Shenjin Lv

Parturient paresis remains a major economic challenge in global ruminant production, causing acute periparturient hypocalcemia and predisposing high-yielding animals to a cluster of secondary pathologies. Traditional narratives often treat regulatory pathways in isolation, whereas this review synthesizes multi-organ endocrine networks to address the kinetic dyssynchrony between mammary calcium drain and homeostatic recruitment velocity. Beyond the classical parathyroid hormone–vitamin D axis, we integrate the mammary–gut–bone axis into a unified endocrine model, highlighting the critical role of the serotonin–parathyroid hormone-related protein rheostat for skeletal mineral mobilization and the fibroblast growth factor 23–Klotho axis in prepartum phosphorus-induced feedback suppression. We evaluate the molecular mechanisms underlying target-organ receptor resistance, driven by vitamin D receptor downregulation and epigenetic aging, which precipitate homeostatic feedback failure. Regarding clinical management, this synthesis contrasts reactive parenteral interventions with proactive nutritional priming strategies, such as negative dietary cation–anion difference acidification, zeolite-based gastrointestinal binders, and exogenous vitamin D or 5-hydroxytryptophan supplementation. Additionally, the role of microbiota-derived short-chain fatty acids in gut-bone communication and the potential of genomic selection to breed livestock with heritable metabolic resilience are explored. Ultimately, this comprehensive framework emphasizes a paradigm shift from emergency treatment to precision nutritional and genetic prophylaxis to mitigate PP across diverse ruminant species.

Lambs are typically weaned at 3–5 months of age, while early weaning (e.g., at one month of age) can readily induce ewe-lamb separation stress. Although improvements in weaning methods have shown some effectiveness in alleviating stress associated with early weaning, previous studies have mainly focused on stress responses in lambs, with relatively little attention given to ewes. Stress training is a method in which animals are exposed to specific stressors in advance to reduce their sensitivity to subsequent stimuli. This study aimed to investigate whether 1 h of pre-weaning ewe-lamb separation stress training (PWLSST) applied to ewes scheduled for early weaning (Day 35) could reduce post-weaning stress responses, improve behavioral performance, and explore the underlying mechanisms. The results showed that, compared with normally weaned ewes, ewes in the PWLSST group exhibited significantly reduced vigilant watching behavior and markedly increased relaxation-type behaviors (lying, exploring after weaning (P < 0.05). Concurrently, catecholamine (CA) levels in the PWLSST group were significantly decreased (P < 0.05). In summary, 1 h of PWLSST significantly reduced vigilant behavior and increased the proportion of relaxed behaviors in early-weaned ewes, which may indicate a marked reduction in stress levels. These improvements may be associated with decreased CA levels, which are related to chronic stress responses. These findings suggest that appropriate ewe-lamb separation stress training before weaning can help alleviate stress responses in early-weaned ewes, improve behavioral performance, and thereby enhance ewe welfare. This study provides a valuable reference for developing appropriate early-weaning protocols in meat sheep production.

This study investigated the effects of different breeding methods on the cecal microbiota and production traits of Yimeng Black Goats (YBGs). Twenty-seven 3-month-old male YBGs were assigned to three groups (n = 9 each): total mixed ration once daily (A), concentrate in the morning and roughage in the afternoon (B), or grazing with supplementary feeding (C). Cecal bacterial communities were analyzed via 16S rRNA sequencing, and functional potential was predicted using FAPROTAX. Breeding method significantly altered microbial composition (p < 0.05). Beta diversity was highest in Group C, while alpha diversity remained similar across groups. Bacteroidetes, Firmicutes, and Proteobacteria were dominant; Proteobacteria were most abundant in Group A. At the genus level, relative abundances of nine taxa, including Lactobacillus and Fusobacterium, differed significantly (p < 0.05). At the species level, including Lactobacillus mucosae, Bacteroides massiliensis and Alistipes finegoldii, differed significantly (p < 0.05). Chemoheterotrophy and fermentation functions were most enriched, particularly in Group C. Total weight gain was highest in Group A and lowest in Group C (p < 0.05), while carcass rate showed no significant differences (p > 0.05). Correlation analysis revealed that Proteobacteria, Fusobacteria, and Euryarchaeota as the key phylum, and Bacteroides, Tyzzerella, Fusobacterium, unidentified_Prevotellaceae, Methanovrevibacter and Faecalibacterium as the key genera were influencing the production traits of YBGs. These findings highlight the adaptive responses of the cecal microbiota to breeding methods and their potential links to host performance.

Context: Different individuals within a group can form strong links through auditory, visual, and tactile senses. Temporarily separating sheep into subflocks, although not involving complete social isolation of individuals, can be stressful, especially when ewes are separated from lambs. Aims: This study aimed to explore the effects of 1-h temporary ewe–lamb sensory separations on stress-related behaviours during separation, as well as its effect on stress-related hormones of ewes. Methods: Small-tailed Han ewes were randomly assigned to the following four groups (six each): the auditory + visual + tactile separation (A + V + T group), visual + tactile separation (V + T group), tactile separation (T group), and the control (C group). Then, the ewes were separated from their lambs for 1 h on Postnatal Days 14, 21, 28, 35 and 42. Ewe behaviours during the separations were observed using focal animal-sampling methods. Key results: Results showed that the separated ewes (A + V + T, V + T, and T groups) spent more time looking and exploring and less time lying (P < 0.05). Ewes showed more exploring behaviour in T group (P < 0.05). Ewes that gave birth to two lambs showed more urinating behaviour (P < 0.05). There was no significant difference in the level of stress-related hormones in ewes among the four different separation-method groups (A + V + T, V + T, T, and C groups). Conclusions: One hour ewe-lamb sensory separation affected the stress related behaviours of Small-tailed Han ewes during separation, but it did not cause differences in stress-related hormones in ewes after the separation. Ewes showed increased exploring or urinating behaviour when they were separated through lack of tactile contact only with lambs, or when ewes give birth to two lambs. Implications: Ewes temporarily separated from their lambs are less stressed if they are unable to hear or see the lambs, thereby improving ewe welfare. These effects appear more pronounced in ewes with multiple lambs and provides new perspectives for further studies on the effect of litter size on ewe-lamb bonding.

Inappropriate management practices of domestic animals during pregnancy can be potential stressors, resulting in complex behavioural, physiological and neurological consequences in the developing offspring. Some of these consequences can last into adulthood or propagate to subsequent generations. We systematically summarized the results of different experimental patterns using artificially increased maternal glucocorticoid levels or prenatal maternal physiological stress paradigms, mediators between prenatal maternal stress (PMS) and programming effects in the offspring and the effects of PMS on offspring phenotypes in sheep. PMS can impair birthweight, regulate the development of the hypothalamic–pituitary–adrenal axis, modify behavioural patterns and cognitive abilities and alter gene expression and brain morphology in offspring. Further research should focus on the effects of programming on gene expression, immune function, gut microbiome, sex‐specific effects and maternal behaviour of offspring, especially comparative studies of gestational periods when PMS is applied, continual studies of programming effects on offspring and treatment strategies that effectively reverse the detrimental programming effects of prenatal stress.

Increasing evidence has indicated the ameliorative effect of milk replacer supplementation in ruminants for regulating their early growth and rumen development. However, it is still unclear whether milk replacer supplementation has a beneficial role in the growth performance and rumen microbiota of Yimeng black goats (YBGs). Therefore, this study was performed to investigate the effects of milk replacer on growth performance and rumen microbiota of YBGs. Our results revealed that milk replacer supplementation could significantly improve the growth performance of YBGs. Additionally, the results of alpha and beta diversities indicated that there was no significant difference in richness and diversity between the control and milk replacer-treated YBGs. At the phylum level, Bacteroidetes, Firmicutes, and Proteobacteria were the most dominant phyla in all the samples at different stages. Moreover, the YBGs treated with milk replacer possessed a higher abundance of Verrucomicrobia than that in the control YBGs, while the level of Actinobacteria was obviously decreased. It is noteworthy that the abundance of Proteobacteria in the control YBGs was higher than that in the YBGs supplemented with milk replacer throughout the experiment. At the level of genus, the differences in the richness between control and milk replacer supplement YBGs were gradually observed. Compared with the control YBGs, the proportion of Akkermansia, Veillonella, Anaerovibrio, Ruminococcaceae_NK4A214_group, Ruminococcus_1, and Ruminococcus_2 was increased in the YBGs treated with milk replacer, whereas Turicibacter was decreased. In conclusion, milk replacer supplementation may serve as a good applicant for ameliorating early YBGs development and rumen microbiota.

Yimeng black goat is one of the national breeds of geographical indication in China and is one of the key protected local livestock and poultry breeds of Shandong province. The complete mitochondrial genome sequence of Yimeng black goat was investigated in this study (GenBank accession no. MT134111). The mitogenome (16,640 bp) consisted of a non-coding control region (D-loop region), two ribosomal RNA (rRNA) genes, 13 protein-coding genes (PCGs), and 22 transfer RNA (tRNA) genes. The complete mitochondrial genome sequence and the neighbour-joining tree of the Yimeng black goat would contribute to further study in genetic mechanism and phylogenomic research of goats.