Meta‐analysis of the energy and protein requirements of hair sheep raised in the tropical region of Brazil

Abstract

SummaryThe objective of this study was to estimate, through mathematical models, energy and protein requirements for maintenance and gain of hair sheep raised in the tropical region of Brazil. To determine the equation parameters, a meta-analysis of seven independent experiments of nutrient requirements was performed, comprising a total of 243 experimental units (animals), which were conducted under tropical conditions, using hair sheep in growing and finishing phases and endowed of the following quantitative data for each animal: body weight (BW), empty body weight (EBW), average daily gain (ADG), empty body gain (EBG), heat production (HP), metabolizable energy intake (MEI), retained energy (RE), metabolizable protein intake (MPI) and body protein content. The regression equations generated were as follows: for Net Energy for main tenance, . Considering an ADG of 100 g, the NP g requirement ranged from 12.4 to 10.5 g/day for animals with BW ranging from 10 to 40 kg respectively. The total metabolizable energy and protein requirements were lower than those reported by the NRC and AFRC systems. Thus, our results support the hypothesis that nutrient requirements of hair sheep raised in tropical regions differ from wool sheep raised in temperate regions. Therefore, the use of the equations designed in this study is recommended. K E Y W O R D Smeat sheep, nutrient requirements, prediction equations

Maintenance and Growth Requirements in Male Dorper × Santa Ines Lambs

“…The NEm obtained in our study was 0.071 Mcal/kg EBW 0.75 /day (or 0.062 Mcal/kg FBW 0.75 /day). This value is 16.9% greater (0.059 Mcal/kg EBW 0.75 /day) in relation to the value obtained with hair sheep by Oliveira et al (5). The value determined in this study was consistent with the unadjusted energy requirement value of the NRC (1), which is 0.062 Mcal/kg FBW 0.75 /day.…”

“…Nutrient requirements are not static ( 4 ) and vary with genetic selection ( 11 ) and crossbreeding ( 28 ). Factors such as mathematical models ( 29 ), environmental conditions ( 5 ), genotype ( 30 ) body composition, and feed quality ( 9 ) may influence the NEm requirements.…”

“…Considerable efforts have been made to cluster scientific data and develop feeding systems for ruminants in warm regions (7). In Brazil, studies on the feed composition and nutritional requirements of hair sheep (5,8,9) have generated information to establish a committee to meet the real requirements of these animals (10). Warm regions are characterized by constantly high temperatures, sometimes associated with high humidity (3), which induces specificities in the characteristics of both feed and animals (8).…”

“…International committees ( 1 – 3 ) play an important role in establishing nutritional recommendations for sheep ( 4 ), especially for those in temperate regions. In tropical scenarios, the nutritional requirements recommended by international committees may not be adequate to meet the physiological needs at different stages of the animal's life ( 5 ). Evolutionary adaptations to the ecological opportunity of selective feeding in smaller animals, rather than by a physiological or metabolic necessity linked to body mass ( 6 ), may explain this phenomenon.…”

Nitrogen Sources in Spineless Cactus-Based Diets for Sheep in Finishing

“…It is worth mentioning that the diets were formulated for gains of 0.20 kg/day, but none of the treatments achieved the gain predicted in the NRC (2007). Possibly, differences in the genetic composition of animals (Oliveira et al, 2018) and in food -diets with spineless cactus -(Knupp et al, 2019) may help explain these differences between the predicted and observed gain.…”