Data on 3908 milk records of Sahiwal cows recorded over a period of 11 months were utilized for the study. The cows were reared at Sahiwal cattle farm, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, India. The least-squares mean and standard errors for fat, solid not fat, protein, and density were reported to be 4.42 ± 0.02%, 8.45 ± 0.01%, 3.23 ± 0.01% and 29.34 ± 0.04 kg/m3, respectively. Analysis of the variance revealed that season had a highly significant effect (P<0.01) on the fat, solid not fat and on the protein percentage but there was no significant effect of season on the density of milk. Again, a period of milking was reported to produce highly significant effects (P<0.01) on fat, solid not fat, protein, and milk density.

Highlights

• Highly significant effect of season and milking period on fat, SNF and protein.
• Milk fat, SNF and protein highest in winter season.
• Milk density highest in pre-monsoon season.