Comparative Study On Feeding Behaviour And Fiber Digestibility Of Three Forage Diets In Sheep And Cashmere Goats

The objectives of this thesis were to comparatively study the feeding behavior and digestibility of dietary fiber fractions in sheep and cashmere goats, so as to optimize feeding and management systems of sheep and cashmere goats under stall-feeding conditions. Feeding motivational states, rumen microflora, the activity of cellulase and passage rate of digesta were also described. The study comprised two parts:Part 1. Study on feeding behaviour of sheep and cashmere goatsThree Mongolian and Han crossbreed wether sheep and three Inner Mongolia white wether cashmere goats (healthy; aged 1.5 to 2 years; weight about 35kg) were used. Comparative studies in behaviour pattern, climbing feeding behaviour and food selection between mixed forages or pellets differing in protein content were carried out. In addition, operant conditioning technology was used to investigated food selection motivational states. The results showed that time spending in feeding and rumination of sheep tended to be longer than that of cashmere goats (P>0.05). Time spending in climbing feeding of cashmere goats was significantly longer than that of sheep (P<0.01), and climbing feeding behaviour was more obviously in goats than in sheep. When two pellets differing in protein content were offered, both of the two species chose high proportion of high protein concentration pellet (HPP). The mean value of the ratio of HPP intake to total feed intake during the five weeks experimental periods was significantly higher in cashmere goats than in sheep (P<0.01). With the experiment progressing, intake of HPP as a proportion to total feed intake gradually declined in sheep, however, the proportion of cashmere goats maintained at steadily and high levels during the whole experimental periods. The results also indicated both sheep and goats had the capacity to satisfy nutrients demand, and to maintain stable rumen environment through food selection. The results of experiment by operant method suggested that both of the two species were willing to do a certain amount of work for their food selection. In order to maintain food selection, cashmere goats would like to do more work than that of sheep, and their selection motivational states were also stronger than that of sheep.Part 2. Comparative study of dietary fiber digestibility in sheep and cashmere goatsThree Mongolian and Han crossbreed wether sheep and three Inner Mongolia white wether cashmere goats (healthy; aged 1.5 to 2 years; weight about 35kg) were used. All the animals were fitted with permanent ruminal and proximal duodenum cannulas. The nylon bag methods in sacco was used to comparatively study wheat straw degradation dynamics in the rumen of sheep and cashmere goats. At the same time, rumen environment and fermentation parameters, dietary fiber fractions apparent digestibility in whole digestive tract, rumen microflora and cellulase activity, as well as passage rate of digesta under three pellets diets (â… : Grass hay pellet,â…¡: Cornstalk pellet,â…¢: Wheat straw pellet) were studied using self-contrast designs. The results showed that effective degradation of wheat straw DM, NDF and ADF in the rumen were significantly higher in sheep than in cashmere goats (P<0.05). Rumen pH value was higher in cashmere goats than in sheep, and the difference between species reached statistical significance for dietâ…¡(P<0.05). Interaction effects were observed between species and diets in NH3-N concentration, which was higher in sheep than in cashmere goats for dietâ… , but the reverse result was observed for dietâ…¢(P<0.01). Rumen BCP concentration of cashmere goats tended to be higher than of sheep (P>0.05). However, TVFA concentration was higher in sheep than in cashmere goats, and the difference was significant for dietâ…¢(P<0.01). The same results were observed for acetic and propionic acid concentration, the ration of acetic acid concentration to propionic acid concentration tended to be higher in sheep than in goats (P>0.05). Sheep showed higher voluntary feed intake, which was 1.21 times as that of cashmere goats (P<0.01). When high quality diet (dietâ… ) was offered, NDF, ADF and CEL apparent digestibility were similar in the two species, and OM apparent digestibility of cashmere goats was slightly higher than that of sheep (P>0.05). However, when dietary quality was low (dietâ…¡,â…¢), sheep showed higher fiber apparent digestibility as compared with cashmere goats, and ADF, CEL digestibility for dietâ…¡, as well as ADF digestibility for dietâ…¢, were significantly higher in sheep than in cashmere goats (P<0.05). The results of experiment in rumen microflora indicated that anaerobic fungi population were significantly greater in sheep than in cashmere goats for dietâ… (P<0.05), there were the same tendency for the other diets. Protozoa numbers of sheep were significantly greater than that of goats for dietâ… andâ…¡(P<0.01), however, the population of total bacteria and cellulolytic bacteria were significantly greater in cashmere goats than in sheep for all three group diets (P<0.05). FPA of rumen solid fractions was significantly higher in sheep than in cashmere goats for dietâ… ,â…¢(P<0.01), and dietâ…¡(P<0.05). The activity of CMCase and xylanase tended to be higher in sheep than in cashmere goats (P>0.05). In addition, the results suggested ruminal solid fraction passage rate was faster in cashmere goats than in sheep for dietâ…  andâ…¡(P<0.05). Ruminal liquid dilute rate was faster in cashmere goats than in sheep, and the difference reached statistical significance for dietâ… (P<0.01). The rumen volume of sheep was significantly larger than that of cashmere goats (P<0.05).