Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2004
Publication Date: 7/20/2004
Citation: Villaguiran, M., Nuti, L.C., Gipson, T.A., Goetsch, A.L., Blackburn, H.D. 2004. Evaluation of predictions of body weight and feed intake by growing crossbred boer goats with a goat simulation model. Journal of Animal Science. 82(Suppl 1):357. Interpretive Summary: Calculations for maintenance energy requirements were changed in a goat simulation model. The modified model was parameterized to simulate the growth of post-weaned crossbred goats when fed ad libitum amounts of a fixed diet quality. All four of the genotypes evaluated were 50% Boer goat. Actual body weight and feed intake were measured at four different times during the test. Compared to regressed observed data there was close agreement between actual and simulated crossbred Boer growth and feed intake. Agreement between simulated and actual growth curves could be increased with improved estimates of mature weight.
Technical Abstract: The Texas A&M Goat Simulation Model, with modifications such as of maintenance energy requirements, is being used in a collaborative project involving institutions primarily in the southern US. However, the model was developed before Boer goats and their crossbreds became prevalent in the US. Therefore, this study was conducted to evaluate model predictions of body weight (BW) and cumulative feed intake (air-dry; FI) of growing crossbred Boer goats. Data for model evaluation were derived from Prairie View A&M University. There were four genotypes of wethers: Boer x Nubian (n=10, age=131.8 to 245.8d, and BW=32.14 to 48.27kg), Spanish x Boer (n=8, age=111.4 to 231.4d, and BW=13.73 to 38.27kg), Boer x Alpine (n=10, age=132.4 to 245.4kg, and BW=21.86 to 41.77kg), and Boer x Nubian x Myotonic (n=10, age=115.0 to 235.1d, and BW=24.00 to 43.05kg). Diet composition was 16% CP and 75% TDN (air-dry basis). Body weight and FI were determined at four times within the growing periods. Model evaluation with pooled data was conducted by regressing observed means of BW (BWO) and FI (FIO) against predicted values (BWP and FIP, respectively). The equation for BW was BWO=3.73 (SE=3.489) + (0.935 (SE=0.0970) x BWP) (R squared=0.86), and that for FI was FIO = -6.84 (SE =8.062) + (1.012 (SE=0.0665) x FIP) (R squared = 0.94). In conclusion, the model explained considerable variation in BW and FI of growing crossbred Boer goats and provided unbiased predictions. Increased prediction accuracy should result from improved inputs, such as mature BW. Key words: Goats, Simulation Model