Desempenho, saúde e resposta imune de vacas leiteiras e de bezerros suplementados com leveduras e extratos de parede celular de leveduras

• Autor(a) principal: Magalhães, Vanessa Jaime de Almeida
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1530
• topic: Vaca leiteira; Bezerro; Nutrição; Produção de ruminantes; Cultura de levedura; Parede celular de levedura; Saccharomyces cerevisiae; Saúde; Brasil.; Dairy cow; Calf; Nutrition; Production ruminants; Yeast Culture; The yeast cell wall; Saccharomyces cerevisiae; Health; Brazil.; Ciências Agrárias; Zootecnia

: These studies were carried out to evaluate animal performance, health and immune response of dairy cows and calves supplemented with yeast culture of Saccharomyces cerevisiae enriched with cell wall extracts. In the first trial were used 333 early postpartum multiparous Holstein cows, randomly assigned at 1 d in milk (DIM) to receive 14 g/d of a commercial yeast culture (Diamond V XPC; YC = 159 cows) or 14 g/d of the same yeast culture with additional 5 g/d of yeast cell wall extracts (Diamond V XPC Plus; YCCW = 174 cows), top-dressed onto the total mixed ration diet once a day for the first 100 DIM. A subset of 80 cows (40/treatment) was evaluated for cellular and humoral immune responses, and plasma metabolites concentrations. There were no effects of treatments on incidence of postpartum disorders, although more cows receiving YCCW were diagnosed with at least one disease. Treatments did not affect body condition score, plasma metabolites concentrations and humoral response of cows. Phagocytic and killing activities of neutrophils were improved with days postpartum, but treatments did not influence cellular immune response. Cows fed YCCW had lesser yields of milk, 3.5% fat-corrected milk, energy-corrected milk, milk fat and milk true protein, although concentrations of milk fat, milk true protein and net energy for lactation in milk were not influenced by treatments. Conception rate at first postpartum insemination was similar between treatments. These results suggest that the inclusion of yeast cell wall extracts to diets of cows fed yeast culture does not improve health, immune response or lactation performance. In the second trial were used 512 Holstein calves in the first 70 d of age, randomly assigned at 2 ± 1 d of age to yeast culture (YC, 218 females and 37 males) or control (223 females and 34 males). Yeast culture was fed at 2% of the grain DM. All calves received colostrum during the first 24 h, pasteurized milk thereafter until 60 d of age, and grain was fed ad libitum for the first 70 d of age. Calves were housed in individual hutches and grain intake was measured 5 d/wk. Body weight was measured at 5, 30 and 68 d of age, and attitude and fecal consistency were scored daily. Incidence and duration of health disorders and treatments were recorded. Neutrophil phagocytic and killing activities and antibody response to immunization with ovalbumin were measured. Glucose and 3-hydroxybutyrate concentrations were measured in plasma. Grain intake did not differ between treatments and averaged 908 g/d throughout the study. Body weight change as well as glucose and 3-hydroxybutyrate concentrations did not differ between YC and control. Minor effects on neutrophil function were observed, and YC tended to increase the number of phagocytized bacteria and killing of phagocytized bacteria, but did not influence humoral immune response. Attitude scores, related to calves' behavior, were similar between treatments throughout the study. Almost all calves experienced mild diarrhea during the study, but feeding YC improved fecal scores, reduced days with watery feces, incidence of fever and diarrhea, and risk of health disorders. Because of the high incidence of diarrhea, mortality pre-weaning was also high, but YC improved survival of calves by decreasing mortality rate past 13 d of age. Net income at the end of the study was improved by $48/calf with YC. Feeding yeast culture in grain improved health, minimized frequency or health treatments, and reduced morbidity and mortality in dairy calves.