Influence of Protein and Energy Level in Finishing Diets for Feedlot Hair Lambs: Growth Performance, Dietary Energetics and Carcass Characteristics

Abstract

Forty-eight Pelibuey×Katahdin male intact lambs (23.87±2.84 kg) were used in an 84-d feeding trial, with six pens per treatment in a 2×2 factorial design arrangement. The aim of the study was to evaluate the interaction of two dietary energy levels (3.05 and 2.83 Mcal/kg ME) and two dietary protein levels (17.5% and 14.5%) on growth performance, dietary energetics and carcass traits. The dietary treatments used were: i) High protein-high energy (HP-HE); ii) High protein-low energy (HP-LE); iii) Low protein-high energy (LP-HE), and iv) Low protein-low energy (LP-LE). With a high-energy level, dry matter intake (DMI) values were 6.1% lower in the low-protein diets, while with low-energy, the DMI values did not differ between the dietary protein levels. Energy levels did not influence the final weight and average daily gain (ADG), but resulted in lower DMI values and higher gain efficiencies. No effects of protein level were detected on growth performance. The observed dietary net energy (NE) ratio and observed DMI were closer than expected in all treatments and were not affected by the different treatments. There was an interaction (p<0.03) between energy and protein level for kidney-pelvic and heart fat (KPH), KPH was higher in lambs fed high energy and high protein diet but not in high energy and low protein diet. The KPH was increased (20.2%, p = 0.01) in high-energy diets, while fat thickness was increased (21.7%, p = 0.02) in high-protein diets. Therefore, it is concluded that dietary energy levels play a more important role in feed efficiency than protein levels in finishing lambs with a high-energy diet (>2.80 Mcal/kg ME). Providing a level of protein above 14.5% does not improves growth-performance, dietary energetics or carcass dressing percentage.

Carcass Yield, Non-Carcass Parts, Internal Organs and Meat Quality Characteristics of Karayaka Male Lambs with Different Birth Weight Fed Free-Choice Feeding

“…Also FCF-fed lambs consumed less alfalfa hay, wheat bran and barley than TMR-fed lambs. This finding is in agreement with the idea that feed intake is regulated by dietary energy density in lambs (Ebrahimi et al 2007;Ríos-Rincón et al 2014). The results on the slaughter weight disagreed with the findings of other study (Sahin et al 2003) who indicated that the slaughter weight did not differ between TMR-and FCF-fed lambs.…”

“…In the present study, relative weights of digestive tract (p<0.05) and stomach (p<0.05) and relative length of intestine (p<0.05) of TMR-fed lambs were higher than those of FCF-fed lambs (Table 3). These findings may be related to the body composition of lambs can be modified by increased energy and protein intakes (Ebrahimi et al 2007;NRC 2007;Ríos-Rincón et al 2014). Therefore, these results indicated that the FCF system did not affect the functions of the GIT traits to improving the efficiency of feed utilization in lambs although FCF system promoted the protein and energy intakes of lambs (Yıldırım et al 2013).…”

“…Indeed, studies evaluating the effects of FCF system or indicated that fattening sheep kept in a controlled environment can successfully select a diet of adequate intake from a suitable pair of feeds to match their nutritional requirements and had an improved the feed efficiency and growth rate similar or over those achieved with conventional feeding systems (Askar et al 2006;Görgülü et al 1996;Rodríguez et al 2007;Sahin et al 2003). Ebrahimi et al (2007) and Ríos-Rincón et al (2014) reported that when a single concentrate diet is allocated during the finishing period, dietary protein and energy levels had effects on carcass characteristics. Lambs which are heavier at birth are usually singles, males or offspring of ewes with both larger body sizes and good feeding conditions .…”

Effects of high-level chromium methionine supplementation in lambs fed a corn-based diet on the carcass characteristics and chemical composition of the longissimus muscle

“…After 56 days of fattening, controls lambs increased up to 11.9% in fat in the LM. Fat deposition is highly correlated to the energy density of diet, level of intake, and length of days of feeding (13,14). There were no effects of treatments on HCW, dressing percentage and size measures of components of carcasses.…”

Efecto de la inclusión de zeolita (clinoptilolita) en ovinos en etapa de finalización: Respuesta productiva y energética de la dieta

“…Ganancias diarias (rango de 0,230 a 0,291 kg/d), consumos de MS (rango de 0,230 a 0,291 kg/d) y eficiencias (rango de 0,180 a 0,210) similares a lo observado para el grupo control en este experimento se han informado para machos enteros cruzados de las razas Katahdin × Pelibuey consumiendo dietas de finalización libres de zeolita o de algún otro tipo de aditivo y con un contenido energético de 1,90 a 2,10 Mcal/kg de EN para mantenimiento (López-Carlos et al, 2011;Ríos et al, 2010Ríos et al, , 2014Estrada et al, 2013Estrada et al, , 2016. Por otra parte, la información sobre la respuesta productiva de borregos consumiendo dietas de finalización suplementadas con zeolitas es escasa.…”