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Heat-No-Service: Reproductive lifetime performance of gilts inseminated on first versus second observed estrus in commercial piglet producing herds
77-80Views:261Heat No Service (HNS) is an increasing managerial decision made in commercial piglet producing herds. Performance of gilts has been shown to be influenced by initial decisions made on them at their introduction in the breeding herds. Lifetime Reproductive performance comprising of parity total born piglets and lifetime total born piglets of gilts initially bred on first observed estrus (0HNS) was compared with that of gilts bred on second observed estrus (1HNS). Stored data from Porcitec database consisted of 2.072 gilts bred on first observed estrus (0HNS) and 2.453 gilts bred on second observed estrus (1HNS) totaling to 4.525 gilts. Data was statistically analyzed using the GLM procedure of IBM SPSS version 25. The results showed a significance difference (p<0.001) in lifetime total born performance of gilts bred at 0HNS (mean 93.9) and 1HNS (mean 95.7). There was also a significant difference (p<0.001) of total born piglets in parity 1, 5 and 6 in the 2 groups. There was an observed increased parity total born and lifetime total born when first time insemination of gilts was delayed to second estrus. The findings in this study favor the 1HNS breeding with an overall increased lifetime total born. Gilts inseminated at 1HNS produce 1.57 more pigs for lifetime as compared with those inseminated at 0HNS when observation is made up to P6. Producers in piglet producing herds could re examine their decisions for increased productivity by promoting many gilts into 1HNS but still maintaining the balance between breed targets and production schedules to remain competitive and profitable in the current global swine industry.
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Estimation of direct and maternal genetic parameters for weaning weight in Hungarian Simmental cattle
17-22Views:130The aim of the current research was to estimate variance components and genetic parameters of weaning weight in Hungarian Simmental cattle. Weaning weight records were obtained from the Association of Hungarian Simmental Breeders. The dataset comprised of 44,278 animals born from 1975 to 2020. The data was analyzed using the restricted maximum likelihood methodology of the Wombat software. We fitted a total of six models to the weaning weight data of Hungarian Simmental cattle. Models ranged from a simple model with animals as the only random effect to a model that had maternal environmental effects as additional random effects as well as direct maternal genetic covariance. Fixed effects in the model comprised of herd, birth year, calving order and sex. Likelihood ratio test was used to determine the best fit model for the data. Results indicated that allowing for direct-maternal genetic covariance increases the direct and maternal effect dramatically. The best fit model had direct and maternal genetic effects as the only random effect with non-zero direct-maternal genetic correlation. Direct heritability, maternal heritability and direct maternal correlation of the best fit model was 0.57, 0.16 and -0.78 respectively. The result indicates that problem of (co-)sampling variation occurs when attempting to partition additive genetic variance into direct and maternal components.
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Optimal age of breeding gilts and its impact on lifetime performance
15-20Views:493Age at first breeding and lifetime reproductive performance was analyzed on 17,558 F1 Landrace x Yorkshire gilts from 9 piglet producing herds of Midwest, United States entered in herds between 1st Jan 2014 and 31st July 2016. At the time of data collection Dec 2018, 15% of the sows were still active in the herds hence excluded from the analysis. Individual gilt data included date of birth, age in days at first mating, piglet total born by parity, lifetime piglet total born and reason for culling. Quality data checks were done before analysis to eliminate all outlier values together with sows that had no entry information for any listed category. The total database of the sows was classified into 6 classes according to age at the first mating in days 170-190(n=754), 191-211(n=4683), 212-232(n=7123), 233-253(n=3385), 254-274(n=1002) and 275-369 (n=611). Piglet total born obtained from each sow during the lifetime production was significantly (P < 0.05) greater for gilts bred between 233-253 days of age at first mating. Gilts that were bred at <233 days appeared to have a higher risk of removal by farrowing productivity as compared to the other groups. However, the results show that the risk of being culled due to health problems and conformation issues increases as the age at first mating is delayed. Overall reproductive failure appears to be the most economical culling reason across all age groups. There is a need to evaluate the best management decisions for gilt initiation in a herd to maximize her lifetime performance. The results indicate that gilts mated for the first time at the right age, 233–253 days, are more productive, both in lifetime total born and have a minimal risk of culling due to farrowing productivity.