RESUMO Pouco é conhecido a respeito da resposta morfológica do omaso de vacas leiteiras que consomem dieta alta em energia no pré-parto. Este estudo visou investigar se a dieta de transição com alto teor de grãos induz mudanças na morfologia do omaso. Seis semanas antes do parto esperado, quatro vacas Holandesas foram alimentadas com uma dieta de padronização e a partir de quatro semanas antes foram alimentadas com dieta com alto (ATG) ou baixo (BTG) teor de grãos. Após o parto, todas as vacas foram alimentadas com dieta lactacional de alta energia. As vacas que foram alimentadas com ATG antes do parto tiveram maior ingestão de matéria seca e de nutrientes do que as vacas que foram alimentadas com BTG. O índice mitótico (IM) do epitélio do omaso foi mais alto do que o do rúmen, mas aparentemente a resposta ao estímulo da dieta foi mais lenta. As papilas do omaso nas vacas que foram alimentadas com ATG foram mais altas uma semana antes e duas semanas após o parto. As vacas que foram alimentadas com ATG tiveram o epitélio do omaso menos espesso devido à menor espessura das camadas não queratinizadas. Concluímos que a mucosa do omaso de vacas leiteiras responde ao estímulo da dieta com ATG fornecida antes do parto, indicado pela maior altura das papilas e menor espessura do epitélio. Parece que o IM responde mais lentamente, porém mais fortemente ao estímulo da dieta no omaso do que no rúmen.

ABSTRACT Little is known about the morphological response of the omasum in dairy cows that consume a high-energy diet pre-partum. The aim of this study was to investigate whether a transitional diet with high grain content is able to induce changes in omasum morphology. Six weeks before the expected calving, four Holstein cows were fed a standardization diet, and four weeks before delivery, the cows were fed a diet with high grain content (HGC) or low (LGC) grain content. After calving, all of the cows were fed a high energy lactation diet. The cows that were fed the HGC diet pre-partum had higher dry matter and nutrient intake than the cows that were fed the LGC diet. The mitotic index of the omasum epithelium was higher than the mitotic index in the rumen, but apparently the response to the diet stimuli was slower. In the cows that were fed the HGC diet, the omasum papillae were taller one week before parturition and two weeks post-partum. Cows that were fed the HGC diet had a thinner epithelium due to thinner non-keratinized layers of the omasum epithelium. We conclude that the omasum mucosa of dairy cows responds to the stimuli of a pre-partum HGC diet, which was indicated by the greater height of the omasum papillae and by the reduced thickness of the omasum epithelium. It seems that the mitotic index responds a little more slowly, but the response to the diet stimuli is stronger in the omasum epithelium than in the rumen.

Feed processing can affect rumen development in new born calves, and potentially define animal performance. Two feed management systems, extruded starter (Ruter) with possible early weaning and ground starter (control), were evaluated in thirty-two Holstein calves (16 females and 16 males). Animals were randomly assigned to the treatments using a randomized block design with birth weight as a covariate. They were weaned when starter intake reached 800 g for two consecutive days. Twenty-one days after the weaning, males were slaughtered and the stomach compartments were isolated. Rumen and omasum fragments were processed for morphological evaluation. Animal performance, clinical condition and stomach compartment weight did not differ between the treatments (P> 0.05), despite weaning weight of animals receiving extruded starter being 5.68% higher than the control animals. Extruded starter stimulated cell proliferation of the ruminal epithelium (P <0.05), but did not affect the dimensions of the papillary rumen and omasum mitotic index (MI). The Ruter feeding system was potentially beneficial for weight gain and morphofunctional rumen development in lactating animals; however, this treatment did not allow early weaning as proposed by the feeding system.

Avaliou-se o efeito de diferentes formas de processamento da casca de mandioca na alimentação sobre o desempenho e as características de carcaça, a morfologia ruminal e a viabilidade técnico-econômica da criação de ovinos. Foram utilizados 20 ovinos machos da raça Santa Inês, desmamados, com peso inicial de 19,02±0,21 kg e 90 dias de vida. O delineamento experimental foi inteiramente casualizado com cinco repetições por dieta. Durante o período experimental de 84 dias, incluindo 14 dias de adaptação, os animais foram mantidos em sistema de semiconfinamento em pastagem de Brachiaria decumbens. Foram avaliadas quatro formas de processamento da casca de mandioca: desidratada triturada em peneira de 12 ou de 5 mm; úmida triturada e ensilada; e úmida triturada e hidrolisada com 0,5% de cal virgem (óxido de cálcio - CaO). O peso médio ao abate foi 30,72±1,46 kg. Não houve influência do tipo de processamento da casca sobre as características de desempenho analisadas, as características quantitativas de carcaça e a morfologia ruminal, sendo influenciado somente o rendimento de paleta. A casca de mandioca hidrolisada foi a que promoveu melhor eficiência econômica. Os tipos de processamento da casca de mandioca não alteram o desempenho, as características de carcaça, os rendimentos de corte e a morfologia ruminal dos ovinos Santa Inês.

The objective of this trial was to evaluate the effect of different forms of processing of cassava peel in sheep feeding on performance traits, carcass, morphology and rumen and economic technical feasibility. Twenty non-castrated male Santa Ines lambs of 19.02±0.21 kg of initial body weight and 90 days of age at the beginning of the study were used in this trial. The design was completely randomized design with five replications per treatment. During the experimental period of 84 days, including 14 days of adaptation, animals were kept in semi-confinement on Brachiaria decumbens. Four forms of cassava peel processing were evaluated: dried cassava peel ground through 12-mm sieve; dried cassava peel ground through 5-mm sieve; ground and ensiled cassava peel, and wet, ground hydrolyzed with 0.5% lime (calcium oxide - CaO). The average weight at slaughter was 30.72±1.46 kg. There was no influence of the type of processing on the performance variables analyzed, quantitative carcass characteristics or ruminal morphology; only the values of width and leg yield palette were influenced. Hydrolyzed cassava peel showed the best economic efficiency between treatments. The different methods of processing cassava peel do not affect performance, carcass characteristics, yield cuts or rumen morphology of Santa Ines sheep.