Browsing by Author "Musa-Azara, I.S"

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    DETERMINATION OF PREDICTION EQUATIONS TO ESTIMATE BODY CONDITION SCORE FROM BODY SIZE AND TESTICULAR TRAITS OF YANKASA RAMS
    (Department of Animal Science, Nasarawa State University, Keffi., 2013-09-15) Yakubu, Abdulmojeed; Musa-Azara, I.S; Fakuade, O.F; Faith, E.A; Ogunwole, O.A
    The study was aimed to develop prediction models using stepwise multiple linear regression analysis for estimating the body condition score (BCS) from the body weight (BW), testicular length (TL), testicular diameter (TD) and scrotal circumference (SC) of indigenous Yankasa rams. Data were obtained from 120 randomly selected rams with approximately two and half years of age, from different extensively managed herds in Nasarawa State, Nigeria. Although pairwise phenotypic correlations indicated strong association (P<0.01) among the measured variables, there was collinearity problem between BW and SC as revealed by the variance inflation factors (VIF) and tolerance valves (T). The VIT was higher than 10 (VIF = 19.45 and 16.65 for BW and SC, respectively). The Twas smaller than 0.1 (T = 0.05 and 0.06 in BW and SC, respectively). BW was retained among the collinear variables, and was singly accounted for 83.7% of the variation in BCS. However, a slight improvement was obtained from the prediction of BCS from BW and TL [coefficient of determination (R2), adjusted R2 and root mean squares error (RMSE) were 85.3%, 85.1% and 0.305, respectively]. The prediction of the BCS of Yankasa rams from BW and testicular measurements could therefore be a potential tool for sustainable production and improvement of small ruminants in Nigeria.
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    Evaluation of Three Mathematical Functions to Describe the Relationship Between Body Weight, Body Condition and Testicular Dimensions in Yankasa Sheep
    (Department of Animal Science, Nasarawa State University, Keffi., 2013-12-15) Musa-Azara, I.S; Yakubu, Abdulmojeed
    Body size and testicularmeasurements have been found to be important parameters utilized in breeding soundness evaluation. The present study therefore, aimed at determining the relationship between body weight (BW), body condition score (BCS), testicular length (TL), testicular diameter (TD) and scrotal circumference (SC) in 120 extensively reared Yankasa rams (approximately 30 months old) using linear, quadratic and cubic predictive models. Coefficient of determination (R2), Adjusted R2, the estimate of Mallows’ Cp, RMSE (Root mean squares error) and the parsimony principle (p=number of parameters) were used to compare the efficiency of the differentmodels. Strong Pearson’s correlation coefficients (r = 0.83-0.94; P<0.01) were found between BW, TL, TD and SC. Spearman correlations between BCS and other variables were also highly significant (r = 0.78-0.85; P<0.01). SC was the sole variable of utmost importance in estimating BW, which was best predicted using the cubic model. However, the optimal model for BW prediction comprised TD, SC and BCS with p, R2, Adjusted R2, RMSE and Cp values of 4, 0.948, 0.946, 1.673 and 4.85, respectively. The present findings could be exploited in husbandry and selection of breeding stock for sustainable sheep production especially within the resource-poor farming system under tropical and subtropical conditions.