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1.
Energy intake prepartum is critically important to health, milk performance, and profitability of dairy cows. The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake (DMI), lactation performance and energy balance (EB) in multiparous Holstein cows which were housed in a free-stall barn and fed for ad libitum intake. Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet [HD, n = 13; 6.8 MJ of net energy for lactation (NEL)/kg; 14.0% crude protein (CP) ], or a middle energy density diet (MD, n = 13; 6.2 MJ NEL/kg; 14.0% CP), or a low energy density diet (LD, n = 13; 5.4 MJ NEL/kg; 14.0% CP) from d 21 before expected day of calving. After parturition, all cows were fed the same lactation diet to d 70 in milk (DIM). The DMI and NEL intake prepartum were decreased by the reduced energy density diets (P < 0.05). The LD group consumed 1.3 kg/d (DM) more diet compared with HD group in the last 24 h before calving. The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum (P < 0.05). The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets. HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation (P < 0.05). The energy consumption for HD, MD and LD groups were 149.8%, 126.2% and 101.1% of their calculated energy requirements prepartum (P < 0.05), and 72.7%, 73.1% and 75.2% during the first 4 wk postpartum, respectively. In conclusion, the low energy density prepartum diet was effective in controlling NEL intake prepartum, and was beneficial in increasing DMI and milk yield, and alleviating negative EB postpartum.  相似文献   

2.
There is little information known about the energy requirements of cats in temperature climates. Energy requirement of domestic short‐haired cats was determined using three groups of mixed gender – old kept outside (approximately 9.9 years of age; 4.8 kg; n = 9), young kept outside (approximately 3.1 years of age; 3.9 kg; n = 8) or young kept inside (approximately 3.1 years of age; 3.9 kg; n = 8). Cats were housed individually for 5 weeks during summer (18.5 ± 0.5 °C) and winter (8.5 ± 0.4 °C) and were fed a commercially available maintenance diet ad libitum. In both periods, energy expenditure was determined from the rates of 2H and 18O elimination for blood H2O over a 12 day period, from a doubly labelled water bolus 2H2O (0.7 g/kg BW) and H218O (0.13 g/kg BW) administered intravenously. During the summer period, macronutrient digestibility was determined. Older cats had a reduction (p < 0.05) in apparent digestibility of dry matter (approximately 9%), energy (approximately 8%) and protein (6%). There was a significant effect of age and season on energy intake and energy expenditure. While lean mass was affected by age and season, there was no effect of age or season on energy expenditure when expressed as a proportion of lean mass. Possible seasonal differences in nutrient digestibility may explain these results.  相似文献   

3.
The objective of this study was to determine the effect of reduced energy density of close‐up diets on ruminal fermentation parameters in transition cows. Fourteen Holstein dry cows were blocked and assigned randomly to three groups fed a high energy density diet (HD, 1.62 Mcal of net energy for lactation (NEL)/kg dry matter (DM)), or a middle energy density diet (MD, 1.47 Mcal NEL/kg DM), or a low energy density diet (LD, 1.30 Mcal NEL/kg DM) prepartum, and were fed the same diet postpartum. The reduced energy density diets decreased the average dry matter intake (DMI) prepartum and tended to increase the DMI postpartum. The ruminal pH of the LD group was significantly higher prepartum and lower during the first week of lactation compared with the other two groups. The reduced energy density diet depressed the average ruminal concentration of propionate and butyrate prepartum, and increased the average concentration of total volatile fatty acids (VFA) postpartum. The LD group had higher populations of Butyrivibrio fibrisolvens and Ruminococcus flavefaciens relative to HD and MD groups on 7 days in milk. In conclusion, the cows fed reduced energy density diet prepartum had higher VFA concentration, but were more susceptible to subacute ruminal acidosis postpartum.  相似文献   

4.
The objective of this experiment was to investigate the effect of fat supplementation during the transition period on pre and postpartum body weight (BW), body condition score (BCS), non‐esterified fatty acids (NEFA), glucose and leptin concentrations in Holstein cows. Holstein cows (n = 15) received a low fat diet (LF; 1.61 Mcal net energy for lactation (NEL)/kg of dry matter [DM]), moderate fat diet (MF; 1.68 Mcal NEL/kg DM) or a high fat diet (HF; 1.74 Mcal NEL/kg DM) for 4 weeks prior to calving. All cows were fed similar lactation diets ad libitum (1.74 Mcal NEL/kg DM) for 30 days after calving. Increasing diet energy density during transition period had no effect on prepartum DMI, BCS, BW, glucose and NEFA concentrations (P > 0.05); but leptin concentrations and energy balance (EB) were affected by treatments (P < 0.05). Animals fed HF had less plasma leptin prepartum. After parturition, BW, milk production, milk fat, protein, urea nitrogen and plasma glucose concentrations were affected by prepartum diets (P < 0.05). Fat supplementation prepartum did not affect postpartum NEFA. In conclusion, prepartum fat supplementation decreased leptin concentration prepartum.  相似文献   

5.
Abstract

This study was conducted in order to develop equations for the prediction of ewe's milk energy content via milk composition. Twenty-four multiparous Chios breed ewes were examined in a eight-week study that started at parturition. Animals were fed in groups (12 ewes), with two, highly concentrated (forage to concentrate ratio 30:70 DM), rations differing in undegradable protein (UP) content. The following equations are proposed: (i) when fat content (F; g/kg) is the only variable: EVL(kJ/kg)=39×F+2090 (SE 0.30 kJ/g), (ii) when total solids (TS; g/kg) is the only variable: EVL(kJ/kg)=33×TS–1222 (SE 0.26 kJ/g) whilst the following equation is proposed when solids non fat content (SNF; g/kg) is an additional known variable: EVL (kJ/kg)=39×F+36×SNF–1990 (SE 0.27 kJ/g). Fat corrected milk (FCM) yield can be calculated by the following equation: Y (FCM 6%; kg/d)=L (kg/d)×[0.472+0.0088×F (g/kg)], where L is milk yield.  相似文献   

6.
The aim was to evaluate the relationship of prepartum plasma estrone sulfate (E1S) and estradiol‐17β (E2β) concentrations with the weight of the calf and the placental parameters. Holstein–Friesian cows (n = 33) inseminated artificially with Japanese Black beef bull semen at Hiroshima University Farm in Japan were used for the experiment. Blood samples were taken every day from day 270 of gestation until the day after calving. The plasma samples were analyzed for E1S and E2β by enzyme immunoassay. The calf birth weight was taken immediately after calving. Complete fetal membranes were collected from 19 cattle and the weights of the placental components and the number of cotyledons were recorded. All 33 cattle delivered singleton normal calves. The prepartum plasma E1S concentration was found to correlate significantly (P < 0.01) with the calf birth weight (r = 0.83), total fetal membrane weight (r = 0.81), cotyledonary weight (r = 0.79) and inter‐cotyledonary membrane weight (r = 0.64), but it did not correlate significantly with the number of cotyledons, whereas prepartum plasma E2β was not found to correlate significantly with the weight of either the calf or any of the placental components except the number of cotyledons. In conclusion, prepartum plasma E1S, not plasma E2β, was found to correlate significantly with the weight of the calf and the placental components.  相似文献   

7.
The objective of this study was to evaluate the effects of grazing on the accretion of energy and chemical components in steers, using the comparative slaughter technique and taking into consideration the growth rate. Twelve Holstein steers aged 6 months and weighing 160 kg were divided into three treatment groups – an initial, grazing and control group. The initial group was slaughtered at the beginning of the experiment. The grazing group was grazed on timothy pastures for 18 weeks. The control group was kept in a stable and offered concentrate and timothy hay in a proportion of 2:1 throughout the 18 weeks. The amount of ration offered to the control group was adjusted in order to obtain a growth rate similar to that of the grazing group. The grazing and control groups were slaughtered at the end of the experiment. The grazing and the control groups had similar growth rates of approximately 0.8 kg/day throughout the experimental period and similar final live weights of approximately 260 kg. The grazing group had lower fat and energy deposition rates than the control group (P < 0.05). Deposition rates of protein, fat, ash, moisture and energy were 130, 32, 30, 374 g/day and 4.4 MJ/day, respectively, in the grazing group and 117, 85, 32, 381 g/day and 6.2 MJ/day, respectively, in the control group. The net energy for growth was lower in the grazing group (7.7 MJ/kg) than in the control group (9.9 MJ/kg, P < 0.05). The grazing group had higher plasma concentrations in growth hormone and lower plasma concentrations in insulin and insulin‐like growth factor 1 than those in the control group (P < 0.05).  相似文献   

8.
Energy intake prepartum is critically important to health,milk performance,and profitability of dairy cows.The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake(DMI),lactation performance and energy balance(EB) in multiparous Holstein cows which were housed in a free-stall bam and fed for ad libitum intake.Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet[HD,n = 13;6.8 MJ of net energy for lactation(NE_L)/kg;14.0%crude protein(CP)],or a middle energy density diet(MD,n = 13;6.2 MJ NE_L/kg;14.0%CP),or a low energy density diet(LD,n = 13;5.4 MJ NE_L/kg;14.0%CP) from d 21 before expected day of calving.After parturition,all cows were fed the same lactation diet to d 70 in milk(DIM).The DMI and NE_L intake prepartum were decreased by the reduced energy density diets(P 0.05).The LD group consumed 1.3 kg/d(DM) more diet compared with HD group in the last 24 h before calving.The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum(P 0.05).The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets.HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation(P 0.05).The energy consumption for HD,MD and LD groups were 149.8%,126.2%and 101.1%of their calculated energy requirements prepartum(P 0.05),and 72.7%,73.1%and 75.2%during the first 4 wk postpartum,respectively.In conclusion,the low energy density prepartum diet was effective in controlling NE_L intake prepartum,and was beneficial in increasing DMI and milk yield,and alleviating negative EB postpartum.  相似文献   

9.
The object of the present study was to determine the influence of different zeolite A doses on dry matter intake (DMI) and mineral metabolism, and to evaluate an optimum dosage for preventing hypocalcaemia. Eighty pregnant dry cows were assigned to four groups (I–IV). They were fed a total mixed ration (TMR) ad libitum. Groups II, III and IV received an average daily dose of 12, 23 and 43 g zeolite A/kg DM for the last 2 weeks prepartum. Individually DMI was recorded daily. Blood and urine samples were taken before, during and after zeolite A supplementation. Serum was analysed for Ca, Mg, Pi, K, non‐esterified fatty acids and β‐hydroxybutyrate (BHB). Urine was analysed for Ca, Mg, Pi, K and net acid‐base excretion (NABE). After calving, milk yield (fat corrected milk) and milk composition were determined. During zeolite A supplementation, mean DMI of Group IV (7.3 ± 1.3 kg/cow/day) was significantly lower compared to Groups I–III (10.1, 10.9, 9.5 kg/cow/day). The reduced feed intake of Group IV resulted in significantly increased BHB as well as decreased NABE after calving. Zeolite A supplementation in higher doses (III and IV) had a stabilizing effect on Ca metabolism around calving for older cows, whereas cows in Groups I and II showed a subclinical hypocalcaemia. The mean serum Mg concentration decreased significantly in older cows in Group IV at calving. The mean Pi concentration in cows of Group IV decreased into ranges of hypophosphataemia already 1 week after beginning of zeolite A feeding. The mean DMI postpartum as well as the milk yield was not affected by zeolite A supplementation. Feeding of 23 g zeolite A/kg DM TMR prepartum proved to be an adequate dosage for reducing subclinical hypocalcaemia frequency without significant effects on feed intake and Pi concentration in serum.  相似文献   

10.
The objectives of the present study were to evaluate fasting metabolism (FM) of water buffalo (Bubalus, Bubalis) at three stages of growth (12, 18 and 24 months) in Guangxi, China. Five female water buffalo were used for each age group and their live weight was on average 254, 326 and 338 kg, respectively. All animals were of average body condition, healthy and de‐wormed before start of the study. Prior to a 6‐day fasting period, buffalo were offered a mixed diet of forage and concentrates (70% and 30%, dry matter basis) on a restricted nutritional level (419 kJ/kg0.75 of metabolizable energy, ME) for 15 days. Gas exchanges for each animal were determined for 3 days from day 4 of starvation, using open‐circuit respiratory head hoods. Fasting body weight was 0.918 of live weight (P < 0.001, r2 = 0.99). Both fasting heat production (FHP) and FM (MJ/day) increased significantly with increased age of animals (P < 0.05). Linear regression analysis indicated a positive relationship between fasting body weight (kg0.75) and FHP (MJ/day, P < 0.01, r2 = 0.49) or FM (MJ/day P < 0.01, r2 = 0.52) when using individual animal data across three groups. However, when expressed as kJ/kg0.75 of fasting body weight, the differences in FHP or FM between three groups of animals were not significant. The present average FHP and FM (322 and 347 kJ/kg0.75 of fasting body weight) were compatible to those published in the literature for water buffalo, beef and dairy cattle. The present FM data were also used to estimate net energy (NEm) and ME (MEm) requirements for maintenance for water buffalo. The results for these two parameters were similar to those for FHP and FM. There was no significant difference between three groups of buffalo in NEm or MEm when expressed as kJ/kg0.75 of live weight. The present average NEm and MEm values (347 and 506 kJ/kg0.75 of live weight) are close to those proposed by the Agricultural and Food Research Council adopted in UK for beef and dairy cattle. The results indicate that the present FM data can be used as a basis for rationing water buffalo in China.  相似文献   

11.
Twenty multiparous Chinese Holstein dairy cows calving in hot summer (S group), were compared with 20 similar control cows calving in cool autumn (C group). Diets were the same for both groups; prepartum diets had relatively low energy density. Average temperature–humidity index was 76.5 and 53.0 in summer and autumn, respectively. S group cows had significantly higher rectal temperatures (39.6 vs. 39.0 °C) and respiration rates (79.0 vs. 31.3 breaths/min) than C group, and consumed less feed (prepartum 8.0 vs. 12.3 kg/day, postpartum 16.3 vs. 21.2 kg/day). Calculated energy balance (EB) was ?7.98 vs. ?5.15 Mcal/day for S group prepartum and postpartum, respectively. In contrast, EB was 1.36 vs. ?2.03 Mcal/day for C group prepartum and postpartum, respectively. S group produced significantly less milk than C group by 15.4 % (5.2 kg/day) and 26.8 % (10.2 kg/d) for milk yield and energy-corrected milk, respectively. Percentages of milk fat (3.28 vs. 4.29 %), protein (3.08 vs. 3.33 %), and solids-not-fat (8.46 vs. 8.78 %) were significantly lower for S group. Milk urea nitrogen (19.54 vs. 13.31 mg/dL) was significantly higher in S group. Significantly lower feed efficiency was observed in S group (1.56 vs. 1.66). During the entire transition period, S group had significantly lower circulating glucose levels. S group had significantly higher levels of nonesterified fatty acids (NEFA) prepartum, but after 14 days in milk, NEFA was significantly lower. We conclude that increasing dietary energy density during transition period (especially prepartum) is necessary to minimize adverse effects of hot season.  相似文献   

12.
The prediction of renal energy excretion is crucial in a metabolizable energy system for horses. Phenolic acids from forage cell walls may affect renal energy losses by increasing hippuric acid excretion. Therefore, the relationships were investigated between renal energy, nitrogen (N) and hippuric acid excretion of four adult ponies (230–384 kg body weight (BW)) consuming diets based on fresh grass, grass silage, grass cobs (heat‐dried, finely chopped, pressed grass), alfalfa hay, straw, extruded straw and soybean meal. Feed intake was measured; urine and faeces were quantitatively collected for three days. Feed was analysed for crude nutrients, gross energy, amino acids and neutral‐detergent‐insoluble crude protein (CP); faeces were analysed for crude nutrients and cross energy; urine was analysed for N, hippuric acid, creatinine and gross energy. Renal energy excretion (y; kJ/kg BW0.75) correlated with renal N excretion (x1; g/kg BW0.75) and renal hippuric acid excretion (x2; g/kg BW0.75): y = 14.4 + 30.2x1+20.7x2 (r = .95; n = 30; p < .05). Renal hippuric acid excretion was highest after intake of fresh grass and lowest after intake of soybean meal. The ratio of hippuric acid to creatinine in urine and the excretion of hippuric acid per gram of dry matter intake was significantly higher for fresh grass than for all other rations. There was no relationship between aromatic amino acid intake and renal hippuric acid excretion. The results of the present study and literature data suggest that feed can be categorized into four groups with regard to the energy losses per gram CP intake: (i) protein supplements (e.g., soybean meal): 4.2–4.9 kJ/g CP intake (ii) alfalfa hay, grains, dried sugar beet pulp: 6.4 kJ/g CP intake, (iii) hay, preserved grass products, straw: 5.2–12.3 kJ/g CP intake (mean 8) and (iv) fresh grass. For group (iii) a negative relationship was observed between renal energy losses per gram of CP and the content of CP or neutral‐detergent‐insoluble CP in dry matter.  相似文献   

13.
Data of comparative slaughter were used to determine Nellore bulls’ net energy requirements classified as efficient or inefficient according to residual feed intake (RFI) and selection lines (SL). Sixty-seven Nellore bulls from the selected (SE) and control (CO) lines of the selection program for postweaning weight gain were used. The animals underwent digestibility trials before being submitted to the finishing trial. Sixteen bulls were slaughtered at the beginning of the finishing trial, and their body composition was used as the baseline for the remaining animals. For body composition determinations, whole empty body components were weighed, ground, and subsampled for chemical analyses. Initial body composition was determined with equations developed from the baseline group using shrunk body weight, fat, and protein. The low RFI (LRFI) and CO animals had a lower dry matter (DMI) and nutrient intake (P < 0.05) than high RFI (HRFI) and SE animals, without alterations in digestibility coefficients (P > 0.05). During the finishing trial, DMI remained lower for LRFI and CO animals. Growth performance was similar between RFI classes, except for empty body weight gain that tended to be higher for LRFI than HRFI (P = 0.091). The SE animals had less fat content on the empty body (P = 0.005) than CO. Carcasses tended to be leaner for LRFI than HRFI (P = 0.080) and for SE than CO (P = 0.066) animals. LRFI animals retained more energy (P = 0.049) and had lower heat production (HP; P = 0.033) than the HRFI ones. Retained energy was not influenced by SL (P = 0.165), but HP tended to be higher for SE when compared to CO (P = 0.075) animals. Net energy requirement for maintenance (NEm) was lower for LRFI than HRFI (P = 0.009), and higher for SE than CO (P = 0.046) animals. There was an interaction tendency between RFI and SL (P = 0.063), suggesting that NEm was lower for LRFI+CO than HRFI+CO (P = 0.006), with no differences for SE (P = 0.527) animals. The efficiency of ME utilization for maintenance (km) of LRFI and HRFI animals were 62.6% and 58.4%, respectively, and for SE and CO were 59.0% and 62.1%, respectively. The breeding program for postweaning weight has not improved feed efficiency over the years, with RFI classification not being a promising selection tool for SE animals. Classification based on RFI seems to be useful in animals that have not undergone the breeding program, with LRFI animals having lower energy requirements than the HRFI ones.  相似文献   

14.
The objectives of this experiment were: (i) to determine the net energy (NE) of soybean oil (SBO) fed to growing pigs using indirect calorimetry (IC); and (ii) to evaluate the effects of inclusion rate of SBO on heat production, oxidative status and nutrient digestibility in growing pigs. Eighteen growing barrows were allotted to three diets based on completely randomized design with six replicate pigs (period) per diet. Diets included a corn‐soybean meal basal diet and two test diets containing 5% or 10% SBO at the expense of corn and soybean meal. During each period, pigs were individually housed in metabolism crates for 14 days, including 7 days to adapt to feed, metabolism crate and environmental conditions. On day 8, pigs were transferred to the open‐circuit respiration chambers for measurement of daily O2 consumption and CO2 and CH4 production. During this time, pigs were fed one of the three diets at 2.4 MJ metabolizable energy/kg body weight (BW)0.6/day. Total feces and urine were collected and daily total heat production (THP) was measured from days 9 to 13 and fasted on day 14 to evaluate their fasting heat production (FHP). The results show that trends of decreased apparent total tract digestibility of neutral detergent fiber (linear, P = 0.09) and acid detergent fiber (linear, P = 0.07) were observed as the content of dietary lipids increased. The average THP for the three diets were 1326, 1208 and 1193 kJ/kg BW0.6/day, respectively. The FHP of pigs averaged 843 kJ/kg BW0.6/day and was not affected by diet characteristics. A reduction of the respiratory quotients in the fed state as the inclusion level of SBO increased was observed. In conclusion, the NE values of SBO we determined by indirect calorimetry were 33.45 and 34.05 MJ/kg dry matter under two inclusion levels. THP could be largely reduced when SBO is added in the feed, but the THP of SBO included at 5% in a corn‐soybean meal diet is not different from the THP of SBO included at 10%.  相似文献   

15.
Light and medium hybrids were allowed to consume, from 24 to 52 weeks of age, ad libitum or approximately 1200, 1154, 1107 and 1062 kJ ME/bird d. A sixth treatment consisted of the lowest level of energy but with higher levels of protein calcium and phosphorus. From 52 to 58 weeks all the birds were fed ad libitum. Treatments were reimposed from 58 to 68 weeks of age.

In the 24‐ to 68‐week period mean rate of lay decreased progressively with decreasing energy intake. Rate of lay of medium and light hybrids allowed 1200 kJ ME/d was, respectively, about 10 and 4 percentage points lower than controls. Initially differences in rate of lay in relation to energy intake were small, particularly in the case of light hybrids, but became more marked as restriction continued. During the 6‐week rehabilitation period previously restricted groups tended to lay more eggs than controls.

With both strains egg weight tended to decrease as energy intake was reduced. In the 6 weeks of rehabilitation most groups tended to lay slightly heavier eggs than controls. At 27 weeks eggs from birds allowed the 1062 kJ/bird d had thinner shells than those from other groups but treatment had no effect on Haugh units. At 48 weeks Haugh units were similar for each restricted group but significantly less for controls (P= 0.05).

Restricted groups lost between 6 and 12% of their body weight in the first 16 weeks but regained a little in the succeeding 12 weeks. During the 6 weeks of rehabilitation they gained weight rapidly but at 68 weeks restricted birds were lighter than they had been at 24 weeks of age. Least‐severely restricted birds were significantly lighter than controls (P = 0.001) and final body weight decreased slightly but progressively with severity of restriction.

Protein or minerals or both, as well as energy, limited egg weight and body weight at the lower level of food intake. The effect on egg weight was more marked in the early stages of lay. There was no evidence that rate of lay or egg quality were limited by nutrients other than energy. Mortality was generally low and there was no evidence of a treatment effect.  相似文献   


16.
Measurements of nitrogen, carbon and energy balances were done on eight female adult cats aged approximately 1.5 years with the help of respiration chambers. The cats were fed with a marked dry food for kittens (Biomill kitten). Faeces and urine samples were collected with the help of a special cat toilet that allows the single collection of both materials. The calculated energy requirement of these eight female cats was 239.6 kJ ME/kg BW/day (R(2) = 0.98). Including the data, on 12 young male adult cats, of L?uger, (2001), an energy requirement of 238 kJ ME/kg BW/day (R(2) = 0.95) could be calculated. From these data, it can be followed that the energy requirements of young, active cats are higher than that of the older cats. The method of indirect calorimetry does not necessarily lead to lower energy requirements.  相似文献   

17.
The present study was conducted to determine the net energy (NE) values and energy efficiency of wheat bran (WB), sugar beet pulp (SBP), corn gluten feed (CGF), soybean hulls (SBH), and defatted rice bran (DFRB) fed to pregnant sows. Thirty‐six multiparous pregnant sows were randomly assigned to six dietary treatments with six replicates per treatment. Each period lasted for 21 days including 14 days for adaptation. On day 15, sows were moved into respiration chambers for heat production (HP) measurement and provided feed at 544 kJ/kg BW0.75/day. On day 20, sows were fasted to measure the fasting heat production (FHP). Experimental diets included corn‐soybean meal basal diet and five diets containing 29.20% WB, SBP, CGF, SBH, and DFRB, respectively. Results showed that inclusion of WB, SBP, CGF, SBH, and DFRB to basal diet decreased (p < 0.05) the apparent total tract digestibility of energy and nutrients. The average adjusted total HP and FHP were 418 kJ/kg BW0.75/day and 326 kJ/kg BW0.75/day, respectively. The average NE:ME ratio of experiment diets was 82.5%. In conclusion, the NE values of WB, SBP, CGF, SBH, and DFRB were 9.05, 8.59, 8.37, 7.64, and 7.93 MJ/kg DM, respectively.  相似文献   

18.
The effect of dietary energy levels on the urinary excretion of purine derivatives (PD) was investigated in sheep fed hay and concentrate diets. In addition, the possibility of using PD concentrations in spot samples of urine as a useful tool for determining daily PD excretion was also examined. Three female lambs (mean bodyweight (BW) ± standard error, 31.4 ± 1.0 kg) were fed three diets consisting of timothy hay (20 g dry matter/kg BW per day) and rolled barley at three different energy levels (low‐energy (LE), medium‐energy (ME) and high‐energy (HE) at 1.0‐, 1.2‐ and 1.5‐fold greater than the maintenance level of energy (450 KJ/BW0.75/day), respectively) in a 3 × 3 Latin square design. The dietary protein level was almost constant (380 mg nitrogen/BW0.75/day as digestible crude protein base) and was adjusted using soybean protein. Digestible organic matter intake (DOMI) increased (P < 0.05) with an increase in the dietary energy level and there was a difference (P < 0.05) in the organic matter digestibility between the LE and HE diets. For urinary PD excretion, the differences between the LE and ME diets and the HE diet were significant (P < 0.05), although there was no clear difference between the LE and ME diets. There was a positive correlation (r = 0.47, P < 0.05) between urinary PD excretion and DOMI. There was also a correlation (r = 0.59, P < 0.05) between the urinary PD level at 7–8 h after the morning feed and the daily total PD excretion, suggesting that the PD level in spot urine samples could be useful for estimating microbial protein synthesized in the rumen and/or digested in the lower gut.  相似文献   

19.
One of the bovine growth hormone (GH) genetic variants is a substitution of leucine (Leu) to valine (Val) at amino acid position 127 of the protein. The GH genotypes of 14 Japanese black steers used in the present study were Leu/Leu (A, n = 7) and Val/Val (B, n = 7). The steers in each genotype group were divided into two groups based on intended growth rate (high, 1.0 kg/day; low, 0.6 kg/day) during 10–17 months of age. The overall mean concentration of plasma GH was higher (P < 0.05) in the A group than in the B group. The serum concentration of insulin‐like growth factor‐I was higher (P < 0.05) in the B group than in the A group. The carcass weight of the A group was greater (P < 0.01) than that of the B group. However, there was no significant difference in carcass weights between the 1.0 kg/day and 0.6 kg/day groups (P > 0.05). The rib thickness of the 1.0 kg/day group was greater (P < 0.05) than that of the 0.6 kg/day group. The crude fat content of longissimus muscle was greater (P < 0.05) for the 0.6 kg/day group compared with the 1.0 kg/day group.  相似文献   

20.
Twelve multiparous sows with an average initial weight of 182 kg were used in a randomized complete block design to determine the effects of feeding Carnichrome (50 mg of carnitine and 200 microg of chromium picolinate per kilogram of feed, as fed) on energy and nitrogen utilization in early, mid-, and late gestation. All sows were fed a diet with or without Carnichrome for the preceding 28-d lactation, the weaning-to-estrus period, and for the duration of gestation. Daily feeding allowances over pregnancy were based on calculated energy and nutrient requirements to achieve a target sow maternal weight gain of 20 kg and remained constant throughout gestation. Heat production (HP) and its partitioning (activity, thermic effect of feeding short term [TEFst], basal) were determined in early (wk 5 or 6), mid- (wk 9 or 10), and late (wk 14 or 15) pregnancy using indirect calorimetry. Net maternal weight gain and total number of fetuses averaged 21.6 kg and 16.4, respectively. Organic matter and energy digestibility for the Carnichrome diet was greater (P < 0.05), which resulted in greater DE and ME contents (0.6%, P < 0.05) compared with the control diet. The digestibility coefficient of energy in the current experiment for a typical corn and soybean meal diet (92%) was greater than that predicted from DE values of corn and soybean meal in feeding tables (88%). Carnichrome had no effect on total HP, energy retained as protein or lipid, and maternal energy retention in early, mid-, or late gestation. Heat production in late gestation increased linearly (4.0 kJ/[kg BW0.75 x d]) for each additional day from d 90 to 110, despite the reduction of ME intake per unit of BW0.75. Metabolizable energy requirement for maintenance was 405 kJ/(kg BW0.75 x d). On average, activity HP was 116 kJ/(kg BW0.75 x d), which was equivalent to 20% of ME intake; however, this value ranged from 11 to 37% between sows, which corresponds to duration of standing ranging from 210 to 490 min/d. Energy cost of standing activity averaged 0.30 kJ/(kg BW0.75 x min). In conclusion, Carnichrome had no effect on the components of heat production and maternal weight gain during gestation, although it improved energy and organic matter digestibility of the diet.  相似文献   

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