Study of some performance traits in Sahiwal cows during different periods
Zafar, A.H. (Livestock Production Research Inst., Bahadurnagar (Pakistan)) | Ahmad, M. (Buffalo Research Inst., Kasur (Pakistan)) | Rehman, S.U.
Data on some production performance traits of Sahiwal cows maintained at the Livestock Experiment Station, Bahadurnagar, Okara, Pakistan during three different periods i.e. period-1 (1973-1982), period-2 (1983-1992) and period-3 (1993-2002) were compared. Each period was spread over 10 years duration. The data set included 1895, 2123 and 1679 lactation records for the three periods, respectively. Five performance traits viz lactation milk yield, lactation length, dry period, service period and calving interval were included in the analysis. The least squares means for lactation milk yield for the periods 1, 2 and 3 were 1429 plus minus 21.27, 1632 plus minus 17.95 and 1527 plus minus 19.34 kg, respectively. The corresponding values for lactation length were 258 plus minus 2.51, 256 plus minus 2.13 and 267 plus minus 2.29 days, respectively. The means for dry period, service period and calving interval were 172 plus minus 3.70, 156 plus minus 4.03 and 437 plus minus 3.74 days, respectively in the period-1, 161 plus minus 3.19, 139 plus minus 3.45 and 420 plus minus 3.23 days, respectively for period-2 and 158 plus minus 3.55, 152 plus minus 3.86 and 429 plus minus 3.60 days, respectively for period-3. The analysis of variance showed that period of calving showed significant variation (P less than 0.01) for all the productive and reproductive traits, while season of calving had significant effect on lactation milk yield and lactation length. The lactation number (parity) had significant effect on all traits except lactation length, which showed non-significant variation among parities.
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