Despite the huge potential of utilising Jersey cattle as diary animals in the tropical countries, the genetic basis of the relationship between milk yield and conformation traits has been scarcely described in the literature especially in West Africa. This trial therefore set a layout to estimate the additive genetic correlations, heritabilities and repeatabilities of milk, udder and body conformation Original Research Article
Nonlinear functions of body weight at different age intervals were used to estimate the growth pattern in New Zealand White and California rabbits. Gompertz and Logistic functions of 3 and 4 parameters were fitted to Age-weight data matrix. Age-weight records of New Zealand White and California rabbits from birth were monitored to 56 days to estimate the average growth curve for Obioma et al.; AJRAF, 5(2): 22-28, 2020; Article no.AJRAF.54482 23 each breed. The weight difference between breeds was consistently in favor of California rabbits as compared to New Zealand White. It was concluded that the Gompertz and logistic models were both parsimonious and adequate in describing the growth patterns of New Zealand White and California rabbits in the tropical conditions of Nigeria. Original Research Article
Inbreeding refers to the mating together of individuals that are more closely related than would be the case if mating was at random. In this study, we investigate inbreeding and its effect on productive traits in NAPRI X broiler chickens. Traits measured were bodyweight and morphometric traits (Neck length, back length, keel length, breast length, thigh length and shank length). Pedigree information which consists of the base generation, 1060 (sire line) and 341 (dam line) birds; in generation 1, there were 565 (sire line selection), 859 (dam line selection), 433 (sire line control), and 592 (dam line control); and in generation 2, there were 595 (sire line selection), 764 (dam line selection), 457 (sire line control), and 654 (dam line control) were used to calculate inbreeding using J.M.P genomics software. Inbreeding significantly (p<0.05) influenced bodyweight and morphometrics in a positive direction (0.020 -1.052) though some of the traits are tending to zero. The trend in inbreeding coefficient was quadratic from the base generation to the second generation with a range of 0.38-0.81 in SLS, 0.41-0.96 in DLS, 0.51-0.80 in SCL and 0.30-1.03 in DCL. It is therefore concluded that there is a gradual build-up of inbreeding in NAPRI X population thus, the use of mate allocation programs is hereby recommended to put a limit or constraint on the level of inbreeding for the future progeny of NAPRI X broiler chickens.
This study was aimed at evaluating on-station performance of indigenous breeds of cattle for milk yield and body conformation traits. The data for the study came from four hundred and fifty (450) genotypes (Bunaji, Friesian X Bunaji and Gudali) of cattle reared on-station from 1995 through 2012. Morphometric variables measured were BW: Body weight (Kg); BL: Body Length (cm); HW: Height at withers (cm); CW: Chest width (cm); HG: Heart Girth (cm); Rumwi: Rump width (cm); TL: Teat Length (cm); RUH: Rear Udder Height (cm); UC: Udder Circumference (cm); TY: Total Yield (Litres). There variations in morphometric traits and milk yield among the genotypes of cows. Bodyweight was significant and highly correlated with total yield in milk for all the genotypes of cows. The accuracy of predicting total yield in milk using morphometric traits was best in FriesianXBunaji (76.24%) followed by Bunaji (70.43%) while Gudali had the least prediction classification (62.06%). It is concluded that performance differences among the indigenous cattle indicate genetic diversity exists among the genotypes.
Genetic parameters for milk and health related traits in low and high milk producing Holstein Friesian cows were estimated using farm collected information on the Jos, Plateau, Nigeria. Milk yield and health related records were extracted from database of the West Africa Milk Company Integrated Dairies Limited. An innovative statistical modeling in this study was the application of repeatability animal models to estimate the genetic parameters. The resulting dataset consisted of 5043 lactations from 608 dams and 39 sires. Genetic correlations were obtained by bivariate analyses of all pair-wise combinations between two traits. In high milk yield Holstein, heritabilities estimate recorded for milk yield (0.43), mastitis (0.26) and lameness (0.33) was high while NIS (0.56), PR (0.22), RR (0.67) and PR (0.22) recorded high estimate in low milk yield Holstein cows. Highest genetic correlation was observed between rectal temperature and vaginal temperature (0.91). Lameness had significant (p<0.05), positive and highest environmental correlation with mastitis (0.95). The heritability estimates of health related traits were low to high; therefore, genetic gain through direct selection alone would be slow, yet still positive and cumulative in the divergently classified Holstein Friesian cows on the Plateau.
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