Genotype by Environment Interactions for Milk and Fat Production Across Regions of the United States

(Co)variance components for regional production of milk, fat, and fat percentage were estimated via multiple-trait REML using DHIA data from California, New York, and Wisconsin. Data consisted of registered and grade first lactation yields of Holstein cattle from 1970 through 1984. Records were limited to daughters from sires common to the pairs of states analyzed. Averaged numbers of records from California, New York, and Wisconsin were 419,185, 460,296, and 449,866. Genetic correlations between New York and Wisconsin for milk, fat, and fat percentage (.99, .98, and .99) were larger than those between California and New York (.95, .95, and .98) and those between California and Wisconsin (.94, .93, and .98). Heritabilities in New York for milk, fat, and fat percentage (approximately .27, .26. and .48) were larger than those of Wisconsin (approximately .23, .22, and .43) and California (approximately .22, .21, and .34). Grade records were also investigated; numbers of records in California were reduced by about 25%. whereas records in both New York and Wisconsin were reduced by about 66%. Genetic correlations were virtually unchanged, but heritabilities for milk and fat in the three states were similar (approximately .17) and significantly smaller than those from combined registered and grade daughters. In conclusion, there appeared to be no sire by region interaction

Estimation of Genetic Parameters for Milk and Fat Yields of Dairy Cattle in Spain and the United States

Interaction of genotype with environment was studied with 10,780 Spanish production records (daughters of 210 Holstein-Friesian bulls) and two subsets of United States data (800,821 records with 1170 sires and 762,152 records with 1186 sires). Only 74 bulls had daughter records in both Spanish and United States data. Genetic and phenotypic (co)variances and correlations and heritability for milk and fat yields were estimated both within country and between countries with countries considered as separate traits (joint analysis). (Co)variance components were estimated with a REML procedure. Heritability estimates for milk and fat in the Spanish population (.16 and .14, within country; .12 and .09, joint) were smaller than for United States data (means of .33 and .31, within country; .26 and .24, joint). Genetic and phenotypic correlations between milk and fat within country were higher for Spain (.94 and .91) than for United States data (means of .66 and .81). Genetic correlation between countries averaged .81 for milk and .50 for fat. Rankings of bulls for milk yield are expected to be similar in Spain and the United States, although a scaling effect on predicted values is expected from different genetic variances in each country. Ranking of bulls for fat yield may be quite different

Modèles alternatifs d’évaluation génétique des caractères reproductifs de la population caprine locale dans les conditions d’aride

The success of small ruminant breeding programs depends on appropriate models for genetic evaluation of breeding animals on traits showing a genetic association between different reproductive phenotypes. The objective of this study is to determine the environmental and genetic components that synthesize the reproductive performance of local goats in arid conditions, in order to make the foundations for future genetic improvement of this population. Two reproductif traits were studied : the interval between kidding and the litter size at birth. Three models were used for each case, univariate and bivariate analyzes, which differ in random effects included in the model, only the additive genetic effects, only the permanent environmental effects, or both effects simultaneously. The obtained results suggest that the Bi-variate model including only the permanent environmental effects of the goat is the most adequate to model the reproductive performance of local goat. Direct genetic variances are mainly higher using the uni-variate model than the Bivariate model. The environmental variance estimates obtained are the same for both models. The heritabilities recorded from the uni-variate model are slightly lower than the estimates from the Bi-variate model. It seems imperative to consider in animal model, all the genetic and environmental effects, that intervene on the determinism of reproductif traits. Keywords: local goat, improvement, evaluation, uni-variate model, Bi-variate model, reproductionLe succès des programmes d'élevage des petits ruminants dépend des modèles appropriés d'évaluation génétique des reproducteurs sur des caractères présentant une association génétique entre les différents phénotypes reproductifs. L’objectif de ce travail est de déterminer les composantes environnementales et génétiques qui synthétisent les performances de reproduction des chèvres locales élevées dans des conditions arides afin de jalonner les bases d’une future amélioration génétique de cette population.   Deux caractères de reproduction ont été étudiés : l'intervalle entre mise bas et la taille de la portée à la naissance. Trois modèles ont été utilisés pour chaque cas, des analyses uni et bi-variées, qui différaient par les effets aléatoires inclus dans le modèle, uniquement les effets génétiques additifs, uniquement les effets environnementaux permanents ou les deux effets simultanément.  Les résultats obtenus suggèrent que le modèle Bi-variée incluant uniquement les effets environnementaux permanents de la chèvre est le plus adéquat pour modéliser les performances de reproduction de la chèvre locale. Les variances génétiques directes sont principalement plus élevées en utilisant le model uni-varié que le modèle Bi-varié.  Les estimations de la variance environnementale obtenues sont les mêmes pour les deux modèles. Les héritabilités enregistrées à partir du modèle uni-varié sont légèrement inférieures aux estimations issues du modèle Bi-varié. Il parait impératif de considérer qu’au niveau du modèle animale, l’ensemble des effets génétiques et environnementaux, susceptibles d’intervenir sur le déterminisme des caractères reproductifs. Mots clés: chèvre local, amélioration, évaluation, modèle uni-varié, modèle Bi-varié, reproductio

Modeling heat stress under different environmental conditions

Renewed interest in heat stress effects on livestock productivity derives from climate change, which is expected to increase temperatures and the frequency of extreme weather events. This study aimed at evaluating the effect of temperature and humidity on milk production in highly selected dairy cattle populations across three European regions differing in climate and production systems to detect differences and similarities that can be used to optimize heat stress (HS) effect modeling. Milk, fat and protein test day data from official milk recording for years 1999 to 2010 in four Holstein populations located in the Walloon Region of Belgium (BEL), Luxembourg (LUX), Slovenia (SLO) and Southern Spain (SPA) were merged with temperature and humidity data provided by the state meteorological agencies. After merging, the number of test day records/cows per trait ranged from 686,726/49,655 in SLO to 1,982,047/136,746 in BEL. Values for the daily average and maximum temperature and humidity index (THIavg and THImax) ranges for THIavg/THImax were largest in SLO (22-74/28-84) in SLO and shortest in SPA (39-76/46-83). Change point techniques were used to determine comfort thresholds, which differed across traits and climatic regions. Milk yield showed an inverted U shaped pattern of response across the THI scale with a HS threshold around 73 THImax units. For fat and protein, thresholds were lower than for milk yield and were shifted around 6 THI units towards larger values in SPA compared with the other countries. Fat showed lower HS thresholds than protein traits in all countries. The traditional broken line model was compared to quadratic and cubic fits of the pattern of response in production to increasing heat loads. A cubic polynomial model allowing for individual variation in patterns of response and THIavg as heat load measure showed the best statistical features. Higher/lower producing animals showed less/more persistent production (quantity and quality) across the THI scale. The estimated correlations between comfort and THIavg values of 70 (which represents the upper end of the THIavg scale in BEL-LUX) were lower for BEL-LUX (0.70 - 0.80) than for SPA (0.83 - 0.85). Overall, animals producing in the more temperate climates and semi-extensive grazing systems of BEL and LUX showed HS at lower heat loads and more re-ranking across the THI scale than animals producing in the warmer climate and intensive indoor system of SPA.DairyHeatStres

Determination of non-market values to inform conservation strategies for the threatened Alistana-Sanabresa cattle breed

Livestock breed-related public good functions are often used to justify support for endangered breed conservation despite the fact that little is known about such non-market values. We show how stated preference techniques can be used to assess the non-market values that people place on livestock breeds. Through the application of a case study choice experiment survey in Zamora province, Spain, the total economic value (TEV) of the threatened Alistana–Sanabresa (AS) cattle breed was investigated. An analysis of the relative importance of the non-market components of its TEV and an assessment of the socio-economic variables that influence people’s valuation of such components is used to inform conservation strategy design. Overall, the findings reveal that the AS breed had significant non-market values associated with it and that the value that respondents placed on each specific public good function also varied significantly. Functions related with indirect use cultural and existence values were much more highly valued than landscape maintenance values. These high cultural and existence values (totalling over 80% of TEV) suggest that an AS in situ conservation strategy will be required to secure such values. As part of such a strategy, incentive mechanisms will be needed to permit farmers to capture some of these public good values and thus be able to afford to maintain breed population numbers at socially desirable levels. One such mechanism could be related to the development of breed-related agritourism initiatives, with a view to enhancing private good values and providing an important addition to continued direct support. Where linked with cultural dimensions, niche product market development, including through improving AS breed-related product quality and brand recognition may also have a role to play as part of such an overall conservation and use strategy. We conclude that livestock breed conservation strategies with the highest potential to maximise societal welfare would be those that secure the breed-related functions that people value most, with appropriate in situ conservation interventions and strategies being identified accordingly

Nutritive evaluation and ingredient prediction of compound feeds for rabbits by near-infrared reflectance spectroscopy (NIRS)

Near-infrared reflectance spectroscopy (MRS) was used to predict the nutritive characteristics of 66 compound rabbit feeds from three countries (Belgium, Spain and Italy) and the main ingredient inclusion rate in 59 of these feeds of known ingredient composition. Principal component analysis (PCA) was performed to classify the compound feeds according to their origin. The coefficient of multiple determination (R-2) for crude protein concentration (CP) was ca. 0.88 in both, calibration and validation with standard errors of calibration (SEC) and prediction (SEP) equal to 7.5 and 7.7 g (kg DM)(-1), respectively. NIRS prediction of gross energy (GE) and digestible energy (DE) concentrations was more precise, with high R-2 (0.90) and low SEP (0.26 and 0.37 MJ (kg DM)(-1), respectively). Satisfactory results were also obtained for both, the dry matter digestibility (DMd) and gross energy digestibility (GEd) prediction. The CP-correlated wavelengths were observed to be associated with the bond vibrations of the protein functional groups, while the wavelengths correlated with GE, DE, DMd and GEd were linked with starch, protein and crude fiber structure. The calibration on absorbance data to estimate the inclusion rate of the main ingredients demonstrated a fair correlation for alfalfa meal, barley and wheat bran, intermediate for sunflower meal and weak for soybean meal. In validation, the precision of the NIRS estimate remained satisfactory for alfalfa and sunflower meal but decreased for barley and wheat bran. The calibration of the spectra transformed in second derivative appeared to improve the quality of estimation by reducing the number of optimal factors from 9-15 to 2-4; moreover, the estimate precision of soybean and sunflower meal inclusions improved (R-2: 0.90 and 0.86, respectively) with the reduction of SEC (13.0 and 12.9 g kg(-1), respectively). In validation, however, the estimate precision for all raw materials became weaker than the degree achieved using absorbance data. PCA on the transformed spectra grouped the compound rabbit feeds according to their country of origin and indicated the possibility of identifying the presence of specific ingredients (i.e. full-fat rapeseed). (C) 1999 Elsevier Science B.V. All rights reserved