Harold Ospina Patino

Consumo e digestibilidade de feno de baixa qualidade suplementado com nitrogênio não protéico em bovinos

The objective of this work was to evaluate the effect of nonprotein nitrogen supplementation levels on the digestibility of low-quality hay (Cynodon dactylon), which was offered ad libitum to Hereford bulls aging 17 months and weighing 220 kg. The evaluated treatments were: hay + no urea supplement; hay + supplement with 0.28 g urea kg -1 BW 0.75 ; hay + supplement with 0.55 g urea kg -1 BW 0.75 ; hay + supplement with 0.83 g urea kg -1 BW 0.75 and hay + supplement with 1.11 g urea kg -1 BW 0.75 . Hay composition presented 3.86% of crude protein and 84.66% of neutral detergent fiber. Digestibility of organic matter, organic matter of forage, neutral detergent fiber, cellulose and hemicellulose were not affected by nonprotein nitrogen level; total intake of these components showed a quadratic response to nonprotein nitrogen supplementation. Organic matter metabolic fecal excretion was not affected by supplementation, suggesting a simultaneous increase in both passage (intake increase) and digestion rates (stable digestibility). The digestible organic matter intake showed a quadratic response with the increase of urea supplementation levels. The relationship between rumen degradable protein intake and digestible organic matter intake showed a maximization point, when rumen degradable protein intake was equivalent to 8.1% of digestible organic matter intake.

Poder germinativo de sementes de capim-annoni-2 (Eragrostis plana Ness) recuperadas em fezes de bovinos

This work was carried out with the objective of evaluating the effect of the bovine digestion process on the germination capacity of the capim-annoni-2 (Eragrostisplana Ness) seeds recovered in feces. The seeds (6 g, 27,273 seeds) were placed in a ruminal ventral sack of eight fistulated steers kept in pen trial. Forthy-three percent of the offered seeds were recovered in the feces. Seeds recovered in the first three days corresponded to 97.2% of the offered seeds. Only 7.2% of the recovered seeds germinated and represented 3.1% of the offered seeds. The permanence time in the digestive trait was the main cause for the disappearance of consumed seeds and for the loss in their germination capacity. The absence of capim-annoni-2 seeds in the feces occurs in the eighth day after ingestion, then, bovines should be kept in quarantine for seven days in an area free of capim-annoni-2 seeds to clean their digestive trait.

Incorporação de uréia encapsulada em suplementos protéicos fornecidos para novilhos alimentados com feno de baixa qualidade

A trial was accomplished with the objective to verify the effect of the coated or common urea supplementation on the utilization of low quality hay in steers. The treatments were: hay + mineral supplement; hay + protein supplement with common urea; hay + protein supplement with coated urea formula 1; hay + protein supplement with coated urea formula 2. Tifton (Cynodon dactylon L.) hay of low quality (CP: 4.62%, NDF: 83.46%) was used. The measures were: digestibility, intake and digestive kinetics. The relation between degradable intake protein and digestible organic mater intake was highest (P 0.05) when compared the supplemented or not supplemented diets with DIP and in the same way, when compared the non-protein nitrogen sources. The ruminal degradable protein supplementation was not effective for modifying the studied parameters, as well as, the coated urea sources showed to be similar to the common urea.

Efeito da suplementação de bezerros com blocos multinutricionais sobre a digestibilidade, o consumo e os parâmetros ruminais

A trial was conduced to evaluate the effects of Tifton hay (Cynodon dactylon) supplemented with multinutrient blocks formulated using different molasses levels on digestibility, intake, and blood urea level. Four Hereford steers, one year old, weighing on average 196 kg in the beginning of the experiment, were assigned to a 4 x 4 latin square. The treatments were: Tifton hay and Tifton hay plus supplementation with either 25, 30, 35, and 40% molasses levels in multinutrient blocks. However, to include the treatment without supplementation, data were analyzed in a completely randomized blocks design. Supplementation significantly increased dry matter and organic matter digestibility. There were no differences on dry matter intake between treatments. Supplementation decreased the hay intake, showing a substitution coefficient of .58. Supplementation increased significantly total dry matter, organic matter and crude protein intakes. Although there was no significant difference between the supplemented treatments, digestible organic matter and blood urea increased significantly with supplementation. Another trial was conduced with three Hereford steers fistulated in the rumen to determine the effects of supplementation on rumen pH and N-NH3 levels, using a 3 x 3 latin square design. The treatments were: Tifton hay and Tifton hay plus supplementation with 25 and 30% molasses levels in multinutrient blocks. Supplementation did not affect rumen pH but N-NH3 concentration was significantly higher in treatments with blocks.

Productive performance, meat quality and fatty acid profile of steers finished in confinement or supplemented at pasture

Thirty Aberdeen Angus crossbred steers (281 ± 16 kg) were used to test the effect of finishing feeding system on growth performance, meat quality and fatty acid (FA) profile in intramuscular fat. Steers were fed in confinement (forage:concentrate ratio of 50 : 50; DM basis) or with different levels of energy supplementation (0, 0.4, 0.8 and 1.2% BW) at pasture (Avena strigosa Schreb and Lolium multiflorum L.). There were no differences between treatments for ADG (average=1.60 kg/day), hot carcass weight (HCW) (average=229 kg) and subcutaneous fat depth (average=3 mm). Dressing % (P=0.06; tendency) and carcass ADG (P=0.02) linearly increased with level of supplementation for pasture steers. No differences were observed between treatments for tenderness, marbling, pH, color b*, or cooking loss and drip loss in samples of Longissimus dorsi. However L* increased linearly (P=0.05) with level of supplementation. The concentrations of myristic, palmitic, estearic and linoleic FA did not differ among treatments. The concentration of n-3 FA increased (P<0.001) in steers at pasture compared with confinement, but n-6 FA concentrations did not differ between feeding system. Supplementation up to 0.4% BW increase (P<0.001) conjugated linoleic acid (CLA) and linolenic FA concentrations in intramuscular fat when compared with confinement. The level of supplementation on pasture linearly decreased (P<0.001) n-3 and CLA and linearly increased (P=0.001) the n-6 : n-3 ratio. Finishing of steers grazing winter pasture with energy supplementation or in confinement fed a medium-concentrate diet did not affect meat quality (tenderness, marbling, parameter b* on the CIE L*a*b* scale, cooking and drip losses) except for a* and L*. However, intramuscular fat of animals finished at pasture with moderate level of supplementation compared to animals fed in confinement had greater concentration of CLA, linolenic, and n-3, and lower n-6 : n-3 in intramuscular fat.

Desempenho e características de carcaça de novilhos terminados em pastagem de aveia preta e azevém anual com diferentes níveis de suplementação energética

The impact of energy supplementation on the performance and carcass caracteristics of 24 Aberdeen Angus x Charolais steers grazing an annual ryegrass (Lollium multiflorum L.) and Oats (Avena strigosa Schreb) pasture managed in order to avoid constrains to animal performance was evaluated. Treatments were levels of supplementation of 0; 0.4; 0.8 and 1.2% BW with a corn and mineral based supplement. Animals were slaughtered as they achieve 4,5mm of fat cover in the rump (P8) evaluated ultrasonography. No differences were observed in fat deposition, measured in live animals with ultrasound at the end of performance period, and in live weight gain, which showed average values of 3,9mm and 1,54kg d-1 respectively. Blood serum levels of urea were linearly decreased and cholesterol linearly increased by energy supplementation, with no differences in the serum levels of glucose and triglicerides. Energy supplementation linearly increased the killing-out proportion and carcass weight gain, but no differences were observed on the rib eye area, slaughter weight and hot carcass weight, wich averaged 67,85cm2, 438,95kg e 227,75kg. Increasing the levels of supplementation resulted in higher killing-out proportion and higher carcass daily gains, without changes in performance and carcass parameters evaluated.