Substituição de monensina sódica por bicarbonato de sódio em dietas de novilhas confinadas / Evaluation of the replacement of Monensin with Sodium Bicarbonate in diets for confined bovines

Avaliaram-se os efeitos da substituição da monensina sódica pelo bicarbonato de sódio em dietas de novilhas em confinamento em relação ao desempenho animal, à conversão alimentar e ao parâmetro de fermentação ruminal. Foram utilizadas 56 novilhas mestiças, confinadas por 112 dias, submetidas a dietas com duas porcentagens de concentrado, 50% e 80% da matéria seca, com adição de monensina sódica ou bicarbonato de sódio, em fatorial 2x2. O volumoso utilizado para compor as dietas testadas foi composto de silagem de milho e cana-de-açúcar na proporção de 60:40, respectivamente. O nitrogênio amoniacal foi maior nos animais alimentos com dietas com alto grão. A monensina, na dieta 80:20, proporcionou maiores valores de nitrogênio amoniacal, uma e nove horas após o consumo da ração. O uso de bicarbonato promoveu os maiores valores de pH ruminal na dieta com 50% de concentrado, de seis a 18 horas após o consumo. Não houve efeito do aditivo sobre o desempenho animal. A alta inclusão de grãos na dieta propiciou aumento do desempenho animal e da eficiência alimentar. Conclui-se que o uso de bicarbonato de sódio em dietas para terminação de animais em confinamento é uma opção viável em substituição à monensina sódica para a manipulação da fermentação ruminal.

The effects of replacing monensin with sodium bicarbonate in diets for confined heifers on weight gain (WG), dry matter intake (DMI), feed:gain ratio (FGR) and rumen fermentation parameters were evaluated. Fifity six heifers were utilized (Santa Gertrudis x Braunvieh). Diets were formulated with two levels of concentrate (50% and 80% concentrate) with sodium monensin or sodium bicarbonate. The DMI was higest in heifers with an intake of 80% concentrate. There was not difference when the same concentrate levels were evaluated in relation to the DMI. The heifers at 80% concentrate showed highest WG. There was no significant difference in relation to WG between monensin and bicarbonate treatments and levels concentrate proportions. There were significant effects regarding FGR between treatments. The heifers on 80% concentrate showed lowest FGR. In the evaluation of N-NH3, the highest values were observed, on the whole, at 80:20 diets in relation to 50:50 diets. In the additive use, the monensin on 80:20 diets promoted the highest values of N-NH3 at 1 for 9 hours after feed intake. In the values of ruminal pH, the bicarbonate increased the values on 50:50 at 6 for18 hours after feed intake, in relation to the 80:20 diet. In this case, it was concluded that the use of sodium bicarbonate in diets for confined finishing heifers is a viable option for the replacement of monensin sodium.

Nutrient digestibility of degermed, dehulled corn, citrus pulp, and soy protein concentrate by barrows.

This study was carried out to determine apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of DM, CP, GE, and their respective digestible content of degermed dehulled corn (Zea mays), citrus pulp, and soy (Glycine max) protein concentrate by pigs using the difference method. Thirty-two barrows (28.1 ± 1.6 kg of BW) were fed a corn-soybean meal basal diet or 1 of 3 diets formulated by replacing 30% of the basal diet with 30% of 1 of the test feedstuffs for 11 d. Chromic oxide (0.3%) was included in the diets. Feces were collected from days 7 to 11 by grab sampling and ileal digesta were collected after pigs were slaughtered on day 12. The AID of DM and AID and ATTD of GE of degermed corn (77.4, 88.7, and 77.7%) were greater (P < 0.05) than those observed in citrus pulp (50.3, 86.5, and 55.8%) and in soy protein concentrate (63.5, 85.1, and 59.4%), which did not differ (P > 0.05). The ATTD of CP, total digestible CP, and total DE of soy protein concentrate (87.5%, 500 g/kg, and 3739 kcal/kg) were higher (P < 0.05) than the values in degermed corn (81.7%, 57.5 g/kg, and 3330 kcal/kg), which were greater (P < 0.05) than those in citrus pulp (60.5%, 39.5 g/kg, and 3223 kcal/kg). Total and ileal digestible DM, AID of CP, and ileal DE of degermed corn (782 g/kg, 673 g/kg, 70.7%, and 2913 kcal/kg) and soy protein concentrate (778 g/kg, 570 g/kg, 78.7%, and 2878 kcal/kg) were similar (P > 0.05) and greater (P < 0.05) than those in citrus pulp (737 g/kg, 436 g/kg, 50.6%, and 2081 kcal/kg). Ileal digestible CP of degermed corn (49.8 g/kg) and citrus pulp (33.0 g/kg) did not differ (P > 0.05) but were smaller (P < 0.05) than the value found in soy protein concentrate (434 g/kg). The DM and energy from degermed corn are more efficiently digested by the pig than those from soy protein concentrate and citrus pulp. Soy protein concentrate was the best protein source evaluated in this study.