Effect of crude glycerin supplementation via drinking water on feed intake, water intake and productive performance of dairy ewes.

This study was performed to determine the effects of crude glycerin (CG) supplementation in drinking water on DM and nutrient intake, milk production, milk composition, and serum glucose. Twenty multiparous Lacaune × East Friesian ewes were randomly distributed into four dietary treatments throughout the lactation cycle. Treatments consisted of doses of CG supplementation via drinking water as follows: (1) no CG supplementation, (2) 15.0 g CG/kg DM, (3) 30.0 g CG/kg DM, and (4) 45.0 g CG/kg DM. DM and nutrient intake were reduced linearly with CG supplementation. CG linearly reduced water intake when expressed as kg d-1. However, no effect of CG was observed when it was expressed as a percentage of body weight or metabolic body weight. The water to DM intake ratio was increased linearly with CG supplementation. No effect of CG doses on serum glucose was observed. The production of standardized milk decreased linearly with the experimental doses of CG. Protein, fat, and lactose yield were linearly reduced with the experimental doses of CG. Milk urea concentration was quadratically increased with CG doses. Feed conversion was quadratically increased by treatments during the pre-weaning period (P < 0.05), in which the worst values were observed when the ewes were supplemented with 15 and 30 g CG/kg DM. The N-efficiency was linearly increased with CG supplementation in drinking water. Our results suggest that dairy sheep can be supplemented with CG up to 15 g/kg DM in drinking water. Greater doses are not beneficial for feed intake, milk production, and the yield of milk components.

Effect of concentrate supplement to ewes on nutritive value of ingested Caatinga native forage nutritive value as affected by season.

The objective of this study was to identify by microhistological technique the reference chemical components for use as indicators of the nutritive value of Caatinga plants forage grazed by sheep throughout the year. A flock of twenty mixed-race meat ewes, multiparous, in production, with an average 34.84 ± 1.75 kg live weight and 36 months of age was assigned to supplement treatment of 0, 200, 350, and 500 g concentrate/head/day for 3 years. The experiment was designed as a randomized complete design with repeated measures over time. Supplementation with concentrate did not influence chemical composition of selected forage. In contrast, season heavily influenced diet chemical composition. Canopy stratum, season, and plant botanical family of selected species affected forage chemical composition selected by ewes. The ewes selected forage with greater nutritive value during the rainy season. Based on principal component analysis of the nutritive value of the primary forage species selected, ewes preferentially grazed plants contained greater neutral detergent fiber, acid detergent fiber, crude protein (CP), C fraction of nitrogenous compounds, and carbohydrate fractions A + B1 and C compared to the average native Caatinga herbage. Rangeland botanical composition and ewe diet varied during the year, affecting forage nutrients on offer, with the best diet selected during the rainy season because of the presence of dicotyledonous herbaceous species rich in CP as well as soluble carbohydrates and nitrogenous compounds. Concentrate supplement strategies for ewes on rangelands, such as Caatinga, should be determined by herbaceous species nutritive value during the rainy season and deep-rooted perennial dicotyledons during the dry season. These include the need to monitor ewe selection of forage species and their nutritive value, which is effectively accomplished with fecal microhistological techniques.