كليدواژه :
مخمر ساكارومايسنر سرويسيا , جمعيت باكتريايي شكمبه , yeast Saccharomyces cerevisiae , عملكرد گوساله , rumen bacterial population , calf performance
چكيده لاتين :
Eighteen female Holstein neonatal calves with an average 41.9±4.9 Kg body wieght were randomly placed on treatments in individual boxes and two levels of yeast 0.5 and 1°/o (Calf starter DM-base) were compared with control (without yeast) in a completely randomized design in order to study effects of yeast (Saccharomyces cerevisiae) on rumen bacterial population and performance of Holstein female calves. Calves were fed colostrum and milk at 10% of birth weight in the first two days and until 52 days old. All calves were fed calf starter containing high quality alfalfa (13%) and concentrate (87%) from seven days of age. Calf starter was offered until 90 days old and the yeast was added daily at 0, 0.5 and 1 percent to the calf starter. Addition of yeast to the ration reduced daily calf starter dry matter intake and total daily dry matter intake (P<0.01), but had no effect on average daily gain or feed to gain ratio and rumen fermentation characteristics at different sampling days. Yeast had no effect on CP, NDF and ADF digestibility, but significantly increased OM and DM digestibility (P<0.05). Yeast had no effect on Glucose and BUN concentrations except at 90 day of age that a significant reduction took place at BUN (P<0.05). There was no significant difference between rectal temperature of calves in different treatments and antibiotics and electrolytes treatment days. Addition of yeast had no effect on body length, pin width, hip width, pin to hook length, metacarpus size, hip height and hearth girth but had a significant effect on wither height, stomach size and metatarsus size (p<0.05). Population of yeasts in digestive tract of calves was significantly different among treatments (P<0.05). Data showed that some of the yeasts remained alive during their transition through the digestive tract. Generally, it seems that using yeast at female Holstein calves up to 90 days old didnʹt have any considerable effect on performance of calves.
