The development of rumen function in the lamb.

Abstract

A series of experiments is presented, describing the development of the rumen function in grazing lambs and the effects of' diet on the rumen development of artificially reared lambs. In grazing lambs the volume of the abomasum contents showed little change with age. The volume of the rumen contents increased with age, and the rate of' this increase was most marked from 3 weeks of age onwards. The volume of the rumen contents, relative to both the liveweight and the volume of the abomasum contents, was constant from 8 weeks of age onwards. The rumen volatile fatty acids (V.F.A.) concentrations in grazing lambs increased from birth and reached adult levels at 8 weeks of age. The total quantity of V.F.A. present in the rumen at a given time, relative to liveweight, increased up to 8 weeks of age but from this age onwards was approximately constant. The rumen ammonia nitrogen (N) concentrations in grazing lambs were high for the first few weeks after birth, but showed a continuous fall, reaching adult levels at 5 weeks of age. The quantity of ammonia N present in the rumen at a given time, relative to liveweight, increased up to 8 weeks of age and then remained approximately constant. The rumen volumes, V.F.A., and ammonia N concentrations were normal only in lambs that had been fed roughage. When lucerne chaff was fed to young lambs, the digestibilities of the dry matter, crude protein, and crude fibre were high, irrespective of whether the previous diet had been milk or chaff. The ad libitum dry matter intake from roughage, relative to the liveweight, increased up to 8 weeks of age and then remained approximately constant. When roughage was fed to lambs which had been reared on 'milk' (a preparation from dried cows' milk) only from birth to 9 weeks of age, the rumen V.F.A. concentrations rose immediately and levelled off at adult levels within 1 week.

Programming rumen bacterial communities in newborn Merino lambs

“…In addition, while the greatest effect of diet seems to be in week 12, effect of inoculation was largest at week 8. These results are consistent with ideas of Wardrop and Coombe (1961) and Abecia et al (2014a,c). Wardrop and Coombe (1961) reported that the post-birth functional and physical development process of the rumen of lambs has 3 stages: non-ruminant (0-3 weeks of age), transition (3-8 weeks of age), and adult (8 weeks of age), where the type of diet and the rumen microbial inoculation from adults would be the most important factors affecting this process.…”

“…These results are consistent with ideas of Wardrop and Coombe (1961) and Abecia et al (2014a,c). Wardrop and Coombe (1961) reported that the post-birth functional and physical development process of the rumen of lambs has 3 stages: non-ruminant (0-3 weeks of age), transition (3-8 weeks of age), and adult (8 weeks of age), where the type of diet and the rumen microbial inoculation from adults would be the most important factors affecting this process. More recently, Abecia et al (2014a,c) studying microbial colonization successions in the rumen of goat kids, found that the greatest scope for altering the bacterial community is during the first 2 weeks of life of the kids because stabilization of the bacterial community was detected after day fourteen of life.…”

Positive consequences of maternal diet and post-natal rumen inoculation on rumen function and animal performance of Merino lambs

“…In relation to quantity, the effects at wk eight indicate that the addition of rumen fluid (from either source) in difference to water stimulates fermentation. Inoculation can affect the complexity of the microflora (Fonty et al, 1983), and rumen development (Bomba et al, 2005) during the transition phase of the lamb from pre-ruminant to ruminant (Wardrop and Coombe, 1961), and our evidence supports the hypothesis that the lambs inoculated with rumen fluid possessed a more developed ruminal fermentation by wk eight that led to differences relative to InW lambs.…”

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

“…They used curarized lambs (20-25 days old) anaesthetized with chloralose. Spontaneous reticular contractions, as would be expected, were absent, since reticulo-ruminal structure and 200 GASTRIC EFFERENT UNITS function in lambs of this age, according to Wardrop & Coombe (1961), would still have been in a very primitive stage of development. Reticular contractions-were evoked by distending the reticulum or stimulating the central end of a cut abomasal nerve.…”