Effects of immunocastration and a ß-adrenergic agonist on retail cuts of feedlot finished Nellore cattle.

Immunocastration (ImC) has been proposed as an animal welfare-friendly alternative to reduce sexual and aggressive behavior and to increase carcass fat deposition with positive effects on meat quality. The ß-adrenergic agonists (ß-AA) are known as repartitioning agents that acts increasing lean tissue deposition. The combined use of these technologies can positively affect meat quality and increase retail cuts yield. Thus, this research was conducted to evaluate the combined effects of ImC and ß-AA (zilpaterol hydrochloride (ZH) and ractopamine hydrochloride (RH)) on retail cuts, bones, and fat trim of feedlot finished Bos indicus (Nellore) cattle. No interaction was observed between sexual condition and diet for any trait. The ImC decreased cold carcass, hindquarter (HQ), forequarter (FQ) and combined brisket, short ribs and flank (BSF) weights. The ImC also showed smaller weights of retail cuts and bones on the HQ and on the FQ than non-castrated (NoC). Fat trim weights did not differ from ImC and NoC. The most of subprimal cuts were heavier in NoC than in ImC. Feeding ß-AA did not affect cold carcass weight; however, animals fed ZH had higher weights of HQ and retail cuts in HQ when compared with RH and control (CO) group, with no differences between RH and CO for both traits. The weights of FQ, BSF, retail cuts in FQ, as well as bones and fat trimmings were not affected by ß-AA. In summary, ImC decreases carcass and retail cut weights, whereas ZH supplementation leads to an improvement in carcass lean tissue and retail cuts.

Porcentagem, perda e digestibilidade in vitro da matéria seca das silagens de 20 genótipos de sorgo / Percentage and loss of dry matter and in vitro dry matter digestiblity of 20 sorghum genotypes silages

O objetivo do experimento foi avaliar a digestibilidade in vitro da matéria seca das silagens de 20 genótipos de sorgo, ensilados aos 104 dias de idade em silos de PVC, com 10cm de diâmetro e 40cm de comprimento. Os silos foram abertos 150 dias após a ensilagem para determinaçäo dos teores e perdas de matéria seca (MS), e da digestibilidade in vitro da matéria seca (DIVMS). As diferenças foram verificadas pelo teste SNK e o delineamento experimental adotado foi o inteiramente ao acaso, com três repetiçöes por tratamento. Os teores de MS das silagens variaram de 23,7 por cento a 31,8 por cento, e todas elas apresentaram pequenas perdas de MS. Näo houve diferença entre as silagens dos vinte genótipos quanto aos teores de MS e perdas de MS, mas houve diferença na DIVMS. Os híbridos C 22 e CMSXS 756 apresentaram os maiores valores (62,8 e 63,0 por cento) e os híbridos 547 e C 11 os menores valores (54,1 e 55,5 por cento de DIVMS, respectivamente