Effects of three anthelmintic regimes on milk yield of ewes and growth of lambs.

Forty ewes were allocated into one of four groups (n = 10) and were treated with albendazole (ALB) (3.8 mg kg(-1)) before lambing (group A), with ALB before and after lambing (group B), with moxidectin (MXD) (0.2 mg kg(-1)) before lambing (group C) or were untreated controls (group D). Counts of nematode eggs in faeces and coprocultures were carried out during the study, as well as ewes' milk yield measurements and lamb weighings. Pre-treatment mean eggs per gram (epg) counts were 640, 715, 625 and 630 for groups A, B, C and D, respectively (P > 0.05); respective counts 21 days after treatment were 5, 0, 0 and 690 epg, whilst 70 days after treatment they were 380, 145, 40 and 1120 epg. Mean lactation milk yield was 3527.5, 3893.5, 3786.4 and 3285.9 ml for groups A, B, C and D, respectively; no significant difference was evident among the four groups in milk yield collected during the suckling period, although subsequently, group B or C ewes yielded significantly more milk than controls (P < 0.05). Mean birthweight of lambs were 3.56, 3.45, 3.59 and 3.26 kg for groups A, B, C and D, respectively (P = 0.045); subsequently, lambs from treated ewes were significantly heavier than lambs from control animals (P < 0.001). We conclude that anti-parasitic treatment during the last month of pregnancy contributed to an increased birthweight of lambs of treated ewes, whilst the cumulative effect of two doses of ALB or the long persistent efficacy of MXD provided a longer protection of animals against new parasitic infections and contributed to a lactation persistence.