Energy and protein requirements of Santa Ines lambs, a breed of hair sheep

Abstract

An experiment was carried to evaluate the energy and protein requirements for the growth and maintenance of lambs of different sex classes. In all, 38 hair lambs (13.0±1.49 kg initial BW and 2 months old) were allocated in a factorial design with diet restriction levels (ad libitum, 30% and 60% feed restriction) and sex classes (castrated and non-castrated males). Four animals from each sex class were slaughtered at the beginning of the trial as a reference group to estimate the initial empty BW and body composition. The remaining lambs were weighed weekly to calculate BW gain (BWG), and when the animals fed ad libitum reached an average BW of 30 kg, all of the experimental animals were slaughtered. Before slaughter, fasted BW (FBW) was determined after 18 h without feed and water. Feed restriction induced reductions in body fat and energy concentration, whereas water restriction showed the opposite effect, and the protein concentration was not affected. The increase in BW promoted increases in body fat and energy content, and these increases were greater in castrated lambs, whereas the protein content was similar between classes tending to stabilize. The net energy required for gain (NEg) and the net protein required for gain (NPg) were not affected by sex class; therefore, an equation was generated for the combined results of both castrated and non-castrated lambs. The NEg varied from 1.13 to 2.01 MJ/day for lambs with BW of 15 and 30 kg and BWG of 200 g. The NPg varied from 24.57 to 16.33 g/day for lambs with BW of 15 and 30 kg and BWG of 200 g. The metabolizable energy efficiency for gain (k g) was 0.37, and the metabolizable protein efficiency for gain (k pg) was 0.28. The net energy required for maintenance (NEm) and the net requirement of protein for maintenance (NPm) did not differ between castrated and non-castrated lambs, with values of 0.241 MJ/kg FBW0.75 per day and 1.30 g/kg FBW0.75 per day, respectively. The metabolizable energy efficiency for maintenance (k m) was 0.60, and the efficiency of metabolizable protein use for maintenance (k pm) was 0.57. Nutritional requirements for growth and maintenance did not differ between castrated and non-castrated lambs. This study emphasizes the importance of updating the tables of international committees and of including data obtained from studies with sheep breeds raised in tropical conditions, with the purpose of improving the productive efficiency of the animals.

Effects of dietary energy level on growth performance, blood parameters and meat quality in fattening male Hu lambs

“…Meanwhile, the roughage surplus in the low‐energy group was higher than that in the high energy group in the actual feeding process. Additionally, the differences may relate to sheep breeds, physiological stages or different test seasons (Arsenos et al, ; Pereira et al, ). FCR significantly decreased by increasing dietary energy levels from 9.17 to 10.41 MJ/kg, but there were no significant differences between 10.41 and 10.82 MJ/kg of dietary energy levels, which suggested that too high dietary energy levels inhibited the DMI of male Hu lambs.…”

“…More type I and fewer type IIB muscle fibres were exhibited in LD muscle with fed a low‐energy diet (Solomon & Lynch ); Joo, Kim, Hwang, and Ryu () find that muscle fibre types have a great influence on meat quality. Additionally, the energy requirements for maintenance and weight gain differ between sheep breeds (Arsenos et al, ) and sex classes (Pereira et al, ).…”

Developing a continuous adjustment factor for dry matter intake of gestating and lactating ewes

“…Salah et al (2014) studied, by meta-analysis, the influence of warm climates on nutritional requirements. However, a number of studies have focused on the determination of the requirement of a specific race, considering that there is a nutritional difference between them (Ji et al, 2015;Pereira et al, 2017Pereira et al, , 2016Rodrigues et al, 2016). Certain researchers have worked on the effect of maternal nutritional requirement on progeny; these studies are called fetal programming, and are not usually studied in prediction equations (Campion et al, 2016;Hoffman et al, 2018;McGovern et al, 2015;Peine et al, 2018;Roca Fraga et al, 2018).…”

Perfil Metabólico De Cordeiros Santa Inês Terminados Em Confinamento Com Manejo Alimentar Restritivo E Ad Libitum

“…Porém as proteínas totais tiveram níveis inferiores quando comparadas com a literatura (6,0 a 7,9 g/dL) (12) , este aspecto pode ser justificado pela menor eficiência metabólica na utilização das proteínas em animais jovens quando comparados a animais adultos e pela redução linear nas exigências para a mantença de ovinos em crescimento pelo decréscimo na taxa de renovação proteica no organismo (2) .…”

“…Manejos alimentares que alternam períodos de restrição energética com períodos de atendimento das exigências nutricionais podem ser utilizados com o objetivo de auxiliar a promover o crescimento compensatório nos animais (1) . Entretanto, o desenvolvimento de estratégias eficientes para maximizar o retorno econômico da atividade exige um aprofundamento no conhecimento do perfil metabólico dos animais submetidos a diferentes níveis de disponibilidade de alimentos (2) .…”