The effect of multispecies swards on ewe and lamb performance from turnout to weaning.

Gaspard Beaucarne; Jean Kennedy; Jane Shackleton; Helen Sheridan, Cornelia Grace; Tommy Boland; School of Agriculture and Food Science, University College Dublin, Belfield, Dublin; Devenish Nutrition, Dowth Hall, Dowth, Co. Meath.

MSS with sheep and beef.jfif — Introduction

Grass based swards dominate Irish grasslands and newly sown swards are almost exclusively composed of perennial ryegrass (PRG). Such swards require high inputs of nitrogen to maintain sward performance and animals grazing these swards are dependent on anthelmintic drugs to combat parasitic infections. Multispecies swards (left), including a mixture of grasses, legumes and herbs have shown higher levels of ewe and lamb performance in sheep only systems. However, co-grazing cattle and sheep can offer an increase in individual animal performance and overall farm production per unit area.
The objective of this study is to investigate the effect of sward type on ewe and lamb performance from turnout to weaning when co-grazing with cattle.

Methods

A complete randomized design grazing experiment was established to investigate the effect of sward type on ewe and lamb performance from turnout to weaning. Four sward types were compared: a monoculture of PRG, a permanent pasture (PP), a 6 species sward (6SP) and a 12 species sward (12SP) (table 1 - below). Each sward type was managed as a separate farmlet (9ha) and ewes and lambs were rotationally co-grazed with cattle at an overall stocking rate of 2 LU ha-1. Lambs were weighed fortnightly from turnout (4 weeks post lambing) to weaning (16 weeks post lambing) and slaughtered at 42 kg. Ewes were weighed and their body condition score (BCS) recorded monthly. Statistical analysis was performed using mixed model procedure for repeated measures design in R.

Sward type species composition and grazing targets.png

Table 2 : a,b,c means with differing subscripts differ significantly; ns = non significant (P> 0.05). Number of weeks indicated correspond to the number of weeks post lambing.

Results

Ewe live weight and BCS at weaning were significantly higher (P<0.05) for ewes grazing the 6SP and 12SP swards than the ewes grazing PP and PRG (figure 2 - below). Live weight of lambs grazing 6SP and 12SP were significantly greater at weaning than lambs grazing PRG and PP (P<0.05) (figure 3 - below). Lamb average daily gain (ADG) was significantly greater for lambs grazing 6SP and 12SP compared to lambs grazing PRG and PP (P<0.05) (table 2 - left). At weaning, 26% of lambs in the PRG had achieved target slaughter weight compared to 40% in the PP, 76% in 6 SP and 54% in the 12 SP.