Environmental factors affecting various productive traits in Sahiwal cattle
2000
Javed, K. (Research Inst. for the Physiology of Animal Reproduction, Kasur (Pakistan)) | Mohiuddin, G. | Abdullah, M.
Data on 8948 performance records of 2532 cows daughters of 213 sires maintained at Livestock Experiment Station, Jahangirabad district Khanewal (Pakistan) during 1939-98 were utilized in the present study. The least squares means for first lactation traits viz. milk yield, lactation length and dry period were 1579.04 plus minus 18.17 kg, 260.52 plus minus 2.64 and 221.68 plus minus 5.20 days, respectively. The corresponding values for the traits considering all lactations were 1862.42 plus minus 42.08 kg, 317.71 plus minus 3.24 and 198.30 plus minus 4.43 days, respectively. Age at first calving, lactation length and lactation number were significant (P less than 0.01) sources of variation for milk yield. The effect of calving interval on first lactation milk yield was significant (P less than 0.05). The influence of year and season of calving was significant (P less than 0.01) on all the traits under study. The milk yield was the highest (1688.00 plus minus 35.46 kg) among the cows calving during autumn season and it was the lowest (1510.86 plus minus 29.88 kg) among the cows calving during dry hot season. The cows calving during winter, spring and humid hot seasons yielded 1565.62 plus minus 27.92, 1565.77 plus minus 23.02 and 1564.95 plus minus 30.22 kg of milk, respectively.
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