Dietary concentrate level affects the feed sorting behaviour of lambs

Abstract

The objective of this study was to evaluate the effect of forage concentration on sorting, nutrient intake and feeding behaviour of growing lambs. Twelve weaned lambs were exposed, in a crossover design with 7-day periods, to each of two treatment diets: (i) lower-concentrate diet (LC; 40.0% concentrate) and (ii) a higher-concentrate diet (HC; 60.0% concentrate). Alfalfa hay was used as forage source. Sorting was determined by subjecting fresh feed and ort samples to particle separation and expressing the actual intake of each particle fraction as a percentage of the predicted intake of that fraction. Lambs sorted against long particles (>19 mm) on both treatments. On the LC diet, lambs sorted for medium particles, whereas animals fed the HC diet did not sort for or against medium particles. Lambs sorted for fine particles (<1.18 mm) on both treatments (p < .05). The extent of sorting for the fine particles was greater on the LC diet compared with the HC diet (p < .05). Dry matter intake was increased by increasing the concentrate content of the diet. Intake per visit and eating rate increased, and total chewing time was decreased in lambs fed HC diet. In conclusion, lambs sorted most against the longest particles and for the fine particles. Furthermore, feed sorting behaviour is affected by the forage level, and lambs sorted more for the fine particles in the LC diet.

Intake, growth performance, carcass traits, and meat quality of feedlot lambs fed novel anthocyanin-rich corn cobs

“…Sheep are known for their sorting behavior, being more intense than cattle and less intense than goats, which may result in an unbalanced intake of nutrients (i.e. not consuming enough or overconsumption), reduction of the nutritive value of the ration, alteration of rumen fermentation, unexpected performance, and increased risks of rumen disorders ( Miller-Cushon and DeVries, 2017 ; Sari et al, 2018 ).…”

“…The sorting index of the material remaining in the bottom pan of BGH diets, which was calculated as the actual DMI of each fraction of the PSPS divided by the predicted DMI of that fraction ( Leonardi and Armentano, 2003 ), was 126%; this indicates that the lambs sorted for it. Indeed, feedlot lambs sort most against the longest particles and fine particles ( Sari et al, 2018 ). Therefore, the capacity of animals that sorted for the concentrate when fed BGH influenced DMI so that they could consume less ration and maintained similar growth performance compared to cob diets.…”

Apart From the Diet, the Ruminal Microbiota of Lambs Is Modified in Relation to Their Genetic Potential for Feed Efficiency or Feeding Behavior

“…Such behavior in lambs has been previously reported. For example, Sari et al (2018) reported increased FI/V and FR with increasing concentrate level in the diet, which may have been due to improved palatability and higher rates of ruminal degradation and passage of concentrates compared to forage. Moreover, the ruminal microbiota is responsible for ruminal degradation of food, which might play a role in the observed differences in eating behavior.…”