STUDY OF
SOME PERFORMANCE TRAITS IN SAHIWAL COWS DURING DIFFERENT PERIODS
A. H. ZAFAR,
M. AHMAD1 AND S. U. REHMAN
Livestock
Production Research Institute, Bahadurngar, Okara;
1Buffalo Research Institute, Pattoki,
District Kasur, Pakistan
Abstract
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 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 ± 21.27, 1632 ± 17.95 and 1527 ± 19.34 kg, respectively. The
corresponding values for lactation length were 258 ± 2.51, 256 ± 2.13 and 267 ±
2.29 days, respectively. The means for dry period, service period and calving
interval were 172 ± 3.70, 156 ± 4.03 and 437 ± 3.74 days, respectively in the
period-1, 161 ± 3.19, 139 ± 3.45 and 420 ± 3.23 days, respectively for period-2.
and 158 ± 3.55, 152 ± 3.86 and 429 ± 3.60 days, respectively for period-3. The
analysis of variance showed that period of calving showed significant variation
(P<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.