Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> vol. 43 num. 4 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Chemical-nutritional composition of maniçoba (<em> <em>Manihot sp.</em>) and its relationship with soil chemical characteristics</em>]]> The objective of this study was to evaluate the chemical composition of leaves of maniçoba (Manihot sp.) according to their development stage and their relationship with the soil characteristics. For this purpose, plants in their natural growth areas in the semiarid region of Paraíba State, Brazil, were sampled. Leaves of maniçoba collected in five different locations at four different development stages were harvested and characterized: expanding leaf, completely expanded leaf, leaf at the beginning of senescence and a pool (mixture of all leaves). The evaluated traits were: dry matter, crude protein, neutral detergent fiber, acid detergent fiber, neutral detergent insoluble protein, acid detergent insoluble protein, ash, lignin, cellulose, hemicellulose, nitrogen, potassium, phosphorus, sulfur and sodium. The experimental design adopted was completely randomized, in a 4 × 5 factorial arrangement: four leaf development stages and five locations, respectively; each plot had 10 replications. There was interaction effect between leaf development stage and locations on dry matter, crude protein, neutral detergent insoluble protein and acid detergent insoluble protein. The results for neutral detergent fiber of leaves at the beginning of senescence were higher than other treatments and similar to the pool, while the acid detergent fiber content of the leaves in early senescence was higher than those of other treatments, averaging 34.8%. Crude protein content had its highest percentage in expanding leaves, averaging 23.0%. Nitrogen, potassium and sodium data showed interaction between the leaf types and locations of harvest, while phosphorus and sulfur did not show interaction. The chemical and mineral composition of maniçoba leaves range according to their development phase and according to their soil and climatic conditions in places of natural occurrence, with a tendency towards reduction of nitrogen and phosphorus as they approach senescence. <![CDATA[Evaluation of sugarcane laboratory ensiling and analysis techniques]]> The objective was to evaluate the effects of laboratory-silo type and method of silage extract production, respectively, on sugarcane silage fermentation and recovery of fermentation products. Sugarcane was mechanically harvested and ensiled in three different types of laboratory silos (five replicates): 9.7 × 30 cm PVC tubes with tight lids, equipped or unequipped with Bunsen valves, and 20 L plastic buckets with tight lids and Bunsen valves. Three methods were used to produce silage extracts for pH, ethanol, acetic and lactic acids determination: extraction of silage juice by a hydraulic press and production of water extracts using a stomacher or a blender. Total dry matter loss (231 g/kg DM) was not affected by silo type. No interactions between silo type and method of silage extract production were observed for ethanol and organic acids contents in the silages. Interaction between silo type and method of silage extract preparation was detected for pH. Silo type affected ethanol content but did not affect lactic and acetic acids concentration in the silages. Dry matter, crude protein, neutral detergent fiber and ash were not affected by silo type. The method used to produce silage extracts affected the recovery of all fermentation products analyzed in the silages. Recovery of ethanol and acetic acid was higher when silage extracts were produced using a blender. For lactic acid recovery, the hydraulic press method was superior to the other two methods. Silage fermentation pattern is not affected by silo type, but the method used to produce silage extracts and some characteristics of silos affect the recovery of volatile fermentation products. <![CDATA[Body chemical composition, tissue deposition rates and gain composition of young Nellore cattle selected for postweaning weight]]> Empty body and carcass chemical composition were determined in 67 Nellore bulls from Selection Nellore (NeS) and Control Nellore (NeC) herds of an animal breeding program for growth, slaughtered at 570 days of average age, after 100 days of feedlot. Selection Nellore animals had, respectively, 360 and 430 kg of initial and slaughter body weight, and NeC animals had 318 and 373 kg for the same traits. Animals were slaughtered and empty body composition was determined by chemical analysis of the components blood, hide, head and feet, viscera and carcass. Tissue deposition rates and gain chemical composition were also determined based on gains estimated by comparative slaughter technique. Significant differences were detected between NeS and NeC animals for slaughter body weight, empty body weight, empty body gain rate, and contents of water, protein, ash and retained energy in empty body, showing that selected animals had greater body sizes and growth rates. There were no significant differences in fat contents in empty body and carcass, suggesting that selected animals had higher growth rates as compared with the control, and were slaughtered with good body and carcass fat contents in the same feedlot time. Control Nellore animals showed a 10% higher gain in fat percentage than NeS in the period. This shows that the growth of bone and muscle ceased earlier and NeC group accumulated more fat. Animals selected for growth have heavier carcasses and greater tissue deposition rates with proportional composition similar to unselected animals. <![CDATA[Cloning and sequencing of c-DNA encoding N-methyl-D-aspartate receptor subunit-1 in the hypothalamus of male sheep]]> The objective of the present study was to report the molecular cloning and determination of the sequences N-methyl-D-aspartate subunit-1 receptor (NMDAR-1) in the hypothalamus of sheep. The re-amplified DNA template for NMDA -1 from the hypothalamus of male sheep was cloned using pBluescript-Sk-plasmids (pBSK, 2958 bp). Purified plasmids containing the NMDA receptor c-DNA were sequenced using the dye-terminator chemistry at the University of Nebraska-Lincoln, Nebraska, USA. Results were entered into the National Center for Biotechnology Web site as accession number AY434689. The sequence of Ovis aries (sheep) NMDAR-1 mRNA from hypothalamus of male sheep has 94-97% homology with Homo sapiens, 94-100% homology with Sus scrofa, and 88-90% homology with Rattus norvegicus NMDAR-1 mRNA sequence, and 94-97% homology with Homo sapiens glutamate receptor and transcript variant NR1-2 and NR1-1 mRNA sequence. These results show high evolutionary conservation of NMDA receptor subunit-1 across species. <![CDATA[Selective breeding of Arabian and Thoroughbred racehorses in Algeria: perceptions, objectives and practices of owners-breeders]]> This survey, conducted with 461 racehorse owners-breeders in Algeria between 2009 and 2011, investigates their perceptions, objectives and practices regarding selective breeding. Racehorse breeding is a full-time professional activity for a third of interviewees. The holdings are small-sized with 77% owning one or two mares. The regular practice of mating is here used to categorize breeders according to their degree of professionalization (38.4% professional vs. 61.6% occasional breeders). Experience in the sector was also used to classify breeders, considering as "junior" the breeders under 10 years experience (38.8%) and as "senior" those above 10 years (61.2%). More than professionalization, experience shows a significant impact on practices and objectives. Thus, experience influences breed choice (junior breeders tend to specialize while senior own both Arabian and Thoroughbreds), age at first foaling (sooner among senior breeders), information sources considered for selecting stallions (senior use more diversified sources), the importance granted to the price of mating (greater for junior breeders), the importance granted to the ranking compared to earnings (the ranking being more important to junior breeders), and the priority given to breeding (junior breeders give higher priority to a buy-race-resell activity). Finally, racehorse breeding is poorly professionalized, the only financial goal being cost coverage. Despite inappropriate practices, an interest for selection is noticed. <![CDATA[Effects of phenolic compounds in propolis on digestive and ruminal parameters in dairy cows]]> Four rumen-cannulated primiparous lactating cows were studied in a 4 × 4 Latin square design experiment to evaluate the effects of propolis-based products (PBP) with different concentrations of propolis and alcohol levels on total digestibility, (TD), ruminal digestibility (RD), intestinal digestibility (ID), pH, ruminal ammonia-nitrogen production (NH3-N), rumen microbial synthesis, and blood parameters. The feed consisted of 591.9 g/kg corn silage and 408.1 g/kg concentrate (dry matter [DM] basis), and treatments differed with regard to the inclusion (via ruminal cannula) or exclusion of PBP as follows: control (without the PBP), PBP B1 (3.81 mg of phenolic compounds/kg of ingested DM), PBP C1 (3.27 mg of phenolic compounds/kg of ingested DM), and PBP C3 (1.93 mg of phenolic compounds/kg of ingested DM). Inclusion of PBP reduced the RD of dietary crude protein (CP). Treatment PBP C1 reduced ruminal NH3-N production, while PBP B1 increased the ID of CP relative to that in the control. These findings indicate that propolis had a positive effect on rumen nitrogen metabolism. Rumen pH, efficiency of microbial protein synthesis, and blood parameters were not affected by addition of PBP, but there were significant effects on the other parameters when the treatments containing propolis were contrasted. Higher TD of DM (0.717 vs. 0.685), OM (0.737 vs. 0.703), and CP (0.760 vs. 0.739), as well as higher NDF (0.622 vs. 0.558) and TDN (0.747 vs. 0.712) were observed when comparing PBP C1 with C3. Inclusion of propolis in diets for dairy cows have positive effects on protein metabolism in the rumen. Variation in the amounts of phenolic compounds in the different PBP may explain the diverse effects on the digestive parameters evaluated. <![CDATA[Effect of different concentrations of dietary safflower seed on milk yield and some rumen and blood parameters at the end stage of lactation in dairy cows]]> In this study, the effects of different concentrations of dietary safflower seeds (SS) were examined for milk production, milk fat and some rumen and blood parameters at the end stage of lactation in dairy cows. Four Holstein cows were assigned to a 4 × 4 Latin Square design with four stages. All stages had 14 d of adaptation and 7 d of data collection periods. The diets were formulated as isoenergetic and isonitrogenous. Cows were fed four concentrate mixtures containing 0% (Control; C), 12.5% (S-I), 25% (S-II), or 37.5% (S-III) crushed SS during the experimental period. Safflower seed intake was distributed as 0 (C), 1 (S-I), 2 (S-II) and 3 (S-III) kg/d/cow. Cows were fed 8 kg concentrate, 2 kg wheat straw, and corn silage ad libitum (approximately 20 kg). Diet S-III caused a decrease in efficiency of milk production and diet S-II provided a much further efficiency in milk production (C = 13.39±0.23, S-I = 12.94±0.26, S-II = 13.46±0.24 and S-III = 11.83±0.52 kg). Diets had no significant effect on milk fat (C = 3.99±0.18, S-I = 4.09 ± 0.16, S-II = 3.87±0.35 and S-III = 3.75±0.30%). There was no difference in rumen fluid and blood parameters. Short-time feeding of up to 2 kg/d safflower seed had no negative effects on milk yield, milk fat, and some serum parameters, but 3 kg/d safflower seed reduced milk production. Safflower seed can be safely fed at up to two kilograms daily at the end stage of lactation in dairy cows. <![CDATA[Effect of unsaturated fatty acid supplementation on digestion, metabolism and nutrient balance in dairy cows during the transition period and early lactation]]> The objective of this study was to evaluate the influence of unsaturated fatty acids in diets for dairy cows during the transition period and early lactation on intake, digestion and nutrient balance. Thirty-six multiparous and pregnant Holstein cows were randomly distributed to receive one of the experimental diets in the period from 35 days before the expected date of parturition to 84 days post-partum. Diets were fed as a total mixed ration and were as follows: control (C); soybean oil (SO), based on inclusion of 30 g/kg (DM basis); and calcium salts of unsaturated fatty acids (CS), based on inclusion of 30 g/kg (DM basis). Pre-partum dry matter intakes (DMI) of cows fed C, SO and CS were 11.9, 9.5 and 9.6 kg/d, respectively. Post-partum DMI was affected by experimental diets (18.5, 15.0 and 17.4 kg/d for C, SO and CS, respectively). The energy balance in the transition period of animals fed CS was 4.41 Mcal/d higher than cows fed SO and 1.3 Mcal/d higher than cows fed C. Supplementing cows with unsaturated fatty acid sources is a strategy for dairy cows in the transition period.