Manipulation of neonatal ruminal populations at birth results in sustained effects on microbial populations and measures of health and production in merino and suffolk lambs

• Published in: Livestock science 2024-02, Vol.280, p.105406, Article 105406
• Main Authors: Greenwood, E.C, Torok, V.A., Agenbag, B., Hynd, P.I.
• Format: Article
• Language: English
• Subjects: Manipulation; Microbiota; Neonatal; Production; Ruminant; Sheep
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2024.105406

•Inoculations resulted in differences in ruminal bacterial genera.•Differences were evident in rumen samples at weaning (10 weeks).•Differences were evident in intestinal samples at slaughter (18 weeks).•Efficiency and the health of the inoculated animals was affected.•Effects differ across inoculation and breeds. The efficiency of the microbial-driven fermentation process in the rumen is closely related to the efficiency of the ruminant host. This experiment examined the effect of manipulating the neonatal microbiota on postnatal development, immune function and productivity (liveweight gain and wool growth parameters). The trial examined the differences between naturally inoculated lambs (maternal control, n = 21) and those given ruminal fluid, which had been collected from ruminally-cannulated ewes, fed either a roughage diet (roughage, n = 14), or a grain-based diet (high grain, n = 14). At lambing, newborn lambs were tagged and weighed. Inoculation lambs received 10 ml of rumen fluid per inoculation, daily, for a total of 7 inoculations. Live weight, body condition scores, wool growth (greasy and clean wool weights), wool length, mean fibre diameter, and differential blood cell counts, and IgG and IgA in both blood and saliva) were quantified from birth until week 18 (slaughter). Total feed intake was recorded from weaning. Ruminal fluid was collected by stomach tube from 12 lambs from each treatment group and their dams (n = 7–8 per treatment, with the lower number of ewes coming about through ewes that had twins) at time of weaning (week 10). The pH of the ruminal fluid, the density of ciliated protozoa in ruminal fluid, and the composition of the ruminal bacterial populations were analysed. At slaughter (week 18), ileal samples were taken from the same focal lambs as were used for microbial analysis. The artificial inoculations resulted in significant differences in ruminal bacterial genera to those of naturally inoculated lambs at time of weaning (some 3 months post-lambing). Significant differences were also apparent in ileal bacterial communities at slaughter, between lambs which had received the inoculum from roughage-fed ewes and naturally inoculated lambs. Both the efficiency (growth, condition, feed conversion efficiency, carcass weight) and indices of health (mortalities, red blood cell count, blood haemoglobin concentration, haematocrit, and eosinophil counts) of the inoculated animals, were affected negatively by the inoculations (