Abstract:
Sahiwal is one of the fifteen documented cattle breeds of Pakistan that has gained international recognition but the productivity of Sahiwal cattle has been reported to vary both across and within countries. The variations in performance traits may be more of an environmental nature. For other reproductive traits, reports disagree even to a great extent. Parity, Herd, year and season of calving affected most of the performance traits in Sahiwal cows. Herd variations represent managemental differences for most of the traits. It was also noted that cows calving in winter season produced highest milk yield as compared to those calving in summer season due to more availability of fodder and comfortable temperature than in summer. The variations in lactation length were slight for herds as compared to season of calving. The age at first calving in Sahiwal's and other cattle breeds was affected by herd, year and season of birth. However, most of the herd differences on age at first calving were reported by only those studies using multiple herd records of Sahiwal breed. Across herd variation in dry period was evident. The highest dry period was noted in winter calvers while the spring calvers had the lowest. The calving interval proved to be dependent in its expression on herd, year, season of calving and parity of cow. The service period was affected by herd, year, season and parity of cow with milk yield as covariable in some studies. Genetic evaluation of Sahiwal cattle is necessary for improved utilization of breed. The traits under consideration were 305-day milk yield, total milk yield, lactation length, age at first calving, dry period, calving interval, service period and genetic parameters include heritability, repeatability, and genetic correlation among different performance traits of Sahiwal cattle. In present study, the pedigree and performance records were utilized from Livestock Experimental Farm of University of Agriculture, Faisalabad to estimate the genetic parameters. For evaluation of environmental effects, year time was divided into four seasons, the winter, the summer, the autumn and the spring. Restricted Maximum Likelihood procedure (REML), ASReml and SPSS software was used to estimate the repeatability, heritability, and genetic correlations of all performance traits. Productive and reproductive traits in Sahiwal cattle had adequate genetic variation but low genetic control. Milk yield had 7% heritability and 30% repeatability. Reproductive traits had low genetic control and were mostly governed by temporary environmental variation. Cows have not changed for their abilities to perform over the last 35 years. Improvement in pedigree and performance recording and culling using first few lactation records may help improve the genetic control of the yield traits.
Page(s):
31-31
DOI:
DOI not available
Published:
Journal: Abstract Book on International Conference on Sustainable Agriculture and Food Security, August 27-31, 2023 , Volume: 0, Issue: 0, Year: 2023
Keywords:
Heritability
,
Sahiwal
,
performance traits
,
Repeatability
,
genetic evaluation