Effect of early weaning and concentrate supplementation at forage intake and ingestive behavior of sheep grazing Tifton 85 (Cynodon spp.)

Abstract

The objective of this study was to evaluate then early weaning and concentrate supplementation effect at pasture characteristics, forage intake and ingestive behavior of lambs grazing Tifton 85 (Cynodon spp.). A randomized block design was used with four treatments, three replications and five lambs per replicate. A total of 60 Suffolk lambs, that 36 were females and 24 steers. The treatments had corresponded to the combinations between early weaning precocious and concentrate supplementation strategies, that resulted in the following ones finishing systems: 1) lambs kept with mothers without supplementation; 2) lambs kept with mothers supplemented with concentrate in creep feeding at 2% of body weigh (BW) in DM/day; 3) weaned lambs at 45 ± 5 days without supplementation and 4) weaned lambs at 45 ± 5 days and supplemented with concentrate at 2% of BW in DM/day. Grazing utilization method was continuous stocking with adjustment every 21 days, to maintain forage offer at 12% of BW in DM/day. To characterize the pastoral environment was assessed: morphological composition of pasture. There were made four observations the behavioral activities for individually lambs per 24 hours, such as: grazing, ruminating, suckling, supplementation, and others activities. The intake rate was measured using the technique of double sampling and determination of bite rate was made by visual observation of the number of bits made for animal. The behavior and the distribution of daily activities made by the lambs are influenced for the strategies evaluated. The exclusive presence of milk or supplement concentrate in the diet are important modulators of grazing activity, and the absence of these nutrient sources were offset per an increase in grazing time. This response considered the decrease in nutritional support and lower efficiency in harvesting the forage by lambs. The weaning influenced the morphological characteristics of the pasture, which showed favored the grazing by lamb when their mother was present. The results obtained in the evaluation of forage intake indicated that weaning was affected by the variables that describe the grazing process, except for bite mass and intake speed. We conclude that the finishing of early weaned lambs at grazing causes changes at pasture characteristics, which may limit forage intake. The concentrate supplementation does not affect the variables that describe the process of grazing lambs on pastures.