Analysis of the Non-genetic Factors Influencing the Performance of High-grade and Inter se Mated Crossbred Dairy Cows at Holetta Dairy Research Farm, Ethiopia

Abstract

Background: The effect of non-genetic factors including feeding, management, climate, calving year, season and others on animal production improvement has attracted considerable attention in recent years. In addition to improving animal genetics, the importance of optimum environmental conditions in enhancing animal production is recognized. Methods: Data collected from 2008 to 2018 on 2036 records from crossbreeding dairy cattle herd at Holeta Agricultural Research Center were analyzed to evaluate the genetic and non-genetic environmental effect on lactation milk yield (LMY), lactation length (LL) and calving interval (CI). The fixed effect used in the data analysis were breed group, parity, years group of calving and seasons of calving. GLM procedure of SAS was used to analyze the data. Result: Results of data analysis indicated that breed group and year group of calving had a significant (P less than 0.05) effect on LMY, LL and CI. Parity significantly (P less than 0.05) affected LMY and CI but had no significant effects on LL. While, season of calving had no significant influence on all traits. Least square mean LMY was significantly (p less than 0.05) highest (3191 kg) for 75% first generation breed group and significantly (P less than 0.05) lowest for pure Ethiopian Borena breed (124 kg LMY). Mean LL was significantly (p less than 0.05) highest (354 days) for 75% first generation breed group and significantly (P less than 0.05) lowest for pure Ethiopian Borena breed (178 days). Least square mean CI was significantly (p less than 0.05) longest (477 days) for 75% first generation breed group and significantly (P less than 0.05) shortest (422 days) for 75% inter se mated breed group. Among 75% crosses, the 75% inter se mated breed group had lower LMY (2553 kg) and shorter CI (422 days) compared to 75% first generation breed group. The decline in LMY and CI for 75% inter se mated breed group by 637 kg (25%) and 54 days (13%), respectively compared to 75% first generation, which can be attributed to recombination effect.