Metabolizable Energy Requirements Research Articles

Determination of energy and protein requirements of preweaned dairy calves: A multistudy approach

The first studies concerning nutrient requirements for preweaned dairy calves were from the 1920s and 1930s; however, few studies were published in the following decades. We aimed to determine energy and protein requirements of preweaning Holstein and Holstein × Gyr dairy calves in a multistudy meta-regression. We used a database composed of individual measurements of 166 preweaned male calves (138 submitted to treatments and 28 used as the reference group) from 4 studies that used the methodology of comparative slaughter. Animals with less than 15/16 of Holstein genetic composition were considered crossbred Holstein × Gyr, whereas other animals were considered Holstein. Net energy requirements for maintenance (NEM) were determined by the regression between heat production and metabolizable energy intake (MEI). The metabolizable energy requirements for maintenance were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance was obtained by NEM divided by the metabolizable energy requirements for maintenance. Net energy requirements for gain (NEG) were estimated using a regression of the retained energy (RE) as a function of empty body weight (EBW) and empty body gain (EBG). The efficiency of use of metabolizable energy for gain was estimated by the regression of RE as a function of MEI, but with partitioning the MEI into MEI from liquid feed and MEI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the slope of the regression. The metabolizable protein requirements for maintenance (MPM) were estimated using the intercept of the regression between the metabolizable protein intake (MPI) and average daily gain. The MPM was determined as the ratio between the intercept and the metabolic body weight. Net protein requirements for gain (NPG) were estimated by the regression between retained protein, EBG, and RE. The efficiency of use of metabolizable protein for gain was estimated by the regression of the retained protein as a function of MPI, but with partitioning the MPI into MPI from liquid feed and MPI from starter feed. Additionally, the effect of a liquid feed (milk or milk replacer) was tested on the regression slope. Breed did not influence any of the nutrient requirements' estimates. The NEM was estimated as 70.2 kcal/metabolic body weight per day. The efficiency of use of metabolizable energy for maintenance observed was 66%. The NEG was estimated by the equation NEG = 0.0901 × EBW0.75 × EBG0.9539. The efficiency of use of metabolizable energy for gain was estimated as 57.6, 49.3, and 41.2% for milk, milk replacer, and starter feed, respectively. The MPM was estimated as 4.22 g/EBW0.75 per day, and the NPG was determined by the equation: NPG = 30.06 × EBG + 70.98 × RE. The efficiency of use of metabolizable protein for gain was estimated as 71.9, 59.2, and 44.4% for milk, milk replacer, and starter feed, respectively. We concluded that no differences were observed in energy and protein requirements between Holstein and Holstein × Gyr crossbred cows. The efficiencies of use of metabolizable energy and protein are greater for milk when compared with milk replacer and starter feed. Therefore, we propose that the equations generated herein should be used to estimate energy and protein requirements of preweaned Holstein and Holstein × Gyr crossbred dairy calves raised under tropical conditions.

Effects of different dietary energy and protein levels on the performance and carcass characteristics of native hilly chicken during growing phase in confinement

Two hundred and sixteen 10 weeks of age hilly chickens were used to determine the effects of dietary energy and protein level on growth performance, carcass characteristics and meat quality. The chicks were randomly allotted in to 3×3 factorial in a completely randomize design. Three levels of energy (2600, 2700 and 2800 ME kcal/kg) and three levels of dietary proteins (16, 17 and 18% CP) were offered ad libitum to the chicks from 10-16 weeks of age. There were no significant interaction effect between dietary protein and energy levels in the diets. At 10-16 weeks of age hilly chickens fed with the medium protein diet (17% CP) showed shortened feed intake (p<0.001) but FCR found better in 16% CP diet. Dietary protein levels higher than 16% CP did not show any significant effect on growth performance. However hilly chicken fed with lower protein diet converted protein to body weight and body weight gain more efficiently than those fed higher protein diets. Dietary energy contents of 2600, 2700 and 2800 ME kcal/kg did not affect the growth performance of hilly chicken except ME, CP intake and protein conversion ratio. ME and CP intake was increased with increasing dietary ME and CP levels (p<0.000). Protein utilization was better (p<0.05) in higher (2800 ME kcal/kg) and medium (2700 ME kcal/kg) ME level diet. L*, a* and b* of breast meat was not affected by dietary ME and CP (p>0.05). Dietary energy and protein level did not significantly (p>0.05) affect the drip loss, cooking loss and pH of breast meat between the treatments. Based on the data of growth performance, carcass characteristics and meat quality, the optimal dietary ME requirement of hilly chicken from 10-16 weeks of age is 2800 ME kcal/kg and the CP requirement is 16%.
 Asian Australas. J. Biosci. Biotechnol. 2021, 6 (1), 1-9

Effect of dietary protein on growth performance, and serum biochemical index in late pregnant Hu ewes and their offspring

The purpose of this study was to investigate the effects of different protein levels in late pregnancy on ewe and lamb growth performance, serum biochemical indexes. Thirty-three ewes (46.4 ± 1.38 kg initial weight) were randomly divided into 3 groups, with 11 ewes in each group. The protein levels of three diets formulated to provide components to meet 10.00 MJ/kg ME requirements diets were: 10.12%, 11.26%, 12.4%. Ewes were raised from the 90th day of pregnancy to the end of delivery, and the lambs were weaned at 60 days. Dietary protein levels had significant effects on blood urea nitrogen, glucose, ammonia nitrogen and triglyceride of ewes (p < 0.05). The height, chest depth, chest circumference, straight crown hip length and curved crown hip length of lambs decreased at first and then increased with the increase of protein. The body length, chest circumference, head width and head length of weaned lambs decreased at first and then increased with the increase of protein. The results showed that when the dietary protein level was increased to 12.4%, the amino acid, glucose and fat metabolism of ewes were affected. The body size development of lambs was better than 10.12% and 11.26% proteins.

Rendimiento de leche derivado de energía y proteína de vacas en pastoreo recibiendo suplementos en un sistema agrosilvopastoril

Dual purpose farms southwest of the State of Mexico produce milk and calves under subtropical agrosilvopastoral systems (ASPS). During the dry season, farmers supplement their cattle due to the low availability and quality of grasses, without considering, besides grasses, the contribution of woody species to dry matter intake, metabolizable energy (ME), and crude protein (CP) requirements of cows. The aim of this study was to determine milk produced from forage energy (MFe) and protein (MFp) of grazing cow with three types of supplement. First supplement consisted of cracked maize and commercial concentrate resulting on 14 % of CP (S14). To the S14 mixture 7 % of soybean meal was added to increase CP to 16 % (S16), and commercial concentrate of 16 % CP was used as a third supplement (SC16). Six lactating cows were allocated in a 3x3 replicated Latin Square (three cows per square), three experimental periods (EP) (three weeks per EP). There were no significant effects of supplements (P=0.80) on performance variables. Mean milk yield was 6.8 kg/cow/d. Milk from forage energy and protein were 0.8 and 6.1 kg/cow/day, respectively. Mean milk urea nitrogen (MUN) was high regardless of supplement; but nitrogen in urine (44.1 mg/dL) and feces (1.4 mg/g) were higher for SC16 (P=0.001 and 0.04, respectively). Cows obtained 90 and 10 % of their CP and metabolizable energy requirements for maintenance and production from the agrosilvopastoral system.

Optimization of Profit for Pasture-Based Beef Cattle and Sheep Farming Using Linear Programming: Model Development and Evaluation

A linear programming optimization tool is useful to assist farmers with optimizing resource allocation and profitability. This study developed a linear programming profit optimization model with a silage supplement scenario. Utilizable kilograms of pasture dry matter (kg DM) of the total pasture mass was derived using minimum and maximum pasture mass available for beef cattle and sheep and herbage utilization percentage. Daily metabolizable energy (MJ ME/head) requirements for the various activities of beef cattle and sheep were estimated and then converted to kg DM/head on a bi-monthly basis. Linear programming was employed to identify the optimum carrying capacity of beef cattle and sheep, the most profitable slaughtering ages of beef cattle, the number of prime lambs (sold to meat processing plants), and sold store lambs (sold to other farmers for finishing). Gross farm revenue (GFR) and farm earnings before tax (EBT) per hectare and per stock unit, as well as total farm expenditure (TFE), were calculated and compared to the average value of Taranaki-Manawatu North Island intensive finishing sheep and beef Class 5 farming using Beef and Lamb New Zealand (B+LNZ) data. The modeled farm ran 46% more stock units (a stock unit consumed 550 kg DM/year) than the average value of Class 5 farms. At this stocking rate, 83% of the total feed supplied for each species was consumed, and pasture supplied 95% and 98% of beef cattle and sheep feed demands, respectively. More than 70% of beef cattle were finished before the second winter. This enabled the optimized system to return 53% and 188% higher GFR/ha and EBT/ha, respectively, compared to the average values for a Class 5 farm. This paper did not address risk, such as pasture growth and price fluctuations. To understand this, several additional scenarios could be examined using this model. Further studies to include alternative herbages and crops for feed supply during summer and winter are required to expand the applicability of the model for different sheep and beef cattle farm systems.

Energy Requirements of Beef Cattle: Current Energy Systems and Factors Influencing Energy Requirements for Maintenance.

Simple SummaryThe accurate estimation of energy requirements for present-day genotypes under current feeding conditions is crucial for improving profitability and reducing the environmental impact of the beef industry. Equations for predicting energy requirements of beef cattle according to the Agricultural and Food Research Council (AFRC) are outdated and require an urgent update. The results from literature review confirmed previous reports on the under prediction of energy requirements for maintenance by the AFRC, especially for growing animals. This may have consequences on the efficiency of use of the dietary energy on productive functions. Although much less research has been conducted over the last decade on energy metabolism for suckler cows, the existing data appears to be relevant as a valid reference for updating AFRC recommendations. The present review also revealed the lack of data on the contribution of both animal and diet-related factors influencing on energy requirements for beef cattle and thus conclusions on this regard are difficult to draw.The present review compared features of the UK system for predicting energy requirements in beef cattle with a number of feeding systems developed from research institutes consortiums around the world. In addition, energy requirements for maintenance calculated from studies conducted at the Agri-Food and Biosciences Institute (AFBI) in Northern Ireland since the 1990s were compared with compiled data from recent peer-review papers published over the last decade (2009–2020). The mean metabolisable energy requirement for the maintenance (MEm) of growing cattle was 0.672 MJ/kg0.75 according to values obtained from calorimetry studies conducted at AFBI. This value is respectively 8.2 and 19.5% greater than the MEm values obtained by the Agricultural and Food Research Council (AFRC), and the National Academies of Sciences, Engineering and Medicine (NASEM) equations, but it is in close agreement with the Institut National de la Recherche Agronomique (INRA) approach, when assuming a Bos taurus bull (300 kg LW) and an efficiency for converting energy for maintenance (km) of 0.65. Most of the literature data on energy requirements for the maintenance for this animal category were obtained from studies conducted with Bos indicus animals and their crossbreds in Brazilian conditions with this confirming lower requirements of these animals when compared to pure Bos taurus cattle. A simulation of the total ME requirements calculated for an Angus × Friesian steer (LW = 416 kg) offered good quality grass silage, indicated that both AFRC and NASEM systems overestimate (38.5 and 20.5%, respectively) the observed efficiency of converting ME for growth (kg). When the total ME requirements (maintenance + growth) were assessed, both systems underpredicted total ME requirement in 15.8 and 22.1 MJ/d. The mean MEm requirements for suckler cows obtained from the literature (0.596 MJ/kg0.75) is on average 19.1% greater than predictions given by both AFRC and INRA (lactation) equations when considering a 550 kg cow and a km value of 0.72. Although no differences in net energy requirements for maintenance (NEm) were detected between dry and lactating suckler cows, as expected the later displayed greater variation as a result of differences in milk production. On this regard, the INRA model recognise increased NEm requirements for lactating animals compared to dry cows. The re-evaluation of the concept of diet metabolisability and the analysis of existing data on compensatory growth responses are recommended for future updates of the British system (AFRC) having in to account the particularities of grass-based systems in the UK.

Determination of Maintenance Energy Requirements for Fattening Castrated Korean Black Goats (Capra hircus coreanae)

Simple SummaryThe energy required for fattening castrated Korean black goats was estimated using the correlation between metabolic energy intake per dietary body weight and average daily gain per dietary body weight. The Y-axis intercept value was the metabolic energy requirement for maintaining the lives of the fattening Korean black goats. It was calculated to be 108.76 kcal/kg BW0.75 (p < 0.05, r2 = 0.6036).Twelve adult (10 months old) castrated Korean black goats, with an average initial body weight of 24.98 ± 3.7 kg, were used in this experiment to determine their maintenance energy requirements. Dry matter intakes (g/d, p = 0.945) were not affected by energy levels, but metabolic energy intake (kcal/d, p < 0.002) and average daily gain (g/d, p < 0.001) were significantly increased at higher energy levels. Nutrient digestibility was similar in the treatments, but crude fat digestibility increased with the addition of protective fat powder (p = 0.001). The energy required for fattening the castrated Korean black goats was estimated using the correlation between metabolic energy intake per dietary body weight and average daily gain per dietary body weight. The Y-axis intercept value was calculated to be 108.76 kcal/kg BW0.75 (p < 0.05, r2 = 0.6036), which was the metabolic energy requirement for maintaining the lives of the fattening Korean black goats. The estimated energy requirements of the black goat can improve specification techniques, such as the energy level and the amount of feed supply required for domestic black goats.

Determination of maintenance energy requirement and responses of dry ewes to dietary inclusion of lucerne versus concentrate meal

An accurate value for metabolizable energy (ME) requirement for maintenance (MEm) is essential to enable sheep husbandry practice to reach its potential. The objectives of the study were to use calorimetry chamber data of dry ewes (Hu × thin-tail Han F1 crossbred) to develop updated MEm, examine effects of substituting concentrate feed with lucerne hay on energy partitioning, and explore the relationships between energy utilization and fasting heat production (FHP). Data were collected from three experiments. In Exps. 1, 2a and 2b, lucerne hay was used to replace concentrates in three levels (0:40%, 15:25% and 30:10%), with diets containing 60% maize stover (Exp. 1), fresh rye forage (Exp. 2a) or dry rye forage (Exp. 2b). Within each experiment, diets were isoenergetic (digestible energy, DE) and isonitrogenous. Exp. 3 aimed at evaluating effects of three BW levels on nutrient utilization of dry ewes offered diets containing 60% maize stover, 15% lucerne hay and 25% concentrates. Energy metabolism data were measured using the respiration calorimeter chamber technique in all three experiments, followed by the measurement of FHP in Exps. 1, 2b and 3. The MEm derived from the linear regression between energy balance (EB) and ME intake was 0.440 MJ/kg BW0.75. The average FHP was 0.326 MJ/kg BW0.75. The fasting metabolism, net energy requirement for maintenance (NEm) and MEm were estimated to be 0.336, 0.359 and 0.511 MJ/kg BW0.75, respectively, through adjustment of FHP using fasting urinary energy output, activity allowance and efficiency of ME use for maintenance. The FHP was negatively correlated to EB/metabolic BW, ME/gross energy (GE), ME/DE, EB/GE intake and EB/ME intake, while positively correlated to HP/GE intake, HP/ME intake and CH4-E/GE intake. Compared to zero lucerne hay diet, the 15% lucerne hay intake decreased HP (MJ/d), and had no negative effects on EB (MJ/d) or energy utilization efficiencies. The results indicate that nutrient requirement standards currently used across the world are likely to underestimate MEm for dry ewes, and the selection of low FHP ewes for breeding has the potential to improve sheep production efficiency.

Foraging behaviour of gestating sows on pasture and damages to vegetation cover are influenced by restriction of concentrate feed

One of the main challenges of outdoor pig production systems is their potential environmental impact due to direct deposition of pigs’ excreta on the land that can lead to nitrate leaching. However, plants can recycle nutrients, and a sufficient vegetation cover can mitigate adverse environmental impacts of outdoor pigs. The aim of this study was to investigate the impact of concentrate feed restriction on gestating sows foraging behaviour and ensuing damages caused to vegetation cover in a pasture-based system. Ten groups of three sows were randomly assigned to two concentrate feed levels, supplying either 90 % (P90) or 40 % (P40) of metabolizable energy requirements, from week 5 of gestation until farrowing. All groups of sows were housed at a density of 8 sows/ha in a rotational pasture system including a permanent area and three 25 × 50-m legume-grass pasture plots, which could be accessed in rotation for periods of 2–3 weeks. Posture and location of sows were assessed at weeks 8–9, 12–13 and 15 of gestation using data loggers. During the same weeks, video recordings were made when the sows were at pasture, in order to determine their time spent foraging. Vegetation cover of pasture plots was determined at the beginning and end of the grazing periods using a method based on Unmanned Aerial Vehicle-acquired image processing. In the second half of gestation, P40 sows spent 60 % more time active on pasture than P90 sows during the daytime (P < 0.01). The feeding level did not influence the number of daily visits to pasture plots, but P40 sows spent more time on pasture and travelled longer distances per visit than P90 sows. While at pasture, P90 sows spent more time rooting (P < 0.001) and less time grazing (P = 0.002) than P40 sows. In pasture plots with P90 sows, an increasing proportion of bare soil was observed over time, whereas in P40 plots, a greater proportion of high vegetation was replaced by medium vegetation. These results indicate that a higher concentrate restriction promoted grazing behaviour in pregnant sows, leading to greater disappearance of high vegetation but not to greater vegetation cover destruction. In contrast, the lower concentrate restriction increased the proportion of rooting activity, leading to greater damage to vegetation cover. In conclusion, this study has shown that concentrate feeding level of gestating sows on pasture can be reduced without adverse effects on pasture vegetation cover.

The Deviation between Dairy Cow Metabolizable Energy Requirements and Pasture Supply on a Dairy Farm Using Proximal Hyperspectral Sensing

This study aimed at determining the extent to which the deviation of daily total metabolizable energy (MEt) requirements of individual cows from the metabolizable energy (ME) supplied per cow (DME) varied throughout the production season in a pasture-based dairy farm using proximal hyperspectral sensing (PHS). Herd tests, milk production, herbage and feed allocation data were collected during the 2016–2017 and 2017–2018 production seasons at Dairy 1, Massey University, New Zealand. Herbage ME was determined from canopy reflectance acquired using PHS. Orthogonal polynomials were used to model lactation curves for yields of milk, fat, protein and live weights of cows. Daily dietary ME supplied per cow to the herd and ME requirements of cows were calculated using the Agricultural Food and Research Council (AFRC) energy system of 1993. A linear model including the random effects of breed and cow was used to estimate variance components for DME. Daily herd MEt estimated requirements oscillated between a fifth above or below the ME supplied throughout the production seasons. DME was mostly explained by observations made within a cow rather than between cows or breeds. Having daily estimates of individual cow requirements for MEt in addition to ME dietary supply can potentially contribute to achieving a more precise fit between supply and demand for feed in a pasture-based dairy farm by devising feeding strategies aimed at reducing DME.

Rumen biohydrogenation and milk fatty acid profile in dairy ewes divergent for feed efficiency

A sustainable increase in livestock production would require selection for improved feed efficiency, but the mechanisms underlying this trait and explaining its large individual variation in dairy ruminants remain unclear. This study was conducted in lactating ewes to test the hypothesis that rumen biohydrogenation (BH) would differ between high- and low-efficiency animals, and these differences would be reflected in rumen fatty acid (FA) profile and affect milk FA composition. A second aim was to identify differences in FA that may serve as biomarkers of feed efficiency. Data of daily feed intake and milk yield and composition, as well as body weight, were collected individually over a 3-wk period in 40 ewes. The difference between the mean actual and predicted feed intake (estimated through metabolizable energy requirements for maintenance, production, and body weight change) over the period was used as the feed efficiency index (FEI) to select 8 of the highest feed efficiency (H-FE) and 8 of the lowest feed efficiency (L-FE) animals. In addition, residual feed intake (RFI) was estimated as the residual term from the regression of feed intake on various energy sinks. Rumen and milk FA composition were characterized by using gas chromatography, and results were analyzed using a statistical model that included the fixed effect of the group (H-FE vs. L-FE). The FEI averaged -0.29 ± 0.046 and 0.81 ± 0.084 in H-FE and L-FE, respectively, whereas RFI averaged -0.16 ± 0.084 and 0.18 ± 0.082, respectively. The correlation coefficient between both metrics was 0.69. Feed intake was similar in both groups, but H-FE showed greater milk yield, with increases in lactose content and yield, and in milk protein and fat production. Results from rumen FA profiles included a lower proportion of 18:2n-6, cis-9 18:1, and of several of their BH metabolites, and a greater concentration of 18:0, which may indicate that the apparent BH would be more complete in more efficient sheep. Milk FA analysis suggested that the greater fat yield in the H-FE group was mostly explained by increased de novo FA synthesis, whereas their milk would have lower proportions of cis-9 18:1 and C20 to 22n-6 polyunsaturated FA than L-FE. Stepwise multiple linear regression suggested that milk C20 to 22n-6 PUFA might be convenient biomarkers to discriminate more efficient dairy sheep. Further research is needed to validate these findings (e.g., under different dietary conditions).

Modeling the Effects of Calcium Overload on Mitochondrial Ultrastructural Remodeling.

Mitochondrial cristae are dynamic invaginations of the inner membrane and play a key role in its metabolic capacity to produce ATP. Structural alterations caused by either genetic abnormalities or detrimental environmental factors impede mitochondrial metabolic fluxes and lead to a decrease in their ability to meet metabolic energy requirements. While some of the key proteins associated with mitochondrial cristae are known, very little is known about how the inner membrane dynamics are involved in energy metabolism. In this study, we present a computational strategy to understand how cristae are formed using a phase-based separation approach of both the inner membrane space and matrix space, which are explicitly modeled using the Cahn–Hilliard equation. We show that cristae are formed as a consequence of minimizing an energy function associated with phase interactions which are subject to geometric boundary constraints. We then extended the model to explore how the presence of calcium phosphate granules, entities that form in calcium overload conditions, exert a devastating inner membrane remodeling response that reduces the capacity for mitochondria to produce ATP. This modeling approach can be extended to include arbitrary geometrical constraints, the spatial heterogeneity of enzymes, and electrostatic effects to mechanize the impact of ultrastructural changes on energy metabolism.

Feed Quality and Feeding Level Effects on Faecal Composition in East African Cattle Farming Systems.

Simple SummarySub-Saharan cattle are often exposed to a feed reduction caused by a seasonal lack of forage, which was investigated in the first experiment. The supplementation of roughage-based diets with sweet potato vine silage and urea molasses blocks is recommended to improve the growth of heifers, in particular, which was investigated in the second experiment. Across all data, the fungal C/bacterial C ratio was positively related to nitrogen and negatively to neutral detergent fiber concentrations in feces. This diet-induced shift in the fecal microbial community is relevant for the fertilizer quality of cattle faces after application to soil.Effects of feeding levels below maintenance requirements of metabolizable energy (MER) and of feed supplementation on fecal nutrient and microbial C concentrations were evaluated. In experiment 1, Rhodes grass hay only was offered to Boran steers at 80%, 60%, and 40% of individual MER, while steers at 100% MER additionally received a concentrated mixture. This reduction in MER decreased N, increased fungal C but did not affect bacterial C concentrations in feces. In experiment 2, Holstein × Boran heifers were offered a poor-quality roughage diet without supplement, with sweet potato vine silage or with a urea-molasses block. These two supplements did not affect the fecal chemical composition or fungal C but increased bacterial C concentrations in feces. Across all data, the fungal C/bacterial C ratio was positively related to N and negatively to neutral detergent fiber concentrations in feces, indicating diet-induced shifts in the fecal microbial community.

Growth Curve and Energy Intake in Male and Female Cats

The aim of this study were (1) to characterize the growth curve in male and female cats, (2) to associate the growth and metabolizable energy intake (MEI) as an indirect measurement of the energy requirements, and (3) to determine the short-term effects of neutering on energy intake to maintain the bodyweight in young adult cats. Eighteen 5-months-old mixed breed cats were used in this study (males, n = 7 and BW = 2.2 ± 0.21 kg; females, n = 11 and BW = 2.0 ± 0.16 kg). The cats were fed to supply their metabolizable energy requirement for growth, adjusting the amounts to maintain an ideal body condition score. The animals were weighed every 15 days for 10 months (from 5 to 15 months old). At 12 months old, the cats were gonadectomized and the MEI was recorded for 3 months, up to 15 months old. Second-order, Gaussian, and spherical models were fitted to growth data. Male cats had higher energy intake for growth (MEI = 176.27−0.037t, R2 = 0.79) than females (MEI = 166.86−0.044t, R2 = 0.62), where t is the age in months. Male cats also reached mature weight later than female cats (16 and 13 months old, respectively). Neutering reduced the energy requirements of male (intact – 116.43 kcal/kg0.67; gonadectomized – 98.65 kcal/kg0.67; P < .01) and female cats (intact – 98.65 kcal/kg0.67; gonadectomized – 76.16 kcal/kg0.67; P < .01) on average 17.6%. This study suggests that in cats, males and females present different energy requirements since the early growth phases and, this difference remains after neutering in young adults. Female cats reach adult weight earlier than males.

INFLUENCE OF CONCENTRATE SUPPLEMENTATION WITH BROWSE PLANT (GLIRICIDIA SEPIUM) ON NUTRIENT UTILIZATION AND GROWTH OF THE WEST AFRICAN DWARF (FOUTA DJALLON) KIDS

TWELVE West African dwarf (Fouta Djallon) kids, 4 to 6 months of age and weighing between 5.96 and 7.24kg, were used in the study of three dietary treatments involving a basal diet of browse plant (gliricidia Septum) supplemented with concentrate feed at 25 and 50% levels of dry matter intake to appetite. The diets were fed for a period of three months in order to estimate nutrient intake and utilization, protein and energy requirements including growth performances of the kids. Kids maintained on gliricidia sepium alone (G1000CO) needed significantly (P/0.05) more dry matter (DM) consumption to appetite (294.66 ± 14.941 g/day) than kids maintained on either 75% gliricidia sepium plus 25% concentrate (G75 C25) or 50% gliricidia sepium plus 50% concentrate (GC)50 (236.26±0.385kg) than either kids on treatments G100C0 or (GC)50 (6.84±0.214 and 6.92±0.313kg respectively). DM intake as a percentage of liveweight was about 3.60 +0.237%. The kids were in positive nitrogen balance and the nitrogen retention value ranged from 31.36 ±1.633 to 50.22 ±0.994%. Metabolic faecal nitrogen (MFN) and endogenous urinary nitrogen (ENU) were 0.232±0.005g/100g DM intake and 0.070 g/day wkg734 respectively. The biological value (BV) of the diets ranged from 56.79 to 75.62%. The digestible crude protein (DCP) requirement for maintenance was 0.853±0.133 g/day/wkg734 while the DCP requirement for liveweight gain was 0.030±0.001 g/day/wkg734 per g of liveweight gain. The digestible energy (DE) and metabolizable (ME) energy requirements for maintenance were 124.42±3.274 kcal/day/wkg734 and 100.78 + 4.588 kcal/day/wkg734 respectively. Results showed that the utilization of the browse plant (gliricidia sepium) by the kids was best when fed at 75% browse plus 25% concentrate.

Evaluation of the net energy for lactation system and estimation of the energy requirements of dairy cows based on a comprehensive analysis of feeding trials

ABSTRACT Respiration experiments with high-yielding dairy cows in Northern Ireland have shown higher energy maintenance requirements than those used in the requirements standards of, e.g. France, UK, USA and Germany. Therefore, the current net energy for lactation (NEL) system of Germany was tested by comparing measured NEL intake with calculated NEL requirements based on a comprehensive dataset from feeding trials conducted at nine research institutions in Germany, Austria and Switzerland. The relationship between NEL requirements and NEL intake is described by the equation: The equation indicates a systematic over-estimation of NEL requirements in the lower performance range and an under-estimation at higher energy intake levels. A multiple regression analysis was conducted by calculating metabolisable energy (ME) requirements [MJ/d] using metabolic body size (MBS) [kg0.75], milk energy performance (LE) [MJ/d] and body weight change (BWC) [kg/d]: These results indicate that the energy maintenance requirements are markedly higher than presumed in the feed evaluation systems commonly in use but confirm the results from Northern Ireland (0.600–0.660 MJ ME/kg0.75 MBS). ME efficiency for lactation is also higher (kL = 1/1.37 = 0.73) than that used in the systems and is also similar to the results of Northern Ireland with 0.64–0.69. The energy contribution of BWC derived by this equation is 12.1 MJ/kg (16.6 · 0.73) and distinctly lower than that of 21–25 MJ/kg presumed by the feeding standards, e.g. in Germany. Further, maintenance requirements were linked to milk yield (energy corrected milk (ECM) [kg/d]), as is practiced in the standard Australian energy system: These results demonstrate that maintenance energy requirements are partly dependent on milk yield. A differentiated analysis by stage of lactation showed that the regressions coefficients for MBS, LE and BWC change with lactation month; however, these findings apply especially to the first lactation months (i.e. in phases of intensive mobilisation).

How to build a synthetic digestive system for Marvel's Vision

Vision is a synthezoid (android or synthetic human), a member of the Avengers, and constantly striving to be more human. In the films of the Marvel Cinematic Universe, Vision is based on advanced robotics and bioengineering technologies. However, his body contains biological cells, and his external appearance consists of eyes, a mouth, a nose, teeth, and fingernails; traditional human attributes. Unlike humans, Vision does not eat as his metabolic energy requirements are met by a fictional alien artefact known as the Mind Stone. Nonetheless, given that Vision has eyes and a tongue, could he also have other organs? Does his body contain the organs for a synthetic digestive system? And if so, how would these organs meet his body’s metabolic energy needs? In this paper, we show how advancements in soft robotics (compliant robotic technologies made from highly deformable materials) can be combined to build an artificial digestive system. We consider the primary systems of the human digestive system – the oesophagus, stomach, intestines, and waste disposal. We show that an artificial digestive system is possible, but additional technologies are needed to support the underlying soft-robotics technologies.

Effect of increasing dietary proportion of plantain on milk production and nitrogen use of grazing dairy cows in late lactation

Abstract Context Plantain has shown promise as a forage that can mitigate nitrogen (N) losses from farm systems, although adoption and regulation requires knowledge of the minimum amount of forage area or diet quantity to observe an effect. Aims A grazing study was conducted to evaluate the effect of offering increasing proportions of spatially adjacent plantain (PL) and perennial ryegrass–white clover (PRGWC) on milk production and N utilisation of dairy cows. Methods Forty-eight late lactating cows blocked into replicated (n = 3) groups of four cows were randomly allocated to one of the following four forage treatments based on percentage area of plantain: 0%, 15%, 30%, or 60%. Cows were allocated 25 kg DM/cow.day of forage above ground level daily on the basis of metabolisable energy requirements. Dry matter intake was estimated from the difference between pre- and post-grazing pasture mass, using a calibrated electronic rising-plate meter. Milk production was measured as yield and milk solids, while N use was estimated from total milk N excretion and spot subsamples of blood, urine and faeces. Key results Offering cows spatially adjacent strips of PL increased apparent dry matter intake compared with PRGWC pasture alone (16.4 vs 15.1 kg DM/cow.day, P = 0.027) and apparent metabolisable energy intake (203 vs 188 MJ/kg.cow.day, P &lt; 0.001). Milk yield (16.1 kg/cow.day), milk solids production (1.6 kg/cow.day) and fat concentration (5.69%) were unaffected by the proportion of plantain in the diet. PL offered at 60% of the area increased milk protein concentration compared with PRGWC (4.65 vs 4.36%, P &lt; 0.01). There was no treatment effect on total apparent N intake (563 g N/cow.day), N excretion in milk (113 g N/cow.day) and N-utilisation efficiency (20 g milk N/100 g N consumed). However, total milk urea, blood urea and urine urea N concentrations declined with increasing plantain in the diet, reflecting an influence on urea metabolism. Conclusions Offering plantain to grazing dairy cows did not improve milk yield or N-use efficiency, but influenced urea metabolism. Implications Sowing plantain in spatially separate strips within perennial ryegrass–white clover pastures is a useful option to achieve target levels of plantain in the diet and, in conjunction with other mitigation strategies, can be used to improve the sustainability of pastoral dairy farming.

Moderate over-feeding of different sources of metabolizable energy and protein improved gestational insulin resistance markers and maternal metabolic status of sheep around lambing

The objective of this study was to determine the effect of moderate over-nutrition of energy (using flaxseed as a source of n-3 fatty acids) and protein (using rumen-protected lysine and methionine) around parturition on prepartal insulin resistance (IR) and periparturient metabolic status and performance of ewes. For this purpose, 32 apparently healthy ewes (2.5 ± 1 years old, 42.19 ± 1.65 kg body weight (BW)) were randomly selected out of 200 pregnant Zell ewes on d 50 before the expected lambing. After receiving a ten-day adaptation diet, eight ewes were randomly allocated to one of the following four dietary treatments: 1) the adaptation diet that meets the metabolizable energy (ME) and protein (MP) requirements of ewes during late pregnancy as recommended by National Research Council = NRC (2007) (Control = CON). 2) A diet with 10% higher levels of ME than NRC (2007) recommendations using corn grain as a source of extra ME (HEC). 3) A diet with 10% higher levels of ME compared to NRC (2007) recommendations using flaxseed for additional ME (HEF). 4) A diet with a 10% higher level of MP than NRC (2007) recommendations using rumen-protected lysine and methionine as a source of extra MP (PRO). While the dietary treatments did not affect animals’ dry matter intake (DMI), the CON ewes lost more BW starting from d 10 to d 30 relative to parturition compared to others (P < 0.05). Milk protein and fat yield (g/d) were significantly higher for PRO and HEF compared to HEC and CON ewes (P < 0.05). Moderately over-fed ewes with MP and ME had an improved insulin sensitivity (IS) compared to CON ones. The source of additional ME also impacted IR indices because HEC showed an enhancement in IS than HEF animals (P < 0.05). A lower IS in CON ewes was parallel with higher concentrations of plasma urea at prepartum (P < 0.01), lower levels of plasma cholesterol, triglyceride (P < 0.01) and glucose post-partum (P < 0.05), and a tendency for higher levels of beta-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) in CON ewes during both pre- and post-partum periods. There were negative correlations between plasma urea, BHB, and NEFA with IR markers on d 7 prepartum in line with these results. Comparing data, we could not find a significant change in metabolic status among ewes fed with either PRO or HEF/HEC. In conclusion, the inclusion of 10% extra MP and ME could improve late gestation maternal IS and the metabolic status of dams around lambing.

Effect of dietary protein to energy ratio on growth performance of pre-and post-weaned lambs

Milk replacers adjusted for crude protein to metabolizable energy (CP:ME) ratio to match the lambs’ changing requirement during first few weeks post-birth have resulted in higher pre-weaning lamb growth rate compared to commercial milk replacers with a static CP:ME ratio. This study aimed to determine if milk replacer with an adjusted CP:ME ratio to meet the lambs changing CP:ME requirement over time improved lambs growth performance during both the pre-and post-weaning periods. Twenty-seven Romney twin-born ram lambs were assigned to one of two pre-weaning milk feeding treatments: i) a commercial milk replacer (CMR, n = 14; CP:ME 12.28 g/MJ); or ii) a regularly adjusted blend of commercial milk replacer and milk protein concentrate (MB, n = 13; CP:ME starting at 16.6 g/MJ and adjusted down to approximately 13 g/MJ). All lambs were fed at 2.1 times their maintenance energy requirement. The CP:ME ratio of the MB treatment was adjusted twice-weekly to match the changing CP:ME requirements. All the lambs had ad libitum access to pellets. Lambs were weaned at 22 kg live weight (LW), transferred to a ryegrass and white clover-based pasture and reared approximately to 46 kg LW. The LW during pre- and post-weaning was recorded twice weekly and fortnightly, respectively. In the pre-weaning period, total daily CP intake and daily CP intake from milk were greatest (P < 0.05) in MB compared to CMR lambs. Daily ME intake of lambs in the pre-weaning period did not differ (P> 0.05) between treatments. Lambs fed MB had greater total and milk CP:ME intake (P < 0.0001), compared to CMR lambs. Average daily LW gain (ADG) during the pre-weaning phase did not differ (P> 0.05) between treatments. The ME intake per kilogram LW gain during the pre-weaning did not differ (P > 0.05) between treatments. The CP intake per kilogram LW gain during the pre-weaning was higher (P < 0.05) for MB lambs than CMR lambs. In the post-weaning period lamb LW gain and ADG did not differ (P> 0.05) between treatments. There was no correlation (P > 0.05) in overall ADG of lambs between pre-and post-weaning periods. The ADG during day one to ten at the start of experiment had a positive and significant effect on the overall post-weaning ADG (r = 0.570, P = 0.007) and ADG in first two weeks (r = 0.470, P = 0.032) of the post-weaning phase. Similar pre-and post-weaning growth rates were observed for lambs in both treatment groups, despite the pre-weaning adjustment of CP:ME to meet lambs requirements. The CMR feeding was cost effective as the pre-weaning feed cost per kilogram live weight gain was lower than that of milk blend feeding. As CMR lambs likely obtaining additional CP from pellet intake during pre-weaning, further research is warranted on the effect of CP:ME ratio of pellets, pellet intake and digestibility on growth performance of lambs reared artificially.