Progress 10/01/03 to 09/30/07

Outputs
OUTPUTS: Various aspects of dairy operations were surveyed and compared to early lactation culling rate and herd mortality rates. Surveys for 305 herds were merged with 2005 DHI culling information to derive comparisons. The average early lactation herd culling rate (21 days prior to a due-date through 60 days in milk) was 6.8%. The average herd mortality rate was 5.7% when herds with no reported deaths were excluded and 4.6% when those herds were included. Cows culled prior to 60 days had a higher sire PTA milk yield than those cows culled after 60 DIM. Tie stall herds had lower early lactation culling and mortality rates than free-stall herds. Tie-stall herds that provided daily pasture access and that had a component feeding system had low early lactation culling and mortality rates when compared to herds that fed a total mixed ration with no pasture access. Producer-recorded health records from PCDART dairy management software were supplied by DRMS to determine the heritability of mastitis. There was significant genetic variation present for mastitis resistance, indicating that there is potential to select for mastitis resistance. Daily body weight for 623 cows was recorded twice daily by AfiFarm upon a cow exiting the milking parlor. The median body weight change during the first 30 days of lactation was -37kg. Cows losing more weight had higher odds of developing a displaced abomasum, metabolic disease, infectious disease and all diseases. Cows with reproductive diseases lost less weight. The estimated heritability of daily body weight was 0.45, and genetic correlation estimates of body weight with milk yield and body condition score were -0.12 and 0.63, respectively. Yield, somatic cell score, days open, and age at first calving between Holstein and Brown Swiss, and crosses among BS and HO were compared for 3,427 cows from 19 commercial dairy herds. Brown Swiss x Holstein crossbred cows had higher daily yields of fat + protein (5.05kg) than pure Holstein (4.90kg) with 12.6 fewer days open. There was evidence of significant recombination loss in future generations. Recombination generally eliminated all expected heterosis in the second generation. The efficiency of Holstein, Brown Swiss and their crosses were compared using data envelopment analysis. In total, 49% of all cows had efficiency scores of 100% and least squares means for efficiency were 0.71, 0.84, 0.84 and 0.82 for Brown Swiss, Holstein, Brown Swiss x Holstein and Brown Swiss backcrosses, respectively. The heterosis estimates for efficiency ranged from 6.4% to 9.3%, and Holsteins and Brown Swiss x Holstein crosses were not significantly different for efficiency. PARTICIPANTS: The principal investigator for this project is Chad Dechow. Rob Goodling is an extension educator that has served as a co-investigator for mortality and culling studies. Jennifer Vallimont is a research technician working primarily with genetic evaluations for mastitis resistance. Select Sires and Dairy Records Management Systems both contributed to the mastitis aspect of this project. Jitesh Toshniwal completed his M.S. in August of 2007. His research project involved daily body weight analysis from the Penn State and Virginia Tech dairy herds. Emily Marion was an undergraduate student and her honors thesis described the relationship of daily body weight with cow health parameters. The Virginia Tech collaborators for the body weight project were Bennet Cassell (Professor) and Ranga Appuhamy (graduate student). Michael Phelps is an undergraduate student working with Brown Swiss crossbreeding. Michael, Emily and Jitesh all had the opportunity to travel to and present their research at the annual American Dairy Science Association meetings. Funding for the project has been provided by the Pennsylvania Department of Agriculture and Select Sires. TARGET AUDIENCES: The primary groups served by this research are dairy producers and artificial insemination cooperatives that are interested in improving the health and fertility of high producing dairy cows. The information has been disseminated to dairy producers through extension meetings, popular press articles, and at conferences and breed association conventions. The results have been disseminated to fellow researchers at regional research project meetings and professional meetings of the American Dairy Science Association. Results have been disseminated to artificial insemination cooperatives through member and technical meetings.

Impacts
Animal welfare concerns are becoming an important issue in dairy production and there are efforts underway to improve cow welfare, either legislatively or through animal welfare audits. However, there is little research to demonstrate what types of management systems are associated with variation in cow welfare. Mortality is an indicator of compromised cow welfare, and death is the third largest reason for cow disposal on PA dairy farms. There appears to be a conflict between efficient dairy production and cow welfare as indicated by mortality rates. Current trends in herd management, like free-stall housing systems and limited pasture access, were associated with higher cow death and early lactation culling rates. Additionally, higher genetic merit for milk yield was associated with higher early lactation culling. There are several opportunities to help prevent declines in cow welfare. Genetic variation exists for resistance to diseases such as mastitis and there is potential to select for healthy cows even at high levels of milk production. Crossbreeding of Holstein with Brown Swiss resulted in improved reproductive performance at high levels of milk yield, which may be an indicator that the crossbred cows had improved cow health. Automated daily body weights and similar management tools could also help identify cows with compromised health so that corrective action can be taken.

Publications

• Appuhamy, J. A. D. R. N., B. G. Cassell, C. D. Dechow, and J. B. Cole. 2007. Phenotypic Relationships of Common Health Disorders in Dairy Cows to Lactation Persistency Estimated from Daily Milk Weights. J. Dairy Sci 90:4424-4434.
• Dechow, C. D., G. W. Rogers, J. B. Cooper, M. I. Phelps, and A. L. Mosholder. 2007. Milk, Fat and Protein Yield, Somatic Cell Score and Days Open Among Holstein, Brown Swiss and their Crosses. J. Dairy Sci. 90:3542-3549.
• Dechow, C. D., and R. C. Goodling. 2007. Labor, housing, feeding, and bedding affects on herd turnover rate and mortality rates of Southeastern Pennsylvania dairy herds. 101st Annual Meeting of ADSA. San Antonio, TX. July 8-12. J. Dairy Sci. 90(Suppl. 1):540 (Abstract).
• Dechow, C. D., M. I. Phelps, S. Roth, G. W. Rogers, and J. B. Cooper. 2007. Efficiency of Brown Swiss, Holstein and their crosses estimated with data envelopment analysis. 101st Annual Meeting of ADSA. San Antonio, TX. July 8-12. J. Dairy Sci. 90(Suppl. 1):263 (Abstract).
• Dechow, C. D., J. Vallimont, C. G. Sattler, and J. S. Clay. 2007. Heritability estimates for producer recorded clinical mastitis events. 101st Annual Meeting of ADSA. San Antonio, TX. July 8-12. J. Dairy Sci. 90(Suppl. 1):262 (Abstract).
• Kehoe, S. I., C. D. Dechow and A. J. Heinrichs. 2007. Effects of Weaning Age and Milk Feeding Frequency on Dairy Calf Growth, Health and Rumen Parameters. Livestock Science. 110:267-272.
• Toshniwal, J. K., C. D. Dechow, J. A. D. R. N. Appuhamy, and B. G. Cassell. 2007. Heritability of electronically recorded daily body weight across lactation using random regression models. 101st Annual Meeting of ADSA. San Antonio, TX. July 8-12. J. Dairy Sci. 90(Suppl. 1):192 (Abstract).
• Yeiser, E. E., C. D. Dechow, J. Vallimont, C. G. Sattler, and J. S. Clay. 2007. Genetic analysis of the relationship between ketosis and milk fat in Holsteins. 101st Annual Meeting of ADSA. San Antonio, TX. July 8-12. J. Dairy Sci. 90(Suppl. 1):240 (Abstract).

Progress 01/01/06 to 12/31/06

Outputs
Daily body weight was available from 623 cows, of which 490 Holstein cows were from the Penn State herd, and 133 Holstein cows were from the Virginia Tech herd. Daily body weights were recorded twice daily by AfiFarm upon a cow exiting the milking parlor. The total disease frequency was 61%. The median body weight change during the first 30 days of lactation was -37kg. Odds ratios were calculated for weight change at the 75th percentile (-17 kg) to weight change at the 25th percentile (-57 kg). Cows losing more weight had higher odds of developing a displaced abomasum (1.56:1), metabolic disease (1.39:1), infectious disease (1.18:1) and all diseases (1.40:1). Cows with reproductive diseases (0.70:1) lost less weight. The estimated heritability of daily body weight was 0.45, and genetic correlation estimates of body weight with milk yield, body condition score and dry matter intake were -0.12, 0.63 and 0.53, respectively. Daily milk, fat, and protein yield, mature equivalent (ME) milk, ME fat, ME protein, somatic cell score, days open, and age at first calving between Holstein (HO) and Brown Swiss (BS), and among BS and HO crosses and backcrosses were generated for 3,427 cows from 19 commercial dairy herds. Brown Swiss x Holstein crossbred cows had higher daily yields of fat + protein (5.05kg) than pure Holstein (4.90kg) with 12.6 fewer days open. There was evidence of significant recombination loss in future generations. Recombination generally eliminated all expected heterosis in the second generation. Culling data for 3970 Pennsylvania dairy herds has been provided by Dairy Records Management Systems (DRMS, Raleigh, NC). An initial analysis of over 790,000 records indicates that cow death is the 3rd most frequently reported reason for a cow exiting a PA dairy herd. Surveys were distributed through Lancaster DHIA to identify herd management characteristics associated with cow mortality. Approximately 250 herd surveys have been received to date.

Impacts
Daily body weight is heritable and can be captured electronically at minimal cost. Change in daily body weight is phenotypically related to dairy cattle disease and selection to limit weight loss in early lactation may limit decline in metabolic health as a correlated response to selection for yield. However, low weight loss is associated with more reproductive disease and genetic relationships among weight loss and various diseases should be investigated. Brown Swiss would be an effective breed in crossbreeding programs. Brown Swiss x Holstein crossbred cows had fat + protein production that was higher than pure-bred Holsteins with fewer days open. Heterosis was favorable for all traits. There was significant evidence of Holstein recombination loss for yield, but not for Brown Swiss. Recombination effects should be considered when making crossbreeding recommendations and allowing heterosis and recombination effects to vary for different breeds may result in more accurate multiple breed genetic evaluations. Death is the third largest reason for cow disposal on PA dairy farms. This causes significant economic losses as well as compromising dairy cow welfare. Factors that lead to cow death must be explored more fully.

Publications

• Marion, E. M., Dechow, C. D., Appuhamy, J. A. D. R. N., and Cassell, B. G. 2006. The relationship between bodyweight change and disease incidence in early lactation. ADSA-ASAS Joint Annual Meeting Abstract. Minnesota, MN. July 19-23. J. Dairy Sci. 89 (Suppl 1) :211
• Phelps, M. I., Dechow, C. D., Mosholder, A. L., Cooper, J. B., and Rogers, G. W. 2006. Comparison of Brown Swiss, Holstein and Brown Swiss x Holstein crosses for production, somatic cell score and days open. ADSA-ASAS Joint Annual Meeting. Minnesota, MN. July 19-23. J. Dairy Sci. 89 (Suppl 1) :16
• Toshniwal, J. K., Dechow, C. D., Appuhamy, J. A. D. R. N., and Cassell, B. G. 2006. Heritability estimates of milk yield and electronically recorded daily body weight. ADSA-ASAS Joint Annual Meeting Abstract. Minnesota, MN. July 19-23. J. Dairy Sci. 89 (Suppl 1) :16

Progress 01/01/05 to 12/31/05

Outputs
The potential of using automated parlor data in genetic evaluations to improve cow health and reproductive performance is being investigated by capturing body weights electronically on cows exiting the milking parlor in the Penn State dairy herd. A total of 159,388 daily body weights have been merged with 1417 BCS and 254,122 daily milk weights. Phenotypic relationships between body weight and disease treatments were also estimated. Body weight and BCS change in the first 30 DIM were merged with disease records from March 2002 through November of 2004 for 346 cows. Phenotypically, electronically recorded body weights were more strongly associated with disease incidence than BCS. Cows losing 90kg of weight in the first 30 DIM were 1.9 times as likely to be treated for a displaced abomasum and 4.51 times more likely to be treated for ketosis than a cow losing no body weight. Heritability estimates for body weight and body weight change are currently being estimated. Dairy Comp 305 or PCDART records were retrieved from 11 herds milking Brown Swiss x Holstein cows. Total lactation milk, fat, protein and days in milk (DIM) were obtained for all herds for lactations 1 through 5. Only cows with valid sire and maternal grandsire were included in the analysis. Least square means for daily milk, fat and protein yield were estimated with 3,875 Holsteins, 1,034 Brown Swiss and 191 cross bred records. Least square mean estimates for average daily milk yield were not statistically different between pure Holsteins (70.83) and Brown Swiss x Holstein crosses (70.20) and both were significantly higher that least square mean estimates for pure Brown Swiss (61.45). Estimates of heterosis for yield ranged from 6.1 percent for daily milk yield to 8.3 percent for daily fat yield.

Impacts
The unfavorable relationship between excessive body weight loss in early lactation and metabolic health was confirmed using electronically captured body weights. Body weight data collection is more objective than visually scored body condition score and collection of body weight data is more easily automated. Large dairy herds can use automated body weight collection to monitor cows at risk of metabolic disease and such weights can be used to generate genetic evaluations for body weight change. Brown Swiss x Holstein crossbred cows had similar levels of production to pure bred Holstein cows. This research has demonstrated that Brown Swiss x Holstein cows are an economic alternative to pure bred Holstein cows and that producers interested in crossbreeding to alleviate inbreeding depression for fertility and health traits do not need to sacrifice production levels.

Publications

• Mitchell, R. G., Rogers, G. W., Dechow, C. D., Vallimont, J. E., Cooper,J. B., Sander-Nielsen, U. and Clay, J. S. 2005. Milk Urea Nitrogen Concentration: Heritability and Genetic Correlations with Reproductive Performance and Disease. J. Dairy Sci. 88:4434-4440.

Progress 01/01/04 to 12/31/04

Outputs
Previous work has demonstrated that bulls which sire daughters that tend to be angular and thin (low body condition score and high dairy form) or that are genetically inclined to lose body weight also sire daughters that have poorer reproductive performance and metabolic health. Daily body weights were obtained from the Penn State dairy herd. The relationship between weight gain or loss in the two weeks prior to insemination on conception likelihood has been analyzed. Cows in the highest quartile for weight change (those gaining the most weight) were more likely to conceive than those cows in the lowest quartile (those losing the most weight). Foot health data from herds using the HoofCare module of PCDART PocketDairy is currently being collected. This data will be used to estimate heritabilities for foot health and lameness using producer recorded data and estimate the genetic relationship among foot health, cow health and reproductive performance.

Impacts
Automated daily parlor weight could be used as a selection or management tool to estimate the amount of body weight change in early lactation or prior to insemination. Genetic evaluations for weight change may be useful as indicator traits for selection to improve cow reproductive performance and health. Additionally, daily body weights can be used as a management tool to monitor early lactation weight loss and take corrective action if needed. On-farm recorded health data, including foot health, is the likely source of future genetic evaluations for cow health traits.

Publications

• Dechow, C. D., Rogers, G. W., Klei, L. T., Lawlor, J. and VanRaden, P. M. 2004. Body Condition Scores and Dairy Form Evaluations as Indicators of Days Open in US Holsteins. J. Dairy Sci. 87: 3534-3541.
• Dechow, C. D., Rogers, G. W., Sander-Nielsen, U., Klei, L., Lawlor, T. J., Clay, J. S., Freeman, A. E., Abdel-Azim, G., Kuck,A. and Schnell, S. 2004. Correlations Among Body Condition Scores from Various Sources, Dairy Form, and Cow Health from the United States and Denmark. J. Dairy Sci. 87: 3526-3533.
• Dechow, C. D., Rogers, G. W., Klei, L. and Lawlor, T. J. 2004. Heritability and Correlations for Body Condition Score and Dairy Form Within and Across Lactation and Age. J. Dairy Sci. 87: 717-728.