ABSTRACT. The aim of this study was to determine the association between a polymorphism in intron 3 of the bovine growth hormone (BGH) gene and growth traits related to the start of the reproductive life of Holstein heifers. This research was conducted using 480 Holstein heifers belonging to eight herds in three municipalities in the Department of Antioquia (Colombia). The phenotypic information used corresponded to information that had been historically recorded for each of the herds and was supplemented with information obtained through bimonthly visits to the herds over a period of 24 months. Genotyping was performed using the PCR-RFLP technique with DNA extracted from peripheral blood using the salting out technique. To determine association, statistical analyses were performed using parametric methods. Allele frequencies for the alleles (+) and (-) were 0.91 and 0.09, respectively. The genotype frequencies were 0.77, 0.2 and 0.03 for the genotypes (+/+), (+/-) and (-/-), respectively. There was an association between genotype and weight at first estrus and first calving (P < 0.01). The regression coefficients for both characteristics were significant, indicating that for each (+) allele, weight at first estrus and first calving decreased by 9.24 and 16.07 kg, respectively. The results indicated the existence of an association between a polymorphism in intron 3 of the BGH gene and both weight at first estrus and first calving, which can be used to facilitate the selection of animals with these genotypes for use in breeding programs.

A B S T R A C TStrawberries are highly sensitive to deterioration by microbial decay after harvest and Botrytis cinerea is one of the most common diseases that infect them. Previous work has reported successful extension of strawberry shelf life through the use of chlorine dioxide (ClO 2 ) gas treatments. In this study, California strawberries purchased at retail stores were treated with continuously generated ClO 2 gas over concentrations ranging from 0.01 to 5.0 mg/L for durations ranging from 7 to 1000 min to determine how ClO 2 gas impacts fungal mortality and fruit quality as a function of treatment concentration, treatment duration, and ClO 2 absorption by the fruit. Repeated measures and Gompertz models were used to infer on the efficacy of the ClO 2 gas, and a novel method was used to quantify the ClO 2 absorption by fresh produce. It was found that ClO 2 gas treatments have minimal effect at delaying the onset or growth rate of Botrytis cinerea for treatments followed by incubation at 4 or 22 C even when corrected for natural variability of Botrytis cinerea presence among batches of strawberries, indicating that treatments are not sufficient for shelf-life extension.

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Actualmente en Colombia no existe un programa que permita la estimación de valores genéticos en bovinos de leche. El objetivo de esta investigación fue determinar la asociación de los EBV (Valor de Cría Estimado) de toros Holstein y Jersey,con el desempeño fenotípico de sus hijas en Colombia; para esto se analizó la asociación de sus EBV con algunos parámetros productivos y sanitarios analizados directamente en su progenie (hijas). Para la estimación de los componentes de varianza, parámetros genéticos y valores genéticos, se utilizó el método de máxima verosimilitud restringida (REML) empleando un algoritmo libre de derivadas con el software MTDFREML. La asociación de las características con los EBV de los toros se realizó utilizando un modelo lineal mixto. Las heredabilidades para producción de leche, proteína, grasa y células somáticas en raza Holstein fueron: 0,19±0,0; 0,37±0,04; 0,37±0,04 y 0,34±0,05 y en Jersey fueron: 0,20±0,0; 0,64±0,0; 0,55±0,0 y 0,14±0,26 respectivamente. Los EBV de los toros Holstein influyeron (p