Comportamiento productivo de novillos Hereford alimentados con dietas de engorda que incluyen niveles crecientes de pomasa de tomate conservada.

The object of this study was to measure the effect of tomato pomace in diets for "feed-lot" fattening of steers from the age of 18 months. This by-product obtained from the processing of tomatoes mainly for concentrated pastes, has the characteristics of high moisture (80-85%), moderate raw protein (19-24%) and high net energy level (5,5 - 6,4 Mcal/kg). 24 steers of 328 kg initial live weight were used, allotted into four treatments with six repetitions each, according to the level of tomato pomace incorporated in the diet, in an experimental design in random blocks. 10% of the by-product in the diet on dry matter basis (DMB) was included in T1; 20% in T2; 30% in T3; and 40% in T4, replacing a basic diet made up of alfalfa hay, wheat straw, rape seed bran and mineral salts. The 4 diets were isoenergetic and isoproteic. A slight tendency to increase consumption at the lowest level of inclusion of tomato pomace (9,48 kg, DMB) was observed, decreasing in the treatment with 40% of the by-product (9,08 kg, DMB). The high content of the pomace's moisture slightly restricted consumption in the treatments with higher percentage of inclusion. The final live weights were similar (P > 0,05) between treatments with T1 reaching 426 Kg; T2, 442; T3, 450 and T4, 445 kg. Daily average gain did not reflect significant differences (P > = 0,05), which were: 0,93; 1,09; 1,15 and 1,11 kg/day for T1, T2, T3 and T4, respectively. The conversion efficiencies on dry matter basis (DMB) were similar for treatments 3 and 4 and worse for T1 and T2. A tendency toward a better productive response measured in the live animal was observed according to the increase in the percentage of incorporation of pomace up to levels of 40%. Similar quantitative and qualitative characteristics of the dressed carcasses were observed with 21 months-old steers. But with the same test duration (105 days), differences in the degree of the final product in different treatments were found, with T4 presenting a better final product in both the muscular and fatty parts. Treatment 2 and 3 obtained a better economic response, and a higher yield.