Effect of concentrate supplementation on performance and ingestive behaviour of lambs grazing tropical Aruana grass (Panicum maximum)

Abstract

The aim of this study was to evaluate the effects of concentrate supplementation on the performance and ingestive behaviour of lambs grazing tropical grasslands of Panicum maximum cv. IZ-5 and its effect on pasture characteristics. Different levels of daily supplementation with concentrate were compared: no supplementation; or supplemented at 1.5% and 2.5% of lamb liveweight. The grazing simulation technique was used for qualitative assessment of the pasture every 28 days. Herbage mass, pasture growth rate, sward height as well as botanical and morphological composition of the pasture were evaluated. Average daily gain, gain per hectare and ingestive behaviour were measured on the lambs. The forage supply was 4% of green leaves (4 kg dry matter per 100 kg of liveweight) in all treatments. Six 3–4-month-old Texel and Corriedale lambs were used per paddock. The design was a randomised block design with three replications. Concentrate supplementation had a direct effect on pasture structure, especially height (significant interaction treatment vs period – P = 0.0373). In the treatment without supplementation, the animals grazed for a longer period than the others. Idle time was higher in the treatment with the highest level of supplementation, and rumination time was similar among the treatments. Supplementation with 2.5% significantly increased the average daily gain (0.143 g vs 0.026 g for no supplementation) and gain per hectare (30 kg vs 258 kg for no supplementation vs supplementation at 2.5% of lamb liveweight, respectively). The results show the potential increase in production and productivity with the use of concentrate supplementation at 2.5% lamb bodyweight. Notwithstanding the increase in production, supplementation with concentrate provided a strong negative impact on pasture structure and behaviour of animals that should be considered when using concentrate supplementation for finishing lambs in tropical regions.

Effects of type of tropical pasture and concentrate supplementation level on the carcass traits of grazing lambs

“…This is related to higher resting intervals, which may explain their superior carcass mean values. The relation between concentrate supplementation muscularity and adiposity of the carcass has also been reported previously (Fernandes et al, 2011;Majdoub-Mathlouthi et al, 2013;Armero and Falagán, 2015). Finished lambs in grazing systems without supplementation results in lower fat accumulation in the carcass (Jacques et al, 2011;Papi et al, 2011;Majdoub-Mathlouthi et al, 2013;Armero and Falagán, 2015;Asadollahi et al, 2017).…”

“…Carcass weight, yield, muscularity, and adiposity were greater in animals on diets with concentrate levels of 1.5 % and 3 %. This was probably due to the greater levels of energy and protein in their diets (Carrasco et al, 2009b;Papi et al, 2011;Fernandes et al, 2011), which also can be a result of associative effect between forage and concentrate supplementation (Silva et al, 2011;Fajardo et al, 2015). Concentrate supplementation probably improved the metabolic efficiency and promoted faster digestion and lower gastrointestinal content at slaughter (Joy et al, 2008;Jacques et al, 2011;Armero and Falagán, 2015).…”

“…Concentrate supplementation probably improved the metabolic efficiency and promoted faster digestion and lower gastrointestinal content at slaughter (Joy et al, 2008;Jacques et al, 2011;Armero and Falagán, 2015). The concentrate may have shortened the grazing time due to the better nutritional status of the animals (Silveira et al, 2015;Fajardo et al, 2015). This is related to higher resting intervals, which may explain their superior carcass mean values.…”

“…'Aru-G. D. Vega Britez et al: Lamb carcasses finished in tropical pastures with supplementation ana'; those are desirable characteristics for the diet of grazing sheep (De Souza et al, 2014). Some studies have reported the effects of feed supplementation on the feeding behaviour and the uniformity of the performance of lambs raised on Aruana grass (Fajardo et al, 2015;Silveira et al, 2015), while other works have evaluated supplementation schemes on animal performance and production costs using Marandu grass (Geron et al, 2012;Carvalho et al, 2015). Also, some previous studies with Tifton indicate the use of concentrate can accelerate growth, improve the carcass yield, and increase fat content in the carcass (Carvalho et al, 2007;Fernandes et al, 2011).…”

Management Strategies for Lamb Production on Pasture-Based Systems in Subtropical Regions: A Review

“…Detailed reviews about the effects of supplementation on grazing sheep were compiled by Dove ( 5 ), Clark and Woodward ( 6 ), and Kenyon and Webby ( 7 ). However, some main effects of supplementation on grazing sheep in subtropical region can be listed: (1) type of supplement ( 8 , 9 ); (2) level of supplement ( 10 , 11 ); (3) type of pasture ( 8 ); (4) type of animal ( 12 ); and (5) animal feeding system ( 13 ). One of the most important feed supplement effects is related to the energy/protein ratio of the animal diet.…”