Ruminal Microbial Development in Conventionally or Early-Weaned Calves

Abstract

Eight bull calves (four Holsteins and four Ayrshire calves with mean birth weight of 38.8 kg) were ruminally cannulated at 3 d of age and allocated to one of two weaning programs. All calves were fed colostrum for 3 d after birth and milk until weaning. Calves in the conventional-weaning program were fed a starter diet from 3 d of age and weaned at 6 wk of age. In the early-weaning program, calves were fed a highly palatable pre-starter diet from 3 d of age until they consumed 227 g/d, and then fed a mixture of pre-starter (227 g) and starter diet ad libitum. Calves in this group were weaned at 4 wk of age. Ruminal samples were collected at 3 and 7 d, then weekly thereafter through 8 wk and at 10 and 12 wk of age to assess microbial activity. Calves in the early-weaned group had a higher concentration of total ruminal volatile fatty acids at an earlier age than the calves in the conventional-weaning program. This was accompanied by a trend toward higher lactate concentrations and lower ruminal pH in the early-weaned group during their first 4 wk of age. Lactate and ammonia concentrations decreased with calf age. The total anaerobic bacterial counts increased slightly with calf age, whereas Streptococcus bovis and facultative bacterial populations decreased with calf age. Amylolytic, proteolytic, lactobacilli, lactate-utilizers, cellulolytic and methanogenic bacterial populations increased progressively in both groups. Cellulolytic and methanogenic bacteria were present in both groups at 3 d of age. No protozoa were detected in calves of either group. In general, the most significant changes in bacterial populations and metabolic activity in both groups occurred between 4 and 6 wk of age. Although calves in both groups had similar patterns of bacterial development, calves in the early-weaning program tended to have high ruminal microbial activity at an earlier age than the conventionally weaned calves.

Essential oils for dairy calves: effects on performance, scours, rumen fermentation and intestinal fauna

“…The growth of amylolytic bacteria was constant over the weeks, and after weaning there was a slight drop in growth. These data do not agree with the study of Anderson et al (1987), where the average proportion of amylolytic bacteria from total anaerobic bacteria tended to increase over the weeks. According to Beharka et al (1998), amylolytic microorganisms are more tolerant to variations in pH and therefore do not undergo oscillations like the cellulolytic bacteria.…”

Influence of weaning regimen on intake, growth characteristics and plasma blood metabolites in male buffalo calves

“…Results of several investigations in cattle calves demonstrated there was no effect of weaning age on growth performance, and in addition there was a reduction in the costs associated with feeding (Anderson et al, 1987;Quigley et al, 1991;Kehoe et al, 2007). Furthermore, despite a lower milk intake, EW calves showed similar growth performance to those weaned later (weeks 10 and 12).…”

Calving seasonality at Pool, Orkney during the first millennium AD: an investigation using intra-tooth isotope ratio analysis of cattle molar enamel

“…It is possible that it could occur later in the first molar profile, although this would not alter the conclusion that these Pool cattle were born during three seasons. Secondly, the age at which the rumen becomes fully functional is variable, occurring between 6 and 10 weeks (Bryant et al 1958;Swanson and Harris 1958;Godfrey 1961b;Anderson et al 1987). Thirdly, there may be unaccounted errors.…”

“…rumen is undeveloped and digestion of milk takes place in its fourth stomach compartment, the abomasum, which digests food in a similar manner to the stomach of a non-ruminant (Davis and Drackley 1998, 13). However, by the age of two weeks, a calf will begin to consume dry food if available (Lengemann and Allen 1959;Godfrey 1961a), which stimulates the rumen to develop quickly, anatomically, microbially and physiologically, so that at 6-10 weeks of age, it is usually able to digest food like an adult ruminant (Bryant et al 1958;Swanson and Harris 1958;Godfrey 1961b;Anderson et al 1987). Rumen digestion involves the fermentation of food which produces methane, depleted in 13 C, and carbon dioxide, enriched in 13 C. Thus, any of this 13 C-enriched carbon dioxide entering the bloodstream and becoming incorporated in the mineralizing enamel of a ruminating calf will raise the δ 13 C value of the enamel with respect to non-ruminant digestion (Cerling and Harris 1999;Passey et al 2005).…”