Twenty-four dual purpose (wool/meat) suckling and early weaned ram lambs were used to study the fatty acid profile in intramuscular fat of longissimus lumborum muscle and lipid oxidation in blood serum. At 60 days of age 12 rams were slaughtered as suckling lambs. The other 12 early weaned and fed according to standards by grass hay and concentrate, and slaughtered at 90 days of age. Suckling lambs had more polyunsaturated fatty acids (P≤0.01) than early-weaned lambs. Younger lambs obtained also higher values of n-3 fatty acids (P≤0.01) and lower n-6/n-3 ratio (P≤0.01) appropriate in relation to their contribution to human health. Muscle tissue of early-weaned lambs compared to suckling group was characterised by significantly higher c9,t11C18:2 content (P≤0.01), which is desirable in human diet with regard to its peculiarities. The higher amount (P≤0.01) of vaccenic acid, which is the substrate for rumenic acid formation, has been observed in early-weaned lambs also.

Abstract.A herd of sheep (40 heads) was divided into two equal groups: group 1 was kept under an overhead shelter and group 2 in a warm barn. The effect of maintenance on ewe's reproductive performance, corpora lutea and corpora lutea of pregnancy rate, as well as the concentration of plasma progesterone and estradiol in peripheral blood was investigated. At the first laparoscopy fewer corpora lutea than during the following one were observed (P ≤ 0.01). In sheep kept under the overhead shelter, a greater number of corpora lutea were noted. More corpora lutea of pregnancy were observed in group 1 than in the group from the barn. On the first day after mating the average level of progesterone was 190 pg mL −1 , and after 2 weeks it increased to more than 300 pg mL −1 (P ≤ 0.01). The positive correlation between the number of corpora lutea of pregnancy and progesterone concentration (P ≤ 0.01) and the negative correlation (P ≤ 0.01) with number of corpora lutea of pregnancy, as well as between the litter size and estradiol concentration, were observed. Harsh environmental conditions did not cause a significant decrease of the reproduction performance of ewes kept under the overhead shed.

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.

Abstract:The experiment was conducted on 30 single born Polish Merino ram lambs. At the age of 112 d, 10 ram lambs were slaughtered at 20 kg (group 1), 25 kg (group 2), and 30 kg (group 3) live weight. Plasma leptin increased between 20 and 25 kg, as well as 25 and 30 kg live weight. The differences between group 1 vs. group 3 and group 2 vs. group 3 were statistically important (P < 0.001). The lack of differences in meat content of the pelvic limb between the groups and, at the same time, the lower fat content (P < 0.001) in group 1, plus the higher fat content of the two remaining groups, are evidence of the higher fatness of carcasses in groups 2 and 3. The fat tissues except the subcutaneous fat were significantly related with the leptin concentrations at slaughter. The leptin concentration of lambs slaughtered at 30 kg live weight surpassed significantly the values noted in groups 1 and 2 (P < 0.001). The correlations between leptin and body composition indicate that plasma leptin concentration at 30 kg live weight can be a predictor of body fat. The correlation of meat weight with leptin concentration has shown no statistical differences.

A herd of polish lowland local sheep was divided into two equal groups: the first group was kept under an overhead shelter, and the second group was kept in a warm barn. The effect of maintenance on ewe’s reproductive performance, survival as well as the growth rate of lambs, and their carcasses quality was investigated. The lack of differences in fertility and prolificacy of ewes as well as in the survival and growth rate between the groups confirmed a good adaptation of Żelaźnieńska sheep to low temperature. Harsh environmental conditions did not cause a significant decrease of the body weight growth; however, they brought in an (insignificant) reduction of subcutaneous fat thickness and meatiness of the loin part of a lamb’s body. The fat content of carcasses obtained from lambs reared under the overhead shelter was significantly lower, with no differences of meat and bones contribution between the groups.

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