Antônio Assis Vieira

Estimativa da digestibilidade aparente de nutrientes em dietas para eqüinos, com o uso de óxido crômico e indicadores internos

Two assays were performed to evaluate the apparent digestibility of nutrients in horses diets, using the total collection of feces method and the markers chromic oxide, indigestible acid detergent fiber (iADF), indigestible neutral detergent fiber (iNDF), indigestible cellulose (iCEL), lignin (LIG), and insoluble acid detergent ashes (ADTA), as markers. In the first assay, five crossbred colts were used, fed five diets with different levels of crude protein, maintaining the relationship 50:50 concentrate to forage. The chromic oxide was used as external marker. In the second assay, four crossbred colts were fed diets composed by coastcross hay as forage and concentrate in the proportions of 40:60, 60:40, 80:20 and 100:00. In both assays, the cotents of indigestible acid detergent fiber, indigestible neutral detergent fiber, indigestible cellulose, lignin and acid detergent insoluble ash were obtained after in vitro incubation. In the first assay, the FDAi showed to be appropriate as internal marker to estimate the digestibility, and in both assays the CELi showed to be appropriate as internal marker for the estimate of apparent digestibility of nutrients of horses diets. The chromic oxide showed low fecal recovery in the first assay and the LIG showed low fecal recovery in both assays, underestimating the apparent digestibility coefficients of nutrients, and was inadequate to estimate the digestibility. ADIA, compared to the total collection of feces method, also showed to be inadequate to estimate the nutrient digestibility in equine.

Cinética de passagem da digesta, balanço hídrico e de nitrogênio em eqüinos consumindo dietas com diferentes proporções de volumoso e concentrado

Este trabalho foi conduzido com os objetivos de avaliar a cinetica de passagem da digesta no trato digestivo e estimar o balanco hidrico e de nitrogenio em equinos consumindo dietas com diferentes niveis de volumoso. Foram utilizados quatro potros nao castrados, mesticos, com idade de 18 meses, alojados em baias individuais e exercitados uma vez ao dia. O delineamento experimental utilizado foi o quadrado latino 4 x 4, em que cada periodo experimental teve duracao de 14 dias de adaptacao a dieta e cinco dias de coleta fecal. As dietas foram compostas por feno de capim-coastcross e concentrado, fornecidos simultaneamente, duas vezes ao dia, nas proporcoes de 40:60, 60:40, 80:20 e 100:0. A cinetica de passagem da digesta foi estimada pelo tempo medio de retencao da digesta (TMR), da taxa de passagem (TxP) e do tempo de trânsito (TT), utilizando dois indicadores externos, o cromo fixado como mordente na fibra em detergente neutro (Cr-FDN) e o complexo cobalto-EDTA (Co-EDTA). O balanco hidrico foi avaliado de acordo com as quantidades de agua ingerida in natura e na dieta e excretada na urina e nas fezes. O balanco de nitrogenio foi avaliado de acordo com as quantidades diarias de compostos nitrogenados consumidos e excretados. As medias dos valores da cinetica de passagem nas fases solida e liquida da digesta foram 42,7 e 33,8 horas para TMR e de 2,4 e 3,1 %/hora para TxP. O TT da fase liquida da digesta apresentou efeito linear negativo, em funcao da inclusao de volumoso na dieta. O consumo medio de agua foi de 13,8 litros. O balanco hidrico variou de 7,9 a 1,8 litros para as dietas com 40 e 100% de volumoso, respectivamente, reduzindo de forma linear, com a inclusao do volumoso na dieta.

Produtividade e eficiência de vacas Nelore em pastagem de Brachiaria decumbens Stapf nos Cerrados do Brasil Central

The productivity of Nelore cows on Brachiaria decumbens Stapf pasture was measured during four years, in a soil initially improved with limestone and fertilizer and with free access to a mineral mixture. Pregnancy rate (PR), calving rate (CR), weaning rate (WR), calves weaning body weight (BWC), productivity (P = kg of calf/cow) and efficiency (E= P/100 kg of cow) per cow, productivity per area (AP = calves kg/ha), as well as cow body weight and body condition before the calving season (CLW and CBC), at the middle of the mating season (MLW and MBC) and at weaning (WLW and WBC) were evaluated. Mean PR, CR and WR of 87.5, 81.7 and 77.2%, respectively, were observed. Mean LWC of 170 ± 21.89 kg and mean weaning age of 202 ± 16.48 days were observed. Significant effect of calving order (CO) on LWC was detected. Cows between CO3 and CO9 weaned the heaviest calves. Values of 130 kg and 32.19 kg were observed for P and E, respectively, with AP of 192 kg/ha. The CLW and CBC, MLW and MBC, and WLW and WBC were of 471 + 19.67 kg and 4.45 + 0.30; 405 + 21.48 kg and 3.32 + 0.44; 410 + 9.35 and 3.54 + 0.19, respectively. The correlation between body weight and body condition was of 0.66. Nelore cows maintained on a tropical pastures of Brachiaria decumbens Stapf, in an initial fertilized soil, had high reproduction level and productivity. Cows with medium calving order had higher productivity than primiparous and older cows.

Lactação em éguas da raça Mangalarga Marchador: produção e composição do leite e ganho de peso dos potros lactentes

Objetivou-se, com este trabalho, avaliar a producao e a composicao do leite de eguas Mangalarga Marchador e o ganho de peso dos potros lactentes. A producao de leite foi avaliada em oito eguas, pelo metodo da pesagem dos potros antes e depois das mamadas, em intervalos de duas horas, em doze observacoes diarias. A partir do somatorio da quantidade de leite produzido nas observacoes, obteve-se a producao diaria de leite. A producao de leite, analisado quanto aos teores de lactose, proteina, gordura e energia, foi avaliada aos 20, 40, 60, 80, 100, 120, 140 e 160 dias da lactacao A producao media de leite variou de 9,95 kg/dia no 40o dia a 7,48 kg/dia no final da lactacao. A producao total de leite estimada foi igual a 1405,56 kg. A producao de leite, expressa em percentual do peso vivo (PV) das eguas, variou entre 2,3% do PV no 20o dia e 1,8% do PV no final da lactacao, sendo similar as quantidades de leite produzidas nos periodos diurno e noturno. Nao foi observado efeito da idade das eguas na producao de leite. O ganho medio diario de peso dos potros ao longo do periodo de amamentacao foi de 0,77 kg, com maiores valores nos meses iniciais do periodo de amamentacao. O leite das eguas apresentou baixas concentracoes de proteina, gordura e energia e altas de lactose, alem de resposta quadratica decrescente, em funcao do periodo da lactacao.

Intake, apparent nutrient digestibility and water balance in horses fed on different forms of coast-cross hay

This study was carried out to evaluate intake, apparent nutrient digestibility and water balance in horses fed on different forms of coast-cross hay. Four crossbreed horses, 30 months of age and 200 kg body weight were used. Horses were fed coast-cross hay in four physical forms: long hay; chopped hay (5 cm); ground hay (5 mm) and ground hay (3 mm). The experiment was performed in a 4 × 4 Latin Square design with 15 days for each experimental period (10 days for adaptation to the diets, four days for feces collection and one day for urine collection). Apparent nutrient digestibility was estimated by total feces collection and urinary collection was carried during 24 hours by urine collectors. Apparent digestibility coefficients and nutrient intake did not differ among the diets but the intake time was reduced with hay processing. There was greater water retention, estimated by water balance, when chopped hay or ground hay (3 mm) were fed. Intake and nutrient digestibility were not influenced by levels of hay grinding, but water balance was influenced by the different forms of hay, but a direct relationship was not observed between fiber length reduction and increased water retention.

Avaliação de dietas para eqüinos de uso militar em atividade física moderada

This study aims to evaluate diets for military horses in moderate activity. This experiment was conducted at Cavalry School of Brazilian Army where diets for horses of Ceremonial Squadron was evaluated. Diets were composed by commercial concentrate, Coast-cross grass hay and hydroponic oat. An performance trial in an randomized block design with three blocks (age of animals) and three treatments (experimental diets) were used. Diet I, fifteen horses fed diets composed by commercial concentrate with alfalfa hay into the pellets; Diet II, fifteen animals fed diets composed by commercial concentrate pellets; Diet III, fourteen animals fed diets composed by commercial concentrate pellets plus 3.0 kg hydroponic oat. Three kilograms of Coast-cross grass hay were added in all diets. At the end of this trial, a digestion trial was carried, in a complete randomized design, with three treatments (diets) and four replications (animals) to evaluate digestibility nutrients of diets, according total feces collection method. Values were submitted by variance analysis and means compared by Tukey test at 5% probability. Animals fed experimental diets maintained body weight and corporal score without any change according to nutrients contents in the diets. The coefficients digestibility of nutrients were changed in function of the diets and experimental diet composed by commercial concentrate with alfalfa hay into the pellets were more digestible. Intake of digestible energy and protein were adequate to military horses in moderate activity. Intake of dietetic fiber as NDF and ADF were adequate to minimum recommendations for horses.

Recria de machos Nelore em pastagens cultivadas com suplementação na seca nos Cerrados do Brasil Central

Body weight gain of 103 Nelore calves until 20/21 months old when weaned on cultivated pasture and supplemented during the dry period was evaluated during three years to obtain steers with body weight to be finished immediately at fedlot. At the beginning and end of supplementation period, the animals averaged body weight and age of 189.51± 21.08 kg and 254 ± 29.22 days and 242.38 ± 29.22 kg and 400 ± 31.08 days, respectively. The mean daily feed intake was 1.52 kg/head. The mean daily body weight gain in this period was of 0.377 kg and in the next rainfall season was of 0.534 kg. The correlation of body weight from the beginning to the end of supplementation and to the end of rainfall season was of 0.78 and 0.65, respectively. The highest correlations found among body weights were: at the end of the dry and rainfall period (r = 0.86); body weight and gain at the end of rainfall period (r = 0.62); body weight and gain at the end of rainfall period and total gain (0.75 and 0.71, repectively), gain at dry season and total gain (0.80). After weaning, the calves were classified into three classes: inferior (140 ± 11.37 kg), medium (187 ± 11.09 kg) and superior (219 ± 8.51 kg). The body weights at the end of rainfall season were of 271 ± 9.56 kg, 362 ± 22.75 kg and 425 ± 15.32 kg. At least 54% of the animals remained as inferior, 60% as medium and 54% as superior at the end of rainfall season. At 20/21 months old, the steers averaged body weight of 366 ± 39.04 kg and conditions to be finished in fedlot. However, there are calves weaned at six/seven months old with less than 150 kg of body weight, with lower potential to body weight gain and less conditions to be finished in fedlot even when supplemented previously.