Effect of propylene glycol on pre- and post-partum performance by dairy ewes

This study was carried out in order to determine the effects, after feeding propylene glycol to Valle del Belice ewes 30 days prepartum and 30 days postpartum, on metabolic profiles, body-condition score, milk yield, milk composition, milk clotting ability and the performance of suckling lambs. Ewes were blocked by parity, body-condition score and previous milk production, and assigned randomly to either a control diet or a diet containing propylene glycol fed at the rate of 80 g/ewe/day (low PG) or 160 g/ewe/day (high PG). Feeding propylene glycol prepartum decreased the concentration of BHBA and NEFA and increased the concentration of glucose in the ewes’ plasma. Milk yield from ewes fed the diet containing the higher and lower levels of propylene glycol, was 25 and 16% greater respectively than milk yield from ewes fed the control diet (P < 0.01). Feeding propylene glycol increased the milk fat and milk protein yield, and the milk cheese-making capacity compared with the control. Lambs of ewes fed the low and high propylene glycol diets, weighed 580 and 370 g more, respectively, at birth, than lambs of ewes fed the control diet (P < 0.01). Lambs of ewes fed the high propylene glycol diet gained 26 g/day more and weighed 1.15 kg more at 30 days compared to the lambs of ewes fed the control diet. In conclusion, feeding propylene glycol to ewes from 30 days prepartum up to 30 days postpartum decreased BHBA and NEFA concentrations in plasma, increased glucose concentration in plasma and milk yield, and improved the growth of nursing lambs.