Substituição do milho pela raspa de mandioca em dietas para vacas primíparas em lactação

Abstract

RESUMO -Com o objetivo de avaliar a influência de níveis de substituição do milho moído pela raspa de mandioca no desempenho dos animais, no consumo e na digestibilidade dos nutrientes de dietas à base de palma forrageira (Opuntia ficus indica, Mill) e silagem de sorgo, cinco vacas primíparas da raça Holandesa (60±15 dias em lactação e 448 kg de PV inicial) foram distribuídas em um único quadrado latino (5 x 5). A raspa de mandioca substituiu 0, 25, 50, 75 e 100% do milho moído nas dietas. Os consumos e a digestibilidade de MS (em kg/dia, % do PV, g/kg 0,75 do PV), MO, PB, EE, CNF, CHOT, FDA, FDN e NDT não foram influenciados pelos níveis de raspa de mandioca nas dietas. A produção de leite, a produção de leite corrigida para 3,5% de gordura e a produção de gordura decresceram linearmente em 20, 30 e 1,15 g/dia, respectivamente. A eficiência alimentar (kg de leite corrigido para 3,5% de gordura/kg de MS) diminuiu linearmente em 0,001 para cada unidade de inclusão da raspa de mandioca, enquanto o teor de gordura não foi influenciado pelos níveis de substituição do milho moído nas dietas.Palavras-chave: consumo, digestibilidade, eficiência alimentar, produção de leite, produção de gordura Replacement of corn with cassava scrapings in diets for primiparous lactating Holstein cowsABSTRACT -This study was conducted to evaluate replacement of ground corn grain with cassava scrapings on nutrient intake, digestibility, and production of primiparous Holstein lactating dairy cows receivind diets containing forage cactus (Opuntia ficus indica, Mill), sorghum silage and concentrate. Five cows averaging 60±15 of days in milk and initial body weight (BW) of 448 kg were randomly assigned to a 5 × 5 Latin square with increasing levels of cassava scrapings in the diet: 0, 25, 50, 75 or 100%. Intakes of dry matter (DM) (kg, %BW and g/BW kg 0.75 ), organic matter (OM), crude protein (CP), ether extract (EE), nonfiber carbohidrates (NFC), total carbohydrates (TCHO), acid detergent fiber (ADF), neutral detergent fiber (NDF), and total digestible nutrients (TDN) all were not affected by replacing ground corn with cassava scrapings in the diet. Similarly, increasing the dietary levels of cassava scrapings did not affect apparent digestibilities of nutrients (P>0.05).However, milk yield, milk yield corrected for 3.5% fat, and fat yield decreased linearly by 20, 30 and, 1.15 g/day, respectively, when corn grain was replaced with cassava scrapings. Feed efficiency, expressed as kg of 3.5% fat corrected milk per kg of DM, also decreased linearly by 0.001 per each unit of cassava scrapings added to the diet. No significant differences for milk fat content were observed among treatments in this trial.

Use of dried waste of cassava starch extraction for feeding lactating cows

“…The reduction in intake may be associated with the MS intake as a percentage of body weight (BW) was not influenced by the treatments, consistent with the results presented by Ramalho et al (2006). In the latter study there was no variation in DM intake as a percentage of live weight of primiparous lactating cows fed with different diets containing cassava chips (0, 25, 50, 75 and 100% replacement of maize), which have a similar composition to WCSEd.…”

“…The reduction in milk production observed in this study reflects the reduction in intake. Ramalho et al (2006) used cassava chips, a product with a composition similar to WCSEd in terms of DM, and also observed a decreasing linear effect on milk production, and attributed this response to differences in the processes of digestion, absorption and metabolism of starch from the corn and cassava chips, and the associative effects of these foods with other dietary ingredients.…”

“…This waste is a cheap energy substitute for the formulation of TATIANE FERNANDES et al feed for ruminants, and as it has a similar nutritive value to corn, it is a viable alternative (Ramalho et al 2006).…”

“…The glucose levels stayed within the appropriate levels for cattle, which can range from 45 to 75 mg dL -1 (Fernandes et al 2012). It is possible that the change in blood glucose levels between treatments was due to differences in degradation and absorption between corn and WCSEd (Svihus et al 2005, Ramalho et al 2006). …”

“…It is likely that this change occurred as a result of the degradation processes and subsequent digestion of food, since propionate, which is produced in the rumen, contributes to the formation of up to 54% of the glucose present in the blood (Silva 1979), and the diet used, has food from high ruminal degradation. Another factor that may have influenced the variation of blood glucose was the action of insulin, the hormone that stimulates glucose uptake by tissues (Grande and Santos 2008), and when high concentrations of starch reach the intestine, it causes elevation in insulin concentration, as a metabolic response (Ramalho et al 2006).…”