Genetic and economic evaluation for the relationship between somatic cell counts, milk yield and milk constituents in Egyptian buffaloes

Abstract

This study aimed to evaluate the effects of somatic cell count (SCC) on buffalo milk and milk components. Data on 3054 lactation records of 506 Egyptian buffalo analyzed. Month and year of calving, parity, herd, stage of lactation and type of milking were used as fixed effects, animal, permanent environmental and residuals as random effects in the analytical model. Means of total milk yield TMY, percentages of fat F%, protein P%, lactose Lact% and total solids TS% and SCC were 2262 kg, 6.8%, 3.9%, 4.8%, 15.5% and 168,232 cell/ml milk, respectively. Milk yield didn’t affected by SCC till 600,000 cells/ml milk. Losses in lactationally milk yield return per buffalo cow due to increase the SCC from 1 million to 4 millions cells/ml milk ranged from 192.96 to 503.24 EGP (EGP=0.156 USD). Heritability estimates for TMY, F%, P%, Lact%, TS% and SCC were 0.34, 0.46, 0.35, 0.48, 0.38 and 0.23, respectively. Genetic correlations between TMY and other traits studied were negative, ranging from -0.04 to -0.46. Positive genetic correlations (0.07 to 0.53) obtained among percentage traits except between F% and P% was negative (-0.61). Breeding values of sires ranged from -687 to 543 kg for TMY, -0.58 to 1.21% for F%, -0.58 to 0.57% for P%, -0.56 to 1.03% for Lact%, -1.21 to 1.61% for TS% and -146,000 to 371,000 cell/ ml for SCC. Results concluded that moderate heritability of SCC and the antagonism relationship between SCC and TMY indicated that could be improve together through selection with improve the environmental conditions.