Editor’s note: This article was written by Jud Heinrichs, professor of Dairy and Animal Science, and Coleen Jones, research associate, Penn State Department of Dairy and Animal Science and first appeared in the Penn State Dairy Digest.
The final results of a long-term research project conducted by Penn State were published in the January 2011 issue of the Journal of Dairy Science. The study investigated possible relationships between management and health events that occurred during calves’ first four months of life and their future performance. Data for this study was collected over 10 years and included management, nutrition, and health information for calves, measurements at first calving, lifetime lactation records, and age at culling. Calves in the study were housed on 18 farms in Wyoming and Susquehanna counties in Pennsylvania. The study was funded initially by the USDA and the lifetime production part by the Pennsylvania Department of Agriculture Animal Health Commission.
Results at first calving (published by Heinrichs et al. in the Journal of Dairy Science in 2005) showed that calves experiencing a difficult birth were older when they calved for the first time. Environmental factors of higher humidity and temperature also were related to older age at first calving. Four other factors: antibiotic treatment for illness, feeding an increased amount of milk or milk replacer before weaning, feeding low quality forage to weaned calves, and ammonia levels in calf housing, tended to be associated with increased age at first calving. Ammonia in calf housing was related to increased body weight at calving, possibly because heifers were older. Body weight at calving also tended to be greater for calves born to cows rather than first-calf heifers; however, sires were not followed in this study.
A difficult birth was associated with reduced first-lactation milk and protein yield. In addition, there was a tendency for difficult birth to be related to lower milk and protein yields over the cow’s entire life. The age at which calves first consumed 2 pounds per day of grain was related to lifetime production of milk, fat, and protein; later grain intake was associated with higher production and also longer productive life, assessed by age at culling. The explanation for this association is not clear from these data. Scours or respiratory illness and treatment for these conditions during the first four months of life were related to production of milk, fat, and protein in the first lactation. Greater days ill reduced production, and greater days of antibiotic treatment improved production. The effect of antibiotic treatment could be related to overall management of calf health and closer attention to finding and treating sick calves, in certain farms, resulting in calves that were healthier overall. Calf health was not related with lifetime production or age at culling in this study. Increased age at first calving was negatively related to 305-day mature equivalent production of milk, fat, and protein. Increasing body weight at calving had a positive relationship with fat production and tended to increase milk and protein production as well (305-day mature equivalent basis).
This study showed that events early in life can have significant long-term impacts on heifer growth and cow productivity. In addition, these results underscore the importance of proper care for calves at birth and throughout their first few months of life. The study reinforces the importance of optimum age and body weight at first calving to first lactation milk production. Finally, this investigation showed the impacts of calf health and treating calf health events on the later productivity of the dairy cow.
Source: Penn State Dairy Digest