• Asian-Australasian Journal of Animal Sciences
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• v.30 no.11
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• pp.1557-1562
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• 2017

Objective: This study was conducted to investigate the effects of weaning times on the growth performance, rumen fermentation and microbial communities of yellow cattle calves. Methods: Eighteen calves were assigned to a conventional management group that was normally weaned (NW, n = 3) or to early weaned (EW) group where calves were weaned when the feed intake of solid feed (starter) reached 500 g ($EW_{500}$, n = 5), 750 g ($EW_{750}$, n = 5), or 1,000 g ($EW_{1,000}$, n = 5). Results: Compared with NW, the EW treatments increased average daily gain (p<0.05). The calves in $EW_{750}$ had a higher (p<0.05) starter intake than those in $EW_{1,000}$ from wk 9 to the end of the trial. The concentrations of total volatile fatty acids in $EW_{750}$ were greater than in NW and $EW_{1,000}$ (p<0.05). The EW treatments decreased the percentage of acetate (p<0.05). The endogenous enzyme activities of the rumen were increased by EW (p<0.05). EW had no effect on the number of total bacteria (p>0.05), but changes in bacterial composition were found. Conclusion: From the present study, it is inferred that EW is beneficial for rumen fermentation, and weaning when the feed intake of the starter reached 750 g showed much better results.