Utilização de feno de erva sal (Atriplex nummularia Lind) e farelo de milho em substituição à palma forrageira (Opuntia fícus-indica Mil) em dieta para ovinos

Abstract

This work aimed to evaluate the effects of replacing the spineless cactus (Opuntia ficus-indica Mill) by saltbush hay (Atriplex nummularia Lind.) and corn bran on feed intake, apparent digestibility of the diet, eating behavior and rumination parameters of sheep. The levels of replacement were of 0,0; 15,3; 35,3; 62,9 and 100 %.Five adult sheep were used, weighing 60kg and canulla inserted in the rumen. The sheep were assigned to five dietary treatments in a Latin square 5 x 5 (5 diets and 5 periods), housed in individual stalls. The intake of dry matter,water and salt were obtained by the difference between the food presented to it and the surpluses. To estimate fecal production we used chromium oxide in two daily 10g doses, applied via the rumen cannulla. The behavioral observations were conducted in the seventh day of adaptation of the experimental diet in intervals of five minutes during 24hr. The samples for determining the rumination parameters were collected 0 and 1, 2, 3, 4, 5, 6,7, 8, 9, 10, and 11 hours after feeding the animals. The intake of dry matter and nutrients, written in g/day, percentage of live weight (%LW) and grams per unit ofmetabolic weight (g/LW0,75), were influenced significantly (P<0,05) for the replacement levels, the largest intake being in the 35,3% and the 62,9% levels. The coefficients of apparent digestibility of dry matter (DCDM) and organic matter (DCOM) were not affected by the replacement. However the coefficient of digestibility of the fiber in neutral detergent (NDF) decreased. The water intake suffered significant influence (P<0,05), with averages of 4549; 4296; 4327, 2907 and 153 mL/day for water through diet. Salt intake was not affected (P>0,05). The times of feeding, rumination and total mastication had quadratic behavior, showing the respective maximum points of 61,39;41,32 and 46,34 %. The concentrations of ammonia, salt and volatile fat acids (VFA), pH and ruminal temperature were influenced significantly (P<0,05) by the increase in the substitution level. The concentration of ammonia nitrogen featured averages of 10,26 and 39,29 mL/100mL for the respective levels 0,0% and 100% of substitution. The largest average for pH was obtained for the level of 100% of substitution with average of 6,06. We can conclude that the substitution of the spineless cactus influences the intake and digestibility of the diet, besides modifying the pattern of the eatingbehavior and the rumination parameters of sheep.