A glimpse of the future in animal nutrition science. 1. Past and future challenges

ABSTRACT If the world population continues to increase exponentially, wealth and education inequalities might become more pronounced in the developing world. Thus, offering affordable, high-quality protein food to people will become more important and daunting than ever. Past and future challenges will increasingly demand quicker and more innovative and efficient solutions. Animal scientists around the globe currently face many challenging issues: from ensuring food security to prevent excess of nutrient intake by humans, from animal welfare to working with genetic-engineered animals, from carbon footprint to water footprint, and from improved animal nutrition to altering the rumen microbiome. Many of these issues are most likely to continue (or to exacerbate further) in the coming years, but animal scientists have many options to surmount the obstacles posed to the livestock industry through tools that are presently available. The frequency, interval, and intensity of livestock impacts, however, differ across regions, production systems, and among livestock species. These differences are such that the generalization of these issues is impossible and dangerous. For instance, when we discuss domesticated ruminant nutrition in the human food context, we look for the most efficient ruminant feeds that complement, rather than compete with, grains grown for direct human nutrition. Greater scrutiny and standardization are needed when developing and validating methodologies to assess short- and long-term impacts of livestock production. Failure in correctly quantifying these impacts may lead to disregard and disbelief by the livestock industry, increased public confusion, and the development of illusionary solutions that may amplify the impacts, thereby invalidating its original intent

Energy and protein requirements during the growing phase of indigenous goats

The objective of this study was to investigate both energy and protein requirements for the maintenance and growth of indigenous goats, based on data from two separate studies. Goats were weaned at 79 ± 4.4 days of age, with milk and solid diet intake recorded daily. To determine energy maintenance requirements, 32 kids of 4.90 ± 0.302 kg initial body weight (BW) were used. Ten kids were slaughtered at 5.40 ± 0.484 kg BW to estimate initial body composition, with the remaining kids randomly assigned to one of two DM intake levels: ad libitum and restricted-fed (1.2-times maintenance level). Heat production (HP) was calculated as the difference between ingested metabolizable energy (MEI) and retained energy. Net energy requirement for maintenance (NEm) was estimated as the ?0 parameter of the relationship between HP and MEI [HP = ?0 × exp (?1 × MEI)]. Metabolizable energy required for maintenance (MEm) was calculated iteratively, as HP = MEI. Efficiency of energy utilization for maintenance (km) was calculated as NEm/MEm. The intercept of the linear regression of retained CP on CP intake was used to calculate net protein requirements for maintenance (NPm). Net energy and protein requirement for gain (NEg and NPg, respectively) were obtained using 26 kids fed ad libitum and randomly slaughtered at 5.40 ± 0.484 kg BW (n = 10), 15.8 ± 0.655 kg BW (n = 10), and 26.3 ± 1.27 kg BW (n = 6). The first derivative of the allometric equation (used to calculate energy and protein contents in empty body weight (EBW)) with respect to EBW yielded estimates of NEg and NPg. A Monte Carlo-based method was employed to simulate variation in MEm, NEg, and NPg. This study indicated that the net energy required for maintenance is 310.1 ± 36.7 kJ kg-0.75 EBW, with MEm estimated at 499.1 ± 52.1 kJ kg-0.75 EBW and km equal to 0.62. This study indicated that 1.246 g CP kg-0.75 EBW is required by indigenous kids weighing from 5 to 25 kg BW to meet their NPm. In addition, indigenous goats require between 186.6 ± 2.97 and 214.3 ± 12.9 g CP, and between 5.39 ± 1.49 and 9.74 ± 2.57 MJ to gain one kilogram of EBW. This study may contribute to future adjustments in feeding system energy and protein recommendations for indigenous kids

Exigências de proteína e energia de caprinos de diferentes categorias sexuais dos 30 aos 45 kg de massa corporal

Utilizamos a técnica de abate comparativo para verificar a diferenças entre categorias sexuais nas exigências de proteína e energia de caprinos Saanen em fase final de crescimento. Os animais foram alocados aleatoriamente em dois ensaios delineados para investigar as exigências em proteína e energia para mantença e ganho. No ensaio de mantença, utilizamos 85 animais (26 machos não castrados, 30 machos castrados e 29 fêmeas), com MC inicial de 30,3 ± 0,87 kg. Destes, 30 animais (8 machos não castrados, 9 machos castrados e 13 fêmeas) foram abatidos ao início do experimento para compor os animais de composição corporal referência inicial. Os demais animais foram aleatoriamente distribuídos em delineamento com parcelas subdivididas, sendo os principais fatores 3 condições sexuais e 3 níveis de alimentação. A parcela foi composta por 3 animais do mesmo sexo, aleatoriamente designados a um nível de alimentação: alimentado à vontade, 75% e 50% do consumo à vontade, de forma que foram abatidos com mesmo número de dias que o animal com alimentação à vontade levou para atingir 45 kg de MC. A exigência líquida de proteína para mantença (PLm) estimada foi 2,09 g/kg PCV0,75 e não diferiu entre condições sexuais. A exigência líquida de proteína para ganho (PLg) foi obtida com dados de 65 caprinos (20 machos não castrados, 22 machos castrados e 23 fêmeas) alimentados à vontade em delineamento inteiramente casualizado, a PLg variou de 154 a 146 g/kg de ganho em PCV entre 30 a 45 kg de MC. Recomendamos que a exigência metabolizável total de proteína (g/dia) para crescimento de caprinos Saanen seja estimada pelo modelo: PMt= [(4,31 * MC0,75) /kpm] + [(127,5* MC))/ kpg] * GPDdesejado)...We used the comparative slaughter technique to verify differences among gender in protein and energy requirements of Saanen goats in the final phase of growth. Animals were randomly allocated to 2 trials, designed to investigate protein and energy requirements for maintenance and growth. To determine the maintenance requirements we used 85 goats (26 intact males, 30 castrate males, and 29 females) with initial BW of 30.32 ± 0.87 kg. 30 goats (8 intact males, 9 castrated males and 13 females) were slaughtered to use as baseline group. The other goats were assigned in a split block design in a 3 × 3 factorial arrangement (3 genders - intact males, castrate males, and females with 3 DMI levels - ad libitum, and 75% and 50% of ad libitum intake). A slaughter group included one kid from each treatment and was slaughtered when the ad libitum kid reached 45 kg of BW. Net protein requirements for maitenance was the same for all genders tested and equal to 2.09 g/kg EBW0.75. Net protein requirements for growth were obtained using 65 goats (20 intact males, 22 castrate males, and 23 females) fed ad libitum in a completely randomized design and ranged from 154 to 146 g/kg of EBW gain as BW varied from 30 to 45 kg. WE recommended the following equation to estimate total metabolizable protein requirements (g/day): PMt= [(4,31 * BW0.75) /kpm] + [(127.5* BW))/ kpg] * ADGexpected)..

A glimpse of the future in animal nutrition science. 1. Past and future challenges

ABSTRACT If the world population continues to increase exponentially, wealth and education inequalities might become more pronounced in the developing world. Thus, offering affordable, high-quality protein food to people will become more important and daunting than ever. Past and future challenges will increasingly demand quicker and more innovative and efficient solutions. Animal scientists around the globe currently face many challenging issues: from ensuring food security to prevent excess of nutrient intake by humans, from animal welfare to working with genetic-engineered animals, from carbon footprint to water footprint, and from improved animal nutrition to altering the rumen microbiome. Many of these issues are most likely to continue (or to exacerbate further) in the coming years, but animal scientists have many options to surmount the obstacles posed to the livestock industry through tools that are presently available. The frequency, interval, and intensity of livestock impacts, however, differ across regions, production systems, and among livestock species. These differences are such that the generalization of these issues is impossible and dangerous. For instance, when we discuss domesticated ruminant nutrition in the human food context, we look for the most efficient ruminant feeds that complement, rather than compete with, grains grown for direct human nutrition. Greater scrutiny and standardization are needed when developing and validating methodologies to assess short- and long-term impacts of livestock production. Failure in correctly quantifying these impacts may lead to disregard and disbelief by the livestock industry, increased public confusion, and the development of illusionary solutions that may amplify the impacts, thereby invalidating its original intent

Protein requirements for growth in male and female Saanen goats

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 × 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

Carcass characteristics and cuts of Santa Inês lambs fed different roughage proportions and fat source

This work aimed at determining the influence of roughage proportions and fat source of the diet on characteristics of carcass and comercial cuts of lambs. It was used 24 non-castrated Santa Inês male lambs, ad libitum fed diet with two proportions of roughage (30 and 70%) and fat (no fat, protected fat, and soybean) slaughtered at an avarage body weight of 35.4 kg (± 1.5 kg). Animals fed 30% roughage diet showed the highest weights and carcass yields. The percentages of posterior arm and ham were higher in animals fed 30% roughage with no addition of fat source. Total leg length and internal length were higher in animals fed 70% roughage diet while leg width was higher for those fed 30% roughage diet. Addition of fat source in diets with high percentage of concentrate can increase carcass yields. This effect is higher when protected fat is used regarded to whole soybean. Although diets do not have effect on most of these cuts, the effect on the ham confirms the influence of the diet on this noble cuts

Quantitative and qualitative characteristics of the non-carcass components and the meat of lambs fed sunflower seeds and vitamin E

The objective of this investigation was to evaluate the weight and percentage of the non-carcass components and the mineral content (macro minerals and trace minerals), crude protein, ether extract, moisture and vitamin E of the heart, liver, tongue, lungs, reticulum, kidneys and meat from the longissimus dorsi of lambs in feedlot finishing. Thirty-two non-castrated Ile de France male lambs, fed diets containing sunflower seeds and vitamin E from 15 to 32 kg of body weight were allotted in a completely randomized design in a 2 × 2 factorial arrangement. The weight of the gastrointestinal tract was higher in the lambs fed diets containing vitamin E (10%). No difference was observed in the liver as to the mineral matter, crude protein, ether extract, moisture (2.01; 20.03; 2.39 and 74.78 g/100 g, respectively), the macro minerals and trace minerals, except iron. In the tongue, lungs, reticulum, kidneys and meat there was no in fluence of diets in the studied variables. The liver and the meat presented different values of crude protein (20.01 and 18.34 g/100 g, respectively), and the heart (1.03 mg/100 g) showed a higher content of vitamin E. High contents of manganese, zinc and copper were observed in the liver. The evaluated non-carcass components were nutritionally equal to the sheep meat, once, in addition to their high yield in relation to the body weight at slaughter, the non-carcass components are sources of nutrients