Industrial hemp could potentially contribute to livestock nutrition including in the sheep industry; however, the impact of feeding industrial hemp on the gastrointestinal microbiome of sheep remains poorly characterised. Previous investigations indicated that rumen parameters, including volatile fatty acid molar proportions, and fibre digestibility of a pelleted diet were altered following inclusion of industrial hemp stubble or hay in sheep diets, suggesting modulation of the gastrointestinal microbiome by industrial hemp. Therefore, to characterise this relationship, a preliminary experiment was conducted by profiling the ruminal fluid and faecal microbiome of sheep fed a pelleted diet containing 42% industrial hemp hay. Twelve Merino ewes were allocated to either a Control or industrial hemp diet (n = 6 per treatment) for 21 d following a 6 d transitional period. A ruminal fluid and faecal sample were collected from each sheep 3 h post-feeding at the end of the feeding trial and subjected to 16S rRNA gene sequencing. While no differences (p > 0.05) in alpha diversity were observed, analyses revealed differences (p < 0.05) in the relative abundance of microbial taxa at both the phylum and genus levels. In the faeces, there was an increase in Firmicutes and subsequent decrease in both Bacteroidota and Spirochaetota at the phylum level and an increase in both Acetitomaculum and Blautia and subsequent decrease in both Treponema and Rikenellaceae_RC9_gut_group at the genus level. In the rumen, there were no differences at the phylum level but at the genus level there was an increase in both Olsenella and Eubacterium_hallii_group. Beta diversity analysis demonstrated a decrease in between-sample phylogenetic similarity in both the faeces and rumen (p = 0.006 and p = 0.002, respectively for ANOSIM analysis) following industrial hemp consumption, indicating a discernible influence on the ovine gastrointestinal microbiome. Variations in the overall microbial community structure following industrial hemp ingestion may have influenced digestion and nutrient utilisation, contributing to the changes in fibre digestibility and ruminal parameters identified following feeding of industrial hemp to sheep. Further research is required to ensure there are no adverse animal health or production effects post feeding.
Blackloss is the unexplained loss of lambs on extensive Scottish hill grazings. This study used historical production datasets to investigate several different factors that may be contributing to blackloss up to weaning. Data were available for 3071 lambs, born in April/May between 2014 and 2021, and reared in three different management groups within the same hill farm, in the West Highlands of Scotland. Lamb presence/absence was recorded using EID tags and lambing to weaning levels of blackloss were calculated. Plochteach photosensitisation, commonly observed in lambs reared in upland environments across north-west Europe, was diagnosed through clinical signs on the ears and/or back. The effect of lamb traits, plochteach, and dam and sire factors on blackloss was investigated using Generalised Linear Mixed Model analysis. Blackloss averaged 7.6% over eight years, and 5.1% of lambs were affected by plochteach. The prevalence of plochteach was 9.9% within the blackloss subset. Generalised Linear Mixed Models identified plochteach (on logit scale affected, −2.7, unaffected −3.3, SED 0.30, P = 0.034) and low marking (at 6–8 weeks after birth) weights (<15 kg, gradient on logit scale –0.198, SE 0.037, P < 0.001) as significant predictors of blackloss. These findings highlight for the first time the role that plochteach and low marking weights play in lamb blackloss and suggest that early identification and targeted management of at-risk lambs could help reduce unexplained losses in extensive hill systems.
The aim of this study was to evaluate the effects of partially replacing elephant grass hay and fully replacing ground corn with three cactus pear genotypes on blood biochemical parameters and on the histopathological and histomorphometric characteristics of the sheep liver. Forty uncastrated male Santa Inês lambs (21.0 ± 2.0 kg body weight) were allocated to four dietary treatments (10 lambs per treatment) in a completely randomized design: a control diet and three experimental diets in which part (750 g/kg) of the elephant grass hay and all corn were replaced by Miúda, IPA-Sertânia, or Orelha de Elefante Mexicana cactus pear. On day 60 after the beginning of the experimental period, blood samples were collected. After 63 days in feedlot, the animals were slaughtered and liver samples were collected from different lobes. Lambs fed cactus pear-based diets showed higher growth performance (P < 0.05), liver weight (+76.92%), alkaline phosphatase activity (+274,45%), and plasma glucose concentration (+46.25%) (P < 0.001). Conversely, serum urea and cholesterol concentrations were reduced in these animals (P < 0.05). Most hepatic lesions were not affected by the diets, except for steatosis, which presented higher intensity in lambs fed the IPA-Sertânia genotype (P = 0.020). In conclusion, the inclusion of carmine cochineal-resistant cactus pear genotypes in feedlot diets for up to 63 days was associated with hepatic alterations in sheep but enhance short-term growth performance.
