The objective of this study was to investigate the effect of maintenance system as well as the effect of Se, Zn, and vitamin E supplementation of ram-lambs on the slaughter value and concentration of mineral elements in the loin muscle of lambs. The experiment was conducted on 72 Polish Merino ram-lambs divided into three groups: group C, indoor with no supplement, 19 lambs; S, indoor with supplement, 23 lambs; G, outdoor with no supplement, 30 lambs. From birth all the lambs were maintained indoor with their dams and then weaned at the age of 8 weeks. The rams from group C and S were placed in individual straw-bedded pens and fattened individually with concentrate mixture offered ad libitum until the age of 16 weeks. The lambs from group G were grazed every day from May to July (2 months). During the fattening period each lamb from the supplemented group S was administered per os 1 mL 0.1% Na2SeO4 (Se, 0.42 mg), 3 mL 10% ZnSO4 (Zn, 68 mg), and 1 mL premix protect vitamin E (0.1 g α-tocopherol, 5 mg lysine, 5 mg methionine) daily. A comparison of half carcasses across the groups has shown no difference between the control group and the one with supplements, while the weight of half carcasses in the grazing group was smaller in comparison with groups C and S (p<0.001). The meat content in the pelvic limb showed no differences across all groups under study. The pelvic limb of grazing lambs contained less fat compared to the control and supplemented groups (p<0.001). The concentrations of Se and Zn in the blood plasma of ram-lambs from the supplemented group were significantly higher than for the control and grazing lambs. Inorganic Se and Zn supplementation with vitamin E to the diet of lambs increased Se and Zn levels in loin muscle (p<0.001) to 0.46 μg/g and 32.9 μg/g in fresh tissue, respectively.

The aim of this study was to determine whether asymptomatic small ruminant lentivirus seropositive (SRLV-SP) goats were more susceptible to bacterial infection of the udder when lactating by comparing the presence and species of pathogenic bacteria in their milk with the values for seronegative goats (SRLV-SN). Milk samples were collected during morning milking on days 20, 40, 60, 150, and 210 of lactation for three consecutive years and subjected to bacteriological examination. Staphylococcus caprae and S. xylosus were the most frequent strains identified in both SRLV-SP and SRLV-SN goats. The prevalence of pathogenic bacteria was the highest in the 1st lactation, regardless of SRLV status. Moreover, the prevalence of pathogenic bacteria was significantly higher in SRLV-SP goats, but only those in the 5th or further lactation (p = 0.010). This suggests a relationship between long-lasting SRLV infection and susceptibility to bacterial infections of the udder.

Abstract. The experiment was conducted on 80 Polish Merino ewes, their 82 lambs and 40 fattening rams. Merino ewes were divided into two groups: experimental (E) and control (C), each composed of 40 animals. Four weeks before lambing, 1 day, 3 weeks and 6 weeks after lambing 40 ewes of the experimental (E) group received intramuscular injection of 5 ml 0.1 % Na2SeO4 (selenium [Se]: 2.09 mg), 10 ml 10 % ZnSO4 (Zinc [Zn]: 227 mg) and 250 mg vitamin E (α-tocopherol), and control group (C) – no received. From birth all the lambs were maintained with their dams and then weaned at the age of 8 weeks, placed in individual straw-bedded pens and fattened individually with a granulated concentrate mixture until reaching a body weight about 32 kg. During fattening 20 lambs from experimental group (E) was given per os 1 ml 0.1 % Na2SeO4, 3 ml 10 % ZnSO4 and 60 mg vitamin E (α-tocopherol) daily, and control group (C) – no administered. The levels of Se, Zn and vitamin E in the blood plasma of ewes and ram- lambs were within the reference values. The lambs born by the treated ewes (E) experienced much lower body live weight at birth (P≤0.05), body weight on day 28 and 56 (P≤0.01), compared to lambs born from group (C). Also the daily live weight gain from birth to 4 week and from birth to 8 week were significantly lower (P≤0.05) in lambs born by the treated ewes. Se, Zn and vitamin E treated rams contained less fat in leg (P≤0.05), less fat thickness over ribs (P≤0.01) and less fat thickness over loin-eye than non treated rams.

The study aims to determine the selected miRNAs expression in milk somatic cells (MSC) and blood leukocytes (BL) of SRLV-seronegative (SRLV-SN) and SRLV-seropositive (SRLV-SP) goats. A functional in silico analysis of their target genes was also conducted. MiR-93-5p and miR-30e-5p were expressed only in BL, while miR-144 was expressed only in MSC, regardless of SRLV infection. In the SRLV-SP goats, higher miR-214-3p and miR-221-5p levels were found in the MSC than in the BL. Only miR-30e-5p was influenced by the lactation stage in BL in both groups, while only miR-93-5p was altered in BL of SRLV-SN goats. The target gene protein products exhibited contradictory functions, protecting the host from virus on the one hand and assisting viruses in their life cycle on the other. The differential expression of the miRNAs observed between the MSC and BL of SRLV-SP goats may suggest that the local immune response to the infection in the udder differs from the systemic response, and acts independently. Some miRNAs demonstrated different expression between lactation stages. It may be influenced by the metabolic burden occurring in early lactation and its peak. Some of the studied miRNAs may influence viral infection by regulating the expression of their target genes.

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