PREDICTION OF LIVEWEIGHT OF HOLSTEIN AND BROWN SWISS CATTLE GROWN IN AN 12 MONTH INTENSIVE BEEF PRODUCTION SYSTEM BY USING REAL-TIME BODY MEASUREMENTS

Bozkurt Yalçin, Varban Stepan, Dogan Cihan

Abstract
   In this study, it was aimed to evaluate the use of some morphometric body measurements to predict liveweight of Holstein and Brown Swiss cattle grown in a 12-month Intensive beef production system. Associations between liveweight (LW) and some body measurements such as heart girth (HG), wither height (WH), body length (BL), body depth (BD), hip width (HW), hip height (HH) and pin bone length (PL) were examined for prediction ability, using the data with 1068 observations for each traits.
   The linear, quadratic and cubic regression models were performed to predict LW for both breeds and since there were no statistically significant differences in body measurements between breeds. The data of these breeds were combined and found that BL and HG would be the best possible traits in predicting LW (R²=95.8% and 95.7% respectively) among the other measurements. All type of regressions showed that addition of quadratic and cubic terms contributed little benefit in predicting LW. Therefore, all linear terms of all body measurements were considered for analysis and they were significant and R² values for other body measurements WH, HW, BD, HH and PL were approximately 93.2, 79.9, 87.1, 90.9 and 79.2% respectively.
   It can be concluded that in management situations where LW cannot be measured it can be predicted accurately by measuring BL and HG alone or both HG and even WH and different models may be needed to predict LW in different feeding and environmental conditions and breeds.

Key words: Prediction, Liveweight, Body measurements, Brown Swiss and Holstein cattle, Feedlot