author(s)
Pandey A and Thakur MS

abstract
In the aim of association study of different genetic variants’ of αs1-casein gene (csn1s1) and their association with lactation length (days) fat (%) and protein (%), the analysis of variance for different genotypes in four breeds of cattle has been observed that the effect of genotypes was found significant 74.31** (P<0.01) for lactation length (LL) trait. Significantly higher LL (Days) was recorded in AA genotype of HF crossbred 329.70^a±8.93 while the lowest LL was noticed in AA genotype of Nimari 202.42^d±3.67. The mean LL between AA and AB genotype of Malvi, Sahiwal and HF crossbred cattle showed non-significant difference. The higher mean Fat (%) was noticed for AA genotype than AB genotype of Malvi and Nimari however in HF crossbred higher Fat (%) was observed for AB genotype. The mean Fat% between AA and AB genotypes showed non-significant difference in Malvi, Sahiwal and HF crossbred cattle but the mean protein per cent was significantly higher in Malvi 3.36^b±0.05 and Nimari 3.74^a±0.07 and non-significantly higher in HF crossbred for AB genotype as compared to AA genotype. Among the different genotypes of all four breeds of cattle, significantly higher protein (%) was recorded in Nimari for AB genotyped animals.