-To determine the effects of a number of non-genetic factors on milk components and estimate their indirect relationships with weaning weight (WW205), the percentages of protein, fat, lactose and solids non-fat in Charolais cows from Mexico were estimated. Lactation period (LP) and calving season (CS) had significant effects on protein and fat, whereas lactose and solids non-fat were only affected by the LP. Sire line and age of the dam had significant effects on calf birth weight, while CS affected WW205. Residual correlations between milk components and WW205 suggest a low but significant correlation with lactose. These results demonstrate the importance of several non-genetic factors on the composition of milk from Charolais cows managed under extensive cow-calf production systems and the indirect relationships between these factors and the weaning weight of a calf.

ABSTRACT. Polymorphisms in candidate genes can produce significant and favorable changes in the phenotype, and therefore are useful for the identification of the best combination of favorable variants for marker-assisted selection. In the present study, an assessment to evaluate the effect of 11 single nucleotide polymorphisms (SNPs) in candidate genes on live weight traits of registered Brahman cattle was performed. Data from purebred bulls were used in this assessment. The dataset included birth (BW), weaning (WW), and yearling (YW) weights. A panel of 11 SNP markers, selected by their formerly reported or apparent direct and indirect association with live weight traits, was included in an assessment previously confirming their minimum allele frequency (<0.05). Live weights were adjusted BW (aBW), WW (aWW), and YW (aYW) using a generalized linear model, which included the fixed effects of herd and season of birth and the random effect of the sire and year of birth. An SNP in a growth hormone gene (GH4.1) was significantly related to aWW (P = 0.035) with an estimate substitution effect of 3.97 kg (P = 0.0210). In addition, a leptin SNP (LEPg.978) was significantly associated with aYW (P = 0.003) with an estimate substitution effect of 9.57 kg (P = 0.0007). The results suggest that markers GH4.1 and LEPg.978 can be considered as candidate loci for assisted genetic improvement programs in Mexican Brahman cattle.

K-casein gene polymorphisms are of major importance in the dairy industry due to their association with different quality and productive traits (i.e., milk protein). Several methods for genotyping this gene have been proposed; however, none are focused on the simultaneous discrimination of nine K-casein variants. A strategy based on PCR-RFLP was designed to characterize nine K-casein variants (A, B, C, E, F 2 , G, H, I and J) and used to genotype three cattle populations: Gyrholando (3/8 Gyr x 5/8 Holstein), Charolais and Carora. The B variant was the most frequent in the Charolais and Carora breeds, with allelic frequencies of 0.60 and 0.59, respectively. In the Gyrholando breed, four variants were found, with the A variant being the most frequent and E and H the least. The genotyping strategy was effective in detection and differentiation of K-casein variants, and it is proposed for use in laboratories with minimal molecular biology equipment for genotyping and evaluation of the phenotypic effects of nine K-casein variants on milk production and quality.

Tempesquistle tree (Sideroxylon palmeri) belongs to family Sapotaceae, and its fruits contain hydrophilic and hydrophobic gums. Aim of this study was to develop an extraction method for pectin, a hydrophilic gum, from green and ripe tempesquistle fruit. The extraction method was gentle to minimize potential structural changes in pectin, a maceration was used, and then pectin precipitation was induced with acetone at room temperature. Pectin characterization was carried out in two steps. The first step consisted of qualitative tests of Molisch, Fehling and Lugol. The second step consisted of quantitative tests to determine esterification degree (ED) by ATR-FTIR and D-galacturonic acid (D-GalA) content with a colorimetric assay. ATR-FTIR spectroscopic method revealed that green and ripe tempesquistle fruit have an ED of 0% and 30.4%, respectively. Both fruit have a low ED pectin. The content of D-GalA in green and ripe pectins was 18.8 ±2.7% and 20.2 ±0.6%, respectively. The yield obtained in green and ripe fruit samples was 1.6 ±0.2% and 3.0 ±0.1%, respectively. The extraction method allowed two types of pectins obtained in function of maturity stage of tempesquistle fruit distinguishable by ATR-FTIR.

Objective: To evaluate the effect of indole-3-acetic acid and budwood type in the vegetative propagation by cutting cuatomate (Solanum glaucescens Zucc.) and to describe the phenological stages, in order to increase production. Design/Methodology/Approach: A completely randomized design with a 22 factorial design was used to estimate the effect of two concentrations of indole-3-acetic acid (1000 and 10000 ppm) and budwood type (secondary and tertiary) on the number of leaves and sprouts of the plant. With regard to propagation, 30-cm budwoods from secondary and tertiary branches of cuatomate were used; transversal and diagonal cuts were made at the ends of the branches that generate the canopy and the root, respectively. Data was subject to an analysis of variance, using the general linear model procedure. Results: Highly significant differences (p ≤ 0.01) were observed between the variables under study. Higher number of leaves and sprouts (16.700 and 20.000, respectively) were observed in tertiary budwoods inoculated with 1000 ppm of IAA. In the evaluation of the phenological stages, the first bud appeared at 30 days, while the first leaf and flowers appeared 40 and 180 days after inoculation, respectively. Study limitations/implications: Commercial candelilla wax was applied in the transversal cut to prevent attacks by pathogens and every single budwood was completely covered with indole-3-acetic acid. Findings/conclusions: The use of indole-3-acetic acid in the vegetative propagation of cuatomate would be an alternative to increase its production; promoting a sustainable activity in the Mixtec region of Puebla.