Weight at maturity of water buffaloes determined by body chemical composition

Abstract This study determined the weight at maturity (WM) of water buffaloes of three genetic groups (GG:Jafarabadi, Mediterranean, and Murrah) slaughtered at different weights (420, 480, and 540 kg). One-hundred-fifty-three non-castrated male (means of initial body weight and age of 314 ±117 kg and 390 ±32 days, respectively) from two similar experiments were used. The animals were slaughtered and the non-carcass components of each animal were weighed to obtain the empty body weight (EBW). The left half-carcasses were dissected into muscle, fat, and bone. Each tissue of each animal was ground separately and subsequently aliquoted for further analyses. The determination of moisture, crude protein (CP), ether extract (EE), and ash was performed by the classical method. Nonlinear regressions were used to predict the body composition of water, CP and ash. An exponential model was used to adjust the data for the content of the EE. Random coefficient models were used to identify fixed and random effects using the NLMIXED procedure in SAS. The genetic group was tested as fixed effect and year as a random effect. Body CP was determined based on CP fat-free dry matter (CPFFDM). The equations predicted the body composition of CP, EE, water and ash, and the results were expressed as a percentage of the EBW. WM was estimated when the non-significant increase in CPFFDM was no longer observed. There was effect of GG for WM model (P = 0.037), thus the WM was determined for each GG. The models suggest that Jafarabadi reach maturity at ~505.93kg of EBW [WMCPFFDM=79.279×(1–1.17×e-0.010×EBW)]; Mediterranean reach maturity at ~494.40kg of EBW [WMCPFFDM=79.186×(1–1.18×e-0.011×EBW)]; Murrah reach maturity at ~423.79kg of EBW [WMCPFFDM=78.793×(1–11.99×e-0.018×EBW)]. In conclusion, the WM of water buffaloes is dependent on the GG reaching 505.93, 494.90, 423.79 kg of EBW for the Jafarabadi, Mediterranean, and Murrah genetic groups, respectively.