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1.
1. This study was conducted to determine the effects of starter and grower diets with differing crude protein (CP) and metabolisable energy (ME) concentrations on the body weight (BW), live weight gain (LWG), feed consumption (FC), feed conversion ratio (FCR), and carcase, breast+back, rump, wing, neck and abdominal fat weights of chukar partridge raised in captivity. 2. Chukar partridges were fed on starter diets containing 4 concentrations of CP (160, 200, 240, 280 g/kg) and 4 concentrations of ME (10.9, 11.7, 12.6, 13.4 MJ/kg) from hatch to 8 weeks of age; they were fed on grower diets containing 4 concentrations of CP (150, 175, 200, 225 g/kg) and 4 concentrations of ME (11.9, 12.6, 13.2, 13.8 MJ/kg) from 9 to 16 weeks of age. All diets contained at least 5.5 g/kg methionine, 15 g/kg lysine and 10 g/kg methionine+cystine. Sixteen starter and 16 grower diets were arranged in a 4 x 4 factorial design with 4 levels of CP and 4 levels of ME. Each treatment was replicated three times with each replicate consisting of 5 males and 5 females. 3. Partridges fed on a starter diet containing 160 g CP/kg were significantly lighter at 8 weeks of age than those in groups given diets containing a higher CP. However, at 16 weeks of age, the differences in BW among treatments had disappeared. Throughout, there were no significant effects of ME concentration on BW and LWG. 4. The daily mean FC for the 0 to 8 week and 0 to 16 week periods was not affected by dietary CP concentration. For the 9 to 16 week period, the partridges fed on a grower diet containing 225 g CP/kg consumed more feed than those given a diet containing 175 g CP/kg. 5. The highest FCR for the 0 to 8 week period was in partridges fed on a starter diet containing 160 g CP/kg. For the 9 to 16 week period, the lowest FCR was in partridges fed on a grower diet containing 150 g CP/kg. For the 0 to 16 week period, there was not a significant effect of dietary CP concentration on FCR. The daily mean FC and the FCR for the 0 to 8, 9 to 16 and 0 to 16 week periods decreased when the ME concentration of the starter and grower diets increased. 6. The carcase, rump and breast+back weights of the male partridges increased when the ME content of the diets increased. Weights of all carcase components of the male partridges were significantly greater than those of the carcase components of the females. 7. There were no significant interactions between CP and ME concentrations on BW, LWG, FC, FCR and carcase characteristics. 8. We conclude that the starter diet for chukar partridges raised for meat production should contain at least 200 g CP/kg, 11.7 MJ ME/kg, and the grower diet should contain 150 g CP/kg, 12.6 MJ ME/kg.  相似文献   

2.
Growing goats, 45 Alpine and 45 Nubian, were used in a 3 x 3 factorial arrangement to quantify the influence of dietary energy and protein levels on daily DM intake and nutrient utilization for growth. Goats had ad libitum access to complete mixed diets containing either 2.46, 2.77 or 3.05 Mcal/kg ME plus 11.2, 12.7 or 15.1% CP for 16 wk. Dry matter intake decreased curvilinearly as dietary ME density increased (P less than .001). Dry matter intake increased linearly (P less than .05) as dietary CP level increased during all growth intervals except wk 25 to 28 of age. Average daily gain was 115, 113 and 99 g/d for goats fed diets containing 2.46, 2.77 and 3.05 Mcal/kg ME, respectively. Average daily gain was 104, 106 and 117 g/d for goats fed diets with 11.2, 12.7 and 15.1% CP, respectively. Dry matter intake was higher (P less than .01) for Alpine than for Nubian goats, whereas ADG was similar between breeds. Intake of ME was 248, 260 and 198 kcal/(kg.75.d) for goats fed the low- medium- and high-energy diets, respectively. Intake of CP was 9.1, 10.7 and 13.2 g/(kg.75.d) for goats fed low-, medium- and high-protein diets, respectively. Average requirements for growth derived from regression analysis of all data points were 4.6 kcal ME and .26 g CP/g ADG. The prediction equation for intake of growing goats of 4 to 8 mo of age was: DMI, g/d = 1,749 - 496 DE, kcal/g + 18 live weight, kg + 3 ADG, g/d; r2 = .73 (Sy.x = 127, P less than .0001, n = 90). The requirement of ME for growth was 33% lower than the value recommended in 1981 by the National Research Council.  相似文献   

3.

An experiment was conducted to investigate the effect of replacing soybean meal with soya waste at different levels on intake, digestibility and growth in goats. Eighteen male goat kids with initial body weight (BW) of 13.0 kg were distributed equally to three dietary groups. They were fed Napier grass (Pennisetum purpureum) and concentrate mixture, and each goat was assigned to an individual pen. Soybean meal in the concentrate mixture was replaced with soya waste at 0% (T1), 50% (T2) and 100% (T3) levels in respective dietary groups. These diets were isocaloric and isonitrogenous. Results showed that animals fed T3 diet exhibited higher Napier grass intake than those fed T1 or T2 diet. There was no influence on total intakes of dry matter (DM), organic matter (OM), crude protein (CP), metabolic BW, per cent BW and metabolisable energy by the dietary groups. However, there was an increasing trend on intake and digestibility of neutral detergent fibre (NDF) with increasing levels of soya waste in the diets. Animals fed T3 diet showed higher intake and digestibility of NDF than those fed T1 diet. There was no influence of the dietary groups on digestibilities of DM, OM and CP. Similarly, there was no effect of them on the final BW, total BW gain, daily BW gain, feed conversion ratio and feed cost. Soya waste can replace 100% soybean meal in diets for growing goats, because no change was observed in nutrient intake, digestibility and growth performance; inclusion of soya waste enhanced the intake and digestibility of NDF.

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4.
A comparative slaughter experiment was conducted with 28 Spanish kids (BW = 20.6 kg) fed a hay-based diet to determine the effects of supplemental energy and protein on growth rate, body composition, and ruminal and blood metabolites. After 84 d, kids were harvested, digesta contents removed and empty body weighed and ground. Samples were freeze-dried and analyzed for DM, CP, ether extract, ash, and gross energy. All kids had increased BW gains. However, unsupplemented kids lost empty BW and weight of all body components except ash. Kids supplemented with energy or protein increased (P<0.05) empty BW, body water, protein, fat, ash, and gross energy when compared with unsupplemented kids. The percentages of body water and ash decreased (P<0.05) when supplemental energy or protein was fed. The percentage of body protein was reduced (P<0.05) by supplemental energy and unaffected (P=0.81) by supplemental protein. Supplemental energy reduced (P<0.05) ruminal acetate and increased (P<0.05) propionate and butyrate. Supplemental protein increased (P<0.05) concentrations of ruminal ammonia N, plasma urea N, and all ruminal volatile fatty acids. Regression equations suggest that intake of 144 kcal of ME and 6.0 g of CP per kilogram of empty BW0.75 are necessary to maintain empty BW.  相似文献   

5.
Effect of sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours.) G. Don.] leaf meal feeding was evaluated in two experiments in indoor reared goats with experimental infection of Haemonchus contortus larvae. In the first experiment, ten 8-10 month old male Spanish and Alpine cross kids pair matched for body weight and age were fed SL or bermudagrass [BG; Cynodon dactylon (L.) Pers.] hay one week before infection and were infected with 5000 H. contortus L(3). The animals were maintained on the same diet for the remaining period and were slaughtered 28 days post-infection (DPI) to determine the establishment of incoming infective larvae. Goats fed SL had lower establishment (P<0.05) of H. contortus larvae than that of the control goats fed BG hay. In the second experiment, twenty-five 8-10 months old male Alpine cross, Saanen, Nubian×Saanen and Spanish kids reared in confinement on BG were experimentally infected with 5000 H. contortus L(3). On 35 DPI, the animals were allocated to two groups after blocking by fecal egg count (FEC), and one group was fed SL leaf meal (n=13), and another control group remained on BG (n=12). Four goats/group were slaughtered successively on days 7, 14, and 28 days post SL feeding, except on day 7, when five SL fed goats were slaughtered. Fecal egg counts and blood packed cell volume (PCV) were measured at weekly intervals and worm count, female worm fecundity, worm length and mucosal eosinophils, mast cells and globule leucocytes were measured after slaughter. Goats fed SL had a lower FEC (P<0.05) one week after feeding, as compared to those fed on BG, and the values remained at low level thereafter. Similarly, PCV was also significantly affected by feeding (P<0.01), and feeding and time interaction (P<0.05). However, worm burden, female worm fecundity, parasite length, and mucosal inflammatory cell count were similar between the groups. Feeding SL reduced the establishment of infective larvae and FEC of H. contortus in experimental studies and this plant could be used for biological control of parasite infection under field conditions to limit the harmful effects of the parasites in goats.  相似文献   

6.
The effect of feeding different levels of foliage from Erythrina variegata on the performance of growing goats was studied using a local breed (Ma T'ou) with an average initial body weight of 11.2?kg (SD?=?0.9). Twenty-four animals were allocated to a randomized design, with six animals (three males and three females) per treatment. The treatments were four different levels of replacement of the diet crude protein (CP) with CP from Erythrina foliage (EF) at 0?% (E-0), 20?% (E-20), 40?% (E-40), and 60?% (E-60). There were no significant differences in the dry matter (DM) intake between treatments, but total CP intake was significantly higher in the goats fed the diet E-60 compared to E-20 (61.1 and 51.4?g/day, respectively). The average daily liveweight gain of the goats did not differ between treatments and ranged from 51 to 63?g/day. Sixteen animals were kept in metabolism cages for a digestibility study and given with the same four diets as in the main experiment. The digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber was significantly higher for diet E-60 than for E-0. Neither the apparent digestibility of CP and N retention nor carcass characteristics (16 animals) differed with an increase in the level of CP from EF in the diets. In conclusion, CP from EF can replace up to 60?% of CP from a mixed diet with soybean meal without any negative effect on the growth in goats.  相似文献   

7.
Olives leaves, accrued during the processing of olive harvests for oil extraction, are poor in N, rich in crude fat and ADF (1.19, 8.03 and 28.2 g/100 g of DM, respectively), and relatively low in condensed tannins (11.1 mg/g of DM). Three experiments were conducted in a 2 x 3 (two animal species: goats vs. wethers; and three experimental diets: olive leaves without or with polyethylene glycol supply and olive leaves supplemented with barley and faba beans) factorial design to evaluate ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to evaluate the effects of condensed tannins contained in olive leaves. Ruminal degradability of CP was low in both goats and wethers, although goats showed higher (P < 0.05) values than wethers. Supplementation of olive leaves with barley and faba beans increased (P < 0.001) ruminal degradability of DM and CP. Both goats and wethers fed olive leaves showed similarly low particulate fractional passage rates (0.021 and 0.023/h, respectively). Ingestion of olive leaves promoted low NH3-N and VFA concentrations, which reflect poor microbial activity. These concentrations, especially that of VFA, increased when barley and faba beans were added. Ingestion of olive leaves affected ruminal protozoa: Entodiniomorphida showed low concentrations and Holotricha completely disappeared. When animals received a diet based on olive leaves, barley, and faba beans, Holotricha appeared in the ruminal liquor and Entodiniomorphida increased (P < 0.001). In goats and wethers fed olive leaves alone, urinary allantoin excretion was very low (163 and 164 micromol/kg BW0.75 in goats and wethers, respectively), and moderate values (352 and 389 micromol/kg BW0.75 in goats and wethers, respectively) were observed when a diet of olive leaves, barley, and faba beans was fed. The polyethylene glycol supply did not have an effect in goats or in wethers, indicating the lack of an effect of condensed tannins in olive leaves. Ingestion of olive leaves promotes a low microbial activity, although its supplementation with readily degraded carbohydrates and protein improves microbial activity and, as a consequence, increases its ruminal degradation. In general, for most of the measured variables, there were no animal species x diet interactions. Thus, goats and wethers had similar ruminal activities when fed diets based on olive leaves.  相似文献   

8.
The present study investigated the effects of breed and diet quality on basal and hormone-stimulated energy metabolism in lambs. Twenty-four 7-mo-old merino (MM; n = 12) and second-cross (2X; n = 12) lambs were maintained indoors and fed ad libitum either a low-quality (7.8% crude protein [CP] and 8.1 MJ metabolizable energy [ME]/kg dry matter [DM]) or a moderate-quality (17.6% CP and 9.1 MJ ME/kg DM) diet in a crossover design. After 3 wk of feeding, lambs were injected intravenously with insulin (10 μg/kg body weight [BW]) and epinephrine (0.8 μg/kg BW) on consecutive days and blood samples were collected at -30, -15, -1, 3, 6, 10, 15, 20, 30, 45, 60, 90, and 120 min relative to time of injection. Lambs fed the low-quality diet had lower DM (P < 0.001), CP (P < 0.01), and ME (P < 0.001) intakes than lambs fed the moderate-quality diet. Baseline nonesterified fatty acid (NEFA) concentrations were higher (P < 0.001) in lambs fed a low-quality diet than in those fed a moderate-quality diet but there were no breed differences. Second-cross lambs had higher basal plasma concentrations of glucose (P < 0.001), lactate (P < 0.001), and cortisol (P < 0.02) than the MM lambs, although there was no effect of diet on any of these plasma variables. Insulin injection caused a rapid hypoglycemic response in all lambs but the response was more pronounced (P < 0.01) in MM lambs compared with 2X lambs. The cortisol response to insulin was twice as great (P < 0.05) in MM lambs compared with 2X lambs. There was a rebound in plasma NEFA concentrations after approximately 30 min postinjection that was most pronounced (P < 0.01) in MM lambs. Epinephrine injection caused a rapid increase in plasma NEFA, which tended to be lower in lambs fed the moderate-quality diet (P = 0.07) than in those fed the low-quality diet, but did not differ between breeds. Epinephrine injection caused rapid hyperglycemia, with the response being lower (P < 0.006) in lambs fed the moderate-quality diet compared with those fed the low-quality diet and greater (P < 0.050) in 2X than in MM lambs. Epinephrine injection caused a rapid increase in plasma lactate that tended to be greater (P = 0.07) in 2X lambs compared with MM lambs. The present study demonstrated clear breed differences in basal and hormone-stimulated metabolism, such that the 2X lambs appeared to be less sensitive to insulin and more sensitive to epinephrine than the MM lambs. These metabolic differences may be related to the fundamental differences in physiology that are associated with meat and wool production from 2X and MM breeds, respectively. They may also be related to adaptation of the MM breed to harsh environments through the ability of the body to metabolize fat resources, which are an efficient source of energy for survival.  相似文献   

9.
The replacement value of Ficus polita for Panicum maximum was evaluated on 32 female post‐weaned West African dwarfs goats. Ficus polita was fed with P. maximum at different proportions of 0:90 (F. polita:P. maximum), 30:60, 60:30 and 90:0 constituting diets 1, 2, 3 and 4 respectively. Each diet was supplemented with 10% cassava peels. Dry matter intake per kg metabolic weight of goats was not significantly (p > 0.05) influenced by the dietary treatments. However, crude protein intake per kg metabolic weight was higher (p < 0.05) in animals fed 60% and 90%F. polita than those fed sole P. maximum diet. Daily weight gain of goats fed diet 3 (60%F. polita) was higher (p < 0.05) (27.3 g) than those fed diets 4 (18.9 g), 2 (20.8 g) and the control (6.6 g). Dry matter (DM), organic matter, crude protein (CP) and neutral detergent fibre digestibilities were higher (p < 0.05) in goats fed 60%F. polita than those fed other diets, except for DM digestibility which was statistically similar to diets 2 and 4 but higher than those fed diet 1 without F. polita. Organic matter and CP digestibility were highest (72.0 and 65.7% respectively) in animals fed 60%F. polita. Nitrogen retention of goats fed 60%F. polita (diet 3) was higher (p < 0.05) than that obtained with other diets. The results suggest that feeding combination of F. polita and P. maximum at ratio 60:30 respectively has associative effects that can enhance growth rate, feed intake, nutrients digestibility and nitrogen utilization for goat production during dry season in the tropics.  相似文献   

10.
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.  相似文献   

11.
Crossbred wether goats (n = 24; 50% Boer, 6 per diet) initially averaging 27.4+/-0.4 kg were fed either wheat middlings (wheat midds), soybean hulls (soyhulls), or corn gluten feed at 1% BW (as-fed) along with orchardgrass hay (10.7% CP) offered to ad-libitum consumption for 72 d followed by 5 d total fecal collection. The Control (hay) diet was supplemented with 5.7% soybean meal to bring total dietary protein to 12.5%, by-products were brought to a higher Ca:P ratio with limestone or dicalcium phosphate to make total dietary Ca:P 1.5:1, and soybean meal was added to soyhulls to bring them up to 17% CP (wheat midds = 17% and corn gluten feed = 21% CP). Total DMI (916 g/d+/-57 or 3.2%+/-0.2 BW) did not differ (P > 0.92) among treatments. Initial BW (P = 0.25), final BW (P = 0.48), and ADG (P = 0.56) did not differ for the four treatments. Carcass weight was greater (P = 0.05) for goats fed soyhulls (16.0 kg) or wheat midds (15.6 kg) as compared with goats fed the hay diet (14.5 kg), with carcass weight from goats fed corn gluten feed being intermediate (15.3 kg, SEM = 0.3 kg). Carcass grade did not differ (P = 0.80) and averaged 5.42+/-0.4. Dressing percentage tended (P = 0.12) to be lower for goats fed the hay diet (46.4%) compared with soyhull (48.3%), corn gluten feed (48.3%), or wheat midd (48.8%) diets (SEM = 0.7). Ruminal pH was highest (P < 0.01) for goats fed the hay diet (6.52) and lowest for goats fed wheat midds (6.23) with soyhull (6.41) and corn gluten feed diets (6.35) being intermediate (SEM = 0.05). Digestibility of DM (70.1+/-2.5%), OM (70.3+/-2.6%,), CP (75.5+/-2.0%), GE (68.5+/-2.7%), NDF (68.1+/-3.0%), ADF (65.4+/-3.4%), cellulose (70.1+/-2.9%), and lignin (31.1+/-8.2%) did not differ (P > 0.15). Total ruminal VFA did not differ (86.0+/-6.1 mM, P = 0.59), but acetate:propionate ratio was higher (P < 0.01) for hay (3.1) and soyhull diets (3.3) than for corn gluten feed (2.4) and wheat midd diets (2.4, SEM = 0.11). Ruminal ammonia (mg/100 mL) was lower (P < 0.01) for goats fed hay (15.4) and soyhull diets (11.6) than those fed corn gluten feed (25.2) and wheat midd diets (23.0, SEM = 1.35). Ruminal pH was lower for goats fed the byproducts, but remained above 6. Serum urea nitrogen (mg/100 mL) averaged 21.0+/-1.0 (P = 0.11) with soyhulls tending to be lowest (19.3) and corn gluten feed tending to be highest (22.8). Soyhulls, corn gluten feed, and wheat midds appear to be viable feed ingredients for meat goat diets.  相似文献   

12.
A digestibility, feed intake, and carcass evaluation experiment using 20 yearling intact male Sidama goats weighing 16.4 ± 0.63 kg (mean ± SD) was conducted in Ethiopia with the objectives to determine feed intake, digestibility, body weight (BW) gain, and carcass parameters. The treatments included feeding natural pasture hay (T1, control) and supplementation with cottonseed cake (284 g—T2), linseed cake (250 g—T3), and noug seed cake (296 g—T4) on dry matter (DM) basis to supply 85 g crude protein (CP) per head per day. Randomized complete block design for feed intake and BW parameters and complete randomized design for digestibility and carcass parameters were used. Hay DM intake was higher (P < 0.01) for T1 than for the other treatments. T3 promoted higher (P < 0.01) DM (29.3 g/kg W0.75/day) and CP (14.1 g/kg W0.75/day) intake than T4 (8.9 g/kg W0.75/day DM and 4.1 g/kg W0.75/day CP). T3 showed better (P < 0.05) organic matter and CP digestibility than T2. Goats in T3 had higher nitrogen intake (P < 0.01) and retention (P < 0.05) than those in T1. Goats in T2 and T3 showed higher (P < 0.05) daily BW gain and final BW than those in T4 and T1. Goats in T2 and T3 had higher (P < 0.05) slaughter weight, empty BW, hot carcass weight, rib-eye muscle area, and dressing percentage on slaughter weight basis than those in T1. The results showed that T2 and T3 had similar effect on CP intake, daily BW gain, and carcass parameters for growing Sidama goats fed natural pasture hay.  相似文献   

13.
The hormonal and nutritional modulation of hepatic arginase activity (HARG) was characterized in growing cattle in two studies. In the first study, 20 steers (initial weight, 182 ± 2 kg) were assigned in equal numbers to either Synovex-S (SYN) (ear implant), recombinant bovine somatotropin (Somavubove; SbV; 0.1 mg/kg intramuscularly daily), SYN + SbV, or nothing (control). Steers were individually fed, for 56 d, a concentrate (80% diet dry matter [DM]) and silage (20% diet DM) diet providing 20 g of crude protein (CP) and 252 kcal metabolizable energy (ME) per kg body weight0.75. On Day 57, samples of liver were obtained at slaughter and subsequently assayed for HARG by the incubation of a tissue homogenate for 2 hr with 250 mM arginine, with and without Mn2+ and heat activation, and the measurement of the resulting urea. HARG was uniformly increased by divalent cation (Mn2+) and heating. SYN had no effect on HARG, whereas SbV treatment resulted in an overall 34% decrease in HARG. Plasma urea nitrogen (PUN) was decreased by SbV but not consistently affected by SYN. In the second study, 16 steers (avg. initial weight, 284 ± 5 kg) were initially fed a concentrate basal diet consisting of 11% CP and 1.96 Mcal ME for 21 d. Steers were then assigned to one of four dietary treatments (6.4 kg DM/hr per day) in a factorial arrangement of high and low CP (8 and 14%) and two levels of energy (1.96 and 2.67 Meal ME/kg of diet DM) for 210 d and slaughtered. HARG and PUN were higher in steers fed 14% CP but were lower at each level of CP fed at the higher level of ME. The data suggest that hormonal repartitioning compounds and diet composition may modulate nitrogen metabolism by affecting the activity of arginase in the liver as well as by affecting the total content of arginase in association with changes in organ size.  相似文献   

14.
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.  相似文献   

15.
Two trials were conducted to evaluate the effects of corn in protein supplements fed to cattle receiving low-quality forages. In Trial 1, four ruminally cannulated steers (avg BW 500 kg) and four intact steers (avg BW 270 kg) were used in a replicated latin square to determine intake and digestibility fo a low-quality meadow hay (4.3% CP) when fed no supplement (NS), 1.12 g CP/kg BW (PS), 1.12 g CP/kg BW with corn supplying 1.98 g starch/kg BW (PLC) or 1.12 g CP/kg BW with corn supplying 3.96 g starch/kg BW (PHC). Hay DMI decreased (P = .001) and total diet DMI increased (P = .001) quadratically as supplemental corn increased. Diet DM digestibility increased (P = .004) and forage DM and hemicellulose digestibility decreased (P less than or equal to .018) quadratically as level of corn in the diet increased. In Trial 2, 135 cows received either ear corn (1.16 kg TDN and 127 g CP.hd(-1).d(-1), ear corn plus protein (1.16 kg TDN) and 290 g CP g CP.hd(-1).d(-1) or protein (.72 kg TDN and 290 g CP.hd(-1.d(-1) while grazing native Sandhills winter range for 112 d and while receiving hay (10% CP) during the following 60-d calving period. Cows that received ear corn lost (P less than .001) more weight than cows fed ear corn plus protein supplement, which lost more weight than cows fed only protein supplement (-54, -18 and 6 kg, respectively) during the 112-d winter grazing period. Cows that received ear corn and ear corn plus protein gained more (P less than .001) weight during calving and summer grazing (after supplement wa withdrawn) than protein-supplemented cows. Reproductive performance was not affected (P greater than .705) by treatments.  相似文献   

16.
We investigated the influence of DM and(or) energy intake and dietary CP levels on the performance and nitrogen (N) retention of beef steers with and without growth promoter implants. In Exp. 1, four implanted (Synovex-S, 200 mg of progesterone plus 20 mg of estradiol benzoate) Angus steers and four Angus steers that were not implanted were assigned to concurrent 4 x 4 Latin squares. Initial BW averaged 296 kg. Each square consisted of moderate and moderately high DM intake treatments (4 and 6 kg/d) and low and adequate CP intake treatments (450 and 600 g/d) in a 2 x 2 factorial arrangement. Periods were 2 wk of adaptation, 5 wk of growth, and 1 wk of balance collection. Experiment 2 consisted of two replicates of 32 Hereford steers each (initial BW 324 kg). Each replicate was a 4 x 2 factorial in which steers were individually fed for 63 d. All steers had ad libitum access to a 60% corn-based concentrate diet containing either 7.9, 10.0, 12.1, or 14.6% CP (DM basis), and steers were either implanted or not implanted with Synovex-S. Experiment 3 was similar to Exp. 2 except that all steers (initial BW 315 kg) received a low-protein diet (7.6% CP) with calculated energy densities of either 1.86, 2.04, 2.22, or 2.42 Mcal ME/kg DM, and steers were limited to an equalized DM intake of 9.5 kg daily. In Exp. 1, gains for the low CP, moderate and moderately high DM intakes and the adequate CP, moderate and moderately high DM intakes were 240, 555, 208, and 730 g/d, respectively, for steers not implanted and 333, 643, 488, and 988 g/d, respectively, for implanted steers (SEM = 102 g/d). Respective values for retained N were .13, .18, .16, and .26 g/kg BW.75 and .13, .15, .22, and .29 g/kg BW.75 (SEM = .04 g/kg BW.75). Implant response was greater (CP x implant, P < .01) for both gain and retained N when adequate CP compared to low CP diets were fed. For Exp. 2, the lowest CP diet reduced ADG (.97 vs 1.27 kg/d) and efficiency of gain (100 vs 120 g gain/kg DM). Synovex-S was less effective in improving efficiency for the lowest protein diet than for the other diets (11.7 vs 20.2%). During Exp. 3, neither Synovex-S nor dietary energy influenced gain and efficiency. We concluded that adequate dietary protein is necessary to optimize the response to estrogenic growth promoters and that the low response under inadequate protein and energy intake is not improved by increasing the energy density of the diet.  相似文献   

17.
Twenty growing Small East African goats were used to determine the effects of feeding sun-dried leaves of the browse forages Berchemia discolor and Zizyphus mucronata as supplements to low-quality basal diet, Rhodes grass (Chloris gayana) hay, on voluntary feed intake (VFI), digestibility and growth performance. The grass hay and maize bran were used as a control. The dried leaves were then included at the rates of 15% and 30% of the dry matter intake (DMI). Berchemia discolor had the highest crude protein (CP) content of 195.5 g/kg DM, while Z. mucronata had CP content of 169.5 g/kg DM. The grass hay had the lowest CP content of 50.9 g/kg DM. The browse forages had low fibre content [Neutral detergent fibre (NDF); 257.9-369.5 g/kg DM], while the grass hay had high fibre content (NDF; 713.1 g/kg DM). Goats in the groups supplemented with either of the browse forages had higher total DMI, nitrogen (N) intake and retention and live-weight gains than those in the control diet group. The digestibility of DM and organic matter (OM) was not affected by supplementation, but the CP digestibility increased with supplementation. The use of the browse forages as supplements for goats fed on poor-quality basal diets would enhance the performance of the animals.  相似文献   

18.

Eight male Cambodian yellow cattle, initial body weight (BW) 136 ± 11.9 (±SD) kg; age 20 ± 2.5 (±SD) months, were randomly allocated to treatments in a double 4 × 4 Latin square design to investigate the effects of different levels of crude protein (CP) from sun-dried groundnut (Arachis hypogaea L.) foliage (DGF) on feed intake, apparent digestibility and nitrogen metabolism. All animals were fed a basal diet of rice straw ad libitum and para grass (Brachiaria mutica) at 1% of BW. The DGF was offered as a supplement at 0, 1, 2 and 3 g CP/kg BW, denoted DGF0, DGF1, DGF2 and DGF3, respectively. The results showed that the intake of DGF contributed 0, 25, 34 and 42% of total dry matter (DM) intake. Rice straw intake decreased when DGF intake increased. Total intake of DM, organic matter (OM), digestible OM, ash, neutral detergent fibre and acid detergent fibre increased with increased level of DGF inclusion but did not differ for the two highest DGF levels. Total DM intake as proportion of BW increased from 2.3% in DGF0 to 2.8% in DGF3. Crude protein digestibility and nitrogen retention improved as DGF intake increased. Daily weight gain of DGF1 cattle was higher than DGF0 but was not further improved at the higher levels of DGF inclusion. Microbial protein synthesis and efficiency of microbial protein production in DGF1 did not differ from DGF0 but both measures were higher in DGF2 and DGF3. The responses were diminished at higher DGF inclusion so it is suggested that DGF supplementation at 1 g CP/kg BW may be the optimal level.

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19.
Twenty-two Kiko crossbred male goats (Capra hircus; initial BW = 27.5 ± 1.04 kg) were used in a randomized complete block design to determine the effects of feeding pine bark (PB; Pinus taeda L.) on animal performance, rumen fermentation, blood parameters, fecal egg counts (FEC), and carcass characteristics in goats. Experimental treatments included the control diet [0% PB plus 30% wheat straw (WS)], 15% PB plus 15% WS, and 30% PB plus 0% WS (on as-fed basis), where PB replaced WS. Freshly air-dried PB and WS were finely (1.5 to 3.0 mm) ground and incorporated in the grain mixes. Experimental diets provided a total of 1.9, 16.3, and 32 g of condense tannins (CT)/kg DM in 0%, 15%, and 30% PB diets, respectively. The grain mixes were fed daily at 85% of the feed offered, with remaining 15% consisting of Bermuda grass hay (Cynodon dactylon). Animals were fed once a day at 0800 h, and feed offered and refused was monitored for an 83-d performance period. Rumen and blood samples were collected at d 0, 50, and 80 of the study. Carcass traits were assessed after slaughter at the end of performance period. There was no difference in initial BW, hay, and total NDF intake among treatments; however, final BW (P = 0.06), ADG (P < 0.01), grain mix intake (P < 0.001), total DMI (P < 0.001), and G:F (P < 0.04) increased linearly as the PB increased in the diets. Rumen ammonia N, acetate, isovalerate and acetate-to-propionate ratio were reduced linearly (P < 0.05). There was no difference in carcass traits except cold carcass weight (P = 0.06), which tended to increase linearly in goats fed 15% and 30% PB. Breast, sirloin, trim trait, liver, and hide weight increased (linear; P < 0.01) with addition of PB. Blood basophils, alanine transaminase, aspartate aminotransferase, albumin, Na, and Cl concentrations decreased (linear; P < 0.02 to 0.01) as PB supplementation increased. Supplementation of PB reduced (linear; P < 0.01) average FEC. Addition of PB in the diets improved performance, reduced FEC, and favorably modified rumen fermentation.  相似文献   

20.
1. Heterozygous naked neck birds were raised under natural spring (average 21.2°C) and summer temperatures (average 27.1°C) to investigate the influence of dietary energy on broiler performance, carcase yield and nutrient composition of breast meat. 2. Birds were fed on a low energy diet of 12.12 MJ ME/kg, a medium energy diet of 12.96 MJ ME/kg and a high energy diet of 13.79 MJ ME/kg with 2 protein concentrations per energy treatment, 230 and 200 g/kg, from 0 to 3 and 3 to 7 weeks of age, respectively. 3. Summer rearing resulted in a decrease in body weight, body weight gain, carcase weight and carcase part yields of birds. 4. Increasing dietary energy from 12.12 to 13.79 MJ ME/kg increased body weight at 3 and 7 weeks, body weight gains from 0 to 3 and 3 to 7 weeks, carcase weights and relative abdominal fat weights of birds in a linear manner. There was no effect of dietary energy on the nutrient composition of breast meat. 5. It was concluded that there was no differences in dietary energy requirements of heterozygous naked neck birds when grown under natural optimum (21.2°C) and summer temperatures (27.1°C).  相似文献   

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