fall of 2006 and collected in early January, 2007. A total of 38 farms returned the completed survey. Descriptive statistics were conducted with the data to provide an overview of management practices on the organically-managed dairies in the project.
DHIA records for each OM dairy providing a completed survey were obtained from DRMS at Raleigh, NC. The records included 2005 and 2006 DHIA 202 sheets, which contain approximately 1200 individual pieces of data. These records were combined with survey data from each farm in order to determine how management practices may affect herd performance. Data were analyzed using the PROC MIXED procedures of SAS version 9.1 for windows (SAS Institute, Cary, NC). For each dependent variable examined, the model included the fixed effects of management practices within a specific management area. For example, the milking procedures model included the fixed effects of wearing gloves (WG), dry wiping (DW), pre-dipping (PRD), fore-stripping (FS), wiping dry prior to unit attachment (WD), and post-dipping (POD). Results were generated using least squares means and standard errors for each dependent variable within the applicable model.
For the comparison of OM dairies to CM dairies, a matched pair experimental design was employed to determine differences. For each OM herd recruited for the study, a CM herd of similar size and breed geographically located within a one-mile radius of the OM herd was selected for the study. These 34 matched pairs were selected to limit the effects of herd size, breed, local weather patterns and soil type on the results of the study. All herds used Lancaster DHIA services, and monthly DHIA 202 report data from 2006 were used for the study. Herds ranged in size from 22 to 105 cows with a mean size of 47 ± 6. Data were analyzed using PROC MIXED procedures of SAS version 9.1 for windows (SAS Institute, Cary, NC). While the majority of herds were Holstein, several (n = 9) of the OM herds were classified in DHIA as crossbred. As a result, the model included the fixed effect of management type with breed (Holstein versus Crossbred) nested inside management type. Results were generated using least squares means and standard errors for each dependent variable within the applicable model.
The average certified OM dairy in the study could be described in the following manner:
47 mature cows with 33 youngstock
83 acres with 50 acres being used for grazing
Certified organic for approximately 5 years
Tie-stall facility with mats/mattresses and using straw/fodder for bedding
Raises and buys forage
Grass hay is main purchased forage
Forage is stored in tower silos and as wrapped baleage
Raises and buys grain
Shelled corn is main purchased grain
Cows are milked twice per day
Dry period is normally 60 days
Manure storage is a pit with 3 months of storage capacity
More specific information on the management practices of the OM dairies participating in the study can be requested by sending e-mail to email@example.com. Refer to project ONE05-042.
Integration of Survey and DHIA data from OM dairies
Due to the enormity of the dataset and the output from the statistical analysis, only portions of the results will be provided in this report. More specific information can be requested by sending e-mail to firstname.lastname@example.org. Refer to project ONE05-042.
An example of the results obtained from the study is:
The milking procedures statistical model included the fixed effects of wearing gloves (WG), dry wiping (DW), pre-dipping (PRD), fore-stripping (FS), wiping dry prior to unit attachment (WD), and post-dipping (POD). The mastitis statistical control practices model included the fixed effects of using California Mastitis Test (CMT), hand stripping infected quarters (HS), using quarter milkers (QM), culturing infected cows (CIC), culturing infected quarters (CIQ), and milking infected cows last (MICL). The dry period statistical model included the fixed effects of abrupt dry off (ADO), seal teat ends (STE), and vaccinate during dry period (VDP). In milking procedure results, only WG and PRD significantly (P < 0.05) improved milk quality and udder health. Wearing gloves was associated with reduced average actual SCC (122,000 vs 374,000; SE = 70.8), and a lower % of cows with SC scores = 7-9 (1.2 vs 9.2; SE = 2.19). Pre-dipping was associated with reduced average actual SCC (134,000 vs 363,000; SE = 69.7), and a lower % of cows with SC scores = 7-9 (1.9 vs 8.5; SE = 2.16). Among mastitis control practices, only CIC was significantly (P < 0.05) associated with improved udder health. Herds that CIC had a greater % of cows with SC scores = 0-3, and lesser % of cows with SC scores = 5 and 6. In the dry period, there was a trend (P = 0.069) for VDP to reduce the % cows with SC scores = 7-9 (1.9 vs 8.8; SE = 2.8). These results suggest that BMP used with conventionally-managed dairy herds can effectively improve milk quality and udder health in OM dairy herds. Comparison of OM and CM dairies Due to the enormity of the dataset and the output from the statistical analysis, only portions of the results will be provided in this report. More specific information can be requested by sending e-mail to email@example.com. Refer to project ONE05-042. An example of the results obtained from the study is: While the majority of herds were Holstein, several (n = 9) of the OM herds were classified in DHIA as crossbred. As a result, the statistical model included the fixed effect of management type with breed (Holstein versus Crossbred) nested inside management type. LS means with standard errors are presented in the table below. The results would indicate that OM herds produced less milk of poorer quality compared to CM herds. However, OM herds had greater milk component percentages, and lower culling rates compared to CM herds. The reduced culling rate resulted from less culling for reproduction and injury/other. Within OM herds, crossbreeding significantly lowered milk production and quality, but improved milk components and pregnancy rate. A significantly greater percentage of cows died in crossbred OM herds compared to Holstein OM herds. These results suggest that OM dairy herds face different production and health challenges compared to CM dairy herds, and the breed of cattle can further impact the production and health challenges in OM herds. Title: Effect of management type and breed on production, health and culling characteristics in Southeastern Pennsylvania dairy herds Management Type Breed within Organic Management Significance (P-value)
Item Conventional Organic SE Holstein Crossbred SE Management Breed
Milk Yield, kg/cow/d 31.4 22.6 0.63 25.5 19.7 0.91 <0.0001 <0.0001
Milk fat, % 3.77 3.94 0.039 3.78 4.09 0.057 0.0039 0.0005
Milk protein, % 3.06 3.15 0.019 3.03 3.27 0.027 0.0021 <0.0001
SCC, 1,000’s 323 348 20.8 313 384 30.3 0.3851 0.1093
SC Score 2.94 3.29 0.090 3.12 3.46 0.132 0.0092 0.0853
Pregnancy rate, % 17.7 19.5 1.03 16.6 22.3 1.50 0.2307 0.0107
Age at 1st Calving, months 25.3 26.2 0.35 25.4 27.0 0.50 0.0655 0.0362
Cows left herd, % 32.5 27.0 1.74 26.8 27.2 2.54 0.0303 0.9181
Cows left for reproduction, % 7.3 4.2 0.90 6.7 1.8 1.27 0.0182 0.0116
Cows left for mastitis, % 3.3 3.2 0.71 3.2 3.3 1.03 0.9625 0.9088
Cows left for injury/other, % 5.7 2.9 0.95 3.8 2.0 1.38 0.0382 0.3736
Cows died, % 3.2 2.3 0.56 1.1 3.6 0.82 0.2963 0.0455
Education & Outreach Activities and Participation Summary
Two abstracts have been prepared for the 2007 American Dairy Science Association National meetings in San Antonio, TX. The titles of the abstracts are:
“Best management practices to improve milk quality and udder health in organically-managed dairy herds in Southeastern Pennsylvania”
“Effect of management type, conventional versus organic, on production, health and culling in Southeastern Pennsylvania dairy herds”
Further, Dr. Karreman has presented or is presenting the results from the study at the following meetings:
January 25, 2007: University of Pennsylvania School of Veterinary Medicine, Kennett Square, PA. Attendance: Approximately 80 veterinarian students.
January 30, 2007: Lancaster Organic Farmer’s Cooperative, Bird-In-Hand, PA. Attendance: Approximately 60 farmers.
January 31, 2007: Dairy Marketing Services, Bird-In-Hand, PA. Attendance: Approximately 100 farmers with 15 Agricultural Professionals.
February 9, 2007: Homestead Nutrition, Inc. Annual Meeting, New Holland, PA. Attendance: Approximately 60 farmers.
February 15, 2007: Alfred State College SARE Conference for veterinarians and extension personnel. Attendance: Approximately 30 attendees.
February 28, 2007: Horizon Organic Meeting, New Holland, PA. Attendance: Approximately 50 farmers.
March 7, 2007: University of New Hampshire SARE Conference for veterinarians and extension personnel, Durham, NH.
It is too early to determine if farmers participating in the study have changed their management practices due to the results of the study. The project team plans to follow-up with participating farmers in the coming year to determine if changes were made as a result of the project.
Areas needing additional study
Several of the participating farmers have expressed interest in conducting a similar type of project focused on the financial and business management of organically-managed dairies.