Apparent Digestibility of Nutrients, Blood Parameters and Body Development of Dewormed and Not Dewormed Weanlings.

Weanlings undergo rapid body development in the first year of life and, in this period, are more susceptible to helminth infection that can impair their growth. The objective of this study was to compare the apparent digestibility of nutrients, blood parameters, and body development of deworming and not deworming weanlings. Fourteen Mangalarga Marchador weanling colts, on a farm in Northern Minas Gerais, Brazil, were divided into two groups: dewormed (D) and not dewormed (ND) groups. The weanlings were kept separately for 3 months in two pastures of Cynodon nlemfuensis cv. African Star Grass. They also were supplemented with Cynodon dactylon cv. Tifton 85 predried hay ad libitum and 1.5 kg.100 kg-1 of body weight (BW) of corn-based concentrate. Eggs per gram of feces (EPG) of the weanlings were measured monthly. Group D was dewormed (200 mcg.kg-1 BW ivermectin + 2.5 mg.kg-1 BW praziquantel) whenever EPG was ≥500. Group ND weanlings were not treated. The weanlings were subjected to an apparent digestibility assay (total fecal collection procedure). Every month, the weanlings were weighed, evaluated for body condition score, and had withers height, croup height, body length, and thoracic circumference measured. Group ND was infected mainly by small strongyles. There was no difference between groups (P > .05) for morphometric measurements, dry matter intake, and digestibility coefficients, except for apparent digestibility of calcium, which was higher (P < .05) in group D. Small strongyles infection in six- to nine-month-old weanlings fed high grain, nutrient-balanced rations apparently did not affect growth, blood parameters, and apparent digestibility of nutrients.

Feeding Behavior of Mangalarga Marchador Weanlings Fed Sorghum Silage Versus Grass Hay.

Mangalarga Marchador foals in Minas Gerais, Brazil, are usually weaned during the dry season, when there is a scarcity of forage. Although sorghum silage has been used to feed weanlings, the effect on their feeding behavior in comparison with grass hay has not been reported. Twelve Mangalarga Marchador weanlings were randomly assigned to two groups of six animals: SS: sorghum silage; VH: Vaquero hay. Both groups received commercial concentrate in the proportion of 1.2 kg.100 kg-1 of the live weight and forage ad libitum. The animals were filmed for 48 hours, being timed: forage intake time, water intake time (WIT), concentrate intake time, and leisure time (LT). Tukey's test was used to compare the parameters between SS and VH groups. Forage intake time and WIT were higher (P < .05) in VH group because the hay had low moisture content, stimulating water intake. Feeding behavior of weanlings kept in individual stalls and consuming sorghum silage was different than those consuming grass hay, providing less forage intake time and longer LT spent in comparison with VH.

Effect of Supplementation of Sorghum Silage in Weanling Fillies During the Dry Period in Brazil.

Young horses reach nearly 90% of their final height in the first year of life. However, to achieve their genetic potential, it is necessary to receive adequate nutrition during this period of rapid growth. The objective of this study was to evaluate the effect of supplementation of sorghum silage during a period of limited pasture forage availability, on the body development, and health of Mangalarga Marchador (MM) weanling fillies. Fourteen healthy MM 6-month-old fillies were randomly assigned to one of two groups: GS (consuming silage) and GH (consuming grass hay (Cynodon spp) in addition to 1.5% of body weight (BW) in dry matter (DM) of a fortified corn-based concentrate (17% CP [crude protein]), which was fed in individual stalls divided into two feedings/day for both groups. After concentrate feedings, the experimental groups remained loose in drylot pens of 50 m2, where the assigned forages were fed ad libitum with free access to salt and water. Group feed intake of the forages was recorded. It was assumed they were consuming a forage:concentrate ratio of 50:50. To assess development, the animals were weighed and measured for height at the withers and croup, body length, girth, and cannon bone circumference. The physical condition of animals, including BW, rectal temperature, mucous membrane color, and body condition score were assessed as well as serum biochemical analyses of creatinine, urea, total protein, gamma glutaminotransferase, aspartate aminotransferase, alkaline phosphatase, glucose, magnesium, calcium, and phosphorus concentrations were evaluated. The weights, morphometric measurements, clinical evaluation, and blood collections were done on the first day and every 21 days during the 84 days trial period. The growth performance and serum were subjected to analysis of variance for repeated measures, factoring treatment, and collection period. Despite higher (P < .05) DM and CP intakes by the GH fillies than those GS, there were no treatment effects (P > .05) on any of the development or health parameters measured. The use of sorghum silage as forage source for 84 days during the dry season had no negative impact on the body development and health of MM fillies (6-9 months of age) that were also fed 1.5% BW of a commercial concentrate balanced for growth.