The objective of this work was to determine the repercussion of the metabolic changes that occur in induced subclinical pregnancy toxemia in single-or twin-bearing ewes on the duration of gestation, type and length of lambing, and placental expulsion time. Fifty-one adult Corriedale ewes with a known gestation date and fed in the wild were randomly divided at day 145 of gestation into four groups. Group A included single-bearing ewes, and C twin-bearing ewes, all of which were fed ad libitum. Group B was composed of single-bearing ewes, and D of twin-bearing ewes, all subjected to a 75% feed restriction until glycemic values were compatible with subclinical pregnancy toxemia. Metabolic parameters were determined in all ewes from day 145 of gestation to 72 h postpartum. Likewise, the duration of gestation, type of lambing (eutocic/dystocic), labor length, and placental expulsion time were recorded. Glycemia and β-hydroxybutyrate values compatible with subclinical pregnancy toxemia were achieved after 48 h of feed restriction, being 30.67±2.37 mg/dL and 1.87±0.12 mmol/L in single-bearing ewes and 28.40±3.39 mg/dL and 2.21±0.42 mmol/L in twin-bearing ewes, respectively. It is concluded that subclinical pregnancy toxemia induced by feed restriction at the end of gestation, frequent situation that occurs in flock management, produces mild metabolic changes, which return to normal values after the delivery. These metabolic changes registered before lambing do not modify the gestation length, do not increase the percentage of dystocical deliveries, nor influence labor length or placental expulsion time.

Polyunsaturated fatty acid (PUFA) deposition in lambs’ muscles could be influenced by their mothers’ diet. The aim was to study the profile of fatty acids in the muscle of lambs from ewes supplemented with different sources of PUFA to achieve a healthier meat for the consumer. On day 100 of gestation, pregnant ewes grazed on natural grass were divided into three groups (n = 20) and supplemented with PUFA: Group A: 700 g of a ration rich in PUFA, Group B: 700 g of a ration for sheep + 20 mL of fish oil and Group C: 700 g of the same ration. After parturition, each group was subdivided: ten ewes continued with the same diet until the end of lactation; the other ten were fed only natural grass. The values of n-3 and n-6 PUFA and alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linoleic acid (LA) and arachidonic acid (AA) were analyzed in Longissimus lumborum muscles of lambs at 90 and 120 days of life. The feeding of ewes during lactation favorably influenced the lipid profile of the lamb muscle, increasing the concentration of n-3 and n-6 PUFA, ALA, LA, AA, DHA and EPA. The supplementation of ewes with fish oil and/or a ration rich in PUFA improved the LA/ALA ratio in lambs’ meat.