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1.
Trop Anim Health Prod ; 55(3): 200, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37188905

RESUMO

Data on Egyptian buffalo first lactation records (n = 1167) available at Mehalet Mousa Farm (between 2002 and 2015) of the Animal Production Research Institute (APRI), Cairo, Egypt, were used to analyse the genetic parameters of total milk yield (TMY), lactation time (LP), and age at first calving (AFC). Additionally, four selection indices were created by using a single phenotypic standard derivation as relevant economic values. The data were evaluated using multiple-trait derivative-free restricted maximum likelihood (MTDFREML). The estimated heritabilities for TMY, LP, and AFC were 0.22, 0.17, and 0.08 respectively and the phenotypic and genetic correlations between TMY and LP were 0.76 and 0.56, respectively, and between AFC with TMY and LP were nеgаtivеs. Using a selection index that incorporates TMY, LP, and AFC (RIH = 0.68) looks to be optimum for increased genetic gain and a shorter generation interval; as a result, selection should thus be exercised near the end of the first lactation.


Assuntos
Búfalos , Feminino , Animais , Búfalos/genética , Egito
2.
Vet World ; 8(9): 1045-50, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27047196

RESUMO

AIM: The present study was carried out at Institute Rabbit Farm of Southern Regional Research Centre, Mannavanur, Kodaikanal, Tamil Nadu, India having sub-temperate climate with winter temperature during night hours going below 0°C with an objective of finding the influence of different factors such as breed, year, season and parity on different reproductive traits of broiler rabbits in order to come out with the best strategies for improving the productivity. MATERIALS AND METHODS: A total of 1793 records (946 White Giant and 847 Soviet Chinchilla) for weight at mating (WM), weight at kindling (WK), gestation length (GL), litter size at birth (LSB) and litter size at weaning (LSW), litter weight at birth (LWB), and litter weight at weaning (LWW) were collected in the period between 2000 and 2009 and the data was analyzed using general linear model option of SAS 9.2. RESULTS: The overall mean GL, WM, WK, LSB, LSW, LWB, and LWW were 31.68±0.04 days, 3.65±0.01 kg, 3.84±0.01 kg, 6.91±0.08, 5.49±0.09, 387.62±4.07 g, and 4.66±0.07 kg, respectively. The breed has significantly influenced GL, WK, LSW, LWB, and LWW. The LSB, LSW, LWB, and LWW were 7.05±0.11, 5.76±0.13, 399.55±5.88 g, and 4.87±0.10 kg, respectively in White Giant and corresponding values for Soviet Chinchilla were 6.78±0.11, 5.22±0.12, 375.91±5.64 g, and 4.46±0.09 kg, respectively. The year of kindling had significantly affected all the reproductive traits under study and is varying over different years. The parity significantly influenced the WM, WK, and LWW. The LWW increased from first (4.16±0.21 kg) to second parity (4.86±0.19 kg) and remained in the same range from third parity onward. WM was significantly higher in spring season (3.72±0.02) than the animals in rainy (3.59±0.02) and winter season (3.65±0.02). Better reproductive performance in terms of higher LSB, LSW, LWB, and LWW as observed in the present study might be due to conducive environmental conditions prevailing in the region. CONCLUSION: The significant effects of the non-genetic factors like year of kindling on all reproductive traits, season, and parity on some of the traits in rabbit breeds are indications that any future production enhancement strategy must take into consideration the environment by providing additional care, feed supplementation and better shelter management to the rabbits, so that the full genetic potential can be realized.

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