Herdabilidade e tendência genética para as produções de leite e de gordura em rebanhos da raça Holandesa no estado do Rio Grande do Sul Heritability and genetic trend for milk and fat yields in Holstein herds raised in the state of Rio Grande do Sul

Com o objetivo de estimar a herdabilidade e a tendência genética para as características produção de leite (PL), produção de gordura (PG) e porcentagem de gordura (%G), foram estudados registros de produção à primeira lactação de 5.007 vacas da raça Holandesa, filhas de 930 touros, pertencentes a 33 rebanhos criados no estado do Rio Grande do Sul entre 1984 e 1998. Para estimar as herdabilidades e predizer os valores genéticos dos indivíduos (VGs) para PL, PG e %G, foi utilizado um modelo animal considerando-se como aleatórios os efeitos genético aditivo direto e residual e, como fixos, o número de ordenhas diárias, o rebanho e o ano/época do parto, além da covariável idade da vaca ao parto e dos efeitos linear e quadrático. Para o cálculo da tendência genética, utilizou-se a regressão dos VGs médios anuais em relação ao ano de nascimento dos animais. As médias observadas e os respectivos desvios-padrão foram de 6.862,80 &plusmn; 1.881,21 kg/ano (PL), 228,63 &plusmn; 78,01 kg/ano (PG) e 3,32 &plusmn; 0,18 %/ano (%G). As herdabilidades estimadas e os respectivos erros-padrão foram de 0,30 &plusmn; 0,008 (PL); 0,28 &plusmn; 0,004 (PG) e 0,22 &plusmn; 0,015 (%G). As correlações genéticas estimadas foram 0,85 &plusmn; 0,19 (PL e PG) e -0,15 &plusmn; 0,17 (PL e %G). As tendências genéticas estimadas foram de 9,51 kg/ano (PL), 0,11 kg/ano (PG) e -0,07%/ano (%G). Apesar de positivos, os ganhos genéticos estimados para PL e PG foram baixos, podendo ser aumentados pela implementação de programas de melhoramento genético eficientes que estimulem o produtor a promover aumentos nestas duas características, além das características de qualidade do leite.<br>Data comprising 5,007 records of first lactation of Holstein cows, daughters of 930 sires, from 33 herds in the state of Rio Grande do Sul, from 1984 to 1998, were used to estimate heritability coefficients and genetic trends for milk (MY) and fat (FY) yields and for fat percentage (%F). An animal model considered the genetic additive direct and residual as random effects and milking/day number, herd and year/season of parturition, and cow age at parturition as fixed effects, linear and quadratic effects, as covariate, inn order to estimate the coefficients of heritability and to predict the breeding values (BVs) for MY, FY and %F. The genetic trend was estimated by the regression of mean annual animal BVs in relation to animal year birth. The averages and respective standard deviations for MY, FY and %F were: 6,862.80 &plusmn; 1,881.21 kg/year, 228.63 &plusmn; 78.01 kg/year and 3.32 &plusmn; .18 %/year, respectively. The estimated coefficients of heritability and respective standard error for MY, FY and %F were: 0.30 &plusmn; 0.008; 0.28 &plusmn; 0.004 and 0.22 &plusmn; 0.015, respectively. The estimated genetic correlations were: 0.85 &plusmn; 0.19 and -0.15 &plusmn; 0.17 for MY and FY and MY and F%, respectively. The genetic trend for MY was of 9.25 kg/year, 0.11 kg/year for FP and -0.07%/year for %F. The values estimated for the coefficients of heritability suggest that it is possible to increase the rates for genetic gain for MP and FP, without change on %F rate. The genetic gains for MY and FY were positive, but low, however they can be improved if breeding programs that stimulate the dairy man to increase both traits milk quality are implemented

Extended exposure to sugar and/or caffeine produces distinct behavioral and neurochemical profiles in the orbitofrontal cortex of rats : implications for neural function

Caffeine is a psychostimulant commonly consumed with high levels of sugar. The increased availability of highly caffeinated, high sugar energy drinks could put some consumers at risk of being exposed to high doses of caffeine and sugar. Notably, research that has examined the consequences of this combination is limited. Here, we explored the effect of chronic exposure to caffeine and/or sugar on behavior and protein levels in the orbitofrontal cortex (OFC) of rats. The OFC brain region has been implicated in neuropsychiatric conditions, including obesity and addiction behaviors. Adult male Sprague-Dawley rats were treated for 26 days with control, caffeine (0.6 g/L), 10% sugar, or combination of both. Locomotor behavior was measured on the first and last day of treatment, then 1 week after treatment. Two hours following final behavioral testing, brains were rapidly removed and prepared for proteomic analysis of the OFC. Label-free quantitative shotgun analysis revealed that 21, 12, and 23% of proteins identified in the OFC were differentially expressed by sugar and/or caffeine. The results demonstrate that the intake of high levels of sugar and/or low to moderate levels of caffeine has different behavioral consequences. Moreover, each treatment results in a unique proteomic profile with different implications for neural health.17 page(s