Leonir Luiz Pascoal

Desempenho de Novilhos Red Angus Superprecoces, Confinados e Abatidos com Diferentes Pesos

The feedlot performance of Red Angus steers, with initial age of eight months and 189 kg of initial live weight, fed to reach the slaughter weight (SW) of 340, 370, 400 or 430 kg, was evaluated. The number of days to reach the respective weight was 114, 144, 168 and 209 days, with 12, 13, 14 and 15 months of age. The animals were fed with a 13.13% crude protein diet, and roughage:concentrate ratio of 56:44. The average daily gain was 1.32, 1.27, 1.23 and 1.15 kg, respectively. Dry matter intake (DMI) expressed in kg/day/animal and metabolic weight, did not show significant relation with slaughter weight. When DMI was expressed per 100 kg of live weight a linear decline occurred (DMI/100 kg W= 3.599 - 0.003152SW) as the final weight increased. Body condition improved linearly with the final weight (Body condtion = 0.159 + 0.0103SW), while feed conversion worsen (FCDM = 1.585 + 0.01019SW), however it can be considered satisfactory, being respectively 5.09, 5.35, 5.55 and 6.04 kg of DM/kg of weight gain. In order to reach the minimum carcass weight and subcutaneous fat thickness required, the regression equation estimation showed that slaughter weight should be of 337 and 327 kg, respectively.

Efeito do Grupo Genético e da Heterose nas Características Quantitativas da Carcaça de Vacas de Descarte Terminadas em Confinamento

ABSTRACT - Quantitative carcass traits of cull cows from two breeding systems, straightbreds (Charolais - C and Nellore - N)and crossbreds F1 1 / 2 CN and 1 / 2 NC, were evaluated. The cows were feedlot finished and fed with a 10% crude protein diet with 65%roughage, sorghum silage, and 35% concentrate. Objective and subjective measurements were taken from the cold carcasses. Charol aisfemales showed higher slaughter weight (522.6 vs 462 kg) and cold carcass weight (255.8 vs 237.5 kg), conformation score (10.7 vs 7.76points) and Longissimus dorsi area (64.08 vs 55.92 cm 2 ). Whereas the Nellore were superior in dressing percentage (51.31 vs 48.93%)and subcutaneous fat thickness (8.22 vs 4.59 mm). Crossbred F1 females were superior to the straightbreds for slaughter weight (525.7vs 492.3 kg), cold carcass weight (269.8 vs 246.6 kg), dressing percentage (51.3 vs 51.12%), conformation score (9.84 vs 9.24 p oints) andsubcutaneous fat thickness (7.77 vs 6.40 mm), being the heterosis values 6.78, 9.41, 2.35, 6.49, and 21.40%, respectively. Cros sing Charolaisand Nellore resulted in cull cows with carcasses with high weight, good conformation and high degree of subcutaneous fat.Key Words:

Desempenho na fase de crescimento de machos bovinos inteiros ou castrados de diferentes grupos genéticos

ABSTRACT - The objective of the experiment was to evaluate, during the growth phase, the dry matter intake, weight gain and feed to gainconversion of young bulls and steers, castrated at eight month, from two breeding systems, straightbred (Charolais - C and Nell ore - N) and crossbred( 1 / 2 CN, 1 / 2 NC), as well as to measure the resulting heterosis. The animals were confined from nine to twelve months and fed a 15% crude p roteindiet and a 70:30 forage to concentrate ratio. There was no difference between bulls and steers for dry matter intake (DMI) in k g/animal.day (DMID),DMI per unit of metabolic weight (DMIM) and DMI per 100 kg of live weight (DMIP). The bulls showed a 13,7% higher average daily weightgain (ADG) and were more efficient in the feed to gain conversion (4.66 vs 4.99 kg of DMI/kg of gain) than the steers. The effe ct of castrationon the weight gain was more pronounced in calves sired by C bulls (1.00 vs 1.19 kg) than in calves sired by N bulls (.91 vs .97 kg). The F1 animalsshowed higher ADG than the average of the straightbreds, resulting in 9.28% heterosis. The C calves presented higher DMID and A DG than theN. However, DMIM and DMIP were similar between the two straightbred groups. The F1

Características da carcaça de novilhos 5/8 Nelore-3/8 Charolês abatidos em diferentes estádios de desenvolvimento

The carcass quantitative characteristics of 5/8 Nellore-3/8 Charolais steers feedlot finished to reach slaughter weight (SW) of 425, 467 and 510 kg, were studied. At the beginning of the feedlot the average age, weight and body condition were, respectively, 660 days, 361 kg and 2.9 points. The diet offered, with 60:40 roughage:concentrate relation, dry matter basis (DM), contained 10.25% crude protein and 72.18% of total digestible nutrients. The roughage was corn silage with 46.5% of grain in the DM. Cold carcass dressing percentage showed linear relation with SW (= 37.618 + .011Pi (initial weight) + .028SW). However, when dressing percentage was expressed in relation to empty body weight (EB), it was not influenced by SW. Subcutaneous fat thickness expressed per cold carcass (= -15.499 - .001Pi + .047SW), per 100 kg of cold carcass weight (= -1.724 - .006Pi + .013SW) and per 100 kg of EB (= -1.124 - .003Pi + .008SW) increased as SW increased. Longissimus dorsi area increased linearly with SW (= -33.472 + .120Pi + .120SW), however, when expressed per 100 kg of cold carcass weight it declined (= 45.173 - .023Pi - .028SW), and when expressed per 100 kg of EB, it did not show relationship with SW. The percentage of sawcut declined (= 63.007 - .001Pi - .026SW) while the side cut increased (= -3.054 + .005Pi + .030SW), as SW increased. Slaughter weight influenced positively cushion thickness (= 6.223 + .014Pi + .031SW), leg length (= 28.326 + .061Pi + .05SW) and arm perimeter (= 9.173+ .053Pi + .017SW). Carcass conformation was not alterated by SW.

Desempenho de vacas Charolês e Nelore desterneiradas aos três ou sete meses

The experiment evaluated the performance of Charolais (C) and Nellore (N) cows of three age classes, young (3 and 4 years), adult (5 to 7 years) and old (8 or more years), weaned at three (early weaning) or seven months in the fall (traditional weaning). The weight of the cows at the fall was 45 kg higher for the cows weaned at three months (T3) than for the cows weaned at seven months (T7). The body condition at seven months was also better for T3 cows (3.3 vs. 2.1 points). The T3 cows had higher weight gain from calving to the end of the reproductive period and showed higher percentage of estrus (81 vs. 51%), of pregnancy (67.2 vs. 37.3%) and shorter interval between calving and first estrus (102 vs. 114 days) than T7 cows. Adult cows displayed better body condition at seven months and showed higher reproductive performance than young and old cows. The difference in pregnancy rate between T3 and T7 was more evident in young cows (42.11 vs. 12.5%) and old cows (51.72 vs. 35.71%) than in adult cows (62.5 vs. 53.33%). The C cows were heavier then N cows, at calving, at three and seven months, and displayed better body condition at seven months. The effect of early weaning on reproductive performance was more evident for C cows. The pregnancy rate of C cows was 80.6% for the T3 and 41.9% for the T7, while for the N cows the percentages were 45.5 and 30.0%, respectively, for T3 and T7. For C cows, milk production and the calves (presence and suckling) showed a stronger suppression on reproduction, than for N cows.

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.

Avaliação do comportamento agronômico da planta e valor nutritivo da silagem de diferentes híbridos de milho (Zea mays, L.)

O experimento foi desenvolvido com o objetivo de avaliar o comportamento agronomico produtivo da planta e as caracteristicas quimico-bromatologicas e fermentativas da silagem de diferentes hibridos de milho (Zea mays, L.): Agroceres AG-5011, Braskalb XL-344 e Cargill C-806. Para as avaliacoes agronomicas dos hibridos, utilizou-se o delineamento experimental inteiramente casualizado e, para a avaliacao das silagens, o delineamento de blocos ao acaso, sendo o criterio de bloqueamento o periodo de utilizacao da silagem. O hibrido C-806 foi o mais precoce, com intervalo de 100 dias da semeadura a colheita para ensilagem, enquanto o hibrido XL-344 foi o mais tardio, com intervalo de 121 dias. As caracteristicas fenotipicas da planta de milho determinaram o potencial produtivo dos hibridos, tendo o hibrido AG-5011 apresentado a maior altura de planta e potencial produtivo de materia verde e materia seca por hectare, em relacao aos hibridos C-806 e XL-344. Verificou-se, nos hibridos AG-5011 e C-806, maior populacao final de plantas em relacao ao hibrido XL-344. O hibrido C-806 apresentou menor proporcao de graos em relacao a planta inteira. Com base nos teores de MS e DIVMS, as silagens dos hibridos AG-5011, C-806 e XL-344 sao classificadas como de boa qualidade. Com relacao as caracteristicas fermentativas, N-NH3/NT e pH, as silagens dos tres hibridos sao classificadas como de muito boa qualidade.

Composição física da carcaça e qualidade da carne de novilhos jovens e superjovens de diferentes grupos genéticos

The objective of this trial was to evaluate the carcass physical composition and meat qualitative characteristics of males of two categories, steers (slaughtered at 22.8 months old) and young steers (slaughtered at 15.2 months old), from two genetic groups, 5/8 Charolais (CH) 3/8 Nellore (NE) and 5/8NE 3/8CH, and to evaluate the relationship among the variables studied. The animals were fedlot finished until reaching 430 kg. The diet, roughage:concentrate ratio of 60:40 (dry matter basis), contained 10.25% crude protein and 3.18 Mcal of digestible energy/kg of dry matter. The experiment was analyzed as a complete randomized design with six replicates, according to a 2 x 2 (two categories x two genetic groups) factorial scheme. Steers showed carcasses with higher percentage and total quantity of muscle (66.45% and 153.93 kg vs. 60.27% and 141.00 kg), higher muscle:fat ratio (3.64 vs. 2.45), carcasses with lower percentage and total quantity of fat (18.59% and 43.59 kg vs. 24.78% and 58.07 kg), meat with less marbling (6.25 vs. 8.42 points), less juiciness (6.83 vs. 7.34 points) and lipid content (1.01 vs. 1.76%) than young steers. Steers showed equal meat color (4.42 points) and similar meat tenderness, evaluated by the test panel (6.53 and 6.92 points) and shear force (3.84 and 4.22 kgf/cm³) in relation to young steers. The 5/8NE 3/8CH animals showed carcasses with higher fat percentage (22.43 vs. 20.95). Meat quality characteristics were not influenced by genetic group. Meat tenderness was positively correlated with percentual (r = 0.27) and total (r = 0.31) carcass fat, and with marbling score (r = 0.28). Meat juiciness showed positive correlation with percentual (r = 0.45) and total (r = 0.47) carcass fat. The two last ones were negatively associated with thawing loss (r = - 0.23 and -0.31, respectively).

Desempenho de novilhos jovens e superjovens de diferentes grupos genéticos terminados em confinamento

The objective of the experiment was to evaluate the performance of males of two categories, steers and young steers, from two genetic groups, 5/8Charolais (CH) 3/8Nelore (NE) and 5/8NE 3/8CH. The average age of the animals at the beginning of the experimental period was 22.8 months for steers and 15.2 months for young steers. The animals were feedlot finished to reach slaughter weight of 430 kg, previously established. The performance characteristics evaluated between categories were compared in two manners: (=FW): until young steers reach final weight similar to steers; and (=FBCS): until young steers reach final body condition score (FBCS) similar to steers. The diet, roughage:concentrate ratio of 60:40 (dry matter basis), contained 10.25% crude protein and 3.18 Mcal of digestible energy/kg of dry matter. The experimental design used was the completely randomized, in a 2 x 2 (two categories x two genetic groups) factorial scheme. Steers showed higher average daily weight gain (ADG) (1.94 kg) in relation to young steers (=FW) (1.52 kg) and (=FBCS) (1.53 kg). Similar behavior was verified for dry matter intake (DMI) and digestible energy intake, expressed per unit of metabolic weight, net energy intake for maintenance (NEm) and for gain (NEg). When NEm was adjusted for 100 kg of body weight, steers showed lower intakes in relation to young steers (=FW) and (=FBCS). The FBCS was higher in young steers (=FW) (4.35 vs. 3.72 points) in relation to steers. The feed and energy conversion showed higher values for steers when compared to young steers (=FBCS). No significant difference was observed between genetic groups for ADG. However, 5/8NE 3/8CH animals showed higher FBCS and DMI adjusted for body weight and per unit of metabolic weight.

Manipulação da altura de corte da planta de milho (Zea mays, L.) para ensilagem visando a produção do novilho superprecoce

The experiment was conducted with the objective to evaluate the performance of feedlot finished calves, fed with silages of AG-5011 corn hybrid harvested with different cutting height: low cut (20 cm) and high cut (42 cm). Twelve Braford calves with an average age of seven months and average live weight of 209 kg, were used. The feedlot period was 126 days, divided in two periods of the 63 days. The roughage:concentrate ratio was 60:40 and 50:50 for the first and second periods, respectively. The high cut silage showed higher IVOMD (66.67 vs 58.60%) and lower NDF (41.47 vs 47.80%). Significant interaction was observed between cutting height and evaluation period for dry matter intake (DMI) expressed per 100 kg of live weight and per unit of metabolic weight, digestible energy intake (DEI), weight gain (ADG), feed conversion (FC) and energy efficiency (EE). Animals fed with the high cut silage during the first period presented higher ADG (1.352 vs 1.198 kg) and better FC (4.82 vs 5.39 kg of DM/kg LW) than animals fed with the low cut silage. However, with the reduction of the roughage:concentrate ratio to 50:50 during the second period, the ADG (1.228 vs 1.336 kg) and FC (6.43 vs 6.34 kg of DM/kg LW) were similar. Slaughter and cold carcass weight, dressing percentage and subcutaneous fat thickness were similar, being, respectively, 371.8 kg; 195.3 kg; 52.46%; and 5.7 mm for the higher cut and 368.2 kg; 195.7 kg; 53.08%; and 3.7 mm for the lower cut.