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This study aimed to evaluate the effect of probiotic (Saccharomyces cerevisiae boulardii CNCM I-1079) supplementation during feedlot adaptation period on performance of Nellore bulls. One-hundred ninety-eight Nellore bulls were used in a completely randomized block design, divided in 22 pens (9 animals/pen). Treatments were: CON – adaptation diet and finishing diet comprised of basal diet (with 28 ppm of monensin); and SCB – same diets as for the previous treatment with monensin plus probiotic (Saccharomyces cerevisiae boulardii CNCM I-1079, ProTernative® 20; Lallemand Animal Nutrition at a dose of 1.0 x 10e10 cfu/animal/d) supplementation. Supplementation was offered for the first 42 days (21 days in the step-up phase and 21 days in the finishing diet with 900 g concentrate/kg DM), then both treatments were fed the same basal diet for another 76d, reaching 118 days in total. Pen was considered the experimental unit and data were analyzed using the MIXED procedure of SAS with Tukey test at 5% significance level. Final carcass weight was 1.69% greater for animals fed SCB (283.8 vs. 288.7 kg, P = 0.04). Total carcass weight gain (111.0 vs. 114.8 kg) and daily carcass weight gain (0.924 vs. 0.956 kg) tended (P = 0.06) to increase by 3.46% in SCB-fed animals compared to the CON ones. Gain yield (P = 0.39), biological efficiency (P = 0.35) and carcass yield (P = 0.71) did not differ between treatments. Probiotic supplementation with live yeast during the first 42 days in feedlot helped Nellore bulls optimize early on growth performance with an interesting carry-over effect on carcass gain through the total feedlot time.

Pasture intensification through higher stocking rates, nitrogen fertilization and intensified grazing management in beef cattle production optimizes pasture use by increasing the forage harvested. We aimed to assess its effects on the morphogenesis and canopy structure of Urochloa brizantha ‘Marandu’ (marandu palisadegrass) pastures. The treatments consisted of marandu palisadegrass pastures managed under continuous stocking and a canopy height of 25 cm, with different levels of intensification: extensive, semi-intensive, and intensive systems N-fertilized with 0 kg, 75 kg, and 150 kg N ha−1 year−1, respectively, as ammonium nitrate (32% of N), with four replicates (paddocks) in a completely randomized design. Phyllochron (9.8 days) and leaf lifespan (34.7 days) were shorter in intensified pastures, whereas herbage mass was similar among treatments. Extensive pastures had a higher proportion of senescent material, thus, more intensive systems showed higher proportions of leaves and stems, although the leaves-to-stem ratio remained similar across production systems. The defoliation interval was lower in intensive (14.4 days) and higher in extensive (18.7 days) treatments. Thus, pasture intensification accelerates leaf appearance, decreases leaf lifespan, shortens the tiller defoliation interval and increased herbage accumulation rate but does not change herbage mass. The extensive system produces excessive forage losses due to dead material.

Made available in DSpace on 2022-05-01T07:58:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study investigated the performance, carcass traits, and greenhouse gas emission of Nellore and F1 Angus × Nellore yearling bulls raised under two [lenient (S1) and intensified (S2)] production systems during the backgrounding and finishing phases. S1 was practiced on a 18.6 ha palisade grass pasture, divided into eight paddocks, which was not fertilized and managed using continuous stocking at a constant rate of two animals per hectare during backgrounding. Then, 20 Nellore [initial body weight (BWi), 277±13 kg; initial age, 15.2±1.1 months] and 20 F1 Angus × Nellore (BWi, 304±21 kg; initial age, 15.8±0.44 months) yearling bulls were randomly allocated to four paddocks for each breed. During finishing, animals remained on the pasture and received high supplementation (at rate of 2.0 kg•100 kg−1 BW). S2 was practiced on a 11.4 ha palisade grass pasture, divided into six paddocks, which was fertilized (150 kg N•ha−1•year−1) and managed using continuous stocking at variables rates during backgrounding. Then, 24 Nellore (BWi, 288±16 kg; initial age, 15.6±0.65 months) and 24 F1 Angus × Nellore (BWi, 325±18 kg; initial age, 15.8±0.42 months) yearling bulls were randomly allocated to three paddocks for each breed. During finishing, the bulls were moved to feedlots. During backgrounding, F1 Angus × Nellore bulls in S2 achieved the highest average daily gain (ADG) and final shrunk body weight (SBWf), whereas Nellore bulls in S1 achieved the lowest ADG and SBWf. During finishing, ADG and SBWf were greater in S2 than in S1 as well as for F1 Angus × Nellore bulls than for Nellore bulls. From the beginning of backgrounding until the end of finishing, the ribeye area of F1 Angus × Nellore bulls in S2 was larger than that of other bulls. The greatest backfat deposition occurred during finishing, resulting in greater backfat thickness of bulls in S2 than that of bulls in S1. The carbon footprint of F1 Angus × Nellore bulls in S2 (10.8 kg•CO2e•kg−1 carcass) was similar to that of Nellore bulls in S1, but it was approximately 13% and 11.5% lower than that of Nellore bulls in S2 and F1 Angus × Nellore bulls in S1, respectively. This study demonstrated that the enhancement of productivity through improving genetic merit and pasture management is a suitable strategy to reduce environmental impact and achieve environmental sustainability. Department of Animal Science São Paulo State University – Unesp Trouw Nutrition Campinas Department of Animal Science São Paulo State University – Unesp FAPESP: 15/16631-5; #17/18750-7; #17/11274-5

The objective of this study was to determine the correlation between ingestive behaviour, apparent digestibility and residual feed intake (RFI) of finishing Nellore bulls fed a high concentrate diet. One hundred and twenty Nellore bulls, housed in individual pens, were evaluated in individual performance tests. The animals were fed a high concentrate diet (23:77roughage/concentrate ratio). The animals were classified as: low RFI, medium RFI, and high RFI. Data from ten animals from each group was used. Faecal production and nutrient digestibility were calculated using indigestible neutral detergent fiber as an internal marker. The feeding behaviour was evaluated over twenty-four hours by direct observation every five minutes. The most efficient animals (low RFI, 8.58 kg DM/day) consumed 27.62% less feed than the least efficient animals (high RFI, 10.95 kg DM/day). Animals with medium efficiency (mean RFI, 9.49 kg DM/day) consumed 15.39% less than high RFI. Nutrient digestibility coefficients were similar except for ether extract (P0.05). Animals spent, on average, three hours twenty-eight minutes feeding, seven hours thirty-two minutes ruminating and thirteen hours forty minutes in idle time. In the present study, ingestive behaviour and dry matter digestibility were not responsible for between-animal variation in residual feed intake in Nellore bulls fed a high concentrate diet.

Made available in DSpace on 2019-10-06T16:12:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-01 Encapsulated calcium nitrate (ECN) has been studied as a source of non-protein nitrogen (NPN) that establishes an alternative sink of free hydrogen in the ruminal environment and, consequently, reduces the emission of methane and probably improves efficiency of energy use. The aim of this study was to assess the impact of ECN as a substitute for soybean meal (SBM) in energy partition, substrate oxidation, and microbial nitrogen (MicN) synthesis. Twelve growing castrated male goats (21.9 kg ± 3.19 kg of initial body weight) were used in four 3 × 3 Latin squares (LS) during three 48-d periods. Goats were grouped by body weight (BW) within each LS and randomly assigned to one of three diets: SBM – control based on SBM, 75 g/kg of SBM on dry matter (DM) basis; ECN12.5 – 12.5 g/kg of ECN on DM basis; and ECN25 – 25 g/kg of ECN on DM basis. Each period included 21 days for adaptation, five days for metabolism trials (d 22 to d 26), and 15 days for indirect calorimetry trials (d 27 to d 41). At the end of each period, a 7-day washout interval was provided during which the goats were fed SBM diet. The goats showed no symptoms of intoxication based on methemoglobin (MetHb) levels (0.7% ± 0.17 of total hemoglobin). Heat production (HP) was not influenced by treatments (P = 0.91), but fast heat production (FHP) was 22% (P < 0.05) lower in ECN25 than in SBM. Methane emission decreased by 0.21 g for each g of nitrate intake. The inclusion of 9.5 g/kg of ECN on DM resulted in a maximum DE and ME intake. The total retained N decreased linearly (P < 0.05) with the increase of ECN; however, microbial nitrogen (MicN) synthesis did not differ between treatments. In conclusion, the use of ECN as a replacement for SBM decreased FHP, which might spare energy for growth. The use of ECN as a substitute for SBM did not affect MicN synthesis. The inclusion of 9.5 g/kg of ECN on DM basis results in maximum DMI, DE, and ME intake in growing goats. Department of Animal Science UNESP – Universidade Estadual Paulista/ Jaboticabal Campus R&D Manager – Ruminant Division – GRASP Ind. e Com. LTDA Department of Animal Science UNESP – Universidade Estadual Paulista/ Jaboticabal Campus

Sustainable intensification of tropical grasslands has been identified by researchers and stakeholders as a solution to decrease greenhouse gas emissions and deforestation. However, there are concerns about food security and the role of livestock in feed-food competition between animals and humans involving land and other resources. We aimed to determine the net protein contribution (NPC), a feed-food competitiveness index, of tropical beef cattle raised on extensive systems or finished in pastures or conventional feedlots, under different levels of intensification. We modelled five scenarios, from cow-calf to slaughter, based on common beef cattle practices in Brazil, whose main production system is grazing. Scenario 1 represented the lowest level of intensification and the most extensive system. Scenario 2 represented a moderately extensive system. Scenarios 3, 4, and 5 represented different degrees and practices of intensification, with animals in cow-calf and stocker phases raised solely on well-managed permanent pastures. In Scenario 3, the animals were finished in a feedlot. In Scenarios 4 and 5, all animals in the stocker phase received a protein-energy supplement, but in Scenario 4, animals were finished in a permanent pasture with high-concentrate intake. In Scenario 5, animals were finished in a feedlot. The human-edible protein (heP) conversion efficiency (hePCE) was calculated as the ratio of heP produced (meat) to heP consumed as feed, and the NPC was the product of hePCE using the protein quality ratio, accounting for the digestible indispensable amino acid score content. An hePCE 1 indicated that meat production did not compete with humans for food, and an NPC 1 indicated that it contributed positively to meet human requirements. Meat production and heP intake consistently increased with intensification. The greatest hePCE values were from Scenarios 1 (9.2), 2 (2.2), and 3 (1.2), which were essentially pasture-fed systems, compared to Scenarios 4 and 5 (average of 1.0). The NPC varied from 24.1 (Scenario 1) to 2.6 (Scenario 5). The area required to produce 1 kg of carcass decreased from 147 to 45 m

This study aimed to evaluate the effect of probiotic (Saccharomyces cerevisiae boulardii CNCM I-1079) supplementation during feedlot adaptation period on performance of Nellore bulls. One-hundred ninety-eight Nellore bulls were used in a completely randomized block design, divided in 22 pens (9 animals/pen). Treatments were: CON – adaptation diet and finishing diet comprised of basal diet (with 28 ppm of monensin); and SCB – same diets as for the previous treatment with monensin plus probiotic (Saccharomyces cerevisiae boulardii CNCM I-1079, ProTernative® 20; Lallemand Animal Nutrition at a dose of 1.0 x 10e10 cfu/animal/d) supplementation. Supplementation was offered for the first 42 days (21 days in the step-up phase and 21 days in the finishing diet with 900 g concentrate/kg DM), then both treatments were fed the same basal diet for another 76d, reaching 118 days in total. Pen was considered the experimental unit. Growth data were analyzed using the MIXED procedure of SAS with Tukey test at 5% significance level, and a linear regression analysis was performed for the dry matter intake (DMI) data. During the first 42 days, average DMI did not differ; however, bulls fed SCB plateaued the curve of at 9.17 kg DMI/d earlier (39 days, R2 = 0.97) than those fed CON (43 days; R2 = 0.96) diets. Final body weight (509.5 vs. 518.0 kg, P = 0.02), total body weight gain (163.7 vs. 170.3 kg, P = 0.01) and average body weight daily gain (1.366 vs. 1.420 kg, P = 0.01) were greater for SCB-fed bulls. Feed efficiency of SCB-supplemented bulls was 8.05% greater than CON (P = 0.04). Probiotic supplementation with live yeast Saccharomyces cerevisiae boulardii CNCM I-1079 during the first 42 days in feedlot contributes to reaching the plateau of DMI curve earlier and improving overall performance of Nellore bulls during the total period.

Made available in DSpace on 2022-05-01T05:29:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-07 This study aimed to estimate the protein requirements for the maintenance of growing Saanen goats of different sexes from 5 to 45 kg of body weight (BW) using two methods and applying a meta-analysis. For this purpose, two datasets were used. One dataset was used to evaluate the effects of sex on the protein requirements for maintenance using the comparative slaughter technique. This dataset was composed of 185 individual records (80 intact males, 62 castrated males, and 43 females) from six studies. The other dataset was used to evaluate the effects of sex on the protein requirements for maintenance using the N balance method. This dataset was composed of 136 individual records (59 intact males, 43 castrated males, and 34 females) from six studies. All studies applied an experimental design that provided different levels of N intake and different levels of N retention, allowing the development of regression equations to predict the net protein requirement for maintenance (NPM) and the metabolizable protein (MP) requirements for maintenance (MPM) in Saanen goats. The efficiency of MP use for maintenance (kPM) was computed as NPM/MPM. The efficiency of MP use for gain (kPG) was calculated using the equation of daily protein retained against daily MP intake above maintenance. A meta-analysis was applied using the MIXED procedure of SAS, in which sex was considered a fixed effect, and blocks nested in the studies and goat sex were considered as random effects. The NPM did not differ between sexes, irrespective of the approach used. The daily NPM estimated was 1.23 g/kg0.75 BW when using the comparative slaughter technique, while it was 3.18 g/kg0.75 BW when using the N balance technique for growing Saanen goats. The MPM estimated was 3.8 g/kg0.75 BW, the kPM was 0.33, and the kPG was 0.52. We observed that the NPM when using the comparative slaughter technique in growing Saanen goats is lower than that recommended by the current small ruminant feeding systems; on the other hand, the MPM was similar to previous reports by the feeding systems. Sex did not affect the protein requirements for maintenance and the efficiencies of use of metabolizable protein. Department of Animal Sciences Universidade Estadual Paulista Institute of Studies of the Humid Tropic Universidade Federal do Sul e Sudeste do Pará Department of Animal Science Universidade Federal Rural da Amazônia University of New England Department of Animal Sciences Universidade Estadual Paulista

The aim of this study was to characterize four corn and sorghum co-products (DDG) in terms of their protein and carbohydrate fractions; we also evaluated the effects of substituting the protein source of the conventional supplement by DDG on consumption and nutrient digestibility in confined finishing cattle. Thirty-six male Nellore cattle with a mean age of 24 months were used. The treatments were: FA: concentrate with corn as an energy source and cottonseed meal as a protein source; DDG50: concentrate with a 50% substitution of the FA protein source by DDG; DDG100: concentrate with 100% substitution of the FA protein source by DDG. The experimental design was completely randomized with three treatments and three replicates (pens) containing four animals per pen. We found that the use of DDG in the finishing phase did not interfere with the animals’ food intake or the digestibility of the nutrients (p > 0.05). Nutrients were used by the animals; therefore, DDGs may be viable substitutes of cottonseed meal. We conclude that the bromatological composition of this co-product is influenced a lot during processing; therefore, the nutritional values of this co-product present in the composition tables may not be true. The aim of this study was to characterize four corn and sorghum co-products (DDG) in terms of their protein and carbohydrate fractions; we also evaluated the effects of substituting the protein source of the conventional supplement by DDG on consumption and nutrient digestibility in confined finishing cattle. Thirty-six male Nellore cattle with a mean age of 24 months were used. The treatments were: FA: concentrate with corn as an energy source and cottonseed meal as a protein source; DDG50: concentrate with a 50% substitution of the FA protein source by DDG; DDG100: concentrate with 100% substitution of the FA protein source by DDG. The experimental design was completely randomized with three treatments and three replicates (pens) containing four animals per pen. We found that the use of DDG in the finishing phase did not interfere with the animals’ food intake or the digestibility of the nutrients (p > 0.05). Nutrients were used by the animals; therefore, DDGs may be viable substitutes of cottonseed meal. We conclude that the bromatological composition of this co-product is influenced a lot during processing; therefore, the nutritional values of this co-product present in the composition tables may not be true.

Made available in DSpace on 2020-12-12T02:38:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Asociación Universitaria Iberoamericana de Postgrado Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The objective of this study was to evaluate the effects of sex on the daily net requirements of calcium (NCam), phosphorus (NPm), potassium (NKm), and magnesium (NMgm) for maintenance in Saanen goats from 5 to 45 kg BW. Two datasets were used: the first dataset was composed of 154 individual records (53 castrated males, 46 females, and 55 intact males) from three studies, and was used to estimate the NCam, NPm, NKm, and NMgm using the comparative slaughter technique (CST). The second dataset was assembled from 160 individual records (67 castrated males, 45 females, and 48 intact males) from four feeding trials, and was used to estimate the NCam, NKm, and NMgm in Saanen goats, using the minimum endogenous losses method (MEL). A meta-analytic approach was applied using a mixed model, in which sex was considered a fixed effect and study a random effect. Using the CST, the results revealed that sex did not affect NCam, NPm, or NKm (21.1, 22.8, and 4.0 mg/kg BW, respectively; P > 0.10), but NMgm of intact males was greater than for castrated males or females (2.6 versus 1.4 mg/kg BW; P = 0.077). On the other hand, sex did not affect the NCam, NKm, or NMgm (38.0, 25.2, and 7.4 mg/kg BW, respectively; P > 0.10), when MEL was used. The findings of this study suggest that Ca, P, and K requirements for maintenance in goats are not influenced by sex. Conversely, Mg requirement for maintenance should be discriminated by sex. Also, that P requirements for maintenance were significantly lower than current feeding system recommendations. Department of Animal Science UNESP - Universidade Estadual Paulista School of Environmental and Rural Science University of New England Department of Animal Science UNESP - Universidade Estadual Paulista Asociación Universitaria Iberoamericana de Postgrado: 1 Asociación Universitaria Iberoamericana de Postgrado: 166754 FAPESP: 2014/14734 FAPESP: 9

The aim of this study was to investigate the effects of sex on the net requirements of growth for Ca (NCa), P (NP), Na (NNa), K (NK), and Mg (NMg) in Saanen goats from 5 to 45 kg BW, with or without consideration of the degree of maturity. A database containing 209 individual records for Saanen goats (69 castrated males, 71 intact males, and 69 females) was generated from 6 comparative slaughter studies. Total amounts of Ca, P, Na, K, and Mg in the body were fitted to logarithmized allometric equations using empty BW (EBW) or degree of maturity (EBW/mature EBW) as regressors. The equations were fitted using a mixed model, where sex was considered a fixed effect and study was considered a random effect. Net requirements were estimated by the first derivative of the logarithmized allometric equations. Then, a Monte Carlo simulation was used to assess the uncertainty of calculated net requirement values. Without considering the degree of maturity, sex did not affect NCa, NP, and NNa ( > 0.10). Conversely, considering the degree of maturity, NCa and NP of intact males were 5% and 2%, respectively, greater than those of castrated males and females ( 0.10), NK decreased by 26% (i.e., without considering the maturity degree) or 27% (i.e., considering the degree of maturity) from 5 to 45 kg BW. Therefore, the consideration of maturity stage highlights differences across sexes in the net macromineral requirements for growth in goats. Elucidation of sex effects on macromineral requirements for growth may be useful for improving the accuracy of recommendations for mineral requirements for dairy goats.

We conducted a study in which body composition, energy and protein requirements, and efficiency of MP and ME were determined in F1 Boer × Saanen goat kids of 5 to 25 kg BW by using the comparative slaughter technique. Two experiments were performed: Exp. 1 estimated the maintenance requirements of kids from 15 to 25 kg BW, and Exp. 2 estimated the gain requirements of kids from 5 to 25 kg BW. In Exp. 1, 28 intact male F1 Boer × Saanen goat kids were utilized, with 7 kids slaughtered (BW of 15.0 ± 0.35 kg) at the onset for estimation of initial body composition and the remaining 21 kids assigned to a randomized block design. Within each block, kids were subjected to 3 levels of feed intake treatments (ad libitum [100%] or restricted to 70% or 40% ad libitum). All kids in each block were slaughtered when the animals fed ad libitum reached 25 kg BW. The NE, ME for maintenance, and partial efficiency of use of ME for NE were 321.6 kJ/kg BW, 525.9 kJ/kg BW, and 0.61, respectively. The net protein and MP for maintenance were 2.43 g/kg of BW and 4.41 g/kg of BW, respectively; thus, the estimated partial efficiency of MP for maintenance was 0.55. In Exp. 2, 32 intact male F1 Boer × Saanen goat kids were distributed in a completely randomized design and slaughtered at 5.6 ± 0.85 kg BW ( = 6), 10.0 ± 0.35 kg BW ( = 6), 15.3 ± 0.52 kg BW ( = 7), 20.4 ± 0.66 kg BW ( = 6), and 25 ± 0.46 kg BW ( = 7). Body composition was then fitted to allometric equations. Body fat composition increased from 37 to 114 g/kg empty BW (EBW; < 0.001), and body protein composition decreased by 10% (from 203.2 to 180.6 g/kg EBW; < 0.001) when kids grew from 5 to 25 kg BW. The NE increased by approximately 60% (from 7.2 to 11.5 MJ/kg of empty BW gain [EWG]; < 0.001), and the net protein for gain decreased by 10% (from 186 to 166 g/kg of EWG; < 0.001). The partial efficiency of the utilization of ME to NE for growth was 0.32 ( < 0.0001), and the partial efficiencies of the utilization of ME for the synthesis of protein and fat were 0.19 and 0.59 ( < 0.011), respectively. These results demonstrate that the protein and energy maintenance requirements in young crossbred goat kids are greater than values reported previously in feeding system studies. In addition, their requirements for gain depend on body composition and are driven by efficiencies of deposition.

Made available in DSpace on 2020-12-11T06:34:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The aim of this study was to investigate the effects of sex on the requirements for maintenance and efficiency of energy utilization in growing Saanen goats. A database from 7 comparative slaughter studies that included 238 Saanen goats was gathered to provide information for the development of prediction equations of energy requirements for maintenance and efficiency of energy utilization. The experimental design provided different levels of metabolizable energy intake (MEI) and empty body weight (EBW). The data were analyzed so that sex (e.g., intact males, castrated males, and females; n = 98, 80, and 60, respectively) was a fixed effect, and blocks nested in the studies and goat sex were random effects. For the development of linear and nonlinear equations, we used the MIXED and NLMIXED procedures in SAS (SAS Institute Inc., Cary, NC). Nonlinear regression equations were developed to predict heat production (HP, kcal/kg(0.75) of EBW; dependent variable) from MEI (kcal/kg(0.75) of EBW; independent variable). Using the comparative slaughter technique, the net energy requirement for maintenance (NEM) was calculated as the value of HP at MEI equal to zero. Additionally, NEM was evaluated based on the degree of maturity. The metabolizable energy requirement for maintenance was calculated as the value at which HP is equal to MEI. Efficiency of ME utilization for maintenance (k(m)) was calculated as the ratio between NEM and the metabolizable energy requirement for maintenance. Efficiency of energy utilization for growth (k(g)) was assumed to be the slope of the linear regression of retained energy (RE) on MEI above the maintenance stage (model intercept equal to 0). Efficiencies of RE as protein (k(p)) and as fat (k(f)) were calculated using the multiple linear regression of MEI above the maintenance (model intercept equal to 0) on RE as protein and as fat, respectively. Sex affected NEm (75.0 +/- 1.76 kcal/kg(0.)(75) of EBW for males and 63.6 +/- 2.89 kcal/kg(0.75) of EBW for females) and sex did not affect k(m) (0.63). In contrast, sex no longer affected NEM when degree of maturity was considered on its estimation. The k(g) was different between sexes (0.31 for castrated males and females, and 0.26 for intact males), but k(p) (0.21) and k(f) (0.80) were similar between sexes. These results may be useful for improving robustness of the energy requirement recommendations for dairy goats. Univ Estadual Paulista, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil Univ Fed Sul & Sudeste Para, Inst Estudos Trop Umido, BR-68557335 Xinguara, PA, Brazil Ohio State Univ, Dept Anim Sci, Columbus, OH 43201 USA Univ New England, Sch Environm & Rural Sci, Armidale, NSW 2351, Australia Univ Estadual Paulista, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 2014/14734-9 CAPES: 001

Made available in DSpace on 2021-06-25T15:20:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Despite the important role of digesta mean retention time (MRT) on digestive efficiency of ruminants, it is poorly investigated in total gastrointestinal tract (GIT) of growing ruminants, especially in goats. The objective of this study was to evaluate the effect of body weight (BW) and sex on GIT MRT of particles and solutes in growing Saanen goats. A dataset from two studies, comprising 103 individual records of castrated males (n = 36), females (n = 34), and intact males (n = 33) Saanen goats slaughtered at 15, 22, 30, 37, and 45 kg BW, was used. Goats were fed basically with total mixed ration composed by dehydrated corn plant (Zea mays) milled to pass a 10-mm screen, cracked corn grain, and soybean (Glycine max) meal. Variables evaluated were BW, feed intake, feed intake level, composition of ingested diet, wet weight of GIT tissues, wet digesta pool size, digesta composition (dry matter and neutral detergent fiber [NDF]), indigestible NDF:NDF ratio of ingested diet and GIT digesta, MRT of particles (MRTiNDF) and solutes (MRTCr), and reticulorumen selectivity factors (large particles/solutes). Reticulorumen, omasum, abomasum, small intestine, cecum, and colon-rectum segments were evaluated. The dataset was analyzed as mixed models considering sex, BW, and sex x BW interaction as fixed effects, and study and residual error as random effects. Sex did not affect MRTiNDF in any GIT segments. Females and intact males presented similar reticulorumen MRTCr (5.6 h; P = 0.92) and they presented lower reticulorumen MRTCr than castrated males (7.0; P = 0.11). Reticulorumen and omasum MRTCr increased as BW increased (P < 0.01), and abomasum MRTCr decreased as BW increased (P = 0.02). Feed intake, and wet tissues and wet pool size of all GIT segments increased as BW increased, except abomasum wet pool size (P

Made available in DSpace on 2018-11-26T17:15:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-01. Added 1 bitstream(s) on 2019-10-09T18:26:28Z : No. of bitstreams: 1 S1516-35982016001200781.pdf: 298523 bytes, checksum: 33a72d41d76cecbedbb8b3bec6eca3a5 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study was carried out to to evaluate how feed restriction and different forage: concentrate ratios affect digestibility, methane emission (using the SF6 technique), and energy utilization of Anglo-Nubian goats. Fifteen (15) dry and non-pregnant Anglo Nubian goats, averaging 30+2.9 kg body weight, were used. The experiment was divided into two trials, the first of which was designed to study the effects of feed restriction (0% or ad libitum; 15% of feed restriction or equivalent to 85% of ad libitum intake; and 40% of feed restriction or equivalent to 60% of ad libitum intake) and the second, to study the effects of forage: concentrate (F:C) ratios (75: 25, 54: 46, and 25: 75) in the diet. The sulfur hexafluoride (SF6) tracer gas method was used to collect and estimate methane (CH4) emissions. Feed restriction level did not affect apparent total tract digestibility of dry matter (DM), organic matter, crude protein, and neutral detergent fiber. Methane emission (g d(-1)) decreased linearly as intake level decreased. However, energy loss in methane proportional to organic matter intake was similar among levels of feed restriction; consequently, dietary metabolizability did not differ among treatments. Methane gas (g d(-1)) as a function of F: C ratio revealed a quadratic response, showing the highest values when animals were fed the 46: 54 F: C ratio diet (18.2 g d(-1)), suggesting that the decrease in absolute CH 4 occurred when the level of concentrate inclusion in the diet surpassed approximately 50%. The results presented herein may be relevant for the ongoing and future efforts towards completion of an IPCC inventory regarding the contribution of goats to the greenhouse gas effects on the planet. Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil Embrapa Meio Ambiente, Jaguariuna, SP, Brazil Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil FAPESP: 2008/58351-5 FAPESP: 2011/14842-8

These experiments estimated Ca, P, Mg, K, and Na requirements of intact male, castrated male, and female Saanen goats. Two experiments were performed: one to determine the net macromineral requirements for maintenance (Exp. 1) and another to determine net macromineral requirements for growth (Exp. 2). In Exp. 1, 75 goats (26 intact males, 25 castrated males, and 24 females) with initial BW (iBW) of 15.76 ± 0.10 kg were used. These animals were divided in 2 groups: baseline animals and pair-fed animals. Twenty-one goats (8 intact males, 7 castrated males, and 6 females) were slaughtered (16.6 ± 0.96 kg BW) at the beginning of the experiment to be used as the baseline group. The 54 remaining goats (18 intact males, 18 castrated males, and 18 females) were pair fed in 6 blocks of 3 goats per sex. The goats within each block were then randomly allocated to 1 of 3 levels of intake: ad libitum, restricted fed to 75% of the ad libitum intake, and restricted fed to 50% of ad libitum intake. When the animal fed ad libitum reached 31.2 ± 0.58 kg BW, it and the other goats from the same block were slaughtered. The effects of sex and level of intake were evaluated in a split-plot design, where sex was the main plot observation and level of intake was the subplot. Daily net macromineral requirements for maintenance did not differ among the sexes ( > 0.05), and the average values obtained were 35.4 mg Ca, 24.7 mg P, 2.5 mg Mg, 5.0 mg K, and 3.30 mg Na per kg BW∙d. The net requirements for growth in Exp. 2 were obtained using 58 goats (20 intact males, 20 castrated males, and 18 females) with 15.8 ± 0.11 kg iBW, all fed ad libitum. These animals were assigned in a completely randomized design and allocated in 3 slaughter weight groups: 16.6 ± 0.96, 23.1 ± 1.33, and 31.2 ± 0.58 kg BW. The net Ca, P, and Mg requirements for growth were not different among the sexes ( > 0.05). There was a sex effect on net K and Na requirements for growth ( < 0.05). The net K requirements for growth (g/kg ADG) of intact males were greater ( = 0.03) and increased approximately 16%, whereas females and castrated males decreased approximately 11% as BW increased from 15 to 30 kg BW. The net Na requirements for growth (g/kg ADG) increased 9.5% for intact males and decreased 22% for females when the goats grew from 15 to 30 kg BW. Sex, therefore, affects net K and Na requirements for growth, but it does not affect net macromineral requirements for maintenance in Saanen goats.

The objective of this study is to provide approaches to determine mature weight of female and intact and castrated male Saanen goats using body composition data. Our database combined 7 comparative slaughter studies and comprised 244 individual records of body composition of intact male ( = 94), female ( = 71), and castrated male ( = 79) Saanen goats weighing from 4.6 to 51.0 kg BW. Nonlinear regressions were fitted to predict empty body water, fat (EBF), protein (EBP), and ash, expressed as amounts and percentages of the empty BW (EBW) and water-free EBW. Candidate equations were selected on the basis of preliminary graphical examination of the observed body composition of the database, and the best one to describe the data was selected on the basis of convergence achievement with coherent biological interpretation. The selected nonlinear functions were the allometric function (Y = β × EBW) to describe the EBF content and the exponential function (Y = β × × EBW) to describe EBP content in the water-free matter basis. None of the tested nonlinear functions were able to describe ash content, possibly because of its large variation. Mature weight was assumed to be the weight when net protein deposition (i.e., accretion minus degradation) tended to zero. The EBP (percentage of water-free EBW) plotted against the EBW using the exponential function enabled us to estimate the mature weight of intact and castrated males and females as 83.9, 33.6, and 26.4 kg EBW, respectively, indicating that the decrease of protein accretion of intact males approaches zero later than in females and castrated males during growth. Replacing these mature EBW estimates in the allometric function to describe the fat content in the EBW, we estimated that at maturity, castrated males and females had 21.6% and 22.4% EBF, whereas intact males had 36.8% EBF, which may not be biologically acceptable because it is too high. On the other hand, assuming that a goat matures at 22% EBF, one can backward estimate mature EBW of 42.6, 34.9, and 26.0 kg for intact and castrated males and females, respectively. This study indicated that fat percentage in the body may be used to describe maturity, as long as dietary challenges are not imposed on the animals. In addition, our results confirmed that female Saanen goats reach maturity at a lighter weight than males.

Made available in DSpace on 2021-06-25T11:06:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study aimed to determine the effect of temperature on energy balance of Saanen and Anglo-Nubian goats, using indirect open circuit respirometry. Six non-lactating and non-pregnant Saanen goats (initial body weight [BW] of 53.7 ± 7.7 kg) and Anglo-Nubian goats (initial BW of 56.4 ± 8.0 kg) were randomly assigned to three groups. Each group was allocated in climatic rooms and randomly assigned to three different room temperatures (treatments) in three 28-d periods, including 20 days for adaptation and eight days for measurements. Treatments consisted of three controlled room temperatures: 10 °C ± 0.23 and 88.10 % ± 0.99 relative humidity (RH), 20 °C ± 0.41 and 80.75 % ± 4.13 RH, and 35 °C ± 1.05 and 45.58 % ± 5.07 RH. Within each 8-day period, metabolism trial and gaseous exchange measurements were performed for five days (from day 21 to day 25). After day 25, goats were subjected to 60-h fasting, with subsequent gas exchange measurement to estimate fast heat production (FHP). Irrespective of breed, the dry matter intake (DMI) and the organic matter intake (OMI) decreased linearly as the temperature increased from 10 to 35 °C. Apparent digestibility of the nutrients showed the lowest values at 20 °C. Respiratory rate (RR) and respiratory volume increased with increasing ambient temperature. At 35 °C, methane production of Saanen goats was higher than Anglo-Nubian goats, and metabolizable energy (ME) and metabolizability (q) of Saanen goats were lower than Anglo-Nubian goats. The daily FHP above 20 °C decreased 8.7 kJ/kg0.75 BW for each degree as the temperature increased up to 35 °C, and below 20 °C decreased 5.4 kJ/kg0.75 BW as the temperature decreased up to 10 °C. Both breeds can maintain homeostasis in ambient temperature between 10 and 35 °C; however, Anglo-Nubian goats seem to cope better in adverse conditions of heat than Saanen goats. Department of Animal Science - São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences Department of Animal Science - São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences FAPESP: 2014/26556-8

Intensification of tropical grassland can be a strategy to increase beef production, but methods for achieving this should maintain or reduce its environmental impact and should not compromise future food-producing capacity. The objective of this review was to discuss the aspects of grassland management, animal supplementation, the environment, and the socioeconomics of grassland intensification. Reducing environmental impact in the form of, for example, greenhouse gas (GHG) emissions is particularly important in Brazil, which is the second-largest beef producer in the world. Most Brazilian pastures, however, are degraded, representing a considerable opportunity for the mitigation and increase of beef-cattle production, and consequently increasing global protein supply. Moreover, in Brazil, forage production is necessary for seasonal feeding strategies that maintain animal performance during periods of forage scarcity. There are many options to achieve this objective that can be adopted alone or in association. These options include improving grassland management, pasture fertilization, and animal supplementation. Improving grazing management has the potential to mitigate GHG emissions through the reduction of the intensity of CO2 emissions, as well as the preservation of natural areas by reducing the need for expanding pastureland. Limitations to farmers adopting intensification strategies include cultural aspects and the lack of financial resources and technical assistance.

The objective of this study was to evaluate sex effects on the daily net requirements of calcium (NCam), phosphorus (NPm), magnesium (NMgm), and potassium (NKm) for maintenance in Saanen goats of 5 to 45 kg BW. For this purpose, two datasets were used: the first dataset was composed of 154 individual records (53 castrated males, 46 females, and 55 intact males) from three comparative slaughter studies, and was used to test the sex effects on NCam, NPm, NMgm, NKm in Saanen goats, using the comparative slaughter technique (CST). The second dataset was assembled from 155 individual records (67 castrated males, 40 females, and 48 intact males) from four feeding trials, and was used to evaluate the sex effects on NCam, NMgm, and NKm in Saanen goats, using the minimum endogenous losses method (MEL). The meta-analyses were performed using a mixed model, in which sex was considered a fixed effect and study a random effect. Sex did not affect NCam, NPm, and NKm in Saanen goats of 5 to 45 kg BW, when mineral requirements were estimated using CST (P > 0.10). The NCam, NPm, and NKm were 21.1, 22.8, and 4.0 mg/kg BW, respectively. In contrast, sex affected the NMgm of Saanen goats (P = 0.077). The NMgm for castrated male and female Saanen goats was 1.4 mg/kg BW, while for intact males, NMgm was 2.6 mg/kg BW. Sex did not affect the NCam, NMgm, or NKm in Saanen goats of 5 to 45 kg BW, when mineral requirements were estimated using MEL (P > 0.10). The NCam, NMgm, and NKm were 38.0, 7.4, and 25.2 mg/kg BW, respectively. The daily net macromineral requirements for maintenance reported herein may be relevant for the development of feeding systems for goats, and for optimizing mineral nutrition management of growing Saanen goats. Key Words

The aim of this review is to describe the main findings of studies carried out during the last decades applying the California net energy system (CNES) in goats. This review also highlights the strengths and pitfalls while using CNES in studies with goats, as well as provides future perspectives on energy requirements of goats. The nonlinear relationship between heat production and metabolizable energy intake was used to estimate net energy requirements for maintenance (NEm). Our studies showed that NEm of intact and castrated male Saanen goats were approximately 15% greater than female Saanen goats. Similarly, NEm of meat goats (i.e., >50% Boer) was 8.5% greater than NEm of dairy and indigenous goats. The first partial derivative of allometric equations using empty body weight (EBW) as independent variable and body energy as dependent variable was used to estimate net energy requirements for gain (NEg). In this matter, female Saanen goats had greater NEg than males; also, castrated males had greater NEg than intact males. This means that females have more body fat than males when evaluated at a given EBW or that degree of maturity affects NEg. Our preliminary results showed that indigenous goats had NEg 14% and 27.5% greater than meat and dairy goats, respectively. Sex and genotype also affect the efficiency of energy use for growth. The present study suggests that losses in urine and methane in goats are lower than previously reported for bovine and sheep, resulting in greater metabolizable energy:digestible energy ratio (i.e., 0.87 to 0.90). It was demonstrated that the CNES successfully works for goats and that the use of comparative slaughter technique enhances the understanding of energy partition in this species, allowing the development of models applied specifically to goat. However, these models require their evaluation in real-world conditions, permitting continuous adjustments.

The aim of this study was to investigate the energy requirements of female and intact and castrated male Saanen goats. Animals were randomly assigned to 1 of 2 experiments designed to investigate the energy requirements for maintenance and gain. To determine the maintenance requirements, 85 goats were used (26 intact males, 30 castrated males, and 29 females) with an initial BW of 30.3 ± 0.87 kg. Thirty goats (8 intact males, 9 castrated males, and 13 females) were slaughtered to be used as the baseline group. The remaining goats were assigned in a split-plot design using a 3 × 3 factorial arrangement (3 sexes-intact males, castrated males, and females-and 3 DMI levels-ad libitum and restricted fed to 75 or 50% of the ad libitum intake). The NE was obtained using 65 goats (20 intact males, 22 castrated males, and 23 females) fed ad libitum in a completely randomized design. Eight intact males, 9 castrated males, and 13 females were slaughtered at 30.5 ± 1.53 kg BW. Seventeen goats (6 intact males, 6 castrated males, and 5 females) were slaughtered at 38.1 ± 0.49 kg BW. The remaining goats were slaughtered at 44.0 ± 0.50 kg BW. The NE did not differ between the sexes ( = 0.59; 258.5 kJ/kg BW), resulting in a ME for maintenance of 412.4 kJ/kg BW. The estimated energy use efficiency for maintenance was 0.627. During the growth phase, NE differed between the sexes ( < 0.001); intact males, castrated males, and females showed an average NE equal to 15.2, 18.6, and 22.7 MJ/kg of empty weight gain, respectively. The energy requirements for growth differed between the sexes. The difference was found to be due to distinct NE and partial efficiency of ME utilization for growth in intact and castrated males and females during the late growth phase. This study may contribute to adjustments in feeding system energy recommendations regarding the NE and NE found for goats during the late growth phase.

Made available in DSpace on 2019-10-04T12:33:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01. Added 1 bitstream(s) on 2019-10-09T18:33:45Z : No. of bitstreams: 1 S1516-35982018000100618.pdf: 561491 bytes, checksum: a2ca38f27714aef67bc8f7426fee863e (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Asociacion Universitaria Iberoamericana de Postgrado (AUIP) The objective of this study was to investigate the multivariate relationship among body protein, fat, and macrominerals in Saanen goats of different sexes (castrated males, females, and intact males) using canonical correlation analysis. Individual records of 274 Saanen goats combined from 10 studies was used. Two sets of body constituents were established: the first one contained variables related to body protein or fat (canonical variate U) and the second contained variables related to body calcium, phosphorus, magnesium, sodium, or potassium (canonical variate V). Two canonical pairs were identified for each sex. However, irrespective of sex, first canonical pairs accounted for more than 87% of variance of the dependent variables, these only being used for the analysis. For canonical variate U 1, canonical weights for protein were greater than that for fat (in castrated males, protein = 0.62 and fat = 0.41; in females, protein = 0.96 and fat = 0.039; and in intact males, protein = 0.81 and fat = 0.20). For canonical variate V 1, in males, the highest canonical weights were for potassium and phosphorus, whereas the lowest were for calcium (in castrated males, potassium = 0.485 > phosphorus = 0.259 > magnesium = 0.206 > sodium = 0.129 > calcium = 0.081, and in intact males, potassium = 0.499 > phosphorus = 0.459 > sodium = 0.105 > magnesium = 0.024 > calcium = 0.001). On the other hand, in females, the highest canonical weights were for potassium and calcium, whereas the lowest was for magnesium (potassium = 0.539 > calcium = 0.201 > phosphorus = 0.178 > sodium = 0.088 > magnesium = 0.081). The current results may help to understand the role of sex on strength and nature of the association among body protein, fat, and macrominerals in growing Saanen goats. Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil FAPESP: 2014/14734-9 Asociacion Universitaria Iberoamericana de Postgrado (AUIP): 166754-1

A comparative slaughter trial was conducted to determine the energy and protein requirements for growth of castrated male Saanen goats weighing from 20 to 35 kg body weight (BW). Regarding maintenance requirements, 36 castrated male Saanen goats with an initial BW of 20.7 ± 0.5 kg, and aged 3.3 ± 0.6 months, were used. Nine animals were randomly chosen and slaughtered at the beginning of the experimental phase (BW of 21.0 ± 0.4 kg), representing the baseline (BL) group. The 27 remaining castrated male goats were pair-fed into nine groups (blocks) of three animals each, fed either ad libitum or restricted to 30 or 60% of ad libitum intake. A group was slaughtered when the animal fed ad libitum reached 35 kg BW. Regarding requirements for gain, 27 castrated male Saanen goats were fed ad libitum and nine were slaughtered at 21.0 ± 0.4 kg BW, nine at 27.7 ± 0.5 kg BW and nine at 35.1 ± 0.3 kg BW. The BL and ad libitum-fed animals used to determine maintenance requirements were also used to estimate gain requirements. The net energy (NE) requirement for maintenance was 261.5 kJ/kg0.75 BW. The metabolizable energy (ME) requirement for maintenance was 404.2 kJ/kg0.75 BW; therefore, the partial efficiency of use of ME for NE was 0.65. The minimal endogenous N losses were 262 ± 48.4 mg N/kg0.75 empty BW (EBW), corresponding to a net protein requirement for maintenance of 1.39 ± 0.257 g/kg0.75 BW. The net energy for gain increased by approximately 40% (from 12 to 17 MJ/kg EBW gain) and the net protein for gain slightly decreased by 3% (from 166 to 160 g/kg EBW gain) as the BW increased from 20 to 35 kg. Our study contributes to the improvement of goat nutrition because it provides estimates of the protein and energy requirements of castrated male Saanen goats.

The aim of this study was to investigate the effects of sex on the net requirements of growth for Ca (NCa), P (NP), Na (NNa), K (NK), and Mg (NMg) in Saanen goats from 5 to 45 kg BW, with or without consideration of the degree of maturity. A database containing 209 individual records for Saanen goats (69 castrated males, 71 intact males, and 69 females) was generated from 6 comparative slaughter studies. Total amounts of Ca, P, Na, K, and Mg in the body were fitted to logarithmized allometric equations using empty BW (EBW) or degree of maturity (EBW/mature EBW) as regressors. The equations were fitted using a mixed model, where sex was considered a fixed effect and study was considered a random effect. Net requirements were estimated by the first derivative of the logarithmized allometric equations. Then, a Monte Carlo simulation was used to assess the uncertainty of calculated net requirement values. Without considering the degree of maturity, sex did not affect NCa, NP, and NNa (0.10). Conversely, considering the degree of maturity, NCa and NP of intact males were 5% and 2%, respectively, greater than those of castrated males and females (0.01), and NNa of males (castrated and intact) was 6% greater than that of females (0.01). Regardless of approach used, NCa and NP remained constant, whereas NNa decreased by 32% as BW ranged from 5 to 45 kg. Without considering the degree of maturity, NMg of castrated and intact males were 8% and 18% greater than that of female goats ( = 0.054), respectively. Hereof NMg of castrated and intact males increased by 8% and 15%, respectively, whereas that of females decreased by 8% as BW ranged from 5 to 45 kg. Considering the degree of maturity, NMg of castrated and intact males were 7% and 17% greater than that of female goats ( = 0.054), respectively. In this regard, NMg of castrated and intact males increased 8% and 16%, respectively, whereas that of females decreased by 7% from 5 to 45 kg BW. Both approaches showed that, regardless of sex (0.10), NK decreased by 26% (i.e., without considering the maturity degree) or 27% (i.e., considering the degree of maturity) from 5 to 45 kg BW. Therefore, the consideration of maturity stage highlights differences across sexes in the net macromineral requirements for growth in goats. Elucidation of sex effects on macromineral requirements for growth may be useful for improving the accuracy of recommendations for mineral requirements for dairy goats.

We conducted a study in which body composition, energy and protein requirements, and efficiency of MP and ME were determined in F1 Boer × Saanen goat kids of 5 to 25 kg BW by using the comparative slaughter technique. Two experiments were performed: Exp. 1 estimated the maintenance requirements of kids from 15 to 25 kg BW, and Exp. 2 estimated the gain requirements of kids from 5 to 25 kg BW. In Exp. 1, 28 intact male F1 Boer × Saanen goat kids were utilized, with 7 kids slaughtered (BW of 15.0 ± 0.35 kg) at the onset for estimation of initial body composition and the remaining 21 kids assigned to a randomized block design. Within each block, kids were subjected to 3 levels of feed intake treatments (ad libitum [100%] or restricted to 70% or 40% ad libitum). All kids in each block were slaughtered when the animals fed ad libitum reached 25 kg BW. The NE, ME for maintenance, and partial efficiency of use of ME for NE were 321.6 kJ/kg BW, 525.9 kJ/kg BW, and 0.61, respectively. The net protein and MP for maintenance were 2.43 g/kg of BW and 4.41 g/kg of BW, respectively; thus, the estimated partial efficiency of MP for maintenance was 0.55. In Exp. 2, 32 intact male F1 Boer × Saanen goat kids were distributed in a completely randomized design and slaughtered at 5.6 ± 0.85 kg BW ( = 6), 10.0 ± 0.35 kg BW ( = 6), 15.3 ± 0.52 kg BW ( = 7), 20.4 ± 0.66 kg BW ( = 6), and 25 ± 0.46 kg BW ( = 7). Body composition was then fitted to allometric equations. Body fat composition increased from 37 to 114 g/kg empty BW (EBW;0.001), and body protein composition decreased by 10% (from 203.2 to 180.6 g/kg EBW;0.001) when kids grew from 5 to 25 kg BW. The NE increased by approximately 60% (from 7.2 to 11.5 MJ/kg of empty BW gain [EWG];0.001), and the net protein for gain decreased by 10% (from 186 to 166 g/kg of EWG;0.001). The partial efficiency of the utilization of ME to NE for growth was 0.32 (0.0001), and the partial efficiencies of the utilization of ME for the synthesis of protein and fat were 0.19 and 0.59 (0.011), respectively. These results demonstrate that the protein and energy maintenance requirements in young crossbred goat kids are greater than values reported previously in feeding system studies. In addition, their requirements for gain depend on body composition and are driven by efficiencies of deposition.

Made available in DSpace on 2018-11-28T13:17:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We conducted a study in which body composition, energy and protein requirements, and efficiency of MP and ME were determined in F1 Boer x Saanen goat kids of 5 to 25 kg BW by using the comparative slaughter technique. Two experiments were performed: Exp. 1 estimated the maintenance requirements of kids from 15 to 25 kg BW, and Exp. 2 estimated the gain requirements of kids from 5 to 25 kg BW. In Exp. 1, 28 intact male F1 Boer x Saanen goat kids were utilized, with 7 kids slaughtered (BW of 15.0 +/- 0.35 kg) at the onset for estimation of initial body composition and the remaining 21 kids assigned to a randomized block design. Within each block, kids were subjected to 3 levels of feed intake treatments (ad libitum [100%] or restricted to 70% or 40% ad libitum). All kids in each block were slaughtered when the animals fed ad libitum reached 25 kg BW. The NEm, ME for maintenance, and partial efficiency of use of ME for NEm were 321.6 kJ/kg(0.75) BW, 525.9 kJ/kg(0.75) BW, and 0.61, respectively. The net protein and MP for maintenance were 2.43 g/kg(0.75) of BW and 4.41 g/kg(0.75) of BW, respectively; thus, the estimated partial efficiency of MP for maintenance was 0.55. In Exp. 2, 32 intact male F1 Boer x Saanen goat kids were distributed in a completely randomized design and slaughtered at 5.6 +/- 0.85 kg BW (n = 6), 10.0 +/- 0.35 kg BW (n = 6), 15.3 +/- 0.52 kg BW (n = 7), 20.4 +/- 0.66 kg BW (n = 6), and 25 +/- 0.46 kg BW (n = 7). Body composition was then fitted to allometric equations. Body fat composition increased from 37 to 114 g/kg empty BW (EBW; P < 0.001), and body protein composition decreased by 10% (from 203.2 to 180.6 g/kg EBW; P < 0.001) when kids grew from 5 to 25 kg BW. The NEg increased by approximately 60% (from 7.2 to 11.5 MJ/kg of empty BW gain [EWG]; P < 0.001), and the net protein for gain decreased by 10% (from 186 to 166 g/kg of EWG; P < 0.001). The partial efficiency of the utilization of ME to NE for growth was 0.32 (P < 0.0001), and the partial efficiencies of the utilization of ME for the synthesis of protein and fat were 0.19 and 0.59 (P < 0.011), respectively. These results demonstrate that the protein and energy maintenance requirements in young crossbred goat kids are greater than values reported previously in feeding system studies. In addition, their requirements for gain depend on body composition and are driven by efficiencies of deposition. Univ Estadual Paulista, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil Univ Fed Campina Grande, Dept Vet Med, BR-58700970 Patos de Minas, Paraiba, Brazil Univ Estadual Paulista, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 2000/00778-1

Made available in DSpace on 2018-11-26T17:29:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Environmental changes during perinatal development can affect the postnatal life. In this sense, chicken embryos that experience low levels of O-2 over a specific phase of incubation can have their tissue growth reduced and the ventilatory response to hypoxia blunted, at least until hatching. Additionally, exposure to low level of 02 after birth reduces the thermogenesis as well. In the present study, we tested the hypothesis that hypoxia over the third week of incubation affects the thermoregulation of juvenile chicks at an age when thermogenesis is already expected to be well-developed. To this end, we measured body temperature (Tb) and oxygen consumption (V0(2)) under acute hypoxia or different ambient temperatures (Ta) of 1 and 10 day-old chicks that have been exposed to 21%O-2 for entire incubation (Nx) or to 15% O-2 in the last week of incubation (Hx). We also assessed the thermal preference under normoxia or acute hypoxia of the older chicks from both incubation groups in a thermocline. Hypoxia over incubation reduced growth but did not affect the cold-induced thermogenesis in hatchlings. Regarding the juvenile Hx, present data indicate a catch up growth with higher resting V0(2), a thermal preference for warmer Tas and a possible higher thermal conductance. In conclusion, our results show that hypoxia over the third week of incubation can affect the thermoregulation at least until 10 days after hatch in chickens. (C) 2017 Elsevier Inc All rights reserved. Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Anim Morphol & Physiol, BR-14884900 Jaboticabal, SP, Brazil Natl Inst Sci & Technol Comparat Physiol, INCI Fisiol Comparada, Jaboticabal, SP, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Anim Morphol & Physiol, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Anim Sci, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 2010/20285-1 FAPESP: 2014/01861-2 FAPESP: 2011/07509-0 FAPESP: 2011/19131-2

Made available in DSpace on 2015-03-18T15:56:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-01Bitstream added on 2015-03-18T16:28:11Z : No. of bitstreams: 1 WOS000344219700007.pdf: 426859 bytes, checksum: 668e9d1ca9a1111fdc44121c772759d2 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Little is known about the gender differences in energetic requirements of goats in early life. In this study, we determined the energy requirements for maintenance and gain in intact male, castrated male and female Saanen goat kids using the comparative slaughter technique and provide new data on their body composition and energy efficiency. To determine the energy requirements for maintenance, we studied 21 intact males, 15 castrated males and 18 females (5.0 +/- 0.1 kg initial body weight (BW) and 23 +/- 5 d of age) using a split-plot design with the following main factors: three genders (intact males, castrated males, and females) and three dry matter intake levels (ad libitum, 75% and 50% of ad libitum intake). A slanghter group included three kids, one for each nutritional plane, of each gender, and all three animals within a group were slaughtered when the ad libitum kid reached 15 kg in BW. Net energy requirements for gain were obtained for 17 intact males, eight castrated males and 15 females (5.1 +/- 0.4 kg BW and 23 +/- 13 d of age). Animals were fed ad libitum and slaughtered when they reached 5, 10, and 15 kg in BW. A digestion trial was performed with nine kids of each gender to determine digestible energy, metabolizable energy and energy metabolizability of the diet. Our results show no effect of gender on the energy requirements for maintenance and gain, and overall net energy for maintenance was 205.6 kJ/kg(0.75) empty body weight gain (EBW) (170.3 kJ/kg(0.75) BW) from 5 to 15 kg BW. Metabolizable energy for maintenance was calculated by iteration, assuming heat production equal to metabolizable energy intake at maintenance, and the result was 294.34 kJ/kg(0.75) EBW and k(m) of 0.70. As BW increased from 5 to 15 kg for all genders, the net energy required for gain increased from 9.5 to 12.0 kJ/g EBW gain (EWG), and assuming k(g) = 0.47, metabolizable energy for gain ranged from 20.2 to 25.5 kJ/g EWG. Our results indicate that it is not necessary to formulate diets with different energetic content for intact male, castrated male and female Saanen goat kids weighing from 5 to 15 kg. Univ Estadual Paulista, Dept Anim Sci, UNESP, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Dept Anim Sci, UNESP, BR-14884900 Jaboticabal, SP, Brazil FAPESP: 08/58351-5 FAPESP: 09/06791-4 FAPESP: 12/07177-0

These experiments estimated Ca, P, Mg, K, and Na requirements of intact male, castrated male, and female Saanen goats. Two experiments were performed: one to determine the net macromineral requirements for maintenance (Exp. 1) and another to determine net macromineral requirements for growth (Exp. 2). In Exp. 1, 75 goats (26 intact males, 25 castrated males, and 24 females) with initial BW (iBW) of 15.76 ± 0.10 kg were used. These animals were divided in 2 groups: baseline animals and pair-fed animals. Twenty-one goats (8 intact males, 7 castrated males, and 6 females) were slaughtered (16.6 ± 0.96 kg BW) at the beginning of the experiment to be used as the baseline group. The 54 remaining goats (18 intact males, 18 castrated males, and 18 females) were pair fed in 6 blocks of 3 goats per sex. The goats within each block were then randomly allocated to 1 of 3 levels of intake: ad libitum, restricted fed to 75% of the ad libitum intake, and restricted fed to 50% of ad libitum intake. When the animal fed ad libitum reached 31.2 ± 0.58 kg BW, it and the other goats from the same block were slaughtered. The effects of sex and level of intake were evaluated in a split-plot design, where sex was the main plot observation and level of intake was the subplot. Daily net macromineral requirements for maintenance did not differ among the sexes (0.05), and the average values obtained were 35.4 mg Ca, 24.7 mg P, 2.5 mg Mg, 5.0 mg K, and 3.30 mg Na per kg BW∙d. The net requirements for growth in Exp. 2 were obtained using 58 goats (20 intact males, 20 castrated males, and 18 females) with 15.8 ± 0.11 kg iBW, all fed ad libitum. These animals were assigned in a completely randomized design and allocated in 3 slaughter weight groups: 16.6 ± 0.96, 23.1 ± 1.33, and 31.2 ± 0.58 kg BW. The net Ca, P, and Mg requirements for growth were not different among the sexes (0.05). There was a sex effect on net K and Na requirements for growth (0.05). The net K requirements for growth (g/kg ADG) of intact males were greater ( = 0.03) and increased approximately 16%, whereas females and castrated males decreased approximately 11% as BW increased from 15 to 30 kg BW. The net Na requirements for growth (g/kg ADG) increased 9.5% for intact males and decreased 22% for females when the goats grew from 15 to 30 kg BW. Sex, therefore, affects net K and Na requirements for growth, but it does not affect net macromineral requirements for maintenance in Saanen goats.

Made available in DSpace on 2018-12-11T17:14:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-05-01 This study aimed to evaluate intake and ingestive behavior of goats rotationally grazing Tanzania (Panicum maximum cv. Tanzânia 1) pastures with 2 levels of post-grazing residue. The experimental area consisted of 1.2 ha of Tanzania pasture divided into 12 paddocks (24 areas), managed under 2 post-grazing residues: low green (leaf + stem) herbage mass (GHM) post-grazing (LR, approximately 1,500 kg/ha GHM); and high GHM post-grazing (HR, approximately 3,000 kg/ha GHM). Each paddock was grazed for 3 consecutive days (D1, D2, D3) followed by 33 days rest and evalu-ated from October 2005 to April 2006. Animal behavior (grazing time, bite rate and bite size/weight) was evaluated on each grazing day. While goats spent more time grazing on LR than HR (P=0.02), bite rate did not differ between treat-ments or among days (P=0.31) and averaged 26.5 bites/min. In contrast, bite weight was greater in HR (0.15 g/bite) than in LR (0.12 g/bite), and decreased from D1 to D3 (P < 0.001). Absolute dry matter intake of goats was greater in the HR (2.19 kg/d) than the LR (1.89 kg/d) treatment; however, differences were not significant (P > 0.05) when intake was determined on a body weight or metabolic weight basis. Our findings are consistent with the general assumption that bite weight is a trade-off between quantity and quality of the herbage mass and is the main determinant of animal per-formance. More studies are needed to determine animal performance on the various treatments and to determine man-agement strategies to provide a desirable balance between animal weight gain and pasture stability. UNESP/FCAV Universidade Estadual Paulista Departamento de Zootecnia UFG/EVZ Universidade Federal de Goias Embrapa Pecuária Sudeste UNESP/FCAV Universidade Estadual Paulista Departamento de Zootecnia

Advances in mineral nutrition of goats have been made during the last decade, especially in our understanding of Ca and P requirements. However, few studies have focused on the mineral requirements of crossbred Boer goats in their growth phase. Our objective for this study was to determine the macromineral (Ca, P, Mg, K, and Na) requirements for the maintenance and growth of intact, male three-fourths Boer × one-fourth Saanen kids (n = 34; 20.5 ± 0.24 kg of initial BW). Two trials were conducted: 1 for maintenance and 1 for growth requirements. In the maintenance trial, 28 kids were used. The baseline (BL) group consisted of 7 randomly selected kids averaging 21.2 ± 0.36 kg BW and 122 d old. The remaining kids (n = 21; age 168 ± 5 d) were randomly allocated into 7 slaughter groups (blocks) including 3 animals distributed among 3 amounts of DMI (treatments: ad libitum and restricted to 70 or 40% of ad libitum intake). Animals in a group were slaughtered when the ad libitum-treatment kid in the block reached 35 kg BW. The BL and ad libitum-fed groups in the maintenance trial were also part of the growth trial. Therefore, in the growth trial, 20 kids fed for ad libitum intake were used as follows: 7 kids slaughtered at 21.2 ± 0.36 kg BW (BL), 6 kids slaughtered at 28.2 ± 0.39 kg BW (intermediate slaughter), and 7 kids slaughtered at 35.6 ± 0.36 kg BW. Empty whole bodies of the kids (head + feet, hide, internal organs + blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Daily maintenance requirements, calculated using the comparative slaughter technique (P < 0.001), were estimated as 32.3 ± 1.1 mg Ca, 30.8 ± 1.2 mg P, 1.31 ± 0.5 mg Mg, 8.41 ± 3.0 mg K, and 5.14 ± 1.0 mg Na/kg of empty BW (EBW). Net requirements for growth increased from 6.2 to 6.6 g Ca, 5.3 to 5.4 g P, and 0.29 to 0.30 g Mg and decreased from 1.20 to 1.07 g K and 0.65 to 0.59 g Na/kg of EBW gain for kids from 20 to 35 kg BW. This study indicated that the net mineral requirements for Boer crossbred goat kids may be different from those of purebred or other genotypes, and more data are needed for goats in general.

The trial aimed to evaluate the effect of sustainable intensification of the production system on final body weight (BWf), average daily gain (ADG), gain by area (GA), stocking rate (SR), production and morphogenic composition of the forage. Nellore young bulls (n=44) and ½Angus x ½Nellore (n=44) were randomly assigned in two systems in growing phase (IS=intensive and SIS=semi intensive). The IS - 6 paddocks of Brachiaria brizanthacv Xaraés with 2 ha each, were fertilized with 40 kg/ha of P(2)O(5), 40 kg/ha of K(2)O and 150 kg/ha N, splitted in three applications of 50 kg/ha during the rainy season, with urea as a nitrogen source. The SIS - 8 paddocks of Brachiaria brizanthacv Marandu, with 2 ha each didn′t receive any fertilization in the last 5 years. The animals were supplemented with mineral salt from December to February. February to May the animals received protein supplementation in 0.1 %BW. The supplement was formulated with ingredients that no compete with human or monogastrics food and without antibiotics. The results were analyzed by ANOVA using PROC MIXED procedures in SAS 9.4, with a 2 × 2 factorial arrangements, and the averages were compared at 5% level of significance. The production system influenced (P

Meat production by goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine the energy and protein requirements for maintenance and growth of 34 (3/4) Boer x (1/4) Saanen crossbred, intact male kids (20.5 +/- 0.24 kg of initial BW). The baseline group was 7 randomly selected kids, averaging 21.2 +/- 0.36 kg of BW. An intermediate group consisted of 6 randomly selected kids, fed for ad libitum intake, that were slaughtered when they reached an average BW of 28.2 +/- 0.39 kg. The remaining kids (n = 21) were allocated randomly on d 0 to 3 levels of DMI (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 kid from each treatment, and kids were slaughtered when the ad libitum treatment kid reached 35 kg of BW. Individual body components (head plus feet, hide, internal organs plus blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Initial body composition was determined using equations developed from the composition of the baseline kids. The calculated daily maintenance requirement for NE was 77.3 +/- 1.05 kcal/kg(0.75) of empty BW (EBW) or 67.4 +/- 1.04 kcal/kg(0.75) of shrunk BW. The daily ME requirement for maintenance (118.1 kcal/kg(0.75) of EBW or 103.0 kcal/kg(0.75) of shrunk BW) was calculated by iteration, assuming that the heat produced was equal to the ME intake at maintenance. The partial efficiency of use of ME for NE below maintenance was 0.65. A value of 2.44 +/- 0.4 g of net protein/kg(0.75) of EBW for daily maintenance was determined. Net energy requirements for growth ranged from 2.55 to 3.0 Mcal/kg of EBW gain at 20 and 35 kg of BW, and net protein requirements for growth ranged from 178.8 to 185.2 g/kg of EBW gain. These results suggest that NE and net protein requirements for growing meat goats exceed the requirements previously published for dairy goats. Moreover, results from this study suggest that the N requirement for maintenance for growing goats is greater than the established recommendations.

Made available in DSpace on 2018-11-27T05:46:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-11-01. Added 1 bitstream(s) on 2019-10-09T18:28:02Z : No. of bitstreams: 1 S1516-35982015001100397.pdf: 598548 bytes, checksum: a9def3fcf48bcaee6cf5aaed630df8f0 (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The objective of this study was to determine the protein requirements for the growth of intact male, female, and castrated male Saanen goats weighing 30 to 45 kg of body weight (BW) and to compare estimates of the protein requirements for maintenance (NPm) by the comparative slaughter and nitrogen balance techniques. To determine the maintenance requirements, 55 goats were assigned in a split-plot design using a 3 x 3 factorial arrangement (three sexes and three dry matter intake (DMI) levels). A linear regression of retained N (as measured by the slaughter technique and estimated from the nitrogen balance) on N intake on a daily basis was used to calculate the net protein for maintenance. The net protein requirement for weight gain (NPg) was obtained using 65 goats fed ad libitum in a completely randomized design. The first derivative of the allometric equation of protein content in the empty BW with respect to the empty BW yielded estimates of the NPg. According to the comparative slaughter technique, the estimated NPm was 1.46 g/kg of metabolic weight, which is 50% lower than the estimate from the nitrogen balance technique. When evaluating the variance of the error, the nitrogen balance also showed greater values, indicating less precision compared with that of the comparative slaughter technique. The daily NPg ranged from 155.7 +/- 10.9 to 153.4 +/- 13.5 g/kg of EBW gain for growing Saanen goats. The protein requirements (NPm and NPg) of intact male, female, and castrated male Saanen goats are similar, from 30 to 45 kg BW, in accordance with current feeding systems. Moreover, the results of the present study indicate that the estimate of NPm using the comparative slaughter technique is more precise and lower than that using the N balance technique. Univ Estadual Paulista, Fac Ciencias Agrarias & Vet, Jaboticabal, SP, Brazil Inst Fed Goiano, Hidrolandia, Go, Brazil Univ Estadual Paulista, Fac Ciencias Agrarias & Vet, Jaboticabal, SP, Brazil FAPESP: 2008/58351-5 FAPESP: 2010/02482-4

Nitric oxide (NO) plays a role in thermogenesis but does not mediate immune-to-brain febrigenic signaling in rats. There are suggestions of a different situation in birds, but the underlying evidence is not compelling. The present study was designed to clarify this matter in 5-day-old chicks challenged with a low or high dose of bacterial LPS. The lower LPS dose (2 μg/kg im) induced fever at 3–5 h postinjection, whereas 100 μg/kg im decreased core body temperature (Tc) (at 1 h) followed by fever (at 4 or 5 h). Plasma nitrate levels increased 4 h after LPS injection, but they were not correlated with the magnitude of fever. The NO synthase inhibitor ( NG-nitro-l-arginine methyl ester, l-NAME; 50 mg/kg im) attenuated the fever induced by either dose of LPS and enhanced the magnitude of the Tcreduction induced by the high dose in chicks at 31–32°C. These effects were associated with suppression of metabolic rate, at least in the case of the high LPS dose. Conversely, the effects of l-NAME on Tcdisappeared in chicks maintained at 35–36°C, suggesting that febrigenic signaling was essentially unaffected. Accordingly, the LPS-induced rise in the brain level of PGE2was not affected by l-NAME. Moreover, l-NAME augmented LPS-induced huddling, which is indicative of compensatory mechanisms to run fever in the face of attenuated thermogenesis. Therefore, as in rats, systemic inhibition of NO synthesis attenuates LPS-induced fever in chicks by affecting thermoeffector activity and not by interfering with immune-to-brain signaling. This may constitute a conserved effect of NO in endotherms.

The aim of this study was to investigate the energy requirements of female and intact and castrated male Saanen goats. Animals were randomly assigned to 1 of 2 experiments designed to investigate the energy requirements for maintenance and gain. To determine the maintenance requirements, 85 goats were used (26 intact males, 30 castrated males, and 29 females) with an initial BW of 30.3 ± 0.87 kg. Thirty goats (8 intact males, 9 castrated males, and 13 females) were slaughtered to be used as the baseline group. The remaining goats were assigned in a split-plot design using a 3 × 3 factorial arrangement (3 sexes-intact males, castrated males, and females-and 3 DMI levels-ad libitum and restricted fed to 75 or 50% of the ad libitum intake). The NE was obtained using 65 goats (20 intact males, 22 castrated males, and 23 females) fed ad libitum in a completely randomized design. Eight intact males, 9 castrated males, and 13 females were slaughtered at 30.5 ± 1.53 kg BW. Seventeen goats (6 intact males, 6 castrated males, and 5 females) were slaughtered at 38.1 ± 0.49 kg BW. The remaining goats were slaughtered at 44.0 ± 0.50 kg BW. The NE did not differ between the sexes ( = 0.59; 258.5 kJ/kg BW), resulting in a ME for maintenance of 412.4 kJ/kg BW. The estimated energy use efficiency for maintenance was 0.627. During the growth phase, NE differed between the sexes (0.001); intact males, castrated males, and females showed an average NE equal to 15.2, 18.6, and 22.7 MJ/kg of empty weight gain, respectively. The energy requirements for growth differed between the sexes. The difference was found to be due to distinct NE and partial efficiency of ME utilization for growth in intact and castrated males and females during the late growth phase. This study may contribute to adjustments in feeding system energy recommendations regarding the NE and NE found for goats during the late growth phase.

The objective of this study was to compare methods for estimative of body composition of goats based on tritiated water space technique (TOH), specific gravity (SG) of carcass and 9-11 th ribs. Ten Toggenburg x Alpine intact male goat kids, from 5.3±0.4 to 25.9±1.3 kg of body weight (BW), were used to estimate body composition by: 1) direct method, 2) TOH method, 3) SG of the carcass and 4) SG of the 9-11 th whole ribs. In addition, update linear equations for predicting body composition were developed using data from direct method. The TOH space overestimated water body composition on average 31%. The SG of the carcass and 9-11 th ribs underestimated water empty body composition (%) on average 21 and 12%, respectively. In spite of its overestimate, the determination of TOH space can be used as a reliable field technique to study relative changes in body composition of growing goats. Specific gravity is practicable in most circumstances and does not require expensive equipment. However, the SG of the carcass and 9-11 th ribs has not a valid equation to predict body composition of growing goats.

Currently, the world is facing challenges related to environmental problems, global warming, and demography. In this context, goats may take part on an important socio-economic role with its potential to use marginal land. In addition, these animals adapt easily to various climatic zones, produce under different systems of husbandry, and successfully convert feed into protein sources. However, it is crucially important to understand this species’ nutritional requirements, that are determined by several factors such as management, breed, environment, gender, age and others. Nutritional requirements for goats have been based on limited data, and are sometimes calculated by extrapolation of other species needs (ARC, 1980; NRC, 1981). We propose to investigate Saanen goats, from 30 to 45 kg of body weight (BW), the effect of gender on net protein and energy requirements for growth.

Knowledge of nutritional requirements is decisive for a successful nutrition system, since animals fed properly convert more efficiently the nutrients ingested in products. Current feeding systems for goats still comprise information extrapolated from sheep and/or cattle. However, the data obtained with these species should not be used for goats, because of differences between these species, such as dietary habits, physical activity, milk and carcass composition, different adaptation mechanisms, among others (NRC, 2007). Therefore, the objective of this study was to determine net energy and protein requirements for growth of goat kids, using meta-analysis as a statistical tool.

The total energy body content is based on protein and fat deposition in growing animals, which can be strongly influenced by gender. In this regard, the accretion rate of protein and fat could be helpful for understanding the efficiency of utilization of metabolizable energy (ME) to net energy (NE) for growth (kg). Previous studies in cattle have found differences in the partial efficiency of use of metabolizable energy (ME) to net energy (NE) for growth between gender, which was 0.54 for bulls, 0.47 for steers and 0.54 for heifers (Chizzotti et al., 2007). However there is a lack of information in this regard with goats. Therefore, this study was conducted to evaluate the effect of the gender on fat and protein deposition in the gain and on energy efficiency for growth in Saanen goat kids.

Gender plays an important role on deposition rates of different body tissues and due to the variation in the composition of gain, net protein requirements can differ between males and females. Souza et al. (2012) reported that bulls had greater protein requirements than castrated males, which were greater than females at the same age because intact males showed greater lean tissue deposition in the body than castrated males and females. In dairy goats, only a few studies dealing with the effect of gender on protein requirements have been published. Thus, the objective of this study was to determine the net protein requirements for growth of intact males, castrated males, and females Saanen goat kids using comparative slaughter technique.

Currently, due to environmental and economic issues, ruminant production system has aimed at maximizing production, concomitant with an increased efficiency. Because of methane is produced in the process of feed energy utilization within the animal, its reduction is usually associated with improved productivity. Therefore, one of the strategies to optimizing energy use in ruminants is to minimize enteric methane (CH4) emission during the fermentation process, by reducing dry matter intake (Shibata and Terada, 2010). Feed restriction is a common practice on goat production in several parts of world, and can be used to exploiting the compensatory gain, resulting in better efficiency of animal feed energy utilization. Therefore, this study was carried out to evaluate the effect of feed restriction on methane emission and digestibility.

Advances in mineral nutrition of goats have been made during the last decade, especially in our understanding of Ca and P requirements. However, few studies have focused on the mineral requirements of crossbred Boer goats in their growth phase. Our objective for this study was to determine the macromineral (Ca, P, Mg, K, and Na) requirements for the maintenance and growth of intact, male three-fourths Boer × one-fourth Saanen kids (n = 34; 20.5 ± 0.24 kg of initial BW). Two trials were conducted: 1 for maintenance and 1 for growth requirements. In the maintenance trial, 28 kids were used. The baseline (BL) group consisted of 7 randomly selected kids averaging 21.2 ± 0.36 kg BW and 122 d old. The remaining kids (n = 21; age 168 ± 5 d) were randomly allocated into 7 slaughter groups (blocks) including 3 animals distributed among 3 amounts of DMI (treatments: ad libitum and restricted to 70 or 40% of ad libitum intake). Animals in a group were slaughtered when the ad libitum-treatment kid in the block reached 35 kg BW. The BL and ad libitum-fed groups in the maintenance trial were also part of the growth trial. Therefore, in the growth trial, 20 kids fed for ad libitum intake were used as follows: 7 kids slaughtered at 21.2 ± 0.36 kg BW (BL), 6 kids slaughtered at 28.2 ± 0.39 kg BW (intermediate slaughter), and 7 kids slaughtered at 35.6 ± 0.36 kg BW. Empty whole bodies of the kids (head + feet, hide, internal organs + blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Daily maintenance requirements, calculated using the comparative slaughter technique (P0.001), were estimated as 32.3 ± 1.1 mg Ca, 30.8 ± 1.2 mg P, 1.31 ± 0.5 mg Mg, 8.41 ± 3.0 mg K, and 5.14 ± 1.0 mg Na/kg of empty BW (EBW). Net requirements for growth increased from 6.2 to 6.6 g Ca, 5.3 to 5.4 g P, and 0.29 to 0.30 g Mg and decreased from 1.20 to 1.07 g K and 0.65 to 0.59 g Na/kg of EBW gain for kids from 20 to 35 kg BW. This study indicated that the net mineral requirements for Boer crossbred goat kids may be different from those of purebred or other genotypes, and more data are needed for goats in general.

Meat production by goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine the energy and protein requirements for maintenance and growth of 34 (3/4) Boer x (1/4) Saanen crossbred, intact male kids (20.5 +/- 0.24 kg of initial BW). The baseline group was 7 randomly selected kids, averaging 21.2 +/- 0.36 kg of BW. An intermediate group consisted of 6 randomly selected kids, fed for ad libitum intake, that were slaughtered when they reached an average BW of 28.2 +/- 0.39 kg. The remaining kids (n = 21) were allocated randomly on d 0 to 3 levels of DMI (treatments were ad libitum or restricted to 70 or 40% of the ad libitum intake) within 7 slaughter groups. A slaughter group contained 1 kid from each treatment, and kids were slaughtered when the ad libitum treatment kid reached 35 kg of BW. Individual body components (head plus feet, hide, internal organs plus blood, and carcass) were weighed, ground, mixed, and subsampled for chemical analyses. Initial body composition was determined using equations developed from the composition of the baseline kids. The calculated daily maintenance requirement for NE was 77.3 +/- 1.05 kcal/kg(0.75) of empty BW (EBW) or 67.4 +/- 1.04 kcal/kg(0.75) of shrunk BW. The daily ME requirement for maintenance (118.1 kcal/kg(0.75) of EBW or 103.0 kcal/kg(0.75) of shrunk BW) was calculated by iteration, assuming that the heat produced was equal to the ME intake at maintenance. The partial efficiency of use of ME for NE below maintenance was 0.65. A value of 2.44 +/- 0.4 g of net protein/kg(0.75) of EBW for daily maintenance was determined. Net energy requirements for growth ranged from 2.55 to 3.0 Mcal/kg of EBW gain at 20 and 35 kg of BW, and net protein requirements for growth ranged from 178.8 to 185.2 g/kg of EBW gain. These results suggest that NE and net protein requirements for growing meat goats exceed the requirements previously published for dairy goats. Moreover, results from this study suggest that the N requirement for maintenance for growing goats is greater than the established recommendations.