Testicular shape and andrological aspects of young Nellore bulls under extensive farming

Aiming to determine the relationship between the frequency of testicular shape and the andrological aspects in young Nellore bulls, 18,676 animals were assessed. All andrological examinations were performed between the years 2000 and 2008. Animals were classified as able for breeding, able for breeding in natural mating system, unable for breeding and discarded. The testicular shape was classified as long, fairly long, oval-long, spherical-oval, and spherical. The analysis of Pearson correlations was performed for testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major defects, minor defects and total defects. Testicles with oval shape prevailed (99.61%). It was obseved that 76.34; 66.34; 64.34; 58.33 and 50.00% of the animals were classified as sound for breeding for shapes long, fairly long, oval-long, spherical-oval, and spherical, respectively. Correlations between testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major, minor and total defects were 0.26; 0.08; 0.00; 0.11; -0.02; 0.02 and -0.01, respectively. Testicular shape had no influence upon the andrological examination results. Testicles of long shape were prevalent within the population.

Performance, carcass traits, meat quality and economic analysis of feedlot of young bulls fed oilseeds with and without supplementation of vitamin E

The objective of this research was to evaluate average daily gain (ADG), carcass traits, meat tenderness and profitability of keeping cattle fed different oilseeds and vitamin E in feedlot. A total of 40 Red Norte young bulls with initial average body weight of 339±15 kg were utilized. The experimental design was completely randomized in a 2 × 2 factorial arrangement. The experiment lasted 84 days and experimental diets presented soybeans or cottonseeds as lipid sources associated or not to daily supplementation of 2,500 UI vitamin E per animal. The concentrate:roughage ratio was 60:40. Diets had the same amount of nitrogen (13% CP) and ether extract (6.5%). The data were analyzed by means of statistical software SAS 9.1. Neither vitamin supplementation nor lipid source affected ADG. There was no interaction between lipid source and vitamin supplementation for the variables studied. The inclusion of cottonseed reduced the carcass yield. There was no effect of diets on hot and cold carcass weights or prime cuts. The inclusion of cottonseed reduced the backfat thickness. No effect of experimental diets on the rib-eye area was observed. There was no effect of lipid source or vitamin supplementation on meat tenderness, which was affected, however, by ageing time. Diets with soybeans presented higher cost per animal. The utilization of soybean implied reduction of the gross margin (R$ 59.17 and R$ 60.51 for diets based on soy with and without supplemental vitamin, respectively, vs. R$ 176.42 and R$ 131.79 for diets based on cottonseed). The utilization of cottonseed enables improvement of profitability of feedlot fattening, in spite of negatively affecting some carcass characteristics.

Performance of Nellore young bulls on Marandu grass pasture with protein supplementation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação das Sub-Frações dos Carboidratos e das Proteinas, Usando as Metodologias do Cncps e In situ com Bovinos da Raça Nelore. 1. Silagem de Milho

To validate the use of the Cornell Net Carbohydrate and Protein System (CNCPS) under Brazilian conditions, the chemical composition, the potential and the effective degradabilities of the carbohydrate and protein subfractions, and the solid phase passage rate were determined for corn silage in diets with forage:concentrate ratios of 80:20 (DI) and 60:40 (D2) using Nellore cattle. The chromium mordant technique was used to determine the particulate passage rate of solids. For diet 2, there was a reduction in the potentially degradable dry matter (DM), and however not significant, a reduction in the degradation rates of neutral detergent Fiber (NDF, 49%) and neutral detergent insoluble nitrogen (NDIN, 32%), and an increase in the degradation rare of starch (ST, 25%). The use of lag time increased the effective DM degradation (EDDM) of corn silage in both diets (23% and 53% for D1 and D2, respectively). The concentrate ratios did not influence the particulate passage rate of the diets. The higher values related ro the availability of the protein subfractions may indicate a underestimation by CNCPS, Rnd(or) could be attributed to the Zebu animals used in this study.

Qualidade e composição química da carne de bovinos de corte inteiros ou castrados de diferentes grupos genéticos Charolês x Nelore

Seventy beef males of three breeding systems (BS), straightbreds Charolais (Ch) and Nellore (Ne), G1 crossbreds: 1/2 Ch + 1/2 Ne (1/2 Ch) and 1/2 Ne + 1/2 Ch (1/2 Ne) and G2 crossbreds: 3/4 Ch + 1/4 Ne (3/4 Ch) and 3/4 Ne + 1/4 Ch (3/4 Ne) were used. The number of animals by genetic group was, respectively, 15, 12,8, 12,14 and 9. Thirty-five males were castrated (C) at seven months and 35 were kept intact (1). The animals were feedlot finished from 20 to 24 months. The longissimus dorsi muscle was used for the meat evaluation. No significant interaction was observed between genetic composition and sexual condition, for the variables studied. The I males displayed meat with darker color (3.05 vs. 3.78 points) with less amount of marbling (4.26 vs. 5.75 points) and less amount of ether extract (1.73 vs. 2.88%). However they presented larger (66.03 vs. 60.50 cm(2)) longissimus dorsi area and meat with better palatability, juiciness and tenderness. Ch animals had larger longissimus dorsi than the Ne. In the G I group, the 1/2 Ch meat showed larger amount of marbling and ether extract and less cooking losses than the 1/2 Ne meat. Between G2 animals, the 3/4 Ne showed meat with larger thawing losses and larger amount of ether extract. In G1 animals meat, the heterosis level reached 18.54% for longissimus dorsiarea, 28.10% for ether extract and 64.01% for amount of marbling. In G2, the heterosis was -17.30% for lean texture and 10.40% for longissimus dorsi area.

USE OF PROGENY TESTING IN BEEF-CATTLE - PREDICTION OF GENETIC GAIN IN A NELORE CATTLE-BREEDING PROGRAM

Genetic gains predicted for selection, based on both individual performance and progeny testing, were compared to provide information to be used in implementation of progeny testing for a Nelore cattle breeding program. The prediction of genetic gain based on progeny testing was obtained from a formula, derived from methodology of Young and weller (J. Genetics 57: 329-338, 1960) for two-stage selection, which allows prediction of genetic gain per generation when the individuals under test have been pre-selected on the basis of their own performance. The application of this formula also allowed determination of the number of progeny per tested bull needed to maximize genetic gain, when the total number of tested progeny is limited.

Avaliação da Gravidade Específica e de Outras Medidas Corporais e da Carcaça para Estimar a Composição Corporal de Novilhos Nelore

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Condição imunológica de bovinos das raças Holandesa e Nelore frente a Babesia bovis e B. bigemina em duas regiões do Estado de São Paulo

The immunological reply of a population to an infectious agent can vary between races and handling of this population. Regional research becomes important, in order to know the interrelation between the agent and its host. In this way, the occurrence of immunoglobulins of class G, anti-Babesia bovis and anti-Babesia bigemina in the Nelore (Bos indicus) and Hostein breed (Bos taurus), was investigated in two regions of the State of São Paulo, 300 km distant from each other. For the indirect method of ELISA, 1, 161 bovine serum samples were tested. The medium frequencies of antibodies showed that in the two regions exists an enzootic stability for B. bovis in both breeds studied; even so there was a tendency of marginal area for the Nelore breed in one of the regions. Regarding B. bigemina, in both regions exists enzootic stability for the Hostein and enzootic instability for the Nelore breed. Therefore, acute cases of the disease or specific outbreaks by B. bigemina infection in the Nelore breed may occur in these regions.

Comparative susceptibility and pathogeny of Nelore and Holstein-Friesian calves to the experimental infection of Haemonchus placei (Place, 1893)

Two groups of Holstein-Friesian and Nelore calves, five animals each, about nine months old, received, by oral route, 1,000 infective larvae (L-3) per kg of body weight of Haemonchus placei. Blood samples were collected by venipuncture, at weekly intervals, from one week before, to eight weeks after infection. Hematological studies comprised the hematocrit, differential leukocyte counts, hemoglobin, fibrinogen and plasma protein determinations. Parasitological examinations covered weekly fecal egg counts (EPG) and worm burden counts at necropsy. Samples of the abomasal mucosa were submitted to gross examination and histopathological studies. Both groups had increasing EPG after the fifth week, with Holstein calves showing higher counts than the Nelore. Holstein calves had anemia and hipoproteinemia from the third week post-infection to the end of the experiment, whereas Nelore calves showed no significant differences in those, parameters. Holstein calves had significantly larger worm counts than the Nelore. The gross and histopathological lesions in the abomasum at necropsy were very similar, although macroscopically they look more apparent in the Holstein group. These results showed that Holstein calves are more susceptible to the infection and pathogenic effects of H. placei than Nelore calves.

Efeito da ovariectomia em novilhas Nelore x Angus, Bos taurus indicus x Bos taurus taurus sobre os ganhos de peso

This study aimed to evaluate the weight gain in cross breed heifers Nelore X Angus, spayed and nonspayed, kept on pasture and confinement. The animals were allotted in two groups as follows: group I consisted of 30 nonspayed heifers with 18 months old. Group 2 was composed of 30 spayed heifers with 18 months old. The animals were allotted in pasture of Brachiaria decumbens and weighted at 39 and 75 days. Significant difference was observed between the average daily gain of the two groups - G1 and G2 (75(th) day), respectively (0.51 kg and 0.65 kg; P<0.0 1). The following day (761 day), all animals were allotted and kept on confinement during 144 days. Significant difference was observed between the average daily gain of the two groups - G I and G2 (1441 day), respectively (0.73 kg and 0.58 kg; P<0.0 1). The results of this experiment show that spayed heifers presented a higher daily gain on pasture.

Avaliação da composição química e física dos cortes da costela para estimar a composição química corporal de novilhos nelore

The objective of this study was to establish equations to estimate the empty body chemical composition of Nellore steers using the following indirect techniques: 1) physical composition of the 9-10-11(th) rib cut;) physical composition of the 10(th) rib cut; and 3) chemical composition of the 10(th) rib cut. Thirty-one Nellore steers with weights ranging from 245 to 489 kg and ages from 20 to 29.7 months at slaughter were utilized. The empty body chemical composition was established through samples collected after grinding all animal tissues. The equations using the percentage of dissectable fat in the 9-10-11(th) rib cut shored a high precision for estimating the percentage of water (r(2) = 0.91; Syx = 1.168) and ether extract (r(2) = 0.94; Syx = 1.298) of the empty body; the same was observed when the percentage of dissectable fat in the 10(th) rib cut was used (r(2) = 0.82 and 0.85; Syx = 1.658 and 1.942, respectively, for water and ether extract). The equations using the percentage of ether extract in the 10(th) rib cut showed a high precision for estimating the percentage of water (r(2) = 0.89; Syx = 1.311) and the ether extract (r(2) = 0.89; Syx = 1.730) of the empty body, but there was no advantage over the physical composition of the 9-10-11(th) and 10(th) rib cut. Multiple regressions using carcass weight and the percentage of bones and kilograms of lean, fat, and bones dissectable in the 10(th) rib cut improved the coefficients of determination for water and ether extract to 0.87 and 0.91. The equations to estimate the percentages of protein and ach showed a low precision, indicating that those techniques are not recommended to estimate these components in the empty body of Nellore steers.