Degree of multicollinearity and variables involved in linear dependence in additive-dominant models

The objective of this work was to assess the degree of multicollinearity and to identify the variables involved in linear dependence relations in additive-dominant models. Data of birth weight (n=141,567), yearling weight (n=58,124), and scrotal circumference (n=20,371) of Montana Tropical composite cattle were used. Diagnosis of multicollinearity was based on the variance inflation factor (VIF) and on the evaluation of the condition indexes and eigenvalues from the correlation matrix among explanatory variables. The first model studied (RM) included the fixed effect of dam age class at calving and the covariates associated to the direct and maternal additive and non-additive effects. The second model (R) included all the effects of the RM model except the maternal additive effects. Multicollinearity was detected in both models for all traits considered, with VIF values of 1.03 - 70.20 for RM and 1.03 - 60.70 for R. Collinearity increased with the increase of variables in the model and the decrease in the number of observations, and it was classified as weak, with condition index values between 10.00 and 26.77. In general, the variables associated with additive and non-additive effects were involved in multicollinearity, partially due to the natural connection between these covariables as fractions of the biological types in breed composition.

Projecte de gestió conjunta de dos ramats de boví de carn a Borredà (Berguedà)

Disseny de dues explotacions de boví de carn, que actuaran com a una única explotació a nivell sanitari i a nivell de maneig. Es farà un estudi de viabilitat de diferents alternatives a nivell de maneig, tant del bestiar com dels camps, de comercialització, de races, d’alimentació i d’estructures productives. Així mateix i com a complement a l’activitat prevista, es projecta la construcció d’un cobert amb cornadís per alimentar les vaques. Les dues explotacions estan registrades a les finques “El Coll” i “Subirà”, confrontants dins el terme municipal de Borredà (Berguedà). A més d’ambdues finques, la ramaderia consta de més finques situades en municipis de la mateixa comarca, de comarques veïnes i d’una finca de regadiu a Salt (Gironès)

Field evaluation of safety during gestation and horizontal spread of a recombinant differential bovine herpesvirus 1 (BoHV-1) vaccine

Bovine herpesvirus type 1 (BoHV-1) is recognized as a major cause of respiratory, reproductive disease and abortion in cattle. Vaccination is widely applied to minimize losses induced by BoHV-1 infections; however, vaccination of dams during pregnancy with modified live virus (MLV) vaccines has been occasionally associated to abortions. We have previously reported the development of a BoHV-1 recombinant virus, constructed with basis on a Brazilian BoHV-1 (Franco et al. 2002a) from which the gene coding for glycoprotein E (gE) was deleted (gE-) by genetic manipulation. Such recombinant has been previously evaluated in its potential as a differential vaccine (gE- vaccine) that allows differentiation between vaccinated and infected animals. Here, in the first part of the present study, the safety of the gE- vaccine during pregnancy was evaluated by the intramuscular inoculation of 10(7.4) tissue culture 50 % infective doses (TCID50) of the virus into 22 pregnant dams (14 BoHV-1 seronegative; 8 seropositive), at different stages of gestation. Other 15 pregnant dams were kept as non-vaccinated controls. No abortions, stillbirths or fetal abnormalities were seen after vaccination. Seroconversion was observed in both groups of previously seronegative vaccinated animals. In the second part of the study, the potential of the gE- vaccine virus to spread among beef cattle under field conditions was examined. Four heifers were inoculated intranasally with a larger amount (10(7,6) TCID50) of the gE- vaccine (to increase chances of transmission) and mixed with other sixteen animals at the same age and body condition, in the same grazing area, at a population density equal to the average cattle farming density within the region (one cattle head per 10,000 m²), for 180 days. All animals were monitored daily for clinical signs. Serum samples were collected on days 0, 30, 60 and 180 post-vaccination. Seroconversion was observed only in vaccinated heifers. These results indicate that, under the conditions of the present study, the gE- vaccine virus did not cause any noticeable harmful effect on pregnant dams and on its offspring and did not spread horizontally among cattle.

Effect of medroxy-progesterone acetate on follicular growth and endometrial cycloxygenase-2 (COX-2) expression during the bovine estrous cycle

The objective of this study was to evaluate the effect of medroxy-progesterone acetate (MAP) with or without estradiol benzoate (EB) on follicular growth during the estrous cycle in cattle. In the first experiment, Hereford cows were synchronized with a synthetic analogue of PGF2 alpha and were treated with two different doses of MAP (250 or 500 mg) with or without EB for 7 days starting on day 8 of the estrous cycle. Follicular growth was inhibited (P<0.05) in all cows except controls and those receiving 250mg MAP without EB. Seventy-five percent of the animals (15/20) showed estrus on days 21 and 22 of the cycle rather than at MAP withdrawal, demonstrating that these treatments did not induce estrus. To determine whether the EB treatment altered endometrial sensitivity to oxytocin and thus the luteolytic cascade, multiparous pre-synchronized cows received 5 mg of EB followed 6 hours later with 50 IU of oxytocin (OT; n=9). Eight hours after EB injection, endometrial fragments were collected from the cows on days 4, 13 and 17 of the estrous cycle and COX-2 gene expression was measured by PCR. EB increased COX-2 mRNA levels only on day 17 of the estrous cycle (P<0.05). In conclusion, MAP alone or associated with EB is able to suppress bovine follicular growth. However, EB in the presence of MAP is not efficient to induce luteolysis in cows when injected on day 8 of the estrous cycle.

Passive immunity transfer and serum constituents of crossbred calves

Passive immunity transfer (PIT) evaluation is an essential tool for the maintenance of healthy calves during the first months of life. Since lactation number and breed have been proven to influence immunoglobulin levels in colostrum, the aim of this study was to evaluate PIT from primiparous and multiparous Canchim cows to their calves. Blood samples were collected from the calves before colostrum intake and 1, 2, 7, 15 and 30 days thereafter, while colostrum samples from the cows were taken immediately after parturition. Activities of gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and concentrations of total protein, albumin, globulins, immunoglobulin A (IgA), immunoglobulin G (IgG), total and ionized calcium, inorganic phosphorus, magnesium, sodium and potassium were evaluated in calves' serum and activities of GGT and ALP and concentrations of total protein, IgA and IgG were assessed in cow's colostrum whey. Immunoglobulins concentrations were evaluated by electrophoresis in polyacrylamide gels. Serum biochemistry evaluations revealed an increase in gamma-glutamyl transferase and alkaline phosphatase activities and in total protein, globulins, immunoglobulin A and immunoglobulin G levels in calves' serum after colostrum intake. Only total protein and light chain immunoglobulin G levels in colostrum whey were affected by the cows' lactation number. Phosphorus and magnesium levels in blood serum increased after colostrum intake, while sodium and potassium levels oscillated in the experimental period. PIT was influenced by the cows' lactation number but was efficient in both groups.

Sugarcane stems as larval habitat for the stable fly (Stomoxys calcitrans) in sugarcane plantations

Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology and ecology of the stable fly, including larval habitats and their reproduction sites is extremely important for further development of control programs. This paper aims to report the occurrence and development of S. calcitrans larvae inside sugarcane stems in three municipalities of Mato Grosso do Sul. The sugarcane stems give protection against bad weather conditions and insecticide application. In this way, for sustainable sugarcane growth specific research concerning this situation should be conducted.

Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae)

Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain. The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme.

Acceptabilitat de la carn de boví uruguaià procedents de diferents sistemes d’alimentació pels consumidors espanyols

L’objectiu principal del projecte és avaluar l'acceptabilitat global, de la tendresa i del gust de la carn de vacum de l’Uruguai per part dels consumidors espanyols. També es va pretendre veure la influència de les característiques dels consumidors (edat, sexe i nivell d'estudis) sobre l'acceptabilitat d'aquesta carn

Análisis de las consecuencias del TLC con Estados Unidos frente al subsector ganadero colombiano

Colombia es un país que gracias a sus características topográficas y ubicación privilegiada se destaca por su amplia variedad de ganado en las diferentes regiones del país, esto le ha permitido tener diversas ventajas frente a otros países. Sin embargo, desde el año 2012 entro en vigencia el Tratado de Libre Comercio con Estados Unidos, en donde se demostró que debido a los subsidios y al bajo costo en la producción ganadera, este país ofrece precios inferiores a los de Colombia, con los cuales es más difícil disputar. Por esto es importante que Colombia logré implementar estrategias para competir con precios como los de Estados Unidos y a su vez debe buscar la admisibilidad sanitaria para lograr exportar nuestros productos a esta Potencia. Además, Colombia debe identificar las oportunidades, fortalezas y amenazas que se tienen con el Tratado de Libre comercio, para establecer diferentes proyectos y programas los cuales permitan potencializar el subsector ganadero colombiano.

Tolerance of ruminant animals to high dose in-feed administration of a selenium-enriched yeast

The objective of the study was to determine if there were adverse effects on animal health and performance when a range of ruminant animals species were fed at least 10 times the maximum permitted European Union (EU) selenium (Se) dietary inclusion rate (0.568 mg Se/kg DM) in the form of selenium enriched yeast (SY) derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060. In a series of studies, dairy cows, beef cattle, calves and lambs were offered either a control diet which contained no Se supplement or a treatment diet which contained the same basal feed ingredients plus a SY supplement which increased total dietary Se from 0.15 to 6.25, 0.20 to 6.74, 0.15 to 5.86 and 0.14 to 6.63 mg Se/kg DM, respectively. The inclusion of the SY supplement (P < 0.001) increased whole blood Se concentrations, reaching maximum mean values of 716, 1,505, 1,377, and 724 ng Se/mL for dairy cattle, beef cattle, calves and lambs, respectively. Selenomethionine accounted for 10% of total whole blood Se in control animals whereas the proportion in SY animals ranged between 40 and 75%. Glutathione peroxidase (EC 1.11.1.9) activity was higher (P < 0.05) in SY animals when compared with controls. A range of other biochemical and hematological parameters were assessed, but few differences of biological significance were established between treatments groups. There were no differences between treatment groups within each species with regard to animal physical performance or overall animal health. It was concluded that there were no adverse effects on animal health, performance and voluntary feed intake to the administration of at least ten times the EU maximum, or approximately twenty times the US FDA permitted concentration of dietary Se in the form of SY derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060.

Modelling the likely impact of healthy eating guidelines on agricultural production and land use in England and Wales

Quadratic programming techniques were applied to household food consumption data in England and Wales to estimate likely changes in diet under healthy eating guidelines, and the consequences this would have on agriculture and land use in England and Wales. The first step entailed imposing nutrient restrictions on food consumption following dietary recommendations suggested by the UK Department of Health. The resulting diet was used, in a second step as a proxy for demand in agricultural commodities, to test the impact of such a scenario on food production and land use in England and Wales and the impacts of this on agricultural landscapes. Results of the diet optimisation indicated a large drop in consumption of foods rich in saturated fats and sugar, essentially cheese and sugar-based products, along with lesser cuts of fat and meat products. Conversely, consumption of fruit and vegetables, cereals, and flour would increase to meet dietary fibre recommendations. Such a shift in demand would dramatically affect production patterns: the financial net margin of England and Wales agriculture would rise, due to increased production of high market value and high economic margin crops. Some regions would, however, be negatively affected, mostly those dependent on beef cattle and sheep production that could not benefit from an increased demand for cereals and horticultural crops. The effects of these changes would also be felt in upstream industries, such as animal feed suppliers. While arable dominated landscapes would be little affected, pastoral landscapes would suffer through loss of grazing management and, possibly, land abandonment, especially in upland areas.

A method for the economic valuation of animal welfare benefits using a single welfare score

Unless the benefits to society of measures to protect and improve the welfare of animals are made transparent by means of their valuation they are likely to go unrecognised and cannot easily be weighed against the costs of such measures as required, for example, by policy-makers. A simple single measure scoring system, based on the Welfare Quality® index, is used, together with a choice experiment economic valuation method, to estimate the value that people place on improvements to the welfare of different farm animal species measured on a continuous (0-100) scale. Results from using the method on a survey sample of some 300 people show that it is able to elicit apparently credible values. The survey found that 96% of respondents thought that we have a moral obligation to safeguard the welfare of animals and that over 72% were concerned about the way farm animals are treated. Estimated mean annual willingness to pay for meat from animals with improved welfare of just one point on the scale was £5.24 for beef cattle, £4.57 for pigs and £5.10 for meat chickens. Further development of the method is required to capture the total economic value of animal welfare benefits. Despite this, the method is considered a practical means for obtaining economic values that can be used in the cost-benefit appraisal of policy measures intended to improve the welfare of animals.

Effluent quality and ammonia emissions from out-wintering pads in England, Wales and Ireland

Out-wintering pads offer a reduced cost system for wintering cattle, minimising damage to pasture, providing animal welfare and production benefits, and generate, potentially, a more manageable effluent and lower ammonia emissions. The objectives of the present study were (i) to contribute to improved understanding of the factors impacting on effluent quality, ammonia emissions and animal welfare via observations on four farm-based out-wintering pads (ComOWPs) in England, Wales and Ireland and more detailed studies undertaken on four experimental OWPs (ExpOWPs) constructed at Rothamsted Research North Wyke, Devon, England and (ii) to corroborate the effluent quality data from both the ComOWPs and the ExpOWPs, with findings in the literature. Woodchip size, feeding management and area allowance were the treatment factors applied on the ExpOWPs. These three factors were randomised across the four ExpOWPs, over four 6–7 week periods. Effluent quality from the ExpOWPs was sampled frequently in a flow proportional way and analysed for total N (TN); total P (TP); total solids (TS); ammonium-N (NH4+-N); nitrate-N (NO3−-N). Beef cattle were periodically weighed for determination of live weight gain (LWG). An approximate nitrogen balance was calculated as a means of understanding its partitioning and fate during and after the ExpOWPs use. Effluent quality from the ComOWPs was sampled frequently, also in a flow-proportional way, and analysed for TN, TP, TS, NH4+-N, NO3−-N, total K and COD. Effluent quality data from the ExpOWPs showed no significant differences (P > 0.05) between treatments, with average concentrations of 1095 mg l−1, and 806 mg l−1, for TN and NH4+-N, respectively. Average effluent concentrations from the ComOWPs were 356 mg l−1 TN and 124 mg l−1 NH4+-N. Ammonia emissions from the ExpOWPs showed no significant differences (P > 0.05) between the treatments, with average mean emission rates of 2.5 g m−2 d−1 NH3-N, respectively. A positive correlation was established between NH3-N emission rate and wind speed. Emission rates from the ComOWPs ranged from 0.7 to 1.6 g m−2 d−1 NH3-N. Average daily LWG on the ExpOWPs was 1.33 kg steer−1 d−1. The effluent from both the ComOWPs and ExpOWPs were more similar with dirty water and of consistently lower strength than beef cattle slurry, as supported by findings in the literature, and therefore, it is suggested to be subject to the regulatory requirements of dirty water rather than slurry.

The potential inefficiency of using marketing margins in applied commodity price analysis, forecasting and risk management

This paper examines the implications of using marketing margins in applied commodity price analysis. The marketing-margin concept has a long and distinguished history, but it has caused considerable controversy. This is particularly the case in the context of analyzing the distribution of research gains in multi-stage production systems. We derive optimal tax schemes for raising revenues to finance research and promotion in a downstream market, derive the rules for efficient allocation of the funds, and compare the rules with an without the marketing-margin assumption. Applying the methodology to quarterly time series on the Australian beef-cattle sector and, with several caveats, we conclude that, during the period 1978:2 - 1988:4, the Australian Meat and Livestock Corporation optimally allocated research resources.

Human-animal interaction, stress, and embryo production in Bos indicus embryo donors under tropical conditions

This study investigated the effect of human-animal interaction (HAI) and the stress response on the quality of embryo production in superovulated Nelore (Bos indicus) cattle, under tropical conditions. Thirty-two females underwent a superovulation protocol for 5 days. Cortisol concentrations were determined in blood plasma collected on days 0, 4, and 5. Artificial insemination was performed on days 4 and 5, and nonsurgical embryo flushing on day 11. Embryo production and viability were determined. Human stimulation, animal behaviors, accidents, and handling time were recorded to assess HAI. Cattle age was negatively correlated with accidents, frequency of aversive behaviors, and negative stimuli by stockperson during transit through corral compartments to receive superovulation treatments. The factor analysis revealed two distinct groups. The first group was called stressed and had higher cortisol concentration than the nonstressed group, 16.0 +/- 2.1 and 12.5 +/- 1.0 ng/mL, respectively. Comparisons between these groups showed that the frequency of voice emissions by the stockperson and the number of accidents were higher in the stressed group, and also, the mean handling time was longer in the stressed group than for the nonstressed. As a result, viability rate of the embryos was 19% lower in the stressed group (P < 0.05). This indicates that intensive negative HAI is likely related to stress, which affects embryo production in a superovulation program.