Sustainable Management of Voluntary Culling Risk in Primiparous Zaraibi Goats in Egypt: Roles of Season and Reproductive and Milk Production-Related Traits

SIMPLE SUMMARY: Sustainable production of livestock farms mainly depends on efficient management and precise decisions. One of the most important managemental decisions that play a great role in the continuation of production and profitability is culling. Excluding non-efficient animals from the production cycle is a very critical decision as a wrong and aggressive culling decision may cause a certain loss in farm profitability by increasing costs of replacement. Identifying factors that affect culling risk can aid breeders in creating suitable interventions to maintain productive animals. In this study, logistic regression analysis was used to study the pattern of culling risk factors in primiparous Nubian goats. The effect of ten independent factors including season, reproductive traits, and milk production traits on the percentage of voluntary culling risk was studied. The presented outcomes clearly indicated that birth weight, total litter size at birth, litter size at weaning, number of kids dead, total milk yield, average daily milk yield, lactation period, and age at first kidding had significant effects on culling risk, while both the birth season of the dam and kidding season did not exhibit significant effects on culling risk. In practice, monitoring of traits that indicate milk imbalance and older age at first kidding could promote identifying goats at high risk of being culled. ABSTRACT: The purpose of the current study is to reconnoiter the relationships between season (birth season, BS, and kidding season, KS), reproductive traits (birth weight, BW; total litter size at birth, TLS; litter size at weaning, LSW; the number of kids dead, NKD, and; age at first kidding, AFK) and milk production (total milk yield, TMY; average daily milk yield, DMY, and; lactation period, LP), with voluntary culling risk in primiparous Zaraibi goats. Records of 637 primiparous does were collected during the period 2008–2014 from a herd of Zaraibi goats raised at the El-Serw Experimental Station, which belongs to the Animal Production Research Institute. Our data revealed that the voluntary and involuntary culling was 89.12% and 10.88%, respectively. Moreover, the BW, TLS, LSW, NKD, TMY, DMY, LP, AFK had significant effects on culling risk (p < 0.05), while both the season of birth and kidding did not exhibit significant effects on culling risk. The thinnest goats at birth were more likely to be culled compared to those with body energy reserves. Does with weaned twins and triplets kids were 9.5% (OR = 0.905) and 43% (OR = 0.570), respectively less likely to be culled compared to those with singles. Likewise, does with dead twins and triplets kids had 2.566 and 2.138 times, respectively higher odds of culling compared to those with singles. Interestingly, culling risk decreased with 74.6% (OR = 0.254), 79.8% (OR = 0.202), and 75.6% (OR = 0.244) in does with TMY, LP, and DMY more than 230 kg, 260 days, and 0.800 kg, respectively compared to their counterparts (less than 185 kg, 240 day, and 0.500 kg, respectively). Moreover, culling risk increased steadily along with increasing AFK; the animals with an AFK of more than 24 months had 2.974 times higher odds of culling compared to those with an AFK that varied between 22 and 24 months. It could be concluded that the most critical issues for higher culling probability in dairy goats were attributed to the lower TMY (<185 kg) and DMY (<0.5 kg), and shorter LP (<245 days), as well as older age at first kidding (>2 years). This putative information could be used as indicators to enhance the management and genetic approaches in dairy goats and thus sustain productivity with low cost.