Effect of shade and water sprinkling on physiological responses and milk yields of Holstein cows in a semi-arid region

The effects of shading and water sprinkling on physiological responses and milk production were studied in Holstein cows managed in an equatorial semi-arid region. Five cows were observed for 36 days during May and June 2009. We studied the effects of sun, shade, shade plus single sprinkling, shade plus sprinkling every 2. h and shade plus sprinkling every hour on physiological responses, i.e., rectal temperature, coat surface temperature and respiratory rate, and on milk production. Environmental variables, i.e., air temperature, black globe temperature, mean radiant temperature, relative humidity and wind speed, were recorded every 30. min throughout the observation period. The statistical analysis utilized a 5×5 replicated latin square, and the results showed reduced values in physiological variables in cows that were protected from short wave radiation and that received water sprinkling; milk yield increased by approximately 3.5. kg in such animals relative to those not receiving such treatment. However, the milk yield for the morning milking presented similar mean values regardless of whether the animals received shading and sprinkling benefits, which indicates that frequency of sprinkling and amount of time (permanence) in the shade were critical for the effect on milk yield. © 2013 Elsevier B.V.

Estimates of genetic parameters and eigenvector indices for milk production of Holstein cows

The objectives of the present study were to estimate genetic parameters of monthly test-day milk yield (TDMY) of the first lactation of Brazilian Holstein cows using random regression (RR), and to compare the genetic gains for milk production and persistency, derived from RR models, using eigenvector indices and selection indices that did not consider eigenvectors. The data set contained monthly TDMY of 3,543 first lactations of Brazilian Holstein cows calving between 1994 and 2011. The RR model included the fixed effect of the contemporary group (herd-month-year of test days), the covariate calving age (linear and quadratic effects), and a fourth-order regression on Legendre orthogonal polynomials of days in milk (DIM) to model the population-based mean curve. Additive genetic and nongenetic animal effects were fit as RR with 4 classes of residual variance random effect. Eigenvector indices based on the additive genetic RR covariance matrix were used to evaluate the genetic gains of milk yield and persistency compared with the traditional selection index (selection index based on breeding values of milk yield until 305 DIM). The heritability estimates for monthly TDMY ranged from 0.12 ± 0.04 to 0.31 ± 0.04. The estimates of additive genetic and nongenetic animal effects correlation were close to 1 at adjacent monthly TDMY, with a tendency to diminish as the time between DIM classes increased. The first eigenvector was related to the increase of the genetic response of the milk yield and the second eigenvector was related to the increase of the genetic gains of the persistency but it contributed to decrease the genetic gains for total milk yield. Therefore, using this eigenvector to improve persistency will not contribute to change the shape of genetic curve pattern. If the breeding goal is to improve milk production and persistency, complete sequential eigenvector indices (selection indices composite with all eigenvectors) could be used with higher economic values for persistency. However, if the breeding goal is to improve only milk yield, the traditional selection index is indicated. © 2013 American Dairy Science Association.

Concentrações de oxitetraciclina de longa ação vias sistêmica ou tópicas no leite, líquido sinovial e plasma de vacas acometidas de dermatite digital papilomatosa

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

Efeitos das injeções epidurais de amitraz ou xilazina em vacas

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

Avaliação da transferência de imunidade passiva em bezerros de vacas da raça Canchim

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

Perfil sanguíneo de fêmeas bovinas em gestação e no periparto e avaliação da transferência de imunidade passiva aos descendentes

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

Influência da raça do touro (Bos indicus x Bos taurus) na tolerância ao estresse térmico calórico de embriões bovinos produzidos in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação da taxa de ovulação e sua relação com diâmetro folicular e isoformas de mRNA para receptor de LH, em vacas da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de quimeras embrionárias bovinas mediante a agregação de embriões diploides (Bos indicus) e tetraploides (Bos indicus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Taxas de prenhez em vacas nelore, em pós-parto recente, tratadas com protocolos hormonais à base de progesterona associados ou não a remoção temporária de bezerros(RTB) e ou eCG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Associação de escores de condição corporal com características reprodutivas de vacas Nelore e com desempenho de seus bezerros

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Indicadores de qualidade microbiológica, físico-química e detecção de resíduos de antimicrobianos no leite de vacas colhidos de tanques de expansão individuais, tanques coletivos e leite informal na região do estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da resposta vacinal contra o herpesvírus bovino tipo 1 (BoHV-1) nos parâmetros reprodutivos de vacas receptoras de embrião

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Anticorpos virusneutralizantes para o genótipo 1 e 2 do vírus da diarréia viral bovina em vacas gestantes abatidas em frigorífico e respectivos fetos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização genotípica de linhagens de Prototheca zopfii isoladas do leite de vacas e sensibilidade in vitroa antimicrobianos e anti-sépticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)