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1.
A 60-d trial was conducted to determine effects of Al citrate and citric acid on DM digestibility (DMD) and metabolism of Mg, Ca, P, K, Na and Al. Eighteen crossbred, yearling wether lambs equipped with ruminal cannulas were fed a basal diet containing .12% Mg and 2.87% K (DM basis) and were allotted to three treatments: 1) control, 2) 2,000 ppm Al as Al citrate and 3) citric acid equivalent to the citrate in treatment 2. Treatments were administered in 200 ml of deionized water twice daily in divided doses via ruminal cannula. Balance trials were conducted during d 0 to 5, 6 to 10, 25 to 35 and 50 to 60. Dry matter digestibility decreased (P less than .05) approximately 3 percentage units in lambs receiving Al. Treatment with Al citrate increased (P less than .01) apparent absorption and retention of Al compared to those receiving citric acid alone. Approximately 30% of ingested and infused Al was apparently absorbed. Compared to citric acid, Al citrate treatment lowered apparent absorption and retention of Mg and Ca during d 0 to 5. Apparent Ca absorption and retention again were lowered during d 50 to 60. Urinary Ca was increased (P less than .01) and apparent P absorption (P less than .10) and retention (P less than .05) were decreased by Al citrate during all measurement periods. Apparent absorption of K decreased (P less than .05) slightly in response to Al treatment. Apparent absorption of Na was not influenced by Al treatment. Serum Mg and P decreased and serum Ca increased in response to Al treatment. Results demonstrate negative effects of ingested Al, but not of citric acid, on DMD and metabolism of Mg, Ca, P and K.  相似文献   

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The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone‐breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps®, Ca, P, Mg and 1,25(OH)2Vit‐D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA‐fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA‐fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance, feed conversion efficiency, carcass weight and carcass quality, but only in numerical terms. The addition of CA up to 0.75% significantly increased the digestibility of macro minerals, bone ash content, bone mineral density and bone strength of the broiler chicks. It may, therefore, be concluded that the addition of 0.75% CA in a standard diet is suitable for growth, carcass traits, macromineral digestibility and bone mineral density of broiler chicks.  相似文献   

4.
To establish the effect of sward height (SH) and concentrate supplementation on performance of grazing cattle, 24 crossbred Angus beef cows (535 kg BW) and calves (114 kg BW) were grouped by weight and calving date. They were randomly assigned to two SH treatments, either 4 to 8 cm or 8 to 11 cm, and fed three levels of supplement, high, low, or none, consisting of 6.24, 3.12, and 0 kg x animal(-1) x d(-1), respectively. The experiment was repeated over three 15-d periods in 1996: May (P1), June/July (P2), and August (P3). No SH x supplement level x period or SH x supplement level interactions (P > 0.10) were evident for responses tested. Cows on lower SH had greater (P < 0.08) DMI but spent an additional 1.3 h/d (P < 0.01) grazing compared with cows on higher SH. Sward height had no influence (P > 0.10) on forage DM digestibility (DMD). Forage DMI, DMD, and grazing time (GT) decreased (P < 0.05) as supplementation increased. Nonetheless, supplemented cows consumed more total DMI (P < 0.08) than unsupplemented cows. Cows consumed 2.4 kg/d more forage DM (P < 0.01) in P1 and P2 than in P3. Cows grazed 1.3 h/d (P < 0.01) less in P1 than in P2 and P3. Grazing efficiency (DMI/h GT) declined as supplementation increased and grazing season advanced to P3 (P < 0.01). Decreased forage DMI and grazing efficiency with increasing supplementation suggests that supplemented cattle should be able to maintain productivity while grazing at SH lower than unsupplemented cattle.  相似文献   

5.
A 60-d trial was conducted to determine effects of A1-citrate and citric acid on tissue mineral composition in wether lambs. Eighteen crossbred, yearling wether lambs equipped with ruminal cannulas were fed a diet containing low (.12%) Mg and high (2.87%) K (DM basis) and were allotted to three treatments: 1) control; 2) 2,000 micrograms A1 as A1-citrate/g of diet DM and 3) citric acid equivalent to the citrate in treatment 2. Treatments were administered in 200 ml of deionized water twice daily in divided doses via ruminal cannula. At the end of 60 d, wethers were slaughtered and samples of rib and tibia bone, liver, kidney, brain, spleen, pancreas, parathyroid and pituitary gland were analyzed for mineral concentration. Concentrations of A1 increased (P less than .05) in rib, tibia, liver, kidney, spleen and pituitary gland and tended to increase in brain (P less than .13) in wethers treated with A1-citrate compared to citric acid. Magnesium was decreased in rib (P less than .01) and tended to be decreased in pituitary gland (P less than .15), whereas Ca tended to be decreased in pancreas (P less than .07), kidney (P less than .11) and parathyroid (P less than .10) by A1-citrate treatment compared to citric acid. Potassium decreased (P less than .01) in liver, Fe increased (P less than .05) in kidney, Zn decreased in pituitary (P less than .05) and tended to decrease in pancreas (P less than .10) due to A1-citrate but not citric acid.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
Tropical Animal Health and Production - Twenty-seven Nellore cow-calf pairs were submitted for feed efficiency testing. The animals were weighed every 21 ± 5&nbsp;days to...  相似文献   

7.
To establish the effect of sward height, concentrate feeding time, and restricted time for grazing on forage utilization by grazing cattle, 32 crossbred beef (24 Angus and eight Hereford) cows (632 kg BW) and calves (104 kg BW) were grouped by weight and calving date. They were assigned randomly to two sward height treatments (4 to 8 or 8 to 12 cm), replicated four times. The herbage comprised mainly Kentucky bluegrass, orchardgrass, some forbs, and white clover. The cows were restricted to 12 h/d grazing (0700 to 1900) or unrestricted to 24 h/d grazing and fed a concentrate supplement (4.1 kg DM.cow(-1).d(-1), approximately 0.65% of BW or 33% of total DMI) either at 0700 or 1800. The experiment was repeated over three 15-d periods in May, June/July, and August 2000. The herbage on high sward height pasture was higher (P = 0.06) in NDF and ADF and lower (P < 0.01) in CP than low sward height herbage. For cows restricted to 12 h/d grazing, supplementing at 0700 as opposed 1800 resulted in greater (P = 0.04) forage DMI (8.6 vs. 8.1 kg/d), whereas cows that were unrestricted showed little change (8.2 kg/d at 0700 vs. 8.4 kg/d at 1800). Supplementing at 1800 as opposed to 0700 resulted in greater (P = 0.03) herbage DM digestibility (67.7 vs. 64.5%) for cows on high sward height, whereas cows on low sward height exhibited minimal differences (65.4% at 1800 vs. 66.3% at 0700). Cows restricted to 12 h/d grazing and supplemented at 0700 as opposed to 1800 resulted in greater (P = 0.06) digestible DMI (5.0 vs. 4.7 kg/d), whereas unrestricted cows exhibited the opposite response (4.6 kg/d digestible DMI at 0700 vs. 4.9 kg/d at 1800). Supplementing at 1800 as opposed to 0700 increased the time spent grazing to a greater (P = 0.09) extent for restricted than for unrestricted cows. When forage availability or grazing time was limiting (due to a low forage allowance and restricted access to forage, respectively) supplementing concentrates at 0700 resulted in greater forage utilization and intake rate because of increased forage DMI, DM digestibility, and digestible DMI. However, when forage or grazing time was not limiting, supplementing concentrates at 1800 resulted in greater forage utilization because of increased forage DM digestibility.  相似文献   

8.
不同营养水平对淘汰荷斯坦奶牛消化代谢、肉品质的影响   总被引:1,自引:0,他引:1  
为了研究不同能量蛋白水平对淘汰荷斯坦奶牛消化代谢、肉品质的影响。采用单因素随机设计,选择体重相近的健康淘汰荷斯坦奶牛32头,随机分成4组,Ⅰ组(低营养水平)、Ⅱ(中营养水平)、Ⅲ(较高营养水平)、Ⅳ(高营养水平),试验分两期进行。结果表明,随着日粮营养水平的增加,各试验组粗蛋白、粗脂肪表观消化率差异显著(P<0.05),其中Ⅲ组最高,分别达到72.47%和80.64%;Ⅳ组背膘厚度比Ⅰ组提高了73.33%(P<0.05)。日粮营养水平能显著影响熟肉率、肉中脂肪和脂肪酸含量。其中,Ⅲ组熟肉率最高,为49.73%,比Ⅰ组、Ⅱ组、Ⅳ组分别提高6.03%,7.87%和4.30%(P<0.01);牛肉中脂肪含量Ⅰ组最低,为4.08%,Ⅳ组最高,达到6.94%;各试验组牛肉中多不饱和脂肪酸(PUFA)差异显著(P<0.05),Ⅳ组PUFA含量最低,为3.67%,Ⅱ组最高,达到5.93%,Ⅱ组比Ⅳ组提高61.58%(P<0.05),Ⅲ组PUFA含量比Ⅰ组、Ⅳ组分别高2.47%和58.31%(P<0.05)。因此,淘汰荷斯坦奶牛育肥营养水平建议值为:体重410~470 kg,干物质采食量为11.03~11.53 kg/d,DE摄入量为147.86~150.05 MJ/d,CP摄入量为1.57~1.66 kg/d(DM);育肥牛体重470~530 kg,干物质采食量为10.76~11.23 kg/d,DE摄入量为149.18~151.21 MJ/d,CP摄入量为1.53~1.62 kg/d(DM)。  相似文献   

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The episodic release of luteinizing hormone (LH) and growth hormones (GH) was studied in three suckling regimens and two breeds of Spanish suckled cows. Parda de Montaña (PA) cows (n = 21) were assigned to once‐daily, twice‐daily or ad libitum (ADLIB) suckling. Pirenaica (PI) cows (n = 7) were used to evaluate the breed effect in twice‐daily suckling. Coccygeal blood samples were collected twice weekly during lactation to determine the interval from calving to first ovulation through peripheral progesterone. On day 32 ± 3 post‐partum, jugular blood samples were drawn at 15 min intervals during 8 h to analyse circulating LH and GH. The interval to first ovulation was greater in PA cows suckling ADLIB than in restricted suckling treatment (RESTR1), whereas in RESTR2 it did not differ from the other two treatments. There were no differences between PA and PI cows in the interval to first ovulation. RESTR1 cows showed a tendency to have shorter LH peak widths than ADLIB cows. PA cows showed a tendency to have longer LH peak widths than their PI counterparts. There were no differences across treatments or breeds in any of the GH measures of secretion. The LH release was more affected by breed than by suckling frequency, whereas that of GH was not influenced by any of these parameters. The variables that best allowed discrimination between ADLIB and restricted nursing systems were the interval to post‐partum first ovulation, LH peak number and the mean GH concentration.  相似文献   

11.
Crambe meal was compared to a combination of sunflower and soybean meal as a protein supplement for mature beef cows in two experiments. In Exp. 1, cows (n = 80, average BW 651+/-14.4 kg) were fed crambe meal at 9.86% of dry matter intake (DMI) during the last trimester of gestation. No differences (P < .05) were detected due to treatment for cow weight, condition score, thyroid hormones, calf birth weight, or calving interval. In Exp. 2, cows (n = 100, average BW 566+/-6.82 kg) were fed crambe meal at 7.44% of DMI during the last trimester of gestation and at 8.33% of DMI during early lactation (53+/-6 d of lactation). Gains were greater during gestation (P = .09) and throughout the supplementation period (P = .06), and days to first estrus were reduced (P < .01) for cows fed crambe meal. During lactation, serum triiodothyronine (T3) concentrations did not decline as much (P = .03) in cows fed crambe meal as in cows fed sunflower-soybean meal-based supplements. No differences (P > .10) were apparent for condition score, birth weight, calf growth rate, weaning weight, thyroid hormones during gestation, or calving interval. These data indicate that crambe meal fed at the levels used in this experiment can be used as a protein supplement for beef cows without negatively affecting cows' performance.  相似文献   

12.
Grazing trials were conducted utilizing individually supplemented lactating beef cows in a 2-yr study to determine the effect of supplemental escape protein (EP) on cow/calf performance during the active growth periods of smooth brome and big bluestem. Graded levels (0, .11, .23, and .34 kg of EP/animal from an equal-protein-basis mixture of blood meal and corn gluten meal were offered daily, replacing corn starch and molasses, which was used as the energy control. All cows received 582 g of supplemental DM/d. Analyses for the smooth brome study indicated a cubic response (P less than .05) to milk production and calf daily gain. No response to EP supplementation (P greater than .10) was observed for the big bluestem study. Analysis of esophageal extrusa samples collected throughout the grazing seasons for both years demonstrated that quality of forage selected by the animal decreased as the trial progressed. Using a 16-h modified dacron bag technique that did not adjust for microbial attachment, protein escaping degradation for smooth brome and big bluestem was estimated to range from 7.0 to 14.5% and 22.2 to 30.3%, respectively. There was limited response to a moderate level of EP supplementation of lactating cows grazing smooth brome, but calf gains were depressed by both the low and the high levels of EP. Lactating cows grazing big bluestem did not respond to EP supplementation, but added energy supplement depressed calf gains.  相似文献   

13.
Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (control) supplement or supplements with cracked, high-linoleate safflower seeds (linoleate) or cracked, high-oleate safflower seeds (oleate) from d 3 to 90 of lactation. Diets were formulated to be isonitrogenous and isocaloric; safflower seed diets provided 5% of DMI as fat. Plasma and milk samples were collected on d 30, 60, and 90 of lactation. Adipose tissue biopsies were collected near the tail-head region of cows on d 45 and 90 of lactation. In Exp. 2, 3-yr-old cows achieving a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr). Beginning 3 d postpartum through d 61 of lactation, cows were fed diets similar to those of Exp. 1. Adipose tissue and milk samples were collected on d 30 and 60, and plasma was collected on d 31 and 61 of lactation. Responses to postpartum dietary treatment were comparable in both experiments. Cows fed linoleate and oleate had greater (P < 0.001) total fatty acid concentrations in plasma than cows fed control. Except for 15:1, milk fatty acids with <18 carbons were greatest (P < or = 0.01) for cows fed control, whereas milk from cows fed linoleate had the greatest (P < or = 0.02) 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA. Milk from cows fed oleate had the greatest (P < 0.001) 18:1cis-9. In Exp. 1, total fatty acid concentrations in adipose tissue samples decreased at d 90 compared with d 45 of lactation, but the fatty acid profile of cow adipose tissue was not affected (P = 0.14 to 0.80) by dietary treatment. In Exp. 2, the percentage of cis-9, trans-11 CLA in adipose tissue of cows with a BCS of 6 decreased (P = 0.001) from d 30 to 60 of lactation. Plasma and milk fatty acid composition reflected alterations in postpartum diet. Less medium-chain fatty acids and more 18-carbon fatty acids in milk were indicative of reduced de novo fatty acid synthesis in the mammary gland of beef cows fed lipid supplements; however, the metabolic demands of lactation prevented the deposition of exogenously derived fatty acids in adipose tissue through d 90 of lactation.  相似文献   

14.
An experiment was conducted to investigate the influence of repeated ingestion of ochratoxin A (OTA) on milk production of lactating Holstein cows over 28 days, and the carry‐over of OTA from the diets into the milk and tissues of the cows. Nine cows were divided into three groups, labeled OTA5, OTA50 and OTA100, and fed a diet containing 5, 50 and 100 µg OTA/kg of dry matter, respectively. Body weight, feed intake and daily milk yield in cows were not different among the three groups during the OTA‐intake period. OTA residues were neither detected in the tissues, such as liver, kidney, muscles, fat and jejunoileum, nor in the milk of any cows in the OTA intake groups. In contrast, a small amount of OTA (0.1 µg/kg) was detected in the blood plasma of one sample in the OTA50 group and multiple samples in the OTA100 group. The results of this study show that the ingestion of diets containing up to 100 µg/kg of OTA over 28 days does not affect feed intake or milk production of cows, and the dietary OTA is not carried over into milk and edible tissues such as the liver, muscles and fat. © 2015 Japanese Society of Animal Science  相似文献   

15.
以3头体况良好,安装有永久性瘤胃瘘管的泌乳前期奶牛为试验动物,在日粮精粗比为55∶45的前提条件下,采用3×3完全拉丁方试验设计,研究了3种不同过瘤胃淀粉日粮对泌乳奶牛消化代谢的影响。研究结果表明:3组不同日粮对营养物质的采食、排泄以及消化利用有着一定的规律性。3组不同日粮之间的采食量和消化率无明显差异(P>0.05);低过瘤胃淀粉日粮组的粪NDF排出量明显高于其他2组(P<0.05),其他2组之间差异不显著(P>0.05),粪中其他营养物质的排出量3组之间没有差异(P>0.05)。与对照组相比,其他2组均使尿氮排出量降低,其中高过瘤胃淀粉日粮组达到了显著水平(P<0.05),并且高过瘤胃淀粉日粮的氮沉积量和可消化氮转化为沉积氮的效率也明显高于其他2组(P<0.05),其他2组之间差异不显著。  相似文献   

16.
We evaluated the effects of mineral salt supplement on enteric methane emissions, ruminal fermentation and methanogen community of dairy cows over a whole lactation period. Ten Holstein cows fed a total mixed ration (TMR) diet were randomly allocated into two groups, one supplied with mineral salts as the treatment group and the other as the control group. The methane measurement showed that the ingestion of mineral salts lowered enteric methane emissions significantly (P < 0.05), with an average of 10.5% reduction over the whole lactation period. Ruminal fermentation analysis showed the mineral salt intake could significantly decrease the acetate : propionate ratio (P < 0.05). Real‐time PCR assay showed that rumen methanogen abundance significantly reduced in the treatment group (P < 0.05) but was not significantly influenced by mineral salt intake over the whole lactation period. Intergroup methanogen community composition was influenced slightly by mineral salt intake; however, significantly different intragroup profiles were apparent throughout the whole lactation period, according to denaturing gradient gel electrophoresis analysis. In conclusion, these results suggested that the effective mitigation of enteric methane emissions by mineral salt intake could be attributed to decreased density of methanogenic archaea and that fluctuations in methane emission over the lactation period might be related to Methanobrevibacter diversity.  相似文献   

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18.
Three experiments were conducted to evaluate the effects of biostimulation (exposure to bulls or androgenized females) on various reproductive variables in suckled beef cows. Bulls or testosterone-treated cows (TTC) were introduced to cows, randomly allotted to one of four groups, within 72 h postpartum. In Exp. 1, Groups 1 and 3 were exposed to bulls and Groups 2 and 4 were exposed to TTC. In Exp. 2, Groups 1 and 3 were exposed to bulls and Groups 2 and 4 served as controls (isolated from biostimulation). In Exp. 3, Groups 1 and 3 were exposed to TTC and Groups 2 and 4 served as controls. Mean postpartum intervals to estrus were not different between cows exposed to either bulls or TTC in Exp. 1 (P greater than .10). However, in Exp. 2 and 3, cows exposed to either bulls or TTC had reduced postpartum intervals to estrus (44 and 41 d, respectively) compared with control cows (52 d; P less than .05). Fewer control cows were in estrus at either 40 d (P less than .05; Exp. 2 and 3) or 60 d (P less than .05; Exp. 3) postpartum than were cows exposed to bulls or TTC. No differences were observed between groups in any experiment for postpartum intervals to pregnancy (P greater than .10). These data indicate that cows exposed to biostimulation from either bulls or TTC immediately after calving return to estrus earlier than do cows isolated from biostimulation.  相似文献   

19.
Insulin responsiveness to glucose and tissue responsiveness to insulin, using the hyperglycemic clamp and the hyperinsulinemic euglycemic clamp techniques, were measured in lactating, late pregnant, and nonpregnant, nonlactating (NPNL) beef cows. The glucose infusion rate (GIR) in the hyperglycemic clamp technique was higher (P less than .05). in lactating cows than in NPNL cows. The plateau in plasma insulin concentration (insulin responsiveness) was higher (P less than .05) in lactating cows than in late pregnant and NPNL cows. Pregnant cows tended to have higher GIR and lower plateau in plasma insulin concentration than NPNL cows. In the hyperinsulinemic euglycemic clamp technique, GIR (tissue responsiveness to insulin) was higher (P less than .05) in lactating cows than in late pregnant cows; values for NPNL cows were intermediate. We conclude that insulin responsiveness to glucose and tissue responsiveness to insulin were enhanced during lactation but tended to be decreased during late pregnancy in beef cows.  相似文献   

20.
The effects of long-term consumption of 1 and 5 ppm of Cd on Cd, Cu, Fe, and Zn concentrations in milk and a variety of tissues of first-lactation dairy cows was investigated. Thirty-six Holstein heifers were allocated to three groups and fed similar diets differing only in the concentration of Cd (.25, 1, and 5 ppm) for a 394-d period before calving. One- and 5-ppm Cd concentrations were achieved using CdCl2. Liver, kidney cortex, and muscle were biopsied from one-half of the heifers of each group before Cd supplementation and again from the same heifers within 5 d after parturition. Colostrum and milk were sampled throughout the 150 d of lactation. Urine was sampled after an average of 450 d of Cd exposure. At slaughter (after an average of 554 d), 11 tissues were sampled from 12 cows representing all treatment groups. During the first 394 d, Cd accumulated in kidney and liver with increasing dietary concentrations of Cd but did not further increase by 554 d. However, by 554 d Cd had also accumulated in the adrenal glands, ovaries, spleen, and uteri of cows consuming 5 ppm of Cd. Dietary Cd did not influence the concentration of Cd, Cu, Fe, or Zn in colostrum or milk. However, urine pH, Zn, and K were lower in cows consuming 5 ppm of Cd. Liver Cu was reduced by 1 and 5 ppm of Cd at both 394 and 554 d.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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