Nutrient and energy retention in weaned Iberian piglets fed diets with different protein concentrations

Fifty-eight purebred castrated male Iberian (IB) piglets (initial BW 9.9 ± 0.1 kg) were used in an experiment to determine the effect of dietary protein content (PC) and feeding level (FL) on the rates of BW gain, whole body protein deposition (PD), and energy utilization between 10 and 25 kg of BW using the serial slaughter method. Treatments followed a 4 × 2 factorial arrangement with 4 PC (201, 176, 149, and 123 g of CP/kg of DM) and 2 FL (0.95 and 0.70 × ad libitum) and 6 or 7 piglets per combination of treatments. All diets were formulated to have an optimal AA pattern. Six piglets were slaughtered at the start of the trial to estimate initial body composition. The experimental pigs were individually housed in an environmentally controlled room (27 ± 2°C) until they reached 25 kg of BW, when they were slaughtered and analyzed for body composition. Positive linear effects of dietary PC on ADG, G:F, and gain:ME intake were observed (P < 0.001). Piglets fed at the highest FL showed greater ADG, G:F, and gain:ME intake (P < 0.001). An average increase was estimated to be 38.0 g of gain/MJ of ME intake. Protein deposition increased linearly from 35.6 to 50.9 g/d with increasing dietary PC (P < 0.001). A daily increase was estimated to be 0.35 g of PD/g of CP intake. Although the maximal genetic potential for PD of the IB piglet was not attained, a maximal value of 59.9 g/d for whole-body PD was achieved when the diet provided 201 g of CP/kg of DM and was fed at 0.95 × ad libitum. Piglets on the highest FL deposited on average 39% more body protein (P < 0.001) than restricted piglets. An average value of 4.39 g increase in PD/MJ of ME intake was obtained for diets containing 201 and 176 g of CP/kg of DM. Maintenance energy requirements and net efficiency of utilization of ME for growth, calculated by linear regression of ME intake on body retained energy, were 427 kJ/kg of BW(0.75)·d(-1) and 0.552, respectively. The corresponding partial efficiencies of utilization of ME for protein and fat deposition were 0.378 and 0.672, respectively, considerably less than the accepted values for conventional pig breeds. Practical diets of the young IB piglet should contain at least 201 g of ideal CP/kg of DM.     

Feeding cluster preferences in four genera of Lories and Lorikeets (Loriinae) that should be considered in the diet of nectarivorous psittacine species in captivity

Lories and lorikeets are popular birds in the pet bird trade, captured from the wild and exported worldwide. Their captive propagation has not been so successful for many species due to health issues, low breeding success and reduced longevity. As a result, uptake from the wild is currently the only way to meet the market’s demand. Field studies on Asian species of loris and lorikeets are limited; therefore, dietary recommendations are based on the well‐studied Australian species such as the rainbow lorikeet (Trichoglossus moluccanus). We aimed to provide an ad libitum diet to diverse Loriinae species at Jurong Bird Park (Singapore) which allowed for them to select between a low and moderate protein diet to compare their nutrient and energy intake with other Loriinae species. We measured the following variables: daily dry matter (DM) intake, nectar‐to‐fruit energy intake ratio (NF ratio), metabolisable energy (ME), protein and non‐protein energy (NPE)‐to‐protein energy (PE) ratio intake (all by kg metabolic body weight MBW, kg^0.75) for 36 pairs over a 1‐month period. A Kruskal–Wallis test revealed every genus had significantly different intakes of DM, NF ratio, NPE‐to‐PE ratio, ME and protein than each other. Post hoc Mann–Whitney U tests confirmed that the majority of variables were ingested in different amounts for each genus except for NF ratio, NPE/PE ratio which Lorius spp. are not different to Charmosyna sp. or Trichoglossus spp. and protein intake of Eos spp. does not differ from Trichoglossus spp. Our conclusion is that no species should be used as a model for a species from another genus of Loriinae; future studies should be species‐specific for each genus to increase captive propagation success.     

No effect of moderate or high concentrate allowance on growth parameters in weanling Warmblood foals fed late‐cut haylage as forage

Two groups of Warmblood foals from the Bavarian federal stud participated in the study beginning from the age of approximately 6 months. The foals were offered a late 1st cut of haylage, oats and foal starter feed. For 2 months after weaning, group ‘R’ (15 foals) received an amount of oats to provide a total digestible energy supply meeting the recommendations of the German Society of Nutrition Physiology (GfE), whereas the other group ‘A’ (16 foals) was offered a higher amount of oats (surplus of approximately 1.3 kg/animal/day). Concentrates were fed individually twice daily; total daily haylage intake of all foals together was recorded. In both groups, individual concentrate intake, body weight (BW), body condition score (BCS) and several growth parameters were documented. Both groups showed an absolutely parallel development of the measured growth parameters and of BW and BCS. BW and BCS increased above the recommendations of GfE and Hois. The amount of concentrates offered was not ingested completely in both groups. The average metabolisable energy (ME) intake from concentrates amounted to 30.3 and 32.1 MJ ME/animal/day (group ‘R’) and 38.7 and 38.2 MJ ME/animal/day (group ‘A’) for the 7th and 8th month respectively. The mean haylage intake of all foals together equalled 26.2 MJ ME/animal/day. The parallel development of all documented growth parameters in both groups leads to the assumption that higher concentrate intake must have caused lower intake of haylage and vice versa, thus resulting in an overall comparable energy intake for each foal, independently of energy source. The calculated average daily energy intake for all foals together amounted to 60.5 and 61.4 MJ ME/animal for the 7th and 8th month. The mean crude protein intake in both groups together amounted to 640 and 647 g/animal/day for the 7th and 8th month.     

Effect of a diet high in energy and protein on growth,carcase characteristics and parasite resistance in goats

The effects of a high-energy and high-protein diet on growth, parasite resistance and carcase characteristics were studied using local goats with an average initial body weight (BW) of 12.0 (SD = 0.7) kg. Thirty-two animals were allocated to a completely randomized factorial design, with four animals of each sex per treatment. The factors were: two diets (diet H with high content of crude protein (CP) and metabolizable energy (ME), and diet L with low content of CP and ME) and deworming (DW) or non-deworming (NDW). The highest dry matter (DM) intake was obtained for goats fed diet H combined with DW, but there was no significant difference between DW or NDW for goats fed diet H. The goats fed diet L and DW had significantly better total DM intake than NDW goats. The average daily gain of animals fed diet H was 86 and 92 g/day compared to 27 and 40 g/day for diet L, for NDW and DW animals, respectively. Feeding diet H resulted in higher slaughter weight and consequently also higher empty BW, carcase weight and dressing percentage and lower feed conversion ratio. Dewormed animals had significantly higher empty BW than NDW animals. There were significant effects of diet and parasite control on Faecal egg count (FEC: number of parasite eggs per gram of faeces (e.p.g.)), with NDW animals fed diet L having higher FEC than animals fed diet H.     

Evaluation of bovine rumen contents as a feed for lambs

This study evaluated effects of increasing levels of dried rumen contents (DRC) on voluntary intake, growth performance, digestibility, nutritive value, N utilization, microbial protein supply (MPS), and purine derivatives excretion (PDE) of lambs fed with Afzelia africana basal forage. Sixteen lambs (13.7?±?0.1 kg body weight (BW)) were randomly assigned to one of the four eight diets containing 0, 200, 400 and 600 g DRC/kg dry matter (DM) in a completely random design. Intakes of concentrate, DM, crude protein (CP), organic matter (OM), digestible CP (DCP), digestible OM (DOM), digestible energy (DE) and metabolizable energy (ME), CP and OM digestibility, DOM, DCP, DE, ME, N intake and retention, weight gain, cost/kg BW gain, MPS and PDE increased with increasing DRC level up to 400 g/kg DRC and declined at 600 g/kg DRC (P?<?0.05; 0.01). Feed conversion ratio and DM digestibility declined as DRC level increased from 0 to 400 g/kg and peaked at 600 g/kg DRC (P?<?0.05; 0.01). Forage intake and DE/DCP ratio decreased (P?<?0.05; 0.01) progressively with increasing DRC level. Results indicate that DRC can be incorporated up to 400 g/kg in a compounded ration for sheep.     

Feeding different dietary protein to energy ratios to Holstein heifers: effects on growth performance,blood metabolites and rumen fermentation parameters

Eighteen Chinese Holstein heifers average age 230 ± 14 days were allocated to 1 of 3 dietary crude protein (CP) to metabolizable energy (ME) ratios to examine the effects on growth performance, blood metabolites and rumen fermentation parameters with 90‐days experiment. Three different dietary CP:ME ratios were targeted based on the formulation of dietary CP contents of 10.85%, 12.78% and 14.63% on dry matter (DM) basis with similar ME contents (10.42 MJ/kg DM), which were categorized as low, medium and high dietary CP:ME ratios. The actual CP:ME ratios obtained in this study significantly increased from low to high CP:ME ratio groups with a value of 10.59, 11.83 and 13.38 g/MJ respectively. Elevated CP:ME ratios significantly increased CP intake (kg/day) and feed efficiency (FE) which was defined as dry matter intake as a proportion of average daily gain (ADG), whereas little difference was observed in body weight (kg), ADG (kg/day), DM intake (kg/day) and ME intake (MJ/day) among the three different CP:ME ratio groups. Increasing dietary CP to ME ratios significantly increased CP digestibility, whereas digestibility of DM and gross energy remained constant in the current experiment. Blood urea nitrogen and insulin‐like growth factor‐1 linearly increased with increasing dietary CP:ME ratios. There was significantly dietary treatment effect on rumen fermentation parameters including acetate, propionate, butyrate and total volatile fatty acids. Therefore, this study indicated that increasing dietary CP levels with similar energy content contributed to increased protein intake and its digestibility, as well as FE. Holstein heifers between 200 and 341 kg subjected to 13.38 dietary CP:ME ratio showed improved feed efficiency, nutrient digestibility, some blood metabolites and rumen fermentation characteristics for 0.90 kg/day rate of gain.     

Efficiency of utilisations of food energy by female growing minks

The efficiency of utilisation of food energy by female growing minks, from weaning to adult age, was studied. The food given, pelleted according to an original technology, has the following chemical composition on a DM basis: 87.0% organic matter, 37.1% crude protein, 11.7% crude fat, 2.6% crude fiber, 35.6% nitrogen-free extractives and 13.0 per cent ash. Young minks had a feed intake, in relation to body weight, warying from 11.6 g to 58.6 g DM/d. Maximum feed intake related to kg0.75 was recorded at 700 g body weight (approximately 98 g DM/kg0.65). Digestibility of the given food expressed in DE, averaged 87.7 +/- 1.2%, while metabolizability, 82.3 +/- 1.1%. Total heat production related to the intaked gross energy, was 48.0 +/- 3.0%, and the retained energy, 34.3 +/- 4.0 per cent. The net efficiency of the metabolizable energy used for maintenance and production could not be accurately determined. However, taking to account the calculated values required for maintenance, of 649 kJ/kg0.75 in 300 to 600 g young minks, and of 607 kJ/kg0.75 in 600 to 1100 g young minks and also the maintenance efficiency, Km = 0.75, the coefficient for ME utilisation in protein and fat synthesis, of 0.50 and 0.75, respectively, it was able to determine the average ME efficiency used as net energy for maintenance and production: 70%. The highest values of nictemeral metabolism were recorded in the evening, and the lowest ones, at noon; the difference between the maximal and the minimal value did not exceed 6 per cent.     

Growth and body composition of dairy calves fed milk replacers containing different amounts of protein at two feeding rates

Previous research has demonstrated that increasing the CP concentration from 16 to 26% in milk replacers fed to male preruminant dairy calves at 1.5% of BW (DM basis) daily resulted in increased ADG, G:F, and deposition of lean tissue. However, the effects of dietary CP would be expected to vary depending on ME intake. Here, male Holstein calves < 1 wk old were used to determine the effects of feeding rate and CP concentration of isocaloric, whey protein-based milk replacers on growth and body composition. After a 2-wk standardization period, calves were assigned randomly to an initial baseline group or to treatments in a 2 x 4 factorial arrangement of feeding rate (1.25 or 1.75% of BW daily, DM basis) and milk replacer CP concentration (14, 18, 22, or 26% of DM). No starter was offered, but calves had free access to water. After a 5-wk feeding period, calves were slaughtered and body composition was determined. Increasing the feeding rate increased (P < 0.05) ADG, G:F, empty-body gains of chemical components and energy, the percentage of fat in empty BW gain and in the final empty body, and concentrations of IGF-I and insulin in plasma. Increasing the feeding rate decreased (P < 0.01) percentages of water and protein in the empty body and decreased urea N in plasma. Increasing dietary CP concentration linearly increased (P < 0.05) ADG, body length, heart girth, and gains of water and protein but linearly decreased (P < 0.05) fat gain. As dietary CP increased, fat content in empty body gain decreased, and water and protein increased. Increasing CP concentration increased (quadratic, P < 0.02) G:F, with greatest efficiencies for calves fed 22% CP. Gross energetic efficiency (retained energy:intake energy) was greater (P < 0.05) for calves fed at 1.75% of BW daily. Efficiency of dietary protein use for protein gain was greater for calves fed at 1.75% of BW daily but was not affected by dietary CP. The ratio of protein gain to apparently digestible protein intake above maintenance decreased as dietary CP increased. Interactions (P < 0.05) of feeding rate and CP concentration for gains of water and protein indicated that when dietary CP was 26% the ME supply limited protein use by calves fed at 1.25% of BW daily. Body composition of preruminant calves can be markedly altered by manipulating the protein to energy ratio in milk replacers. These dietary effects on body composition and growth are not predicted by current NRC standards.     

Effect of supplementing urea-treated barley straw with lucerne or vetch hays on feed intake,digestibility and growth of Arsi Bale Sheep

The study was conducted at Sinana Agricultural Research Center, Ethiopia to assess the supplementation of graded levels of vetch (Vicia dasycarpa `lana’) and lucerne (Medicago sativa,’ Hunter river’) hay on feed intake, digestibility and body weight (BW) change of Arsi-Bale sheep fed urea treated barley straw (UTBS). A 7 day- digestibility and a 90 day- feed intake trials were conducted using 28 and 35 sheep, respectively. The experimental design was a randomized complete block design with seven dietary treatments that consisted of feeding UTBS (T1) as the control treatment, UTBS plus 150, 250 and 350 g dry matter (DM) per day of vetch for T2, T3, T4, respectively and UTBS plus 150, 250 and 350 g DM per day of lucerne for T5, T6 and T7, respectively. Intake of UTBS was not affected (P > 0.05) by inclusion of lucerne hay at 25–35% of daily DM intake. The supplements increased daily intake of total DM, organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) (P < 0.001) as well as apparent digestibility of DM, OM (P < 0.001), NDF (P < 0.01), ADF, crude protein (CP) (P < 0.05) and daily BW gain (P < 0.001). Supplementation with lucerne than vetch hay promoted higher (P < 0.001) CP and ME intakes and daily BW gain. Feeding with the UTBS without supplementation was enough to meet the maintenance requirements of the sheep and allow small BW gain. The results of the study showed that urea treatment of barley straw in conjunction with supplementation of lucerne or vetch hay could serve as a useful strategy in improving smallholder sheep production in the tropics.     

Growth, carcass quality, and protein and energy metabolism in beef cattle with different growth potentials and residual feed intakes

Twenty-four beef steers (predominantly Angus x Hereford, 14 to 18 mo of age, 403 +/- 3 kg of BW), were housed and fed in individual pens for about 122 d. Twelve steers came from a herd that had been selected for growth (high growth; HG) and the other 12 from a herd with no selection program (low growth; LG). Another 6 steers (3 from each group) were slaughtered at the beginning to obtain the initial composition. All steers were fed the same corn-based diet (3.06 Mcal of ME/kg of DM, 13.6% CP) on an ad libitum basis. Two weeks before slaughter, total urine was collected for 5 d for estimation of 3-methylhistidine excretion and myofibrillar protein breakdown rates. Compared with LG steers, HG steers had less initial BW but greater final BW, DMI (7.52 vs. 6.37 kg/d), ADG (1.33 vs. 0.853 kg/d), G:F (0.176 vs. 0.133 kg/kg), ME intake (0.233 vs. 0.201 Mcal x kg of BW(0.75) x d(-1)), and retained energy (RE; 0.0711 vs. 0.0558 Mcal x kg of BW(0.75) x d(-1)); gained more fat (676 vs. 475 g/d); and tended to gain more whole body protein (100 vs. 72 g/d), with no difference in residual feed intake (RFI). Estimated net energetic efficiency of gain (k(g)) and ME for maintenance (ME(m)) did not differ between the 2 groups, averaging 0.62 and 0.114, respectively. The HG steers had greater HCW (350 vs. 329 kg), backfat (16.1 vs. 11.6 mm), and yield grades (3.53 vs. 2.80), with a similar dressing percent, KPH fat, LM area, and marbling score. Skeletal muscle protein gain (70.2 vs. 57.6 g/d) and fractional protein accretion rate (0.242 vs. 0.197%/d) tended to be greater in HG than in LG steers. Steers were classified into low (-0.367 kg/d) and high (0.380 kg/d) RFI classes. Compared with the high RFI steers, low RFI steers consumed less DM (6.61 vs. 7.52 kg/d) and ME (0.206 vs. 0.234 Mcal x kg of BW(0.75) x d(-1)) and tended to gain less fat (494 vs. 719 g/d), but were similar for initial and final BW, ADG, G:F, protein gain, HCW, dressing percent, backfat, KPH fat, LM area, marbling score, and yield grade, as well as for all observations related to myofibrillar protein metabolism. Residual feed intake may be positively [corrected] correlated with ME for maintenance. The maintenance energy requirement increased by 0.0166 Mcal x kg(-0.75) x d(-1) for each percentage increase in fractional protein degradation rate, confirming the importance of this process in the energy economy of the animal.     

Cow/calf preweaning efficiency of Nellore and Bos taurus x Bos indicus crosses

The objectives of this study were to determine if percentage Bos taurus (0 or 50%) of the cow had an effect on ME requirements and milk production, and to compare cow/calf efficiency among 3 mating systems. Metabolizable energy requirements were estimated during a feeding trial that encompassed a gestation and lactation feeding trial for each of 2 groups of cows. Cows were 0 or 50% Bos taurus (100 or 50% Nellore) breed type: Nellore cows (NL; n = 10) mated to Nellore bulls, NL cows (n = 9) mated to Angus bulls, Angus x Nellore (ANL; n = 10) and Simmental x Nellore (SNL; n = 10) cows mated to Canchim (5/8 Charolais 3/8 Zebu) bulls. Cows were individually fed a total mixed diet that contained 11.3% CP and 2.23 Mcal of ME/kg of DM. At 14-d intervals, cows and calves were weighed and the amount of DM was adjusted to keep shrunk BW and BCS of cows constant. Beginning at 38 d of age, corn silage was available to calves ad libitum. Milk production at 42, 98, 126, and 180 d postpartum was measured using the weigh-suckle-weigh technique. At 190 d of age, calves were slaughtered and body composition estimated using 9-10-11th-rib section to obtain energy deposition. Regression of BW change on daily ME intake (MEI) was used to estimate MEI at zero BW change. Increase in percentage Bos taurus had a significant effect on daily ME requirements (Mcal/d) during pregnancy (P < 0.01) and lactation (P < 0.01). Percentage Bos taurus had a positive linear effect on maintenance requirements of pregnant (P = 0.07) and lactating (P < 0.01) cows; during pregnancy, the ME requirements were 91 and 86% of those in lactation (131 +/- 3.5 vs. 145 +/- 3.4 Mcal x kg(-0.75) x d(-1)) for the 0 and 50% B. taurus groups, respectively. The 50% B. taurus cows, ANL and SNL, suckling crossbred calves had greater total MEI (4,319 +/- 61 Mcal; P < 0.01) than 0% B. taurus cows suckling NL (3,484 +/- 86 Mcal) or ANL calves (3,600 +/- 91 Mcal). The 0% B. taurus cows suckling ANL calves were more efficient (45.3 +/- 1.6 g/Mcal; P = 0.03) than straightbred NL (35.1 +/- 1.5 g/Mcal) and ANL or SNL pairs (41.0 +/- 1.0 g/Mcal). Under the conditions of this study, crossbreeding improved cow/ calf efficiency and showed an advantage for cows that have lower energy requirements.     

Effects of growth hormone-releasing factor and feed intake on energy metabolism in growing beef steers: whole-body energy and nitrogen metabolism.

Effects of growth hormone-releasing factor (GRF) on energy and N metabolism in six growing Hereford x Angus steers were measured using a split-plot design with 4-wk injection periods within 8-wk intake periods. Steers were fed a 75% concentrate pelleted diet at two intakes (low: 50 g/BW.75 and high: 90 g/BW.75 as fed) and injected s.c. with saline or 10 micrograms/kg of BW of human GRF(1-29)NH2 twice daily for 3 wk. Measurements of energy and N balance were obtained during wk 3 of treatments. Diet DM digestibility (%) was decreased by greater intake (P less than .05) and increased by GRF (P less than .06). Treatment with GRF increased (P less than .01) N retention by decreasing (P less than .05) fecal and urinary excretion: N retention averaged 10.0 and 20.8 g/d at low intake and 25.9 and 46.7 g/d at high intake for control- and GRF-treated steers, respectively. Increased ME (P less than .05) in GRF-treated steers also resulted from decreased fecal (P less than .05) and urinary (P less than .07) energy excretion but was countered by increased (P less than .06) heat energy (HE). Tissue energy (TE), partial efficiency of ME use for TE retention, and estimated maintenance energy were not affected (P greater than .10) by GRF treatment. In summary, GRF treatment altered the partition of TE by increasing protein retention (108 and 80% for low and high intake, respectively) at the expense of fat retention.     

Pigs weaned from the sow at 10 days of age respond to dietary energy source of manufactured liquid diets and exogenous porcine somatotropin

Previous research indicates that the neonatal pig does not alter feed intake in response to changes in the energy density of manufactured liquid diets. Also, the limited response of IGF-I to exogenous porcine ST (pST) previously observed in young pigs may be influenced by the source of dietary energy. Our objectives were to 1) determine the effect of a high-fat (HF; 25% fat and 4,639 kcal/kg ME; DM basis) or low-fat (LF; 2% fat and 3,481 kcal/kg ME; DM basis) manufactured liquid diet on pig performance; and 2) determine whether the limited response to exogenous pST in young pigs depends on the source of dietary energy. Two replicates of 60 pigs (n = 120; barrows and gilts distributed evenly), with an initial BW of 4,207 +/- 51 g, were weaned from the sow at 10 d of age and used in a randomized complete block design. Pigs were assigned by BW to one of six pens. Diets were formulated to provide a constant lysine:ME ratio and were fed on a pen basis for a duration of 9 d. On d 5, barrows and gilts within a pen were assigned randomly to receive either 0 or 120 microg of pST.kg BW(-1).d(-1) for 4 d. Pigs gained 336 +/- 9 g/d, which resulted in an ending BW of 7,228 +/- 120 g, regardless of dietary treatment (P > 0.15). Pigs fed the LF diet consumed 17% more DM per pen daily than pigs fed the HF diet (2,777 +/- 67 vs. 2,376 +/- 67 g/d, P < 0.01), but calculated ME intake did not differ between dietary treatments (P > 0.20). The G:F was 24% greater in HF- than in LF-fed pigs (P < 0.01). Plasma urea N concentrations were higher in the HF-fed pigs (11.0 +/- 0.6 mg/dL) than in pigs fed the LF diet (6.2 +/- 0.6 mg/dL; P < 0.05). Treatment with pST increased circulating IGF-I (P < 0.01) and decreased PUN (P < 0.01) concentration 32 and 25%, respectively, regardless of dietary treatment (P > 0.30). Circulating leptin averaged 1.8 +/- 0.1 ng/mL and was not affected by dietary treatment (P > 0.35) or pST (P > 0.40). These results suggest that the ST/IGF axis is responsive in the young pig and the increase in circulating IGF-I and growth is independent of the source of dietary energy. Also, young pigs respond to a lower energy density liquid diet with increased feed intake, without altering growth performance, apparently utilizing a mechanism other than circulating leptin.     

Energy components of growth in Holstein steers fed formaldehyde- and formic acid-treated alfalfa or orchardgrass silages at equalized intakes of dry matter

Energy retention was compared in Holstein steers fed either alfalfa or orchardgrass silages for 164 d at either 65 or 90 g DM/kg.75 BW daily in a 2 x 2 factorial. Energy retention was estimated by slaughter-balance using an initial kill of eight steers at 216 kg and a final kill of eight steers per treatment at 326 kg. The ADG was not affected (P greater than .05) by silage, but steers fed alfalfa gained less (P less than .001) gut fill (they lost gut fill) and gained more (P less than .001) of the following than steers fed orchardgrass: empty body, 23%; fat, 50%; fat-free matter, 18%; protein, 16%; water, 17%; ash, 43%; gross energy, 31%; and carbon, 38%. With retained energy at 1.15 Mcal/d, retained energy was equally distributed between fat and protein. Increments of daily retained energy greater than 1.15 Mcal were deposited as 76% to fat and 24% to protein; this distribution was not affected by silage. The energy requirement for maintenance, with BW adjusted to equal gut fill, was not different (P greater than .05) at 130 kcal ME/kg.75 BW for steers fed alfalfa vs 125 for steers fed orchardgrass. Although not significant (P greater than .05), retained energy/ME intake above maintenance was 13% greater for steers fed alfalfa (.261) than for steers fed orchardgrass (.230), which supports the difference observed by calorimetry. The difference in dietary protein (25.6 vs 20.5%) did not contribute to the difference in energy retention because the differences in fat and protein retention could be explained totally by differences in daily energy deposition. The higher NDF of orchardgrass, or other fiber components, seems to be the most probable cause of its somewhat lower partial energetic efficiency relative to alfalfa.     

Energy and protein requirements for maintenance and growth of Boer crossbred kids

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.     

Metabolizable energy value of meat and bone meal for pigs

Metabolizable energy and N-corrected ME (MEn) values of 12 samples of meat and bone meal (MBM) were determined using 288 barrows with an average BW of 35 +/- 3.1 kg. For each of 12 MBM samples, diets were formulated by substituting 0, 50, or 100 g/kg MBM (as-fed basis) in a basal 170 g of CP/kg corn-soybean meal diet; corn and soybean meal were adjusted at the same ratio to account for the substitution. Each diet was fed to eight barrows in individual metabolism crates in metabolism studies that used a 5-d acclimation, which was followed by a 5-d period of total, but separate, collection of feces and urine. The GE, CP, crude fat (CF), ash, Ca, and P contents of the MBM samples, per kilogram (DM basis), ranged from 3,493 to 4,732 kcal, 496.7 to 619.1 g, 91.1 to 151.2 g, 200.3 to 381.9 g, 54.3 to 145.8 g, and 25.6 to 61.7 g, respectively. For each of the 12 MBM samples, MBM intake and MBM contribution to ME and MEn increased linearly (P < 0.05) with increasing level of MBM in the diets. The ME and MEn content of each of the MBM samples was calculated from the slope of the regression of MBM contribution (in kilocalories) to ME and MEn intake, respectively, against quantity (in kilograms) of MBM intake. The ME and MEn of the 12 MBM samples ranged from 1,569 to 3,308 kcal/kg DM and 1,474 to 3,361 kcal/kg DM, respectively. The variation in ME was described by the regression equation: ME = 6,982 + 0.283 GE (kcal/kg) - 6.26 CP (g/kg) - 3.75 CF (g/kg) + 129.47 P (g/kg) - 54.91 Ca (g/kg) - 6.57 ash (g/kg), with an R2 of 0.612 and SD of 376. For MEn, the corresponding equation was: MEn = 3,937 + 1.089 GE (kcal/kg) - 8.74 CP (g/kg) + 3.58 CF (g/kg) + 60.89 P (g/kg) - 15.92 Ca (g/kg) - 9.57 ash (g/kg), with an R2 of 0.811 and SD of 314. Simpler regression equations describing variation in ME or MEn were 9,254 - 7.41 CP (g/kg) - 9.41 ash (g/kg), with R2 of 0.504 and SD of 278; or 12,504 - 10.71 CP (g/kg) - 13.44 ash (g/kg), with R2 of 0.723 and SD of 249. Pearson correlation analysis indicated that the variations in ME and MEn of the MBM samples were not related to any of the major chemical components. The results indicated that variation in each of the chemical components of MBM alone is not the sole determinant of ME or MEn content of MBM, but that the interactions among these components influence energy use in MBM for pigs.     

Growth rates and energy intake of hand-reared cheetah cubs (Acinonyx jubatus) in South Africa

Growth rate is an important factor in neonatal survival. The aim of this study was to determine growth rates in hand-reared cheetah cubs in South Africa fed a prescribed energy intake, calculated for growth in the domestic cat. Growth was then compared with previously published data from hand-reared cubs in North America and the relationship between growth and energy intake explored. Daily body weight (BW) gain, feed and energy intake data was collected from 18 hand-reared cheetah cubs up to 120 days of age. The average pre-weaning growth rate was 32 g/day, which is lower than reported in mother-reared cubs and hand-reared cubs in North American facilities. However, post-weaning growth increased to an average of 55 g/day. Growth was approximately linear prior to weaning, but over the entire age range it exhibited a sigmoidal shape with an asymptotic plateau averaging 57 kg. Energy intake associated with pre-weaning growth was 481 kJ ME/kg BW(0.75). Regression analysis described the relationship between metabolic BW, metabolisable energy (ME) intake, and hence daily weight gain. This relationship may be useful in predicting energy intake required to achieve growth rates in hand-reared cheetah cubs similar to those observed for their mother-reared counterparts.     

A dynamic model of metabolizable energy utilization in growing and mature cattle. III. Model evaluation

Component models of heat production identified in a proposed system of partitioning ME intake and a dynamic systems model that predicts gain in empty BW in cattle resulting from a known intake of ME were evaluated. Evaluations were done in four main areas: 1) net efficiency of ME utilization for gain, 2) relationship between recovered energy and ME intake, 3) predicting gain in empty BW from recovered energy, and 4) predicting gain in empty BW from ME intake. An analysis of published data showed that the net partial efficiencies of ME utilization for protein and fat gain were approximately 0.2 and 0.75, respectively, and that the net efficiency of ME utilization for gain could be estimated using these net partial efficiencies and the fraction of recovered energy that is contained in protein. Analyses of published sheep and cattle experimental data showed a significant linear relationship between recovered energy and ME intake, with no evidence for a nonlinear relationship. Growth and body composition of Hereford x Angus steers simulated from weaning to slaughter showed that over the finishing period, 20.8% of ME intake was recovered in gain. These results were similar to observed data and comparable to feedlot data of 26.5% for a shorter finishing period with a higher-quality diet. The component model to predict gain in empty BW from recovered energy was evaluated with growth and body composition data of five steer genotypes on two levels of nutrition. Linear regression of observed on predicted values for empty BW resulted in an intercept and slope that were not different (P < 0.05) from 0 and 1, respectively. Evaluations of the dynamic systems model to predict gain in empty BW using ME intake as the input showed close agreement between predicted and observed final empty BW for steers that were finished on high-energy diets, and the model accurately predicted growth patterns for Angus, Charolais, and Simmental reproducing females from 10 mo to 7 yr of age.     

Assessment of feeding varying levels of Metabolizable energy and protein on performance of transition Murrah buffaloes

Fifteen close up pregnant Murrah buffaloes of mean body weight (668.3 ± 24.03) kg, lactation number (2.8 ± 0.17) and expected producing ability (EPA) (2125.7 ± 46.34) were randomly distributed into three groups each of five animals to investigate the performance at different levels of metabolizable energy and protein. Control group was fed as per ICAR Nutrient requirements of animals (2013) recommendation whereas treatment group (1) high metabolizable energy and high metabolizable protein (HMEMP) and group (2) low metabolizable energy and low metabolizable protein (LMEMP) were offered with ration containing 15% more and 15% less ME and MP, respectively. The feeding trial was carried out for the period of 40 days before parturition and continued for 120 days after parturition. Intake of dry matter (DM) (%BW) was similar among experimental groups. Metabolizable energy (ME) (MJ/100 kg BW) and metabolizable protein (MP) (g/100 kg BW) intake was highest in HMEMP followed by control and LMEMP group, respectively. Digestibility trial of 7 days was conducted at 60 days post-partum and it was observed that apparent digestibility coefficients (%) of DM, organic matter (OM), crude protein (CP), ether extracts (EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were similar among the experimental groups. Milk yield (kg/kg DMI) was similar among treatment groups whereas 6% fat corrected milk (FCM) was lower in LMEMP group as compared to HMEMP and control. No significant effect of dietary MP and ME levels on milk composition was observed among experimental groups. There were no significant difference in non esterified fatty acid (NEFA), blood urea nitrogen(BUN), growth hormone (GH) and insulin like growth factor-1(IGF-1) concentration among different experimental groups whereas concentration of immunoglobulin G (IgG) (μg/ml) was found to be lower in LMEMP. The study results indicate that nutrient digestibility and lactation performance was not affected with 15% variation in intakes of ME and MP in lactating Murrah buffaloes.     

Selenium supplementation improves nutrient intake and digestibility,and mitigates CH4 emissions from sheep grazed on the mixed pasture of alfalfa and tall fescue

Low selenium (Se) in soil and forage can adversely affect on the quality of animal-derived foods, and hence on human health. Lambs grazed on mixed pastures of alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea) were supplemented with five levels of Se [0, 3, 6, 9 and 12 µg/kg body weight (BW)]. The intake of dry matter (DM) and organic matter (OM) varied with the level of Se supplementation, with a peak at 6 µg Se per kg BW (p ≤ 0.05). Gross energy (GE) intake, digestive energy (DE) intake and metabolic energy (ME) intake were higher at 6 µg Se per kg BW than at other Se levels (p < 0.01); in addition, methane energy (CH₄-E) output was lower at 6 µg Se per kg BW. Supplementation with Se significantly increased nitrogen (N) intake, faecal N and urine N, for which the peak values were 20.2 g N/, 5.62 g N/day and 7.92 g N/day, respectively, at 6 µg Se per kg BW. Se intake, blood Se, faecal Se, urine Se and retained Se were negatively correlated with forage crude protein (CP) content (p < 0.001) but were positively correlated with the content of neutral detergent fibre (NDF) (p < 0.001) and acid detergent fibre (ADF) (p < 0.001). Thus, we recommend the addition of 6 µg Se per kg BW to sheep grazed on pastures in regions with low soil Se.