Nutritive value of sheep diets made up of hay from Tifton 85 grass and leucaena

Abstract

-The intake, digestibility, nitrogen balance and energetic balance were evaluated in sheep diets consisting of hay from Tifton 85 grass at two ages of regrowth (28 and 42 days) and hay from leucaena at 40 days of regrowth, in the proportions of 20 and 40%. Twenty Santa Inês sheep, kept in metabolic cages, were used in a randomised block design according to body weight. The hay from the Tifton 85 grass, processed at 28 days of regrowth, resulted in a higher CP intake than when processed at 42 days of regrowth. There was higher protein intake for the 40% proportion of leucaena hay in relation to that of 20%, regardless of the regrowth age of the grass. Diets containing Tifton 85 grass processed at 28 days resulted in greater values for both DE and ME. There was greater intake, absorption and urinary excretion of N, and a lower N faecal to N urinary ratio, with diets containing Tifton 85 grass processed at 28 days, as well as with those diets containing 40% leucaena hay. When formulating sheep diets containing hay from Tifton 85 grass processed at 28 days of regrowth and combined with 20% hay from leucaena, the grass, despite showing good energetic value, is not enough to provide full use of the nitrogen available to the ruminant, making it necessary need to find combinations with concentrated food sources which are able to optimise the use of nitrogen, reduce environmental impact and maximise sheep production. RESUMO -Avaliou-se o consumo, a digestibilidade e o balanço de nitrogênio e energético de dietas para ovinos constituídas por feno de capim-Tifton 85 em duas idades de rebrota (28 e 42 dias) e feno de leucena aos 40 dias de rebrota, nas proporções 20 e 40%. Foram utilizados 20 ovinos da raça Santa Inês, em gaiolas de metabolismo, em delineamento de blocos ao acaso, quanto ao peso vivo. O feno de capim-Tifton 85 processado aos 28 dias de rebrota resultou em maior consumo de PB que aos 42 dias de rebrota. Houve maior consumo de proteína quando da proporção 40% de feno de leucena em relação a 20%, independente da idade de rebrota da gramínea. As dietas contendo feno de capim-Tifton 85 processado aos 28 dias resultaram em maior valor para ED e EM. Houve maior ingestão, absorção e excreção urinária de N e menor relação N fecal /N urinário para as dietas contendo feno de capim-Tifton 85 processado aos 28 dias, assim como para as dietas contendo 40% de feno de leucena. Quando da formulação de dietas para ovinos contendo feno de capim-Tifton 85 processado aos 28 dias de rebrotação associado a 20% feno de leucena, embora a gramínea apresente bom valor energético, este não é suficiente para propiciar o aproveitamento do nitrogênio disponível ao ruminante, do que resulta necessidade de se buscar associação com fontes de alimentos concentrados capazes de otimizar o aproveitamento do nitrogênio, reduzir o impacto ambiental e potencializar a produção de ovinos.Palavras-chave: Balanço de nutrientes. Consumo voluntário. Cynodon spp. Digestibilidade. Leucaena leucocephala.

Effects of different hay: concentrate ratios on body and testicular-epididymal biometry and metabolic profile of Santa Ines lambs

“…Blood urea concentration decreased significantly in the control treatment, suggesting inadequate intake of nitrogen by the animals. Some research has shown that exclusive provision of Tifton 85 hay to ovine may result in low retention of nitrogen and high excretion in urine (ATAÍDE JÚNIOR et al, 2000;SANTANA et al, 2014). According to Santana et al (2014), Tifton 85 grasses, despite showing good energetic value, are not enough to provide full use of the nitrogen available to the ruminant, making it necessary to combine the hay with concentrated food sources that are able to optimize the use of nitrogen.…”

“…Moreover, this forage has good growth in pastures with nitrogen (QUARESMA et al, 2011). Therefore, the diet should have sufficient amounts of highly fermentable energy components when Tifton 85 hay or non-protein nitrogen is used (RANKINS JÚNIOR et al, 2002;SANTANA et al, 2014). Oscillations in urea concentration were observed in other treatments, suggesting that the inclusion of urea in the concentrate given to the Santa Ines lambs was beneficial when Tifton 85 hay was supplied.…”

Overcoming seed dormancy and evaluation of viability in Leucaena leucocephala

“…The presence of legumes in tropical grass pastures improves ruminant nutrition due to higher protein contents for development of microorganisms that digest forage (Valente et al, 2016). The tropical legume grasses have shown good results on production of goats (Rubanza et al, 2007), sheep (Santana et al, 2014), buffaloes (Kang et al, 2012) and cattle (Díaz et al, 2009).…”

Different Treatments for Breaking Dormancy of Leucaena Seeds (Leucaena leucocephala)

“…The presence of legumes in tropical grass pastures improves ruminant nutrition, due to the higher protein necessary for the development of microorganisms that digest forage (Gomes et al, 2011;Valente et al, 2015Valente et al, , 2016a. With good results of tropical grass pastures production with goats (Kanani et al, 2006;Rubanza et al, 2007), sheep (Karda, 2007;Santana et al, 2014), buffaloes (Kang et al, 2012;Hung et al, 2013) and cattle (Lourenço et al, 2001;Díaz et al, 2009). …”