Comparison of heritability estimates of first lactation fertility traits in Mehsana buffaloes

Abstract

First lactation records of 3068 Mehsana buffaloes sired by 118 sires, under field progeny testing programme distributed in different 149 villages of 14 talukas maintained at Dudhsagar Research and Development Association, Dudhsagar Dairy, Mehsana over a period of 24 years (1989-2012) were used to estimate least squares means and heritability of fertility traits like, first service period (FSP), first calving interval (FCI) and daughter pregnancy rate (DPR). The least squares means of these traits were found to be 189.05±3.34 days, 472.97±2.87 days and 31.08±0.59%, respectively. Non genetic factors such as age at first calving and period of calving were found to have highly significant effect on all the traits, whereas, cluster found to be non-significant for FSP and significant for FCI and DPR. Heritability were estimated for FSP, FCI and DPR as 0.02±0.02, 0.004±0.015 and 0.095±0.031; 0.04±0.03, 0.026±0.024 and 0.089±0.032; and 0.01±0.02, 0.032±0.026 and 0.095±0.034 by LSML, BLUP-SM and BLUP-AM, respectively. BLUP-AM was found to be the best model for heritability estimation based on error variance and BLUP-AM gave highly significant and more accurate results than BLUP-SM and LSML in Mehsana buffaloes.

Investigating non-genetic factors impacting calving interval of Mehsana buffaloes

“…The range of calving interval varied significantly across different groups for each factor (Table 3 and Figure 3). In concordance with the present study, Parmar et al (2017) [7] and Purohit et al (2021) [11] reported a significant effect of the AFC group on the calving interval in Mehsana. The findings of this study underscore the importance of non-genetic factors in influencing the fertility of Mehsana buffaloes.…”

“…It is depicted in Figure 2 that the overall calving interval has shown declining trends in the last few years indicating that female fertility is also taken care of. Similar significant effects of the period of calving were also observed by Purohit et al (2021) [11] , Parmar et al (2017) [7] , and Galsar et al (2016) [5] in the same breed. This variation may be attributed to the selection and breeding over the years, facilitated by progeny testing programs.…”

“…The least squares mean calving interval was observed as 458.83±3.43 days (Table 3). Similar findings of least squares mean for calving interval by Purohit et al (2021) [11] , Galsar et al (2016) [5] , and Patel et al (2019) [15] in Mehsana buffaloes. The variation in calving interval due to changes in the AI workers was notable, and the range spanned from population mean by -170.85 days to 498.23 days (Table 3).…”

“…The non-significant effect of these factors may be due to the known fact that fertility is influenced by many factors and the common reasons are observed throughout the breeding tract. However a significant effect of the cluster was observed by Patel et al (2004) [16] , Parmar et al (2017) [7] , and Purohit et al (2021) [11] on the calving interval but they observed a nonsignificant effect of the cluster on the service period. These studies, include only one union and make clusters based on the socioeconomic condition of the farmers or based on the geographic locations.…”

“…Continuous selection for milk production traits often leads to a negative correlation with fertility traits (Windig et al, 2006) [13] . Many works have been conducted to find the impact of the various non-genetic factors on fertility traits (Purohit et al, 2021, Parmar et al, 2017, Galsar et al, 2016 [11,7,5] , However, there hasn't been any studies undertaken regarding non-genetic aspects like the AI worker or union with such a huge data collection. The one of the key elements to take into account when analyzing fertility characteristics is the AI worker's skill, since it has a significant effect on the number of days open, which changes the calving interval.…”