Performance and nutritional characteristics of beef heifers in growing submitted different strategies of supplementation in grazing / Desempenho e características nutricionais de fêmeas de corte em cria e recria submetidas a diferentes estratégias de suplementação em pastejo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

With the objective of evaluate the productive performance and nutritional characteristics of beef females in growing, submitted to different supplementation strategies on grazing, four experiments were conducted contemplating the periods of transition rainy-dry, dry, transition dry- rainy and rainy. In the first experiment, its was evaluated the productive performance, pasture and milk intake, and the nutrients digestibility ingested by Nelore or crossbreed female calves, with predominance of blood zebu, supplemented with different amounts of energy, in creep-feeding regime at pasture of Brachiaria decumbens Stapf, during the transition rainy-dry season. Fifty one female calves with blood predominance Nelore and your respective mothers were used, the calves had initials average ages and weights of 120 days and 133.4 3.12 kg, respectively, for the evaluation of the productive performance, intake and diet digestibility. Were evaluated four treatments: mineral mixture - MM; T250 250g of supplement/animal/day; T500 500g of supplement/animal/day; T750 750g of supplement/animal/day; totaling three groups with thirteen animals each and a group with twelve animals. All the supplements were balanced for supply 100g of crude protein / animal/day. Were used LIPE and oxide chromic as external indicators for estimate of the fecal excretion and intake of DM individual of supplement, respectively and the NDF indigestible as internal indicator for the pasture intake. There was not difference in the performance between the supplemented animals and non- supplemented. The total intake of DM of pasture was larger for the animals supplemented, as well the digestibility of the DM and of NDFacp ingested by the animals. The average of cows milk production was 5.33 kg/day, with 3.51% of protein and 4.85% of fat. With this can conclude that the use of the multiple supplementations in different levels, containing 100g of CP, compared to animals receiving mixture mineral, it doesn t promote significant improvements in the performance of beef female calves in pasture at Brachiaria decumbens Stapf supplemented during the rainy to dry transition season. In the second experiment it was aimed to evaluate the productive performance, intake and nutrients digestibility ingested by Nelore or crossbreed heifers, with predominance of blood zebu, in growing, supplemented in two levels, with sources of energy based on corn grain - rich in non fibrous carbohydrate (Corn) and the second based on wheat bran - rich in digestible fiber (Wheat), in pasture of Brachiaria decumbens Stapf, during the dry season. Forty heifers were used (20 Nelore and 20 crossbreed), with predominance of blood zebu, recently-weaned, with initials age and weights average, respectively, of 8.5 months and 197.9 3.74 kg. Two supplements were formulated, being the first based of corn maize and soybean meal - rich in starch and the second based of wheat meal - rich in fiber. The treatments were: Supplement based in corn or wheat in the amount of 0.5 or 1.0 kg/animal/day, one more controls treatment supplemented with mineral mixture. The average daily gain was larger for the animals supplemented in relation to the no-supplemented. In the same way, animals supplemented with source starch of energy in the supplement containing about 30% of CP, presented larger performance in relation to the animals receiving supplement based in wheat meal. The intake of DM of pasture was smaller for the animals supplemented with larger supplementation level, and the substitution index was from -0.72 to the animals supplemented with 0.5 kg supplement/animal/day against 0.48 for the animals supplemented with 1.0 kg supplement/animal/day. The supplementation of heifers during the dry season makes possible improvements in the productive performance. The use of the corn/soybean mixture meal as base of the multiple mixture results in better productive performance of heifers when compared to wheat meal. In the third experiment it was aimed to evaluate the use of nitrogenous compositions profile of the supplement for adaptation of global microbial activity in the rumen evaluating the productive performance, intake and nutrients digestibility of the nutrients ingested by Nelore or crossbreed heifers, with predominance of blood zebu, in pastures of Brachiaria decumbens Stapf, during transition dry-rainy season. Forty heifers were ( 20 Nelore and 20 crossbreed), with predominance of blood zebu, with ages and weights average initials, of 11.5 months and 213.4 3.82 kg, respectively. Were evaluated the mineral mixture and four multiple supplements, formulated with different profiles protein presented in the amounts of 0.5 kg/animal/day, totaling five treatments. The treatments were: T0 - 100% of the protein coming of the mixture corn and soybean meal (true protein); T25, T50 and T75 - with 25; 50 or 75% of the protein coming of the mixture urea/ammonium sulfate 9:1 (non protein nitrogen), besides a controls supplemented with mineral mixture - MM. All supplements were formulated to contain 35% of crude protein. There was not difference in the average daily gain (ADG) and final live weigh (FLW) between the supplemented animals and non supplemented (P>0.10). However, decreasing lineal effect was verified in the body weight gain of the animals increasing the of non protein nitrogen level (P<0,10). The supplementation with different protein profiles does not improve the performance of heifers at pasture of Brachiaria decumbens Stapf. during the dry to rainy transition season. As larger the non protein nitrogen in the supplement smaller the average daily gain of the animals. In the fourth experiment forty heifers (20 Nelore and 20 crossbreed) with predominance of blood zebu, were supplemented with the objective of evaluate the productive performance by heifers in phase of growing, receiving different supplementation levels, in pastures of Brachiaria decumbens Stapf, during the rainy season. The heifers had 14.5 months of age and 233.4 4.00 kg of corporal weight on average to the beginning of the experiment. Multiple mixture was evaluated supplied in the amounts of 0; 0.3; 0.6; 1.2 and 2.4 kg for animal/day. The supplement was formulated to contain 25% of crude protein and about 74,5% of TDN. Positive correlation was verified between the supplement intake and average daily gain. The age at puberty of heifers is not only related with chronological age, but also with physiologic condition to the pubescent age. Better performances of reproduction animals are usually accompanied of better corporalcondition propitiating to females larger conception conditions to the covering. This way, the supplementation level to be adopted for beef females in pasture during the rainy season should be exclusive function of the cost of the determined resources sees that the performance is increased lineally with the supplementation levels.

ASSUNTO(S)

suplementação bovino de corte nutricao e alimentacao animal beef cattle heifers supplementation novilhas

ACESSO AO ARTIGO

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