Effect Of Pasteurized And Non-pasteurized Colostrum On Growth Performance And Development Of Gastrointestinal Tract Of Calves

This paper was based on the problem that how to scientifically used colostrum to feed calves,and was conducted to investigate the effect of pasteurized and non pasteurized colostrum on growth performance and development of gastrointestinal tract of calves. That would provide the theory reference for the scientific cultivation of calves, optimize the use of colostrum and improve the economic benefits of farms.Experiment 1: The Effects of pasteurization on component and bacteria count of colostrum were studied. The pasteurized colostrum processed at 60 ? for 60 min. The pasteurized and non-pasteurized colostrum were respectively collected and determined the component and bacteria count of colostrum. The results indicate that there were no significant effects of pasteurization on milk protein, milk fat, lactose, milk urea nitrogen content of colostrum (p > 0.05),But, the total bacterial count and escherichia coli in colostrum were all obviously decreased after pasteurizing (p< 0.01). Thus it can be seen that there was no significant effects of pasteurization on nutrients of colostrum, however, the bacterial counts in colostrum was obviously decreased after pasteurizing.Experiment 2:The effects of pasteurized and non-pasteurized colostrum on growth performance of calves were studied. Twenty healthy newborn Holstein calves were randomly divided into two groups (n=10) according to similar body weights and ages, and were distributed individually in 20 pens. Calves were either fed non- pasteurized colostrum (NPC) or pasteurized colostrum (PC). The experiment was carried out over 90 days. Measurements of the body weight,body length and metatarsal circumference of the calves were recorded every 30 days during the trial, and The daily gain and body size index were calculated, while the dietary intake and diarrhea frequency were measured daily. Total numbers of cases of diarrhea were calculated as percentage to find the incidence rate of calf diarrhea. The results indicate that the calves in PC treatment had higher (P< 0.05) metatarsal circumference and tended to have longer (P = 0.09) body length at 90 days of age. There were no significant effects of pasteurized and non-pasteurized colostrum on body weight, chest circumference, abdominal circumference and body height of calves in 90 days of age (p > 0.05). Likewise, there were no significant effects of pasteurized and non-pasteurized colostrum on chest circumference index, abdominal circumference index, metatarsal circumference index, body length index and body body index of calves in 90 days of age (p >0.05). The daily feed intake and the daily gain of group PC were increased by 1.74% and 2.33%than NPC (P > 0.05), and the diarrhea rate and the feed/gain ratio was decreased by 0.67% and 2.46% (P > 0.05). Thus it can be seen that the pasteurized colostrum has a positive impact on growth performance for calves in 90 days of age, and reducing the diarrhea rate and feeding cost of calves in a certain degree.Experiment 3:The effects of pasteurized and non-pasteurized colostrum on development of gastrointestinal tract of calves were studied. The selection and management of experimental animals were the same as experiment 2. Five calves from each group were randomly selected and slaughtered at 90 days of age. The pH value of rumen, the weight of the stomach complex(including all 4 stomach compartments) as well as the weight and length of the small intestine were measured, and then calculate the organ indexes. While, the dorsal sac and ventral sac of the rumen and the small intestine were taken to make paraffin sections in routine,and then observed its morphological changes. The results indicate that the colostrum type had no effect on the pH value of rumen, the volume and the weight of complex stomach, the weight and the length of the small intestine, the ratio of Small intestine weight to body weight (p > 0.05). But, the reduction of the ratio of complex stomach weight to body weight in PC calves warrants further studies. There were no significant effects of pasteurized and non-pasteurized colostrum on papilla height and muscular layer thickness of rumen dorsal sac and rumen ventral sac of calves in 90 days of age (p > 0.05). However, The papilla width of rumen dorsal sac (1.25 vs. 1.02 mm) and rumen ventral sac (1.18 vs. 0.96 mm) in PC group were significantly improved than in NPC group(p < 0.05). Feeding the pasteurized colostrum had no any differences on the crypt depth and muscular layer thickness of duodenum, but the villus height of duodenum (0.55 vs. 0.43 mm) were significantly improved (p < 0.01). The calves in PC treatment had higher (p < 0.01) villus height of jejunum and smaller (p < 0.05) crypt depth of jejunum and tended to have thicker (p = 0.09)muscular layer thickness of jejunum at 90 days of age. There were no significant difference in the villus height, crypt depth and muscular layer thickness of ileum between the control and experiment group (p > 0.05). Thus it can be seen that the pasteurized colostrum has a positive impact on development of gastrointestinal tract for calves in 90 days of age, mainly in the morphological development of small intestine, but the reduction of the ratio of complex stomach weight to body weight in PC calves warrants further studies.The experiment results showed that there was no significant effects of pasteurization on nutrients of colostrum, however, the bacterial counts in colostrum was obviously decreased after pasteurizing; The pasteurized colostrum can reduce the diarrhea rate and feeding cost of calves in a certain degree. The pasteurized colostrum has a positive impact on growth performance and development of gastrointestinal tract for calves in 90 days of age, mainly in the body size development and morphological development of small intestine, but the reduction of the ratio of complex stomach weight to body weight in PC calves warrants further studies.