Pedro Veiga Rodrigues Paulino

Validação das equações do NRC (2001) para predição do valor energético de alimentos nas condições brasileiras

This research was developed to estimate the energy values (TDN) of feeds, concentrate and roughage, through equations proposed by NRC (2001) and validate from the comparison among TDN values estimated by these equations and those observed in the total collection feces. Five concentrate feeds (wheat bran, soybean meal, corn ground, whole soybean and whole cotton seed) an five roughage feeds (brachiaria hay, corn silage, tifton haylage, elephant grass silage and elephantgrass) were evaluated by using 20 crossbred Holstein x Zebu steers. The procedure to validate the variables evaluated was done by adjusting models of simple linear regression using predicted and observed values. The observed and predicted value of TDN values for roughage and concentrate feeds were similar (P>0,05). It was concluded that the equations proposed by NRC (2001) were efficient to estimate the TDN values of feeds under brazilian conditions.This research was developed to estimate the energy values (TDN) of feeds, concentrate and roughage, through equations proposed by NRC (2001) and validate from the comparison among TDN values estimated by these equations and those observed in the total collection feces. Five concentrate feeds (wheat bran, soybean meal, corn ground, whole soybean and whole cotton seed) an five roughage feeds (brachiaria hay, corn silage, tifton haylage, elephant grass silage and elephantgrass) were evaluated by using 20 crossbred Holstein x Zebu [...]

Desempenho, digestibilidade e características de carcaça de novilhos zebuínos alimentados com dietas contendo diferentes níveis de concentrado

This research was developed to evaluate the intake and digestibility of nutrients; feed/gain conversion (FC); average daily live weight (LWG), empty body weight (EBWG) and carcass (CG) gains; the carcass dressing percentage and the basic cuts percentage; the carcass length (CL); the loin eye area (LEA) and the subcutaneous fat thickness (SFT) of Zebu steers, with initial average live weigth of 270 kg, fed with 5, 35 e 65% of concentrate, in feedlot. The dry matter and organic matter intake were quadractily influenced by the increasing levels of concentrate in the diet. The ether extract and nonfiber carbohydrate intakes increased and the neutral detergent fiber intake decreased linearly as the concentrate level increased. The crude protein intake was not affected by the concentrate level. The TDN level and digestibility of the dry matter, organic matter, ether extract and non-fiber carbohydrate increased and the neutral detergent fiber digestibility decreased linearly as concentrate level in the ration incresead. The digestibility of the CP was not affected, when Brachiaria brizantha haylage was used as roughage. However, the digestibility of the CP increased linearly, when the Cynodon dactylon was used in the feeding of the animals. The FC decreased and the LWG, EBWG, CG, LEA and SFT increased linearly as the concentrate levels in the diets increased. The CL, the carcass dressing percentage and the basic cuts percentage, excluding leg percentage, were not affected by the concentrate levels in the diet. The inclusion of concentrate in the diets increased the digestibility and improved the productive performance of the animals.

Desempenho produtivo de bovinos Nelore de diferentes classes sexuais alimentados com dietas contendo dois níveis de oferta de concentrado

Objetivou-se avaliar os efeitos de classe sexual e nivel de oferta de concentrado sobre o desempenho, o consumo e a digestibilidade dos nutrientes em bovinos Nelore. Trinta e cinco animais, 12 machos inteiros, 11 machos castrados e 12 femeas, provenientes de um mesmo grupo contemporâneo, foram distribuidos aleatoriamente a dois tratamentos, correspondentes aos niveis de oferta de concentrado, 0,6 e 1,2% do peso corporal, respectivamente. Os animais foram alimentados individualmente durante 112 dias, sendo abatidos ao final do experimento, com um grupo referencia abatido ao inicio. Os machos inteiros foram mais eficientes, pois apresentaram maior peso final e de corpo vazio, como resultado da maior taxa de crescimento em relacao as femeas, ficando os machos castrados em posicao intermediaria. Os consumos relativos de materia seca e de todos os demais nutrientes foram superiores nas femeas em relacao aos machos inteiros, de modo que os castrados apresentaram valores intermediarios. As digestibilidades, a excecao do extrato etereo, nao foram afetadas pela classe sexual. As digestibilidades da materia seca e materia orgânica foram superiores para a dieta com nivel de oferta de concentrado de 1,2% do PV. Classe sexual afetou o crescimento e a capacidade de consumo dos animais, porem nao teve efeito sobre a digestibilidade dos nutrientes da dieta. Niveis de oferta de concentrado de 0,6 e 1,2% do PV nao foram suficientes para promover diferencas no desempenho de bovinos Nelore, independentemente de classe sexual.

Avaliação de modelos não-lineares e da relação do consumo voluntário de vacas primíparas e de bezerros com a curva de lactação de vacas Nelore

This research was carried out to evaluate five non-linear mathematical models to describe lactation curves of Nelore cows and effect of the cow and calf intake on milk yield. In this study we compared the models of Sikka (1950), Nelder (1966), Wood (1967), Jenkins & Ferrell (1984) and Jenkins & Ferrell (1984) with a fit parameter. Data of production were collected from 12 primiparous cows with a mean live weight of 359 kg (± 8) and its offspring. The milk production was estimated weighing the calf before and after suckling, from birth to 180 days of age. Measurements were made twice a day in a weekly period after 6 hour fasting of liquid and solids. The mathematical models of Sikka, Jenkins & Ferrell, Nelder and Wood failed to describe lactation curve appropriated due to over or underestimation of milk yield peak. Better adjustement was found for the model of Jenkins & Ferrell with a fitting parameter. Cow and calf intake evaluated separately was no correlated with milk yield. Conversely at evaluating both cow and calf together, it was found a positive and a negative correlation with milk yield, respectively. Milk yield is is closely correlated wiht cow and calf intake, and the capacity of the calf to ingest non-dairy solids results in reduction of milk needs from dam.

Increasing dietary concentrate levels for Nellore of three sexual categories: intake, partial and total tract digestibility, microbial protein synthesis and ruminal metabolism

Twelve Nellore of three sexual categories (four heifers, four bulls and four steers) averaging 15 months of age and body weight of 235, 249, and 239 kg, respectively, were assigned to a completely randomized design with a 2 × 3 factorial arrangement (two levels of concentrate – 25 or 50% and three sexual categories) to evaluate intake, partial and total digestibility of nutrients, microbial protein synthesis and ruminal metabolism. The collection of ruminal fluid was done before and at 2, 4, and 6 hours post-feeding to determine pH and ammonia concentration. With the exception of EE, no other significant effect of concentrate levels and sexual categories was observed on intake and partial or total tract digestibility of nutrients. The intakes of DM, OM, EE, CP, NFC, and TDN (kg/day) and DM (% BW or g/kg0.75) were affected neither by the concentrate levels nor by sexual category. Increasing dietary concentrate levels decreased NDF digestibility. Average bacterial N contents ranged from 6.91 to 7.39. No significant effect of concentrate levels and sexual category was observed on duodenal flow of nutrients and microbial efficiency excepted when expressed as gNmic/kgOMDR. Maximum ruminal NH3 concentration (14.55 mg/dL) was estimated at 1.83 hours after-feeding. It was concluded that increasing dietary concentrate levels did not affect intake, partial and total tract digestibility of most nutrients and microbial protein synthesis.

Performance, digestibility and carcass characteristics of feedlot dairy steers fed diets with different urea levels

The effects of urea levels on feed intake, digestibility and carcass traits of 27 confined cross bred steers weighing 303.25 ± 60.8kg, were evaluated. After weighing, castrating, vaccinating and a period of seven days, three steers were slaughtered at the beginning of the experiment and the remaining 24 were allotted in a completely randomized design to four isonitogenous experimental diets (12% of crude protein) and increasing level of urea on the dry matter-basis (0.0; 0.65; 1.30 and 1.65%) to replace soybean meal, so that the final content of the experimental diets were approximately 22, 37, 50 and 63% of crude protein in the form of NPN. Corn and elephant grass silages were supplied at a 70:30 ratio and the total diet had a 65:35, forage: concentrate ratio on a DM-basis. The urea level did not affect nutrient intake, except for rumen degradable protein (RDP) and total digestible nutrients (TDN) linearly increased in function of diet urea level. The nutrient digestibilities linearly increased except for ether extract and non fiber carbohydrate (NFC). A quadratic effect of diet urea level on daily weight gain and no effect of urea level on carcass traits were observed. Urea can totally replace soybean meal in diets for confined crossed dairy steers allowing gains of 1kg/day. Urea can enhance nutrient digestibility of diets.

Exigências nutricionais de vacas nelores primíparas lactantes

This study was conducted to evaluate the nutritional requirements of protein and energy of primiparous lactating Nellore cows from 0 to 180 days after calving. A total of 20 lactating primiparous cows with average body weight at calving of 362±25 kg were used. Four cows were slaughtered soon after calving and were considered as reference group. From calving to 90 days post partum four cows were fed restricted at 1.5% of body weight (BW) in dry matter (DM) basis and 12 were fed ad libitum. At 90 days post partum eight cows were slaughtered (four from each feeding system). From 90 to 180 days, four cows were realocated for maintenance (1.8% BW in DM) and four remained in voluntary intake, and all were slaughtered at the end of the period. The contents of protein and energy were estimated by the equation Y = a. Xb, in which X is the empty body weight (EBW), and a and b are the parameters of the allometric equation. Ratios obtained for empty body weight (EBW)/BW and empty body gain (EBWG)/BWG were 0.894 and 0.936, respectively. The net energy for maintenance (NEm) were 97.84 kcal/EBW0.75 and the metabolizable energy for maintenance (MEm) were 140.17 kcal/EBW0.75. The efficiencies of energy use for maintenance and gain were 0.70 and 0.44, respectively. The content of protein and minerals, except calcium, decreased with the increase in BW while the energy increased. The milk of cows had average contents of 3.71, 3.88 and 4.74%, respectively, for crude protein, fat and lactose. The NEm requirement for lactating Nellore cows is 97.84 kcal/EBW0,75, while MEm is 140.17 kcal/EBW0,75 and metabolizable protein requirement is 52.8 g. To produce 1 kg of milk with 4% fat Nellore cows need 0.300 kg TDN.