Models for estimating feed intake in small ruminants

Abstract

-This review deals with the most relevant limits and developments of the modeling of intake of sheep and goats reared intensively and extensively. Because small ruminants are normally fed ad libitum, voluntary feed intake is crucial in feeding tactics and strategies aimed at optimal animal production. The effects of genetic, neuroendocrine, hormonal, feed and environmental factors on voluntary feed intake were discussed. Then, several mathematical models to estimate dry matter intake (DMI) were examined, with emphasis on empirical models for sheep and goats in intensive farm systems or in extensive areas under pasture or rangeland conditions. A sensitivity analysis of four models of prediction of DMI in housed lactating dairy sheep and meat sheep breeds was also presented. This work evidenced a large variability in the approaches used and in the variables considered for housed sheep and goats. Regarding the estimation of feed intake for grazing sheep and browsing goats, the accuracy of estimates based on empirical models developed so far is very low when applied out of the boundaries of the studied system. Feeding experiments indoors and outdoors remain fundamental for a better modeling and understanding of the interactions between feeds and small ruminants. However, there is a need for biological and theoretical frameworks in which these experiments should be carried out, so that appropriate empirical or mechanistic equations to predict DMI could be developed.

Feed Intake, Digestibility, Growth Performance and Blood Profiles of Three Ethiopian Fat Tail Hair Sheep Fed Hay Supplemented with Two Levels of Concentrate Supplement

“…Significant breed effect on total DM intake is also reported by Tsegay et al [38]. The review work of Pulina et al [39] showed that voluntary feed intake in sheep is transmitted from parent to offspring with h 2 value of 0.11 to 0.66. Higher nutrient digestion and better FCE by Horro breed may be due to higher CP and ME intake than BHO and Washera breeds.…”

Dorper sheep utilizing feed resources efficiently: a Mediterranean case study

“…Regarding the estimation of feed intake for grazing sheep, the accuracy of estimates based on empirical models developed so far is very low when applied out of the boundaries of the studied system. Feeding experiments indoors and outdoors remain fundamental for a better modelling and understanding of the interactions between feeds and small ruminants (Pulina et al, 2013). Commonly, the intake of forage dry or organic matter (DM or OM) is expressed in weight unit per animal and per day, but the expression cannot be used to compare animal species or forages.…”

Feeding behavior of goat kids fed diets containing peach palm meal

“…The integration of factors can affect feed intake in small ruminants, with a direct effect on ingestive behavior, such as NDF content (Van Soest, 1994), fat content and physical form of the feed (Pulina et al, 2013). Consistently, the peach palm meal presents high EE content with oxidation feature and lignin in the fiber, both are factors that possibly contributed to restrict voluntary intake in level of palatability and ruminal digestion, respectively.…”