Leandro da Silva Freitas

Ingestive behavior of feedlot finished young bulls fed different concentrate levels in the diet

This study was developed to evaluate the ingestive behavior of beef cattle finished in feedlots with different concentrate levels in the diet. Sixteen bulls fed 22, 40, 59, or 79% of concentrate in the diet were assigned to a complete randomized design, with four replicates each. The supplied diets were isoproteic and the roughage used was corn silage. Data collection was carried out during the finishing period, with a total of six days. The time given to food intake, rumination, the number of bouts per meal and neutral detergent fiber rumination efficiency decreased linearly as the concentrate levels in the diet increased. Idle time increased linearly accordingly to the increment of concentrate in the diet. The animals have greater feed intake and rumination efficiency when fed higher levels of concentrate (79%).

Performance and economic evaluation of young finished feedlot bulls fed different concentrate levels in the diet

This study was conducted to evaluate the performance and economic viability of young bulls slaughtered at 14-16 months old, fed on different concentrate levels in the diet. Sixteen young bulls were randomly distributed and fed with 22, 40, 59 or 79% concentrate in the diet, resulting in four replications per treatment. The initial age and weight were 9.32 months and 192.44 kg, respectively. Final age, final weight, neutral fiber detergent intake, feed conversion and monthly profit decreased with increasing concentrate levels. The dry matter intake as percentage of live weight and metabolic size showed quadratic variation, increasing to 67 and 75% concentrate in the diet, respectively. The digestible energy intake and average daily weight gain increased with increases in concentrate levels. The increase in the level of dietary concentrate from 22 to 79% increased the animal performance, but decreased the profitability of young finished feedlot bulls at 14-16 months old.

Características da carcaça de vacas de descarte de diferentes grupos genéticos terminadas em confinamento com distintos pesos

The objective of the experiment was to evaluate the carcass characteristics of crossbred cull cows, from the second (G2- 3/4Charolais (C) Nellore (N) and 3/4NC) and third (G3-5/8CN and 5/8NC) generations of Charolais - Nellore rotational crossbreeding, feedlot finished and slaughtered with 465, 507 and 566 kg. At the beginning of the experiment the average age, weight and body condition were, respectively, 8.5 years, 388.6 kg and 2.35 points. The diet, with 48:52 roughage:concentrate ratio, contained 12.5% crude protein and 2.99 Mcal of digestible energy per kg of dry matter. Cows slaughtered with 566 kg produced heavier carcasses (318.5 kg), higher dressing percentage (56.24%) and subcutaneous fat thickness (7.54 mm) than cows slaughtered with 465 kg (245.0 kg, 52.71% and 4.72 mm, respectively) or 507 kg (264.6 kg, 52.12% and 4.4 mm, respectively). The increase of slaughter weight (465, 507 and 566 kg) did not alter the sawcut percentage (51.17, 50.64 and 50.63%), reduced the forequarter (36.93, 37.26 and 35.23%) and increased the sidecut percentage (11.9, 12.09 and 14.14%), respectively. For the measurements related to the carcass muscular expression, conformation was improved by slaughter weight increase (8.13, 9.47 and 10.9 points), respectively. Cushion thickness increased significantly when slaughter weight raised from 465 to 507 kg and Longissimus dorsi muscle area increased only in cows with the highest slaughter weight. The 3/4CN cows showed higher sidecut and lower forequarter percentages in relative to 3/4NC cows.

Composição física da carcaça e aspectos qualitativos da carne de bovinos de diferentes raças alimentados com diferentes níveis de energia

The objective of this trial was to study the physical composition of carcass and the qualitative characteristics of the meat of 16 finishing young bulls, eight Aberdeen Angus (AA) and eight Hereford (HE), fed diets with two energy levels (lower: 3.07 Mcal/kg of digestible energy - 12% of concentrate; or higher: 3.18 Mcal/kg of digestible energy - 32% of concentrate). Animals were feedlot fed since 9 months of age and an average body weight of 220.31 kg and were slaughtered when the estimate carcass weight reached at least 190 kg. A completely randomized design with a 2 x 2 factorial arrangement of treatments (two breeds vs. two energy levels) was used. Within breed, meat from HE showed the lowest loss of liquid during thawing and cooking. Meat from HE animals also showed the greatest tenderness when evaluated either by a panel or by the Shear force technique. Animals fed the higher energy diet had greater proportion of muscle, lower loss of liquid at thawing (2.54 vs. 7.22%), and a more tender meat (Shear force) than those fed the lower energy diet. A significant interaction was observed between breed and energy level for both meat flavor and color; AA bulls fed the higher energy diet had meat with greater flavor and better color.

Corn silage substituted by sunflower silage in the diet of fedlot steers: ingestive behavior

The objective of this experiment was to evaluate the effect of replacing corn silage with sunflower silage (0, 33 e 66% DM) on the ingestive behavior of fedlot steers. Nine castrated steers were used, with average 288 kg initial live weight and 20 month old from the Nellore (N), 21/32Charolais (C) 11/32N and 21/32N 11/32C genetic groups. A randomized complete block experimental design was used, with three replications per treatment. The tested diets were: 100% corn silage and 0% sunflower silage; 70.94% corn silage and 29.06% sunflower silage and 38.27% corn silage and 61.73% sunflower silage, all with a 60:40 roughage:concentrate ratio. Time spent lying idle was greater for steers that consumed only corn silage as roughage compared to those that consumed sunflower silage. Time spent standing idle was similar between 33 (1.84 h) and 66% sunflower silage (1.96 h) and lower for 0% sunflower silage (1.62 h). The animals rumination time increased with the inclusion of sunflower on diet, with values of 8.61; 8.76 and 9.45 h, respectively for 0; 33 and 66% sunflower silage. Animals fed only with corn silage show better dry matter and neutral detergent fiber rumination efficiencies. The time spent feeding decrease with higher participation of sunflower silage.

Carcass and meat characteristics from young Devon steers finished in different feeding systems

Avaliaram-se as caracteristicas de carcaca e da carne de novilhos Devon terminados em confinamento, em pastagem temperada (pastagem de azevem -Lolium multiflorum Lam) ou em pastagem tropical (milheto, Pennisetum americanum (L.) Leeke + capim-papua, Bracharia plantaginea). No inicio da terminacao, os novilhos apresentaram em media 320 kg e 15 meses de idade. Os animais em confinamento foram alimentados com relacao volumoso:concentrado de 60:40 e abatidos com pesos semelhantes, de 388,3; 391,5 e 375,8 kg, respectivamente. A terminacao em pastagem tropical elevou a idade ao abate de 17 para 19 meses, como resultado do menor ganho de peso medio diario observado em relacao ao confinamento e a pastagem temperada. O sistema de alimentacao nao influenciou os pesos de carcaca quente e fria, nem seus rendimentos, mesmo que as carcacas dos animais terminados em pastagem tropical tenham apresentado maior quebra ao resfriamento em comparacao aos da pastagem temperada. A espessura de gordura subcutânea e a conformacao nos animais terminados em pastagem temperada foram maiores que naqueles terminados em pastagem tropical, enquanto os animais terminados em confinamento mantiveram-se em posicao intermediaria. Animais terminados em pastagem tropical apresentaram carcacas com maior porcentagem de ossos e menor porcao comestivel/osso. Os animais terminados em pastagem temperada apresentaram carcacas com maior espessura de coxao em relacao aqueles do confinamento. A carne dos animais terminados em pastagem temperada foi mais escura, apresentou maior forca ao cisalhamento e textura mais grosseira, com menor maciez, avaliada pelo painel de degustadores, em comparacao a carne daqueles terminados em confinamento ou em pastagem tropicale. Animais terminados em pastagem tropical apresentam carne menos palatavel que a de animais terminados em confinamento.

Características dos componentes externos e das gorduras descartadas de novilhos superprecoces não-castrados ou castrados de dois genótipos terminados em confinamento

The objective of this study was to evaluate the characteristics of external components and discard fat of young steers with two different sexual conditions and two different genotypes, finished in feedlot. Average age and weight of the animals at the beginning of the experimental period were 12 months and 267.0 kg, respectively. The steers were in feedlot until reaching pre-established slaughter weight of 400 kg. Diet contained roughage:concentrate ratio of 50:50, on dry matter basis, with 10% crude protein. It was used a complete randomized experimental design, in a 2 × 2 factorial arrangement, composed of two sexual conditions and two genetic groups. Empty body weight (EBW), carcass dressing in relation to empty body weight and the relationship between empty body weight and slaughter weight were similar among genotypes and sexual conditions. For absolute weight of ears, it was observed significant interaction between genotypes and sexual conditions of steers. Castrated animals showed greater values of intestinal fat in relation to empty body weight (1.62 versus 1.18%). Animals with Charolais predominance showed greater absolute values to tail broom (0.16 versus 0.11 kg) and Nellore steers predominance presented greater weight related to rawhide and renal fat. There is no correlation among carcass dressing and non-integrant components of carcass.

Características da carcaça de novilhos de diferentes grupos genéticos, terminados em confinamento, recebendo diferentes níveis de concentrado

The carcass quantitative characteristics of feedlot finished Charolais or Nellore steers, receiving three levels of concentrated in the diet: 35; 50 and 65%, were evaluated. Sorghum and corn silages were used as roughage. A significant interaction (P .05) of the concentrated level for the others characteristics studied was observed. The Charolais steers had presented higher slaughter weight (372.2 versus 325.6kg), hot carcass (201.1 versus 180.0kg) and cold carcass (196.6 versus 175.5kg), saw cut weight (52.0 versus 43.6kg) and side cut weight (42.4 versus 11.0kg), carcass length (118.4 versus 111.8cm), cushion thickness (25.4 versus 23.3cm), arm perimeter (39.1 versus 34.6cm), conformation (11.3 versus 9.5 points), Longissimus muscle area (66.4 versus 53.8cm2) and saw cut percentage (52.0 versus 49.4%). The Nellore steers presented higher leg length (68.5 versus 58.1cm) and fore quarter percentage (38.1 versus 35.5%).

Behavior patterns of cows with Charolais or Nellore breed predominance fed diets with plant extract or monensin sodium

The objective of this research was to study the ingestive behavior of feedlot cows fed additives based on plant extracts or monensin sodium. Twenty-four Charolais and Nellore crossbred cows with age and average initial weight of 7 years and 423 kg, respectively, were used. The experimental diets were plant extracts: basal diet + 5 g/animal/day of a natural additive composed of 750 mg of essential oil of thyme (Thymus vulgaris), 150 mg of garlic (Allium sativum), 250 mg of rosemary extract (Rosmarimus officinalis), 250 mg of canola oil (Brassica napus), 250 mg extract of quillaja (Quillaja saponaria), and 3350 mg of corn starch; sodium monensin: basal diet + 300 mg/monensin/animal/day; and control: basal diet without additive. The basal diet contained sorghum silage and concentrate in a 62:38 ratio. The experimental design was completely randomized with a 3 × 2 (3 diets and 2 breed predominances) factorial arrangement, and means were compared using DMS test at 5% of significance. The type of additive consumed did not alter animal feeding behavior. Cows with Charolais predominance consumed more dry matter (13.78 vs. 12.38 kg/day) and neutral detergent fiber (7.81 vs. 6.89 kg/day), ruminated for longer (8.47 vs. 7.82 h), spent more time chewing (13.05 vs 12.01 h), had a greater number of chews per minute (58.88 vs 53.21) and a greater number of ruminal bolus (541.43 vs. 464.09 boluses/day); however, cows with Nellore predominance had greater idling time (11.82 vs. 10.74 h).

Órgãos internos e trato digestório de novilhos superprecoces não castrados ou castrados, de dois grupos genéticos

Avaliaram-se as caracteristicas dos orgaos e do trato gastrintestinal de novilhos com duas condicoes sexuais - castrados e nao castrados -, com predominio genetico Charoles ou Nelore com idade e peso medios iniciais de 12 meses e 267kg, respectivamente. Os novilhos foram confinados ate o peso de abate medio preestabelecido de 400kg. A dieta alimentar continha relacao volumoso:concentrado de 50:50 (base na materia seca), com 10% de proteina bruta. O delineamento experimental utilizado foi o inteiramente ao acaso, em arranjo fatorial de 2x2 (duas condicoes sexuais x dois predominios geneticos). Para o peso absoluto do omaso, observou-se interacao significativa de genotipo versus condicao sexual dos novilhos. Animais nao castrados apresentaram maiores pesos absolutos dos rins (0,81 versus 0,66kg), do abomaso (1,20 versus 1,00kg) e dos intestinos, nas diferentes formas de expressao, em comparacao aos castrados. Os animais com predominio Charoles apresentaram maiores pesos absolutos do omaso (4,24 versus 3,46kg), dos intestinos (8,18 versus 6,84kg) e do total do trato digestorio (16,88 versus 14,90kg) em relacao aos animais com predominância Nelore. Nao houve correlacao entre o rendimento de carcaca e os componentes nao integrantes da carcaca.