Gilberto Vilmar Kozloski

Energy requirements of Texel crossbred lambs1

Two trials were conducted to determine the energy requirements of feedlot Texel crossbred lambs. In a comparative slaughter trial, thirty 11/16 Texel x 5/16 Ile de France crossbred noncastrated male lambs, weaned at 42 d of age (16.2 +/- 2.1 kg of shrunk BW; SBW), were used. Five lambs were randomly chosen and slaughtered after 10 d of experimental management and diet adaptation (baseline group). Fifteen lambs then were fed for ad libitum intake and slaughtered at 25, 30, or 35 kg of SBW. The remaining 10 lambs were randomly assigned to 2 levels of DMI, either 70 or 55% of the ad libitum intake, and were slaughtered concomitantly with lambs of the 35 kg of SBW group. Total body N, fat, and energy contents were determined. In a digestibility trial, 6 Texel x Ile de France crossbred lambs (30.4 +/- 2.6 kg of SBW) were housed in metabolic cages and used in a replicated 3 x 3 Latin square experiment to evaluate the energetic value of the diet at different feed intake levels. Net and ME requirements for maintenance were 58.6 and 91 kcal/kg(0.75) of SBW, respectively. Consequently, partial efficiency of energy use for maintenance was 0.64. Body fat content varied from 72.7 to 125.9 g/kg of empty BW, respectively, for 13.1 and 28.2 kg of empty BW. Net energy requirements for growth of lambs at 15 and 35 kg of SBW at an ADG of 250 g were 424 and 553 kcal/d, respectively. Partial efficiency of energy use for growth was 0.47. Texel x Ile de France crossbred growing lambs used in this study showed decreased nutritional requirements than those reported by most nutritional systems.

Perfil de ácidos graxos de cadeia longa e qualidade da carne de novilhos terminados em confinamento com diferentes níveis de monensina sódica na dieta

The chemical composition and meat quality of 48 feedlot finished Charolais-Nellore steers, fed ad libitum with a 52% corn silage and 48% concentrate, diet that included 0, 100 or 200mg/day of sodium monensin, were evaluated in a completely randomized design. Diets contained 12.3% of crude protein and 58.3% of neutral detergent fibre. Monensin was mixed with the concentrate. Monensin addition did not alter the Longissimus dorsi muscle content of dry matter, crude protein and ether extract (P>0.05), nor influenced meat thawing or cooking losses, shear force, tenderness, color and marbling (P>0.05). However, the palatability and juiciness decreased linearly with monensin addition (P 0.05), but increased linearly the content of oleate cis and trans isomers (C18:1 n9c e C18:1 n9t). Although the proportion of these specific fatty acids increased, monensin addition reduced meat quality, mainly by decreasing palatability and juiciness.

Uso da creatinina como indicador da excreção urinária em ovinos

This study was carried out to evaluate the use of creatinine as an indicator of urinary production in sheep. Total creatinine urinary excretion was determined based on data and samples collected from four digestibility experiments previously conducted with lambs maintained in metabolic cages. In all experiments total urinary production was collected during five days in each animal and experimental period. Additionally, in one experiment, urine samples were taken at intervals of two hours during a 24 hours period. Total excretion of creatinine (mean of 660mg day -1 ) was different among experiments (P 0.05). In the other hand, the urinary concentration of creatinine was different among experiments (P<0.01), animals (P<0.01) and periods (P<0.05). There were also differences among sampling times through a 24 hours period (P<0.01). The estimate of urinary production based on urinary concentrations of creatinine in spot samples, may be reliable only if, at least in one animal, representative of experimental group, total urine collection be carried out to measure the mean daily excretion of creatinine relative to body weigh. Moreover, spot samples should be collected in different times to constitute a composite sample representative of a 24 hours period.

Technical note: Evaluation of markers for estimating duodenal digesta flow and ruminal digestibility: Acid detergent fiber, sulfuric acid detergent lignin, and n-alkanes

The amount of digesta flowing to the duodenum is a relevant measurement for the evaluation of nutrient supply to ruminants, which is usually estimated in animals fitted with a duodenal T-type cannula using internal or external markers. This study evaluated acid detergent fiber (ADF) compared with external (C32n-alkane) and internal [sulfuric acid lignin (ADL) and n-alkanes C31 and C33] markers for estimating duodenal flow and(or) ruminal digestibility of dry matter (DM) in cattle and sheep. In the first assay, 4 duodenally cannulated Holstein steers housed in metabolism cages, dosed with C32n-alkane, and fed Avena strigosa plus concentrate and increasing levels of tannin extract to reduce ruminal digestibility, were used in a Latin square design. The mobile-bag technique was used to measure the intestinal disappearance of ADL and ADF from forage (Avena strigosa, Pennisetum purpureum, Cynodon dactylon, and Medicago sativa) and concentrate (corn grain, soybean meal, and sunflower meal) samples that were previously incubated in the rumen of additional fistulated steer for 12, 24, 36, or 48 h. The ADF concentration in residues recovered in the feces was strongly related to the ADF concentration in residues at the duodenum (R(2)=0.93, standard deviation=30.0, n=901). This relationship showed a lower precision for ADL fraction (R(2)=0.88, standard deviation=12.6, n=590). In a second assay, duodenal flow and ruminal DM digestibility were calculated from the duodenal and fecal concentration of either marker. We observed a significant effect of marker type on ruminal DM digestibility values, and the effect of tannin treatments was observed only when ADF or ADL was used as the marker. The lowest residual error was obtained for ADF. Ruminal DM digestibility was, on average, higher for C31 and C(33)n-alkanes, and the use of dosed C(32)n-alkane resulted in a negative value. In the third assay, a data set of 235 individual observations was compiled from digestibility trials to compare ADF and ADL as markers for estimating duodenal digesta flow in wethers (n=204) and cattle (n=31). We observed a strong relationship between markers (R(2)=0.84 in sheep and R(2)=0.88 in cattle), but variance analysis within trials indicated that ADF was more precise than ADL. In conclusion, in digestibility trials in which fecal output was measured and spot samples of the duodenal digesta were obtained, duodenal flow and ruminal digestibility of the DM may be estimated from the relationship between the ADF concentration in feces and that in the duodenal digesta of ruminants.

Profile of ingested fatty acids and in the duodenal digest of steers fed different diets

It was evaluated in this study the effect of the type of the diet on duodenal flow of long-chain fatty acids in steers. The tested diets were the following: conventional (feedlot diet composed of 60% corn silage and 40% of concentrate); winter forage silage - rye grass (Lolium multiflorum, Lam); or tropical forage silage - association of millet (Pennisetum americanum, Leeke + alexander grass, Brachiaria plantaginea). Six Charolais × Nellore crossbred steers with cannulas in duodenum were used in a 3 × 3 double Latin square. Dry material intake was similar among the groups (mean of 4,037 g/day), but the intake of total fatty acids and saturated fatty acids were higher in the group fed tropical pasture silage. On the other hand, the animals which received the conventional diet consumed higher quantity of unsaturated fatty acids. Tropical pasture silage provided higher consumption of vacenic acid (C18:1 t-11) and the winter forage silage offered higher consumption of conjugated linoleic acid. The intake of omega-6 fatty acids was higher in the group fed conventional diet and for omega-3, intake was higher in the group fed tropical pasture diet. The total fatty acid flow in the duodenum was not affected by the diets, but in all treatments it was higher than the consumed one. The animals fed diet with concentrate show the greatest changes on the profile of fatty acids during the ruminal fermentation. Conventional diets provide the highest intake of unsaturated fatty acids and the highest availability of vacenic acid in the small intestine, but they do not increase the supply of intestinal conjugated linoleic acid.

Evaluation of indigestible feed fractions as internal markers for predicting digestibility in lambs

The use of indigestible dry matter (iDM) and indigestible neutral detergent fiber (iNDF) as internal markers to estimate digestibility in lambs was evaluated. Data and samples were obtained from six independent digestion trials with lambs housed in metabolism cages given ad libitum different forage and concentrate feedstuffs. Indigestible residues were determined after 144 hours of in situ incubation of feed and faeces samples. Recovery rate varied from 64.8 to 108.5% for iDM, and from 49.5 to 67.9% for iNDF. As the marker ratio between marker concentration in the faeces and the feed was not corrected for fecal recovery, the large part of the estimated apparent organic matter digestibility (AOMD) of the experimental means were lower than the in vivo that obtained. As the marker ratio was corrected for fecal recovery of the marker, the AOMD means estimated using both markers were similar to the in vivo data in all experiments. As individual estimates, corrected for fecal recovery of the marker, were related to in vivo observations through regression analysis, the slope of the regression for iDM was not different from 1 whereas for iNDF, the slope was lower than 1. Individual AOMD values estimates using both markers, however, were poorly related to the in vivo observations (r2 varied from 0.60 to 0.63). Once corrected for fecal recovery, residual DM after 144 hours of in situ incubation is suitable for use as an internal marker to estimate mean diet digestibility consumed for a group of animals. However, individual estimates were not accurate to detect small differences in digestibility imposed by different treatments within an experiment.

Baixa dosagem de óxido de cromo para estimativa da produção fecal em bovinos

The aim of this research was to evaluate the use of a low level of chromium oxide (Cr2O3) incorporated into the concentrate ration to estimate faecal output (FO) in cattle. Four in vivo digestibility essays were conducted using four steers with live weights of 214±31kg, receiving fresh Italian ryegrass (Lolium multiflorum Lam.). About 200g of concentrate with 5g kg-1 of Cr2O3 was daily rationed during 12 days, where 7 days were used for animal adaptation and 5 days for measurements. The total faecal output was collected and compared with faecal output estimated from grab samples, collected twice a day (8:00 am and 4:00 pm) or at 2-hour intervals, from 8:00 am to 10:00 pm. The average faecal chrome concentration collected at 08:00 am and 04:00 pm (445mg kg-1) was similar with the average of samples collected at a 2-hour interval (447mg kg-1). The marker recovery rate (RR) increased linearly, from approximately 40% to around 80%, with the faecal chrome concentration until approximately 250mg kg-1 OM. When the faecal chrome concentration was higher than 250mg kg-1 OM the RR was relatively constant, with values around 0.76. The faecal output was overestimated up to 35% when the RR was not considered. When the RR was used, faecal output estimative was similar to the total faecal output collected. The faecal output can be accurately estimated in cattle eating ryegrass using a low level of Cr2O3 incorporated into the concentrate ration concomitant with twice-a-day faecal grab samples collection.

Perfil de ácidos graxos na carne de novilhos Charolês e Nelore puros e de gerações avançadas do cruzamento rotativo, terminados em confinamento

The objective of this research was to evaluate the heterozygosis and genetic group effects on fatty acids profile of feedlot finished steers, straightbreds (Charolais - C and Nellore - N), and crossbreds from second (G2) (¾C ¼N and ¾N ¼C), third (G3) (5/8C 3/8N and 5/8N 3/8C) and fourth (G4) (11/16C 5/16N and 11/16N 5/16C) generation of rotational crossbreeding. The Nellore and 11/16N 5/16C meat showed higher proportion of myristic acid (C14:0) in relation to Charolais and 11/16C 5/16N meat, respectively. On the other hand, the meat of the 11/16C 5/16N steers showed higher presence of heptadecanoic acid (C17:0) and arachidonic acid (C20:4 n6) in relation to 11/16N 5/16C. The 3/4C 1/4N steers of G2 which were superior in stearic acid (C18:0) and linoleic acid (C18:2 n6c) in the total polyunsaturated fatty acids participation studied and in the ratio between polyunsaturated and saturated fatty acids, while the 3/4N 1/4C showed superiority in oleic acid (C18:1 n9c). In G3 the meat of the 5/8C 3/8N steers showed superiority in the stearic and elaidic acids (C18:1 n9t) and in the total saturated fatty acid, while the 5/8N 3/8C steers showed higher participation of the meristoleic (C14:1), cis-10-heptadecanoic(C17:1) and oleic acids and total unsaturated fatty acids. The heterosis was significant in the G2 for C17:0, C18:0, C18:1 n9c, C18:2 n6c, in the total saturated, unsaturated and polyunsaturated fatty acids. The 3/4C 1/4N steers showed the healthiest meat among the genetic groups studied, with higher presence of polyunsaturated fatty acids and higher polyunsaturated: saturated ratio.

Consumo de forragem por cordeiras suplementadas em pastagem de milheto

This research evaluated the influence of different levels of supplement (0.0; 0.5; 1.0 and 1.5% in relation to the live weight (LW)) on the forage intake of beef lambs, in Pearl millet (Pennisetum americanum (L.) Leeke) pasture. The forage intake was conditioned by the levels of supplement only at the beginning of the pasture utilization (days 1-21), with maximum ingestion of dry matter when lambs received supplement at the ratio of 0.84% of the LW. The influence of the levels of supplement on the daily weight gain and live weight gain was observed only in the half and in the end of the cycle of the pasture (days 22-64).The intake and performance of lambs in Pearl millet are more dependent on the phenological stage of the pasture rather than the level of supplement received.

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.