Published in Scientific Papers. Series D. Animal Science, Vol. LX
Written by Yalçın BOZKURT, Nazire MIKAIL, Ümit Deniz ULUŞAR, Hakan AKTAŞ,Cihan DOGAN
This research aimed to develop prediction models for accurate estimation of performance and body measurements of beef cattle grown in feedlot beef system by using Digital Image Analysis (DIA). For this purpose, 40 animals were used in total and composed of 20 animals of the Brown Swiss breed and 20 animals of the Holstein breed with the age of about 4-5 months at the beginning of the experiment. Animals were fed the same dietary rations throughout the experimental period of 12 months. When the animals reached 500-550 kg bodyweights (BW), they were slaughtered. The digital images of each live animal were taken and the same parameters (digital wither height (DJWH), digital body length (DJBL), digital body depth (DJBD), digital hip width (DJHW), digital hip height (DJHH) and digital pin bone length (DJPL) were also determined from the images, using the data with 1069 observations for each traits. Then, prediction models were developed by DIA. The linear, quadratic and cubic regression models were performed to predict BW for both breeds and since there was no statistically significant differences (P˃0.05) in body measurements between breeds. The data of these breeds were combined and found that DJBL and DJWH would be the best possible traits in predicting BW (R2 =93.9% and 90.7% respectively) among the other measurements. The linear terms of all body measurements by DIA were considered for analysis and they were significant and R2 values for other body measurements DJHW, DJBD, DJHH and DJPL were approximately 78.4, 81.4, 87.7 and 67.7% respectively. It can be concluded that in management situations where BW cannot be measured it can be predicted accurately by measuring DJBL and DJWH alone or both DJBD and even DJHH and different models may be needed to predict BW in different feeding and environmental conditions and breeds.
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