Progress 09/01/08 to 08/31/11
Outputs
OUTPUTS: The objective of this study was to provide genetic selection tools that, in an era of rising grain prices, facilitate selection of dairy cows that optimize feed utilization to improve dairy profitability. Improving the feed utilization of dairy cows requires that genetic evaluations of elite bulls be made available to dairy producers. Semen from elite dairy bulls are provided by commercial bull studs and evaluations of those bulls are primarily provided by geneticists at USDA and breed associations. Therefore, the primary target audiences of output from this research project are dairy farmers and their consultants, providers of bull semen, and providers of dairy genetic evaluations. Strategies to optimize genetic selection for feed utilization were disseminated to dairy farmers and their consultants at conferences such as the Penn State Nutrition Conference, Mid-Atlantic Nutrition Conference, and Delmarva Dairy Days. Popular press articles in magazines or newsletters directed toward dairy farmers were also produced. This information was also provided to those who sell elite bull semen or perform bull evaluation at conferences such as the annual meeting of the American Dairy Science Association and through peer-reviewed popular press articles. A final output of this research is the development of a feed intake database with genotypes on high and low cows that is available to help facilitate genome wide association and validation studies in national efforts to provide genomic evaluations for feed utilization in the future. PARTICIPANTS: The following faculty members from Penn State participated in the project: Chad Dechow, Wansheng Liu, Jud Heinrichs, Gabriella Varga, and Craig Baumrucker. Jared Daubert is a research technician and visited each herd 7 times to collect feed intake data, assign body condition scores, measure body weight and collect blood for DNA analysis and hormone assays. He was assisted by a graduate student (Matt Dekleva) that completed a MS at Penn State investigating genotype by environment interactions, undergraduate students (Michael Phelps, Dustin Brown and Turner Swartz), the principal investigator, and other co-investigators (Dr. Blum). Database management and data analysis have been conducted by the principal investigator, research technicians (Jared Daubert, Jennifer Vallimont, and Charlene Barlieb) and undergraduate students (Shane Hall). Dr. Baumrucker (co- investigator) has collected and processed colostrum and milk samples for immunoglobulin and hormone assays, and Dr. Liu (co-investigator) has participated in DNA extraction. Erika Frigo was a visiting PhD student from the University of Milan and investigated genetic relationships between body weight loss in the Penn State and Virginia Tech dairy herds and cow health. Data from Virginia Tech was provided by Dr. Bennet Cassel. Erika was supervised at the University of Milan is Dr. Ottavia Pedron. Dustin Brown and Jennell Coulter conducted DNA marker analysis. Drs. Stewart Bauck and Brent Woodward of Merial Limited assisted in DNA marker analysis. TARGET AUDIENCES: The primary target audiences for this research are dairy producers, bull stud personnel and geneticists that produce evaluations of elite bulls. Genetic improvements in feed efficiency are expected to primarily occur through selection decisions made by bull studs and dairy farmers. Bull stud personnel have been updated on progress of the project regularly at scientific meetings. Strategies to optimize genetic selection for feed utilization were disseminated to dairy farmers and their consultants at conferences such as the Penn State Nutrition Conference, Mid-Atlantic Nutrition Conference, and Delmarva Dairy Days, and in popular press articles. PROJECT MODIFICATIONS: The project ending date was extended by one year (to 8/31/2011) to allow for blood assays to be completed and additional DNA marker analysis to occur.
Impacts
This research was facilitated by the collection of feed intake data on 970 cows from 11 commercial tie-stall dairy farms in Pennsylvania. Each herd was visited on 6 occasions to collect 24-hour feed intake on all cows in the herd and to collect blood for DNA extraction. During each herd visit, cows were also evaluated for body condition score and weighed. The feed intake, body condition, and body weight data was then merged with milk, fat and protein yield. The data was also merged with cow fertility measures, survival data, and hormone profiles. Genetic evaluations were then conducted to identify the level of genetic variation for feed utilization traits and the association of feed utilization with other more commonly recorded traits. The results of the genetic evaluations had several impacts. The most limiting factor to direct selection for feed utilization in dairy cattle is a lack of feed intake measurements on a large number individual dairy cows. The dairy industry currently has economical and well established procedures to determine milk yield levels and conformation of dairy cows, but determination of feed intake is labor intensive if done manually, and expensive if done with automated feed-weighing technology. This study demonstrated that is feasible to get feed intake measurements with sufficient accuracy to conduct genetic evaluation on a relatively large number of dairy cows in commercial dairy farms in a short time frame. Additionally, the research demonstrated that our current genetic evaluation system can facilitate much improvement in feed utilization by using highly reliable genetic evaluations for milk yield and body conformation. Feed utilization is expected to improve indirectly by simultaneous selection for higher milk yield and lower body weight; however, results also suggest that more precise and accurate genetic evaluations of feed utilization could be achieved by development of genetic markers. The results also emphasize the need for a balanced approach to genetic selection as some cows appear to have high feed efficiency, but are inferior for cow fertility and survival. Moreover, the research has demonstrated that failure to account for early lactation body condition loss will limit improvement in feed utilization and increase cow health disorders. Finally, we have demonstrated to dairy producers the impact of underfeeding high genetic merit dairy cows. Farmers have increased focus on limiting overfeeding due to high feed costs, but walk a fine line between reducing expenses and limiting the production potential of high genetic merit cows which reduces income. We have also shown that larger cows are more negatively impacted by such management decisions. The outcome of improved feed utilization in dairy cattle will result from implementation of recommended selection strategies by bull studs and dairy farmers.
Publications
- Dechow, C. D. 2011. Genetic selection in dairy cows using residual feed intake and other feed efficiency measures. 9th Annual Mid-Atlantic Nutrition Conference. Timonium, MD. March 29. http://manc.umd.edu/Abstracts2011/Summary%202011MANC%20Dechow%5B1%5D. pdf.
- Dechow, C. D. 2011. Selecting for feed efficiency. Farmshine. June 3. p 35.
- Vallimont,J. E., C. D. Dechow, J. M. Daubert, M. W. Dekleva, J. W. Blum, C. M. Barlieb, W. Liu, G. A. Varga, A. J. Heinrichs, and C. R. Baumrucker. 2011. Short communication: Heritability of gross feed efficiency and associations with yield, intake, residual intake, body weight, and body condition score in 11 commercial Pennsylvania tie stalls. J of Dairy Sci. 94:2108-2112.
- Vallimont, J. E., C. D. Dechow, J. M. Daubert, M. W. Dekleva, and J. W. Blum. 2011. Genetic association of days open with feed intake and efficiency. J. Dairy Sci. 94, E-Suppl. 1:706-707
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: Genetic analysis of feed efficiency has occurred in the past year for this research project. Measures of gross feed efficiency included milk yield over dry matter intake and protein yield over protein intake. The efficiency traits were shown to be moderately heritable and had a genetic correlation between them of 0.70. It was documented that early lactation mobilization of body tissue is associated with inflated estimates of feed efficiency, and that selection programs that fail to account for this will increase cow heath problems. DNA marker associations with measures of efficiency demonstrated that marker assisted selection may be feasible. Genotype by environment interactions due to differences in feeding management were also investigated. Herds that did not allow enough feed for their cows experienced a reduction in response to selection. Output from this research has been disseminated through several channels. Results have been published in the Journal of Dairy Science. They have been presented at the American Dairy Science Association meeting in Denver, CO to fellow scientists that include personnel from bull studs. The results have been presented internationally at a scientific exchange in Paris, France and a seminar at the University of Milan, Italy. Results were also presented to dairy farm nutrition consultants and producers at the Penn State Nutrition Conference. PARTICIPANTS: The following faculty members from Penn State participated in the project: Chad Dechow, Wansheng Liu, Jud Heinrichs, Gabriella Varga, and Craig Baumrucker. Matthew Dekleva completed a MS at Penn State investigating genotype by environment interactions. Erika Frigo was a visiting PhD student from the University of Milan and investigated genetic relationships between body weight loss in the Penn State and Virginia Tech dairy herds and cow health. Data from Virginia Tech was provided by Dr. Bennet Cassel. Erika was supervised at the University of Milan is Dr. Ottavia Pedron. Jennifer Vallimont (project associate) and Charlene Barlieb (research assistant) have conducted much of the database building and data analysis. DNA extraction was performed by Jared Daubert in the lab of Dr. Wansheng Liu. Jared also prepared plasma samples for hormone analysis in the lab of Dr. Craig Baumrucker. Dustin Brown conducted DNA marker analysis. Drs. Stewart Bauck and Brent Woodward of Merial Limited assisted in DNA marker analysis. TARGET AUDIENCES: The primary target audiences for this research are dairy producers and bull stud personnel. Genetic improvements in feed efficiency are expected to primarily occur through selection decisions made by bull studs. Bull stud personnel have been updated on progress of the project regularly at scientific meetings. Dairy producer consultants, particularly nutrition consultants, were alerted to study finding at the Penn State Nutrition Conference. PROJECT MODIFICATIONS: The project ending date was extended by one year to allow for blood assays to be completed and additional DNA marker analysis to occur.
Impacts
Genetic selection for feed efficiency has become a much larger focus in the US and internationally due to high feed prices. This research has filled a critical role identifying selection strategies that will enable the improvement of feed utilization. The research has provided clear evidence that selection for higher yield coupled with lower body weight and body condition will enhance feed utilization. Moreover, the research has demonstrated that failure to account for early lactation body condition loss will limit improvement in feed utilization, and increase cow health disorders. We have demonstrated that full expression of genetic potential for yield is limited by underfeeding cows on farms that are trying to minimize feed wastage. We have also shown that larger cows are more negatively impacted by such management decisions. The outcome of improved feed utilization in dairy cattle will result from implementation of recommended selection strategies by bull studs and dairy farmers. Dissemination of research results to the stakeholders that will implement genetic selection and management changes has begun. An additional outcome of this research is that a wider array of feed intake and utilization data will become available to researchers as we have demonstrated that high quality feed intake data can be collected from commercial farms. Previously, feed intake data has resulted almost exclusively from observations at research facilities.
Publications
- Brown, D.E., C.D. Dechow, J.M. Daubert, W. Liu, and S. Bauck. 2010. Associations of DNA marker profiles for dry matter intake and efficiency with DNA marker profiles for fat-corrected milk yield and body weight. J. Dairy Sci. 93(E-Suppl.1):247.
- Dechow, C.D., J.E. Vallimont, M.D. Dekleva, J.M. Daubert, and J.W. Blum. 2010. Genetic correlations of gross feed efficiency with yield, body weight, body condition score, and energy balance in dairy cattle. J. Dairy Sci. 93(E-Suppl. 1):184.
- Dekleva, M.W., C.D. Dechow, J.M. Daubert, S. Bauck, J.W. Blum, and G.A. Varga. 2010. Genotype by environment interaction: Effects of nutritional management on production traits. J. Dairy Sci. 93(E-Suppl. 1):593.
- Frigo, E., C.D. Dechow, O. Pedron, and B.G. Cassell. 2010. The genetic relationship of body weight and early-lactation health disorders in two experimental herds. J Dairy Sci. 93:1184-1192.
- Vallimont, J.E., C.D. Dechow, J.M. Daubert, M.W. Dekleva, J.W. Blum, C.M. Barlieb, W. Liu, G.A. Varga, A.J. Heinrichs, and C.R. Baumrucker. 2010. Genetic parameters of feed intake, production, body weight, body condition score, and selected type traits of Holstein cows in commercial tie-stall barns. J Dairy Sci. 4892-4901.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: Dry matter intake (DMI), body weight (BW) and body condition score (BCS) were recorded within 7 days of monthly milk recording on 11 Pennsylvania dairy farms. In order to minimize disruption to the farm feeding routine, herd managers were instructed to distribute feed evenly for all cows. Any feed subsequently moved to or taken from a cow was recorded by the research technician, and all feed refusals were weighed the following morning. Records from cows more than 500 days in milk or in greater than seventh parity were removed. A total of 3,999 daily DMI, 4,998 BCS and 2,195 BW observations from 957 cows were available for analysis. Milk yield was retrieved from all prior lactation for cows in second lactation or greater, resulting in 35,398 daily yield observations. Dry matter intake was genetically correlated with higher yield (0.54), and higher BW (0.58). Some cows were genetically inclined to eat more or less than predicted based on milk yield and BW, which indicates that genetic selection may improve feed efficiency. The associations of intake and efficiency with early lactation metabolic health profiles will help determine how such selection will impact the health of cows. Preliminary results have been disseminated at scientific meetings and will be disseminated to dairy cattle nutritionists at a conference November of 2009. PARTICIPANTS: The principal investigator is Dr. Dechow. Jared Daubert is a research technician and visited each herd 7 times to collect feed intake data, assign body condition scores, measure body weight and collect blood for DNA analysis and hormone assays. He was assisted by a graduate student (Matt Dekleva), undergraduate students (Michael Phelps, Dustin Brown and Turner Swartz), the principal investigator, and other co-investigators (Dr. Blum). Database management and data analysis have been conducted by the principal investigator, research technicians (Jared Daubert, Jennifer Vallimont, and Charlene Barlieb) and undergraduate students (Shane Hall). Dr. Baumrucker (co- investigator) has collected and processed colostrum and milk samples for immunoglobulin and hormone assays, and Dr. Liu (co-investigator) has participated in DNA extraction. Other project co-investigators (Dr Varga, Dr. Van Saun, and Dr. Heinrichs) will participate in analysis of nutritional and feed efficiency aspects of the study. DNA marker genotypes and Igenity(R) profiles were provided by Merial. TARGET AUDIENCES: The target audiences for this research project are researchers, dairy farmers and dairy cattle nutritionists that are interested in improving feed efficiency in dairy cattle. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Individual cow feed intake was successfully collected from over 900 cows on 11 commercial PA dairy farms and the cows have been genotyped for over 100 DNA markers. Our initial results indicate that genetic variation for feed efficiency exists. Over 800 blood and milk samples from early lactation cows have been collected and will be analyzed for hormone profiles to determine the metabolic health of those cows. This is the only dataset that we are aware of with a large number of feed intake observations on individual cows in a commercial production setting. The outcomes of this research are expected to result in genetic selection strategies intended to improve the efficiency of dairy production without compromising cow health.
Publications
- Hall, S. M., C. D. Dechow, J. M. Daubert, M. D. Dekleva, J. W. Blum, G. A. Varga, C. R. Baumrucker, and W. Liu. 2009. Genetic correlations of dry matter intake with fat corrected milk yield, body weight, and body condition score in eleven commercial tie-stall dairy farms. J. Dairy Sci. Vol. 92, E-Suppl. 1. (Abstract).
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