Association analyses: The association of Pit-1 gene polymorphism with MY305, TDMY and milk components in the population was analyzed (Table 4).
But, take account of P values, the genotypes at Pit-1 polymorphisms (HinfI_451 bp) did not show a significant association with the MY305, TDMY and milk components (P greater than 0.
Table 4: The association of Pit-1 gene polymorphism with MY305, TDMY and milk components.
Aiming to obtain greater data consistency, only data from cows that had their first TDMY record up to 45 days after calving or with consecutive interval between TDMY exceeding 45 days were included; cows having at least four TDMY records per lactation collected between 5 and 305 days-in-milk (DIM); and those cows with both parents known.
After data editing, remained 32,817 TDMY records from 4,056 first calving cows, belonging to six genetic groups (1/4H to 3/4G, 3/8H to 5/8G, 1/2H to 1/2G, 5/8H to 3/8G, 3/4H to 1/4G, 7/8H to 1/8G) as their racial composition of Holstein (H)-Gir (G), daughters of 276 sires collected from 118 herds between 2000 and 2011.
Distribution of the number of TDMY records and the corresponding daily milk yield over the lactation are showed in Figure 2.
When assessing the estimates of (co)variance additive genetic and permanent environmental components between the random regression coefficients it revealed that the variances of the first two coefficients of additive genetic effects were greater than the third one (Table 4), indicating that they have contributed significantly in the variation description of the TDMY records.