Author:
HEMMATABADI REZA NESHAGARAN,JAFARABADI GHOBAD ASGARI,KASHAN NASER EMAM JOME,AMINAFSHAR MEHDI
Abstract
Records (111543) of first calving test day milk production with three milking times during the years 1983 to 2016 were used for 62 herds in the Breeding Center data file. The dairy cows under study had 10 test day records. Variables from the herd-year-calving combination as random effect and herd-test-month-age combination at the time of record as fixed effects were created for each animal. Average milk yield in hot and dry climate was higher than hot and wet climate. The average traits of milk fat and milk protein percentage in hot and dry climates were higher than hot and wet climates, but somatic cell traits were higher in hot and wet climates. The phenotypic variance of milk yield was higher in hot and dry regions in all ten test day records. The phenotypic variance of milk fat percent was higher in hot and dry area on the first, second, fifth and sixth test days. The average genetic variance of milk fat percentage in hot and wet region at 9 test day records was higher than in hot and dry region. Phenotypic variance of milk protein percentage in hot and dry area was higher than in hot and wet regions in all test days. In countries where calving occurs throughout the year, mastitis is dependent to the pattern of growth of pathogens in different seasons and years. Changes in animal physiological conditions (calving and changes in breast status) increase the number of somatic cells in milk, which has a physiological effect.
Publisher
Indian Council of Agricultural Research, Directorate of Knowledge Management in Agriculture
Subject
General Veterinary,Animal Science and Zoology
Reference23 articles.
1. Baltay Z. 2002. Influence of time of day the milk and season on the somatic cell count under Hungarian conditions. Arxhiv Fur Tierzucht-Archives of Animal 45(4): 349–57.
2. Boichard D and Rupp R. 1997. Genetic analysis and genetic evaluation for somatic cell score in French Dairy Cattle. Station de Genetic Quantitive et Applique. INRA 54–60.
3. Bohmanova J, Misztal I and Cole J B. 2009. Temperature-Wetity indices as indicators of milk production losses due to heat stress. Journal of Dairy Science 252: 1242–56.
4. Dube B, Dzama K and Banga C B. 2008. Genetic analysis of somatic cell score and udder type traits in South African Holstein cows. South African Journal of Animal Science 38(1).
5. Faraji H, Aslaminejad A A, Rokouei M and Nasrabadi M T. 2012. Estimation of Variance—Covariance Component for Somatic Cell Score in Iranian Holstein Cows. Proceedings of the 15th AAAP Animal Science Congress, 26–30 November 2012, Thammasat University, Rangsit Campus, Thailand.