Interação genótipo-ambiente e sensibilidade ambiental em características de crescimento em bovinos de corte

Pós-graduação em Zootecnia - FMVZ

Componentes principais na elaboração de índices de provas de desempenho em bovinos

The principal component analysis assists the producers in making decision of which evaluated features must be maintained in performance tests indexes, according to the variation present in these animals evaluated. The objective in this study was to evaluate a set of characteristics measured in a performance test in semifeedlot cattle of the Simmental and Angus breeds, by means principal component analysis (PC), aim to identify the features that represent most of the phenotypic variation for preparation of indexes. It was used data from 39 Angus and 38 Simmental bulls from the Santa Éster farm, located in Silvianópolis - MG. The performance test period was from october 2014 to february 2015. The features evaluated in the test were: final weight (FW), average daily gain weight (GW), respiratory rate (RR), haircoat temperature (HT) and rectal (RT), hair number (HN), hair length (HL), hair thickness (HT), muscularity (MUSC), racial characteristics, angulation, reproductive and balance (BAL), height of the front and back, width and length of croup, body length, depth and heart girth, subcutaneous fat thickness and rump (FTR), loin eye area and marbling (MAR). It was used PRINCOMP from SAS program for procedure the PC analysis. It was found that of the 27 features evaluated, the first four PC for Simmental breed explained 74% total variation data. The four PC selected with the corresponding weighting coefficients formed the following index: (0.27 * FW) + (0.47 * MUSC) + (0.50 * HL) + (0.39 * HT). Since the characteristics related to the adaptability of great importance for the studied breed, it was decided to keep the index of evidence for the Angus breed, the feature hair number, because there is a feature that presented a great variability and occupied one of the first principal component. Thus, the Angus index was composed by five features, with 79% total variation data, resulting in the following formula: (0.26 * FW) + (0.33 * BAL) + (0.58 * MAR) - (0.43 * FTR) – (0.38 * HN). By the principal component analysis it was possible to minimize the features number to be evaluated on performance tests from that farm, making the animal selection rapidly and accurate.

Family facts.

Mode of access: Internet.

Encyclopædia of agriculture by the most eminent authorities.

I. Aberdeen-Angus cattle to drains.--II. Drills to joint-ill.--III. Kainit to Zelkova.--IV. Calendar of operations. Tables of manures, feeding stuffs, weights and measures and other matters. Statutes and statutory orders relating to agriculture. Coloured plates of animal anatomy, and an index to this and the preceding three volumes.

Beef quality of young Angus x Nellore cattle supplemented with rumen-protected lipids during rearing and fatting periods

This work evaluated the beef quality parameters of 108 bulls randomly administered to three treatments during rearing in pastures and two treatments during fatting in feedlots, including mineral and rumen-protected lipids. Meat and fat color, cooking yield, shear force, sensorial traits and chemical and fatty acid compositions were evaluated. Generally, the beef quality parameters were not affected by the rumen protected lipids; however, supplementation with rumen-protected lipids during the rearing period yielded darker beef and brighter fat and increased beef tenderness in meat aged for 28 days compared to the meat from animals that received only mineral supplementation. In addition, the percent of meat polyunsaturated fatty acids was negatively affected by the inclusion of protected lipids, yielding 5.58 and 3.72% in animals fed with and without rumen-protected lipids, respectively, during the fatting period. (C) 2014 Elsevier Ltd. All rights reserved.

Finishing precocity visual score and genetic associations with growth traits in Angus beef cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cyanide poisoning in cattle from Dysphania glomulifera (red crumbweed): Using the internet for rapid plant identification and diagnostic advice: Case Report

A 300-strong Angus-Brahman cattle herd near Springsure, central Queensland, was being fed Acacia shirleyi (lancewood) browse during drought and crossed a 5-hectare, previously burnt area with an almost pure growth of Dysphania glomulifera subspecies glomulifera (red crumbweed) on their way to drinking water. Forty cows died of cyanide poisoning over 2 days before further access to the plant was prevented. A digital image of a plant specimen made on a flat-bed scanner and transmitted by email was used to identify D glomulifera. Specific advice on the plant's poisonous properties and management of the case was then provided by email within 2 hours of an initial telephone call by the field veterinarian to the laboratory some 600 km away. The conventional method using physical transport of a pressed dried plant specimen to confirm the identification took 5 days. D glomulifera was identified in the rumen of one of two cows necropsied. The cyanogenic potential of D glomulifera measured 4 days after collection from the site of cattle deaths was 18,600 mg HCN/kg in dry matter. The lethal dose of D glomulifera for a 420 kg cow was estimated as 150 to 190 g wet weight. The plant also contained 4.8% KNO3 equivalent in dry matter, but nitrate-nitrite poisoning was not involved in the deaths.

Sulfur-associated polioencephalomalacia in cattle grazing plants in the Family Brassicaceae

Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July-August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.

Estimating daily methane production in individual cattle with irregular feed intake patterns from short-term methane emission measurements

Spot measurements of methane emission rate (n = 18 700) by 24 Angus steers fed mixed rations from GrowSafe feeders were made over 3- to 6-min periods by a GreenFeed emission monitoring (GEM) unit. The data were analysed to estimate daily methane production (DMP; g/day) and derived methane yield (MY; g/kg dry matter intake (DMI)). A one-compartment dose model of spot emission rate v. time since the preceding meal was compared with the models of Wood (1967) and Dijkstra et al. (1997) and the average of spot measures. Fitted values for DMP were calculated from the area under the curves. Two methods of relating methane and feed intakes were then studied: the classical calculation of MY as DMP/DMI (kg/day); and a novel method of estimating DMP from time and size of preceding meals using either the data for only the two meals preceding a spot measurement, or all meals for 3 days prior. Two approaches were also used to estimate DMP from spot measurements: fitting of splines on a 'per-animal per-day' basis and an alternate approach of modelling DMP after each feed event by least squares (using Solver), summing (for each animal) the contributions from each feed event by best-fitting a one-compartment model. Time since the preceding meal was of limited value in estimating DMP. Even when the meal sizes and time intervals between a spot measurement and all feeding events in the previous 72 h were assessed, only 16.9% of the variance in spot emission rate measured by GEM was explained by this feeding information. While using the preceding meal alone gave a biased (underestimate) of DMP, allowing for a longer feed history removed this bias. A power analysis taking into account the sources of variation in DMP indicated that to obtain an estimate of DMP with a 95% confidence interval within 5% of the observed 64 days mean of spot measures would require 40 animals measured over 45 days (two spot measurements per day) or 30 animals measured over 55 days. These numbers suggest that spot measurements could be made in association with feed efficiency tests made over 70 days. Spot measurements of enteric emissions can be used to define DMP but the number of animals and samples are larger than are needed when day-long measures are made.

Performance and carcass characteristics of beef cattle fed with ammoniated marandugrass hay

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

Efeitos ambientais que afetam o ganho de peso pré-desmama em animais Angus, Hereford, Nelore e mestiços Angus-Nelore e Hereford-Nelore

Foram utilizados dados de 66.035 animais das raças Nelore, Hereford, Angus e mestiços Nelore x Angus e Nelore x Hereford, para avaliar a influência da idade da vaca, idade do bezerro e data juliana de nascimento sobre o ganho médio diário dos bezerros no período pré-desmama (GMD). A análise estatística revelou que estas três covariáveis tiveram efeito significativo sobre o GMD. Observou-se também que o ajuste linear para idade à desmama não foi suficiente para retirar o seu efeito sobre o GMD. Estes resultados mostram que tais fatores ambientais podem ser importantes fontes de variação para esta característica nos programas de melhoramento genético.

Heteroses materna e individual para ganho de peso pré-desmama em bovinos Nelore × Hereford e Nelore × Angus

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