Analysis of culling probability in dairy buffalo using survival models

Abstract

In order to contribute to the genetic breeding programs of buffaloes, this study aimed to determine the influence of environmental effects on the stayability (ST) of dairy female Murrah buffalo in the herd. Data from 1016 buffaloes were used. ST was defined as the ability of the female to remain in the herd for 1, 2, 3, 4, 5 or 6 years after the first calving. Environmental effects were studied by survival analysis, adjusted to the fixed effects of farm, year and season of birth, class of first-lactation milk yield and age at first calving. The data were analyzed using the LIFEREG procedure of the SAS program that fits parametric models to failure time data (culling or ST 5 0), and estimates parameters by maximum likelihood estimation. Breeding farm, year of birth and first-lactation milk yield significantly influenced ( P , 0.0001) the ST to the specific ages (1 to 6 years after the first calving). Buffaloes that were older at first calving presented higher probabilities of being culled 1 year after the first calving, without any effect on culling at older ages. Buffaloes with a higher milk yield at first calving presented a lower culling probability and remained for a longer period of time in the herd. The effects of breeding farm, year of birth and first-lactation milk yield should be included in models used for the analysis of ST in buffaloes.

Genetic Trend for Milk Production and Longevity Traits of Egyptian Buffalo

“…Khattab et al (2017) proved that the year of calving had a significant effect on longevity traits. Moreever, the significant effect of the year of first calving on longevity traits reported by (Bashir et al ,2007;Galeazzi et al ,2010 andJakhar et al , 2016), that what agreement with the result reported in this study. And the significant effect of the year on longevity traits may be due to different nutrition and management system at different periods and phenotypic trend (Khattab et al, 2017).…”

“…The longevity traits results of the study were agreement with that recorded by Bashir et al (2007) who found significant effect of herd on longevity traits in Nili-Ravi buffalo. The same results reported by Galeazzi et al (2010) in Murra buffalo in Brazil. In addition to, season of calving effect significantly one productive live and insignificant effect on life time milk yield and herd life (Bashir et al, 2007) that agreement with the results of the present study.…”

Selection strategies for dairy buffaloes: economic and genetic consequences

“…Brazilian buffalo production must increase its efficiency and productivity to attend market demands. Recent studies have shown that buffaloes have significant genetic potential for both production and reproductive traits (Aspilcueta-Borquis et al 2010a,b,c;Galeazzi et al 2010;Seno et al 2010), and Seno et al (2007) found that the high fat and protein percentages in buffalo milk provide high economic returns to Brazilian farmers that produce their own mozzarella cheese. Investments in AI, the adoption of systematic milk-recording programs and genetic evaluations are all tools that can improve the current economic situation.…”

“…Recent studies have shown that buffaloes have significant genetic potential for both production and reproductive traits (Aspilcueta‐Borquis et al. 2010a,b,c; Galeazzi et al. 2010; Seno et al.…”

A Comparison Between Sire and Animal Model for Lifetime Production Traits in Egyptian Buffaloes.

“…A high female lifetime production is desirable because it reduces the cost of rearing heifers moreover it allows a greater proportion of culling decisions to depend on production, instead of involuntary culling. Dairy females have been chosen intensively for productivity traits while lifetime production within the herd has decreased (Galeazzi et al 2010 a). In other words, satiability is an important economic trait that is analyzed in some programs of breeding.…”