Animal performance and nutritional characteristics of Piatã-grass in integrated systems / Desempenho animal e características nutricionais de capim-piatã em sistemas integrados

The objective was to evaluate animal performance and nutritional characteristics of Brachiaria brizantha cv. BRS Piatã in two integrated systems, during the summer and winter, five years after the initial establishment of the area. The randomized block experimental design was adopted with treatments consisting of a control (five native trees per hectare) and an integrated crop-livestock-forestry (ICLF) system with 227 eucalyptus trees per hectare. Animal performance, canopy height, soil cover, forage mass (leaf, stem and senescent material), and forage nutritive value were evaluated. Differences between systems were observed in forage mass (total, leaf, stem and senescent material), soil cover and forage nutritive value in both seasons. Shading conditions provided by eucalyptus in the ICLF system lead to a reduction in forage mass and neutral detergent fiber content, and to an increase in crude protein and in vitro organic matter digestibility. However, no effect on animal performance was obtained. The presence of trees improves the forage nutritive value without impacting animal performance in integrated systems.(AU)

O objetivo foi avaliar o desempenho animal e as características nutricionais de Brachiaria brizantha cv. BRS Piatã em dois sistemas integrados, durante o verão e o inverno, cinco anos após o estabelecimento inicial da área. O delineamento experimental em blocos ao acaso foi adotado com tratamentos constituídos por um controle (cinco árvores nativas por hectare) e um sistema integrado lavoura-pecuária-floresta (ILPF) com 227 eucaliptos por hectare. Desempenho animal, altura do dossel, cobertura do solo, massa de forragem (folha, caule e material senescente) e valor nutritivo da forragem foram avaliados. Diferenças entre os sistemas foram observadas na massa de forragem (total, foliar, caule e material senescente), na cobertura do solo e no valor nutritivo da forragem em ambas as estações. As condições de sombreamento proporcionadas pelo eucalipto no sistema ICLF levaram a uma redução na massa de forragem e no teor de fibra em detergente neutro e a um aumento na proteína bruta e na digestibilidade in vitro da matéria orgânica. No entanto, nenhum efeito no desempenho animal foi obtido. A presença de árvores melhora o valor nutritivo da forragem, sem impactar o desempenho animal em sistemas integrados.(AU)

Genetic evaluation and selection response for growth in meat-type quail through random regression models using B-spline functions and Legendre polynomials.

The objective was to estimate (co)variance functions using random regression models (RRM) with Legendre polynomials, B-spline function and multi-trait models aimed at evaluating genetic parameters of growth traits in meat-type quail. A database containing the complete pedigree information of 7000 meat-type quail was utilized. The models included the fixed effects of contemporary group and generation. Direct additive genetic and permanent environmental effects, considered as random, were modeled using B-spline functions considering quadratic and cubic polynomials for each individual segment, and Legendre polynomials for age. Residual variances were grouped in four age classes. Direct additive genetic and permanent environmental effects were modeled using 2 to 4 segments and were modeled by Legendre polynomial with orders of fit ranging from 2 to 4. The model with quadratic B-spline adjustment, using four segments for direct additive genetic and permanent environmental effects, was the most appropriate and parsimonious to describe the covariance structure of the data. The RRM using Legendre polynomials presented an underestimation of the residual variance. Lesser heritability estimates were observed for multi-trait models in comparison with RRM for the evaluated ages. In general, the genetic correlations between measures of BW from hatching to 35 days of age decreased as the range between the evaluated ages increased. Genetic trend for BW was positive and significant along the selection generations. The genetic response to selection for BW in the evaluated ages presented greater values for RRM compared with multi-trait models. In summary, RRM using B-spline functions with four residual variance classes and segments were the best fit for genetic evaluation of growth traits in meat-type quail. In conclusion, RRM should be considered in genetic evaluation of breeding programs.

Effects of hydroxychloride sources of copper, zinc, and manganese on measures of supplement intake, mineral status, and pre- and postweaning performance of beef calves.

Our objective was to evaluate the effect of Cu, Zn, and Mn source on measures of 1) preferential intake of mineral-concentrated supplements and 2) mineral status and pre- and postweaning performance of beef calves. In Exp. 1, 4 trials were conducted to assess the effect of source of Cu (750 mg/kg; Trial 1), Zn (2,000 mg/kg; Trial 2), Mn (3,000 mg/kg; Trial 3), and all 3 elements (Trial 4) on preferential intake of mineral-concentrated supplements. Supplements differed only by source of Cu, Zn, and Mn, which included hydroxychloride (hydroxy), sulfate, and organic options. In each trial, the 3 supplements were simultaneously offered to 8 pens of early-weaned calves (2 calves/pen; 126 ± 8.0 kg average BW) for a 4-h period and preferential intake was determined. When offered the opportunity to select among 3 supplement options, calves consumed more ( < 0.001) supplement containing hydroxy vs. organic or sulfate sources of Cu (Trial 1), Zn (Trial 2), and Mn (Trial 3). In Trial 4, when all 3 elements were combined within a single supplement, calves almost exclusively selected ( < 0.001) the hydroxy vs. organic or sulfate sources (82.9, 10.4, and 6.7% of total supplement intake, respectively [SEM 3.16]). In Exp. 2, calves were supplemented at a rate of 114 g/calf daily for 84 d before weaning (2 calves/pasture; 10 and 12 pastures in yr 1 and 2, respectively). Supplements were formulated to contain no supplemental minerals (control); hydroxy Cu, Zn, and Mn; or copper sulfate, zinc sulfate, and manganese oxide (sulfate/oxide). Total supplement intake was greater ( = 0.01) for calves consuming the hydroxy vs. the sulfate/oxide sources of Cu, Zn, and Mn (9.0 vs. 7.2 kg [SEM 0.45]). Preweaning calf BW gain did not differ ( ≥ 0.15) among treatments; however, calves provided mineral-fortified supplements had greater ( = 0.003) liver concentrations of Co and Se and tended ( = 0.07) to have greater liver concentrations of Cu at weaning compared with the controls. Calves provided mineral-fortified vs. control supplements had greater ( ≤ 0.05) peak concentrations of ceruloplasmin and haptoglobin and less BW gain during in the 16-d postweaning period. These data demonstrate greater voluntary intake of mineral-concentrated supplements among calves offered hydroxy vs. sulfate or organic sources of Cu, Zn, and Mn. Preweaning mineral-fortified supplementation increased calf mineral status, heightened inflammatory responsiveness, and decreased BW gain during the immediate postweaning period.

Sensitivity of breeding values for carcass traits of meat-type quail to changes in dietary (methionine + cystine):lysine ratio using reaction norm models.

Our objective was to evaluate changes in breeding values for carcass traits of two meat-type quail (Coturnix coturnix) strains (LF1 and LF2) to changes in the dietary (methionine + cystine):lysine ([Met + Cys]:Lys) ratio due to genotype by environment (G × E) interaction via reaction norm. A total of 7000 records of carcass weight and yield were used for analyses. During the initial phase (from hatching to day 21), five diets with increasing (Met + Cys):Lys ratios (0.61, 0.66, 0.71, 0.76 and 0.81), containing 26.1% crude protein and 2900 kcal ME/kg, were evaluated. Analyses were performed using random regression models that included linear functions of sex (fixed effect) and breeding value (random effect) for carcass weight and yield, without and with heterogeneous residual variance adjustment. Both fixed and random effects were modelled using Legendre polynomials of second order. Genetic variance and heritability estimates were affected by both (Met + Cys):Lys ratio and strain. We observed that a G × E interaction was present, with changes in the breeding value ranking. Therefore, genetic evaluation for carcass traits should be performed under the same (Met + Cys):Lys ratio in which quails are raised.

Effects of roughage sources produced in a tropical environment on forage intake, and ruminal and microbial parameters.

Our objective was to study the effect of different roughage sources produced in a tropical environment on intake, digestibility, and ruminal parameters of crossbred bulls. Five rumen-fistulated 30-mo-old Holstein × Bos indicus bulls (average BW =459 ± 32.5 kg) were utilized in a 5 × 5 randomized Latin square design. The experiment consisted of five 19-d experimental periods (10 d for adaptation and 9 d for data collection) and 5 treatments. Experimental diets consisted of corn (Zea mays L.) silage (CS), Brachiaria grass (Brachiaria decumbens Stapf.) silage (BGS), elephant grass (Pennisetum purpureum Schumach.) silage(EGS), Tifton 85 (Cynodon spp.) hay (T85), and fresh sugarcane (Saccharum officinarum L.; SC). Diets were formulated to have approximately 11% CP (DM basis)using a mixture of urea and ammonium sulfate (9:1 ratio) that was diluted in water and then mixed with roughage. Intake, ruminal outflow, digestibility coefficients,ruminal pool, intake, passage (kp) and digestion rates, microbial parameters, and pH data were assessed.D ry matter intake was greater (P < 0.01) for CS compared with SC. Among treatments, lesser (P < 0.01)potentially digestible NDF, ash- and protein-free NDF(apNDF), and digestible ash- and protein-free NDF intake values were observed for SC. Ruminal outflows of DM and nonfibrous carbohydrates were lesser (P <0.01) for SC compared with other treatments. Dry matter apparent digestibility and ruminal digestibility did not differ (P > 0.27) among treatments. No differences (P = 0.11) were observed for ruminal apNDF pool and ruminal kp of apNDF (P = 0.06) among treatments. No treatment effect (P > 0.28) was observed for DM and nitrogen of rumen-isolated bacteria, and microbial efficiency was greater (P = 0.02) for BGS among treatments.A treatment × time interaction (P < 0.01) was found for ruminal pH, with a quadratic pattern in terms of time for CS, BGS, EGS, and T85, whereas pH values for CA linearly decreased as a function of time. In summary, these roughages, when supplemented with an additional nitrogen sources, show similar overall apparent digestibility and ruminal pool values, but conversely, bulls fed sugarcane had less overall nutrient intake and lower ruminal outflow and digestion rate values. We conclude that fresh-cut sugarcane, when provided with urea, can affect digestion rate and, consequently, impact nutrient intake.

Effects of trace mineral injections on measures of performance and trace mineral status of pre- and postweaned beef calves.

Three experiments were conducted to examine the effects of injectable trace minerals (ITM) on measures of trace mineral status and performance in pre- and postweaned Brangus-crossbred beef calves. In Exp. 1, calves were assigned to treatments in alternating birth order (n = 150; 75/treatment), consisting of a 1-mL subcutaneous injection of ITM (MultiMin 90; MultiMin USA, Inc., Fort Collins, CO) or sterile saline. The ITM formulation consisted of 60, 10, 15, and 5 mg/mL of Zn, Mn, Cu, and Se. Treatments were readministered at 100 and 200 d of age. Calf BW was recorded at birth and on d 100, 150, 200, and 250 (weaning). Trace mineral status was assessed in liver biopsy samples (n = 12/treatment) collected on d 150, 200, and 250. Administration of ITM had no impact on BW gain (P ≥ 0.55) but did result in greater (P ≤ 0.02) concentrations of liver Cu and Se and lesser (P = 0.05) liver Fe concentrations compared to saline-injected calves. In Exp. 2, 24 heifers were selected from the weaned calves of Exp. 1 (n = 12/treatment) and transported 1,600 km. Remaining on their original treatments, heifers were administered 5 mL of ITM or saline following transport (d 0). Blood samples, for acute phase protein (APP) analysis, were collected on d 0, 1, 3, 6, 9, and 13 and liver biopsy samples for assessment of trace mineral status on d 13. Plasma APP concentrations increased in all calves following weaning and transport but concentrations were greatest (P < 0.05) in ITM- vs. saline-injected heifers on d 6 and 9. Liver concentrations of Cu, Se, and Zn were greater (P ≤ 0.04) but ADG lesser (P = 0.05) for heifers receiving ITM vs. saline. In Exp. 3, 34 heifers, without previous exposure to ITM, were enrolled in a 177-d development study (n = 17/treatment). Treatments consisted of 2.5-mL injections of ITM or sterile saline on d 0, 51, and 127. Humoral immune response to an injection of porcine red blood cells (PRBC) was evaluated on d 51. Trace mineral status was evaluated in liver biopsy samples collected on d 177. Overall heifer ADG, PRBC antibody titers, and liver Se concentrations were greatest (P ≤ 0.06) for ITM vs. control heifers. Collectively, these studies demonstrate an increased trace mineral status, a greater humoral response to novel antigen, and a heightened APP response to weaning and transport stress in pre- and postweaned beef calves administered ITM.