Marco Aurélio Alves de Freitas Barbosa

Dinâmica da pastagem e desempenho de novilhos em pastagem de capim-tanzânia sob diferentes ofertas de forragem

This experiment was carried out from March to August 2000, to study the dry matter yield dynamic and performance of steers grazing Tanzania grass (Panicum maximum Jacq. cv. Tanzânia), under continuous stocking with variable stocking rate, and four forage allowances (3, 7, 11, and 15% BW). Crossbred Nelore x Charolais steers, averaging 18 months and 350 kg BW, were used. A randomized block design, with three replicates, was used. When tanzaniagrass was managed in the 7 to 11% interval of forage allowance, the fertilizer input was minimal (30 kg/ha/yr N), and high average daily gain (ADG) was obtained, with no effect on the gain/ha (G/ha). Under this condition, pasture showed 1,528 kg/ha green leaf lamina dry matter (GLLDM); 56 cm of stubble height; 97% soil cover; 62 kg/ha/day of GLLDM accumulation rate; and 34% green leaf lamina in the total dry matter, with ADG of 0.5 kg/day and 126 kg of G/ha.

Evaluation of production and any physiological characteristics of genotypes of Panicum maximum Jacq. under two cutting heights

The experiment was carried out from September 1995 to September 1996, to evaluate the total dry matter/ha (TDM), of leaves/ha (LDM), regrowth vigor (RV), tillers number (TN), and percentage of eliminated apical meristems (AME) in six grass cultivars (Aruana, Centenario, Coloniao, Mombaca, Tanzania and Tobiata) and two genotypes (K249 and KK8) of Panicum maximum Jacq., at two cutting heights (20 and 40 cm), during dry and rainy season. A split plot experimental design was used. The height cutting only influenced the yield of TDM and LDM of Tanzania grass that was higher in lower cuttings during rainy period. The Centenario and KK8 grasses presented higher AME at 20 cm height and Aruana at 40 cm, in both periods. The lowest RV was to Aruana grass in the two cutting heights in the two experimental periods. The Centenario, KK8, Mombaca, Tanzania e Tobiata grasses presented higher TDM and LDM both two periods, in the two cutting heights. By the results, the grasses can be managed in any cutting height, except the Tanzania grass, which can be management with low height.

Effects of dietary fat sources on intake, nutrient digestibility and plasma urea nitrogen for lactating water buffaloes.

The effects of fat sources on intake, nutrient digestibility and plasma urea nitrogen were evaluated in lactating water buffalo. Twelve females were randomly distributed into four treatments: without additional lipid, soybean grain, soybean oil and cottonseed. The experimental period was 84 days, with four 21-day periods (14 days for diet adaptation and 7 for collection). Diets were offered ad libitum, twice daily, as total mixed ration. At the collecting period, samples of food and surpluses were weighed and collected for chemical analysis. Faeces samples were collected from rectum for estimation of faecal dry matter production, using indigestible neutral detergent fiber as indicator, and consequently for apparent digestibility calculations. Dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) intakes were similar between treatments. The ether extract intake was higher for soybean oil diet. The same behavior was observed for the total digestible nutrient (TDN) intake for this diet, since the previous diet showed higher TDN percentage. The digestibility coefficient for DM, CP, non-fibrous carbohydrate, and serum urea nitrogen were similar between diets. Different lipid sources in the diets for lactating water buffalo did not influence the DM intake and digestibility coefficient, when ether extract content was under 5%. However, the ether extract and fibrous fractions digestibility coefficients in diets with soybean grain and cottonseed were the lowest.

Efeito do fornecimento de diferentes fontes de lipídeos na dieta sobre o consumo, a digestibilidade e o N-uréico plasmático de novilhos bubalinos em confinamento

The objective of this trial was to evaluate the effect of different dietary fat sources on intake, digestibility, and plasma urea N in feedlot water buffalo steers. Thirteen castrated Murrah steers averaging 297±9 kg of body weigh were assigned to one of the following three treatments: no added fat (control), soybean oil or whole soybean in a completely randomized design. The experiment lasted 84 days with three experimental periods of 28 days each. Samples of feeds, orts and feces were collected in the last six days of each period for determination of intake. Diets were fed twice a day (8 a.m. and 4 p.m.) as total mixed ration and the amount of feed offered was adjusted daily to yield refusals equal to approximately 10 to 20% of intake. Intakes of DM and CP were greater in the control compared to treatments supplemented with fat while the opposite was observed for ether extract intake. Apparent total tract digestibility of dry mater did not differ across treatments but animals fed the diet containing soybean oil had the lowest fiber digestibility. Feeding whole soybean to feedlot steers had no negative impact on fiber digestibility showing that the polyunsaturated fatty acids of this fat source were less available in the rumen. It can be concluded that the higher energy content of diets supplemented with fat sources increased DM intake but feeding soybean oil reduced fiber digestibility in this study.

Desempenho produtivo e custos com alimentação de búfalas lactantes submetidas a dietas com diferentes fontes de lipídeo

The objective was to evaluate the performance of lactating water buffalo fed diets with different fat sources. Twelve lactating water buffaloes were randomly distributed in four diets: without additional fat, soybean seed, cottonseed and soybean oil. The experimental period was 84 days, with four periods of 21 days (14 days for diet adaptation and 7 days for sample collections. The diets were fullfed, twice daily, as total mixed ration. At sample collections period, milk yield (kg/day) and 4% fat corrected milk (4%FCM) yield were evaluated. Four kg of milk were collected for mozzarella type cheese production. After mozzarella cheese production, it was determined the efficiency in relation to milk in natura and milk 45FCM. The fat sources did not affect daily milk production of water buffalo cows, however affected the 4%FCM, which was higher in the water buffalo cows that was fed diet with soybean seed. The efficiency of milk for Mozzarella production was higher for soybean oil diet. Feeding costs, per day and total (84 days) were higher for the diet with cottonseed, followed by soybean oil, without additional fat and soybean seed. The profitability for the milk sale was higher for diet with soybean grain, soybean oil, without additional lipid and with cottonseed, respectively, and for mozzarella sail was higher for soybean oil. As the main buffalo milk product is the mozzarella, results suggested that the diet with soybean oil content would be the best for lactating water buffalo.

Desempenho produtivo e custos com alimentação de novilhos bubalinos alimentados com dietas com diferentes fontes de lipídeos

The objective of this trial was to evaluate the effect of different dietary fat sources on weight gain, feed conversion, and feeding costs in feedlot water buffalo steers. Thirteen castrated Murrah steers averaging 297±9 kg of body weigh were assigned to one of the following three treatments: no added fat (control), soybean oil or whole soybean in a completely randomized design. The experiment lasted 84 days with three experimental periods of 28 days each. Samples of feeds, orts and feces were collected in the last six days of each period for determination of intake. Diets were fed twice a day (8 a.m. and 4 p.m.) as total mixed ration and the amount of feed offered was adjusted daily to yield refusals equal to approximately 10 to 20% of intake. Body weight was measured at the beginning and at the end of each experimental period after 16 hours of fasting. The average daily weight gain was 990, 1,090 and 1,280 g/day for animals fed the control, whole soybean, and soybean oil diets, respectively. Feed conversion was greatest in the diet containing soybean oil while that containing whole soybean resulted in the highest costs. The soybean oil diet increased performance and reduced costs; therefore, it can be used to improve meat production in feedlot water buffalo.

Influence of environmental factors on ponderal performance and morphometric characteristics of lambs of different genetic groups from birth to weaning

The objectives of this work were to evaluate the environmental effects (age of dam, type of birth and sex of lamb) and genetic groups (Hampshire Down and Ile de France, ½ and ¾ Hampshire Down, Ile de France and Suffolk, and ½ Texel) on performance and morphometric characteristics (height, length and heart girth) of lambs; to test regressions to predict live weight of lambs from body measurements; and to describe the growth type of the measurements as function of the weight. Weights and measurements were collected from birth to weaning, every 14 days. For evaluations of performance in relation to environmental effects and genetic groups, only data from birth and from weaning were used; for type of growth all collected data were used. Lambs from younger ewes (2 teeth) presented smaller average for weight at birth, heart girth and height at weaning. Single-birth lambs presented greater averages than twins. Genetic group influenced all traits evaluated, except heart girth at birth and average heart girth gain. Means for birth weight were higher in ¾ Ile de France (3.93±0.16 kg) and lower in ½ Texel lambs (3.04±0.24 kg), and for weaning, they were higher in ½ Texel (14.86±0.87 kg) and lower in Ile de France lambs (11.66±0.83 kg). Year of birth influenced all traits. Heart girth and length showed a negative allometric growth in relation to weight, while between weight and height the relation was positive allometric. The factors that most influenced the performance of lambs from birth to weaning are the type of birth, genetic group and year of birth. Correlations between body weight and morphometric measurements are significant, so it is possible to predict one from the other.

Effect of environmental factors on performance of purebred and crossbred Santa Inês lambs from birth to 154 days of age

The objectives of this study were to evaluate the environmental effects (age of dam at lambing, type of birth and sex of lamb) and genetic groups (Santa Ines and ½ Santa Ines) on weight and morphometric measurements (heart girth, body length and height) of lambs; to test linear and allometric regressions to predict the weight through the measurements; and to describe the type of growth of the measurements from weight. Weight and morphometric measurements were sampled from birth to 154 days of age, at every 14 days. For the evaluation of the environmental factors and to predict the regressions the data of birth, weaning and 154 days of age were used; and to determine the type of growth all the data collected were used. The lambs derived from younger (two-tooth) ewes recorded lower averages than the ones from eight-tooth ewes for weight, heart girth and body length at birth and length at weaning. The animals born from single births presented higher average weight from birth to weaning, as well as of all the measurements from birth to 154 days of age than those from twin births. There was no difference between the genetic groups Santa Ines and ½ Santa Ines. The correlations between the weight and measurements were significant, and it was possible to predict the weight from the morphometric measurements through regressions. The type of weight gain with heart girth was isometric, while with length it was positive allometric, and with height it was negative allometric. Thereby, in the absence of a scale it is possible to predict the weight from the morphometric measurements, and the type of birth is the most important factor that affects the development of lambs from birth to weaning.