Genetic Influnce of Lactation Length on Reproductive Performance of Egyptian Buffaloes

(Ashraf Abdul Rahman Amin and Fahad Sulaiman free)

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Abstract

Reproductive records of 2289 Egyptian buffaloes were collected from four different farms in Ismailia region. Two data sets were considered for analysis of variance. The 1st data set was the records of lactation length less than 305 days (LP>305) and the 2nd was the records of lactation length more than or equal 305 days (LP>305). These sets were analysed using multi-trait animal model to estimate genetic variations for some reproductive traits in Egyptian buffaloes. Random effects of sire for all studied reproductive traits were significant at P<0.01 and accounted for 11.2 to 24.9% of the total variance. Heritabilities for days open (DO), calving interval (CI) and number of services per conception (NOS) were ranged from 0.22 to 0.29, 0.10 to 0.19 and 0.10 to 0.19, respectively. The highest heritability estimates for age at calving (AC) were 0.37 and 0.44. The highest separate lactation heritability estimates were obtained for DO in the 2nd, 3rd and 4th parities. Phenotypic (rp) correlations between the all studied reproductive traits were higher than the corresponding estimates of genetic (rg) correlations. Estimates of rp and rg for AC with other reproductive traits were negative and relatively high. Estimates of rp and rg generated from data set of LP>305 for AC with DO and CI were lower than that estimated from data set of LP>305. In general, these results of genetic variations and parameters were in moderate values indicating that genetic improvement of the reproductive performance traits in Egyptian buffaloes could be possible. Key Words: Buffaloes, reproductive traits, heritabilities, correlations.
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