Coffee hull or soybean hull replacing corn in diets based on sugar-cane for dairy cows / Casca de café ou casca de soja em substituição ao milho em dietas à base de cana-de-açúcar para vacas leiteiras

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The objective of his work was to evaluate the effect of corn grain replacement by coffee hull or soybean hull in sugar-cane based diets, with 60% concentrate, for dairy cows, on intake and apparent nutrient digestibility, milk production and composition, animal body weight variation, body reserve mobilization, ingestive behavior and milk activity economic performance, pH and ruminal liquid ammonia concentration, urea excretion in the urine, plasma and milk urea concentration, nitrogen compounds balance and microbial protein production, compared with corn silage diet. 12 purebred and crossbred Holstein cows were assigned to three 4X4 latin squares, balanced according to lactation period. Diets were isonitrogenous, with 14% crude protein, based on dry matter (DM). Diet control consisted of corn silage (AG-1051) and 40% concentrate, in DM. Three sugar-cane based diets (RB 73-9735) with 60% concentrate were used, with corn being replaced by 0% hull (without hull), 10% coffee hull or 20% soybean hull, in DM total diet. DM intake, organic matter (OM) and total carboydrates (TC) did not differ (P>0,05) among diets, whereas neutral detergent fiber intake (NDF), no fiber carboydrates (NFC), ether extract (EE), caffeine and total polyphenols (TPF) differ (P<0,05). In spite of the crude protein intake (CP) and observed total digestible nutrients (TDNobs) differ (P<0,05) among diets, they were enough to meet the nutrient requirements. No differences were observed (P>0,05) for the coefficients of apparent digestibility of DM, OM, CP, EE, TC, NFC, and TDNobs. The FDN coefficient of apparent digestibility was higter (P <0,05) for the diet based on corn silage compared to diets with sugar-cane without hull and with 10% coffee hull, but it was not different (P>0,05) from the sugar-cane diet with 20% soybean hull. There were no differences (P>0,05) for milk production with and without correction for 3,5% fat, body weight variation, plasma levels of non-esterified fatty acids (NEFA), milk crude protein (CP), fat (F), total solids (TS), and daily productions of CP, F, lactose (LA), TS and non fat solids (NFS) among the diets. The average times spent with feeding and rumination for the corn based silage diet were higher (P<0,05) than the ones obtained with the sugar-cane based diets, which did not differ (P>0,05). The simulations of economic performance of the milk production system indicated that the replacement of the corn silage diet in the dry period of the year by sugar-cane diets, showed potential for increasing the rate of return on the capital (% per year), being dependent of favorable combinations of sugar-cane relative costs and of the concentrate relative prices, mainly corn. Ruminal pH did not differ (P>0,05) at the collection times zero and three hours after the morning feeding. Immediately before the feeding there was no difference (P>0,05) for ruminal ammonia concentration. However, three hours after feeding, the sugar-cane based diet with 10% coffee hull showed lower concentration (P<0,05) of ruminal ammonia than the diets containing corn silage and sugar-cane with 20% soybean hull, not differing (P>0,05) from the sugar-cane diet without hull. No differences were found (P>0,05) for urea excretion in the urine (UE) and milk urea nitrogen (MUL), with mean values 179,31 mg/kg PV and 12,59 mg/dl, respectively. Plasma urea nirogen (PUL) was lower (P<0,05) in the corn silage diet than sugar-cane diets without hull and with 20% soybean hull. Among the sugar-cane based diets, the one including 10% coffee hull gave lower (P<0,05) levels of NUP. The nitrogen compounds balance (NB) of the sugar-cane diet with 10% coffee hull was lower (P<0,05) than the diets with corn silage and sugar-cane without hull, but it did not differ (P>0,05) from the diet with 20% soybean hull; however, NB was positive in all diets. Microbial nitrogen compounds synthesis and microbial efficiency were not influenced by the diets (P>0,05), with mean values of 273 g/day and 130,08 gPBmic/kg NDT, respectively. Inclusion levels in sugar-cane based diets, with 10% coffee hull or 20% soybean hull, replacing corn, for cows producing 20 kg of milk, can be used according to availability and economic convenience.

ASSUNTO(S)

urea nitrogen intake digestibilidade nutrição de ruminantes produção animal uréia ruminants nutrition milk production efficiency rentabilidade profitability proteínas microbianas digestibility animal production bovino de leite microbial protein avaliacao de alimentos para animais dairy cow leite eficiência produtiva

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