Interrelationship between diseases and calving season and their impact on reproductive parameters and milk production of tropical dairy cows

• Published in: Tropical animal health and production Vol. 54; no. 3; p. 158
• Main Authors: Castro-Montoya, Joaquín M., González, F. L., Mendoza, M. V., Harper, K., Corea, E. E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2022; Springer Nature B.V
• Subjects: Ambient temperature; Animals; Biomedical and Life Sciences; Cattle; Dairy cattle; Dairy farming; Disease; Diseases; Environmental conditions; Farms; Female; Fertility; Lactation - physiology; Life Sciences; Mastitis; Milk; Milk production; Physiological responses; Pregnancy; Regular Articles; Relative humidity; Reproduction; Seasons; Tropical environment; Tropical environments; Veterinary Medicine/Veterinary Science; Yield; Zoology; Intrauterine infections; Placenta retention; Tropical dairy; Mastitis; Heat stress; Fertility
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-022-03151-5

The interactions between calving season, the occurrence of retained placenta, intrauterine infections (IUI), and early mastitis, and their effects on the reproductive performance and milk yield of Holstein–Friesian cows in a tropical environment were studied using data from 3320 calvings (1948 cows) from two farms in El Salvador. Based on environmental conditions, season of calving was categorized into: quadrimester 1 (November–February), quadrimester 2 (March–June), and quadrimester 3 (July–October) where quadrimester 2 and 3 had the highest ambient temperature and relative humidity, respectively. Cows were classified into 1, 2, and 3 + parities. The effects of quadrimester and of diseases on days to first service, services per conception, days open, interval between services and 305-day milk yield were studied in separated multivariate regressions. The likelihood of experiencing a disease contingent on the calving season and the likelihood of a cow being culled due to poor fertility associated with experiencing a disease were evaluated using logistic regression. Cows calving in quadrimester 2 and 3 were more likely to suffer from IUI and showed poorer reproduction than cows calving in quadrimester 1. Reproduction was more strongly affected by IUI. Mastitis increased the days to first service, days open, and interval between services. Mastitis and IUI also caused a lower 305-day milk yield. Overall, hotter and more humid conditions lead to higher incidence of disease and poorer reproductive performance. The physiological responses that lead to these phenomena should be further studied to understand the interactions between diseases, environmental conditions and reproduction.