Delayed weaning improves the growth of lambs grazing chicory (Cichorium intybus) pastures

Abstract

The Midwestern United States is characterized by summers with limited precipitation and as such pastures mature and feed quality decreases from mid to late summer. The poor forage quality impedes sheep production at weaning. Alternative forages such as chicory have been shown to maintain forage quality for a greater time compared to grass pastures and may increase body weight growth of weaned lambs. To improve system efficiency producers may consider delaying lamb weaning age to improve the growth and health of pasture-reared lambs if forage quality can be maintained. The objective of this experiment was to investigate the effects of delayed weaning on the growth and health of lambs grazing chicory (Cichorium intybus). We hypothesized that delaying lamb weaning age would increase lamb body weight and improve parasite resilience. A total of 18 cross-bred ewes and 36 cross-bred lambs (25.2 ± 0.5 kg) were stratified by weight, sex, and randomly assigned to one of two weaning treatments: 1.) lambs weaned at 60 days of age (control) and 2.) lambs, 60 days of age, remained with their dam and weaned at 116 days of age (delayed weaned). Delayed weaning resulted in greater weight gains as delayed weaned lambs were heavier on days 42 and 56 of the grazing period when compared with control lambs. In addition, delayed weaned lambs had a greater average daily gain (ADG) on days 14 and 42 of the grazing period and overall ADG when compared with control lambs. In monitoring lamb health, there were no differences in lamb FAMACHA© eye score, packed cell volume, fecal egg count, and total plasma protein concentration. Delayed weaning has shown to be beneficial in improving lamb growth; however, within the context of the current study delayed weaning did not improve lamb parasite resilience.