SELECTION FOR MASTITIS RESISTANCE AND SOMATIC CELL COUNTS TO IMPROVING MILK PRODUCTION IN EGYPTIAN BUFFALOES | ||
| Journal of Animal and Poultry Production | ||
| Article 2, Volume 6, Issue 2, February 2015, Pages 73-84 PDF (217.83 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jappmu.2016.52731 | ||
| Author | ||
| Set El-Habaeib S. Awad* | ||
| Buffaloes Research Department, Animal production Research Institute, Egypt | ||
| Abstract | ||
| Estimates of (Co)variance components and genetic parameters by using MTDFREML program for milk yield (MY), somatic cell count (SCC) and mastitis (MAST ) based on 1901 records of Egyptian buffaloes during the period from 2005 to 2008 at Mehallet Mousa Experimental farms were obtained. The mixed model used in the analysis included the fixed effects of month and year of calving and parity and the random effects of additive direct genetics and residual. Means of MY and SCC, were 2003 kg and 280,000 cells/ml, respectively in the animal without mastitis, 1230 kg and 1,500,000 cells/ml, respectively, in the animal with mastitis. Estimates of direct heritability for MY, SCC and MAST were 0.42, 0.30 and 0.32, respectively. Estimates of genetic correlation among MY with SCC and MAST were -0.26 and -0.45, respectively. Corresponding estimates of phenotypic correlation were -0.15 and -0.30, respectively between the same traits. Single-traits selection for MY resulted in genetic improve of 320.7 kg, -24990 cells/ml, -0.05 of MY, SCC and MAST, respectively. Comparisons between four selection indices in two methods of the relative economic values showed that the selection indices first and second in two methods which incorporated all studied traits and dropped MAST were the best indices. Ranking correlation between two methods was 0.95. Thus, it was recommend to use the method 2 of the relative economic values because its simplicity and ease of calculation. Selection for MY with either SCC and MAST or SCC and MAST together lead to improve the efficiency of response of aggregate genotype compared with selection based on MY only. The selection indices which incorporated all studied traits and constructed by each the two methods of the relative economic values were recommended for use if selection is to the practiced at the end of the first lactation in Egyptian buffaloes. | ||
| Keywords | ||
| genetic parameters; Somatic cell count; mastitis; relative economic value; selection index and Buffaloes | ||
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