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1.
OBJECTIVE: To measure and compare the concentration and composition of very low-density lipoprotein (VLDL) in plasma and selected lipids in serum of horses fed mixed grass hay ad libitum or denied feed for 36 hours. ANIMALS: 4 healthy adult mares. PROCEDURE: Mares were either fed mixed grass hay ad libitum or denied feed for 36 hours beginning at 8:00 AM. Blood samples were collected every 2 hours during the study period and analyzed for nonesterified fatty acid (NEFA), triglyceride (TG), VLDL, and glucose concentrations and composition of VLDL. RESULTS: Withholding feed significantly increased mean serum concentrations of NEFA. By 36 hours, a 16-fold increase in mean serum NEFA concentration and 2-fold increase in mean plasma VLDL concentration, compared with baseline values, were detected. Mean plasma TG concentrations significantly increased with time in feed-deprived horses. Significantly lower overall mean plasma glucose concentrations were detected in feed-deprived horses. Mean percentage of protein in VLDL was significantly lower in feed-deprived horses. Plasma VLDL concentrations varied widely among horses in response to withholding feed. Plasma TG and VLDL concentrations remained unaltered in 2 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Withholding feed significantly increases blood lipid concentrations in horses, but individual horses respond differently. Serum NEFA concentrations were increased in all 4 horses denied feed, indicating mobilization of tissue triglyceride stores. Variation in plasma VLDL concentration in response to withholding feed suggests that its metabolism is strongly influenced by other, as yet undetermined, factors in horses. Differences in the plasma VLDL concentrations among horses in response to withholding feed may be used as an indication of susceptibility to the hyperlipemic syndrome of Equidae.  相似文献   

2.
In the horse, resting insulin concentration (INS), the glucose-to-insulin ratio (G:I), and the reciprocal of the square root of insulin (RISQI = 1/√INS) are commonly used to estimate insulin sensitivity, whereas the modified insulin-to-glucose ratio (MIRG = [800 – 0.30 × (INS -50)2]/(GLU – 30) is used to estimate pancreatic beta-cell responsiveness. Because no estimates of their within-horse variability and repeatability have been reported, the objective of this study was to evaluate the within-horse variation of these estimates. Resting blood samples were obtained from six healthy equids (three geldings, two mares; mean ± SD body weight, 525.0 ± 43.36 kg; mean age, 9.8 ± 8.2 years; and one pony gelding: 293 kg; 12 years) on three consecutive days in week 1 and again in week 2. Samples were collected at 12:00 noon, approximately 6 hours postprandially. Serum insulin and plasma glucose (GLU) concentrations were analyzed and used to calculate G:I, RISQI, and MIRG, as well as the insulin to glucose ratio (I:G). The coefficient of variation was used to determine within-horse variation, and repeatability was determined using the repeatability coefficient (RC; measurements from a single horse should differ less than the RC for 95% of the pairs). The mean coefficients of variation (CVs) for resting GLU, INS, G:I, I:G, MIRG, and RISQI were 5.5%, 33.7%, 36.0%, 31.6%, 22.3%, and 18.6%, respectively. All variables had values that differed more than the RC in at least one horse. These data suggest that care should be taken when interpreting insulin sensitivity estimates from a single blood sample.  相似文献   

3.
ABSTRACT

Aims: To compare urine urinary pH, blood pH and concentration of electrolytes in blood of healthy horses fed an anionic salt supplement to achieve diets with a dietary cation-anion difference (DCAD) of ?40 or 0?mEq/kg DM, with horses a fed a diet with a DCAD of 85?mEq/kg DM.

Methods: Eight healthy horses received each of three diets in a randomised crossover design. Diets consisted of grass hay and concentrate feed, with a varying amount of an anionic supplement to achieve a DCAD of 85 (control), 0 or ?40?mEq/kg DM. They were fed for 14 days each with a washout period of 7 days between. Urine pH was measured daily and blood samples were collected on Days 0, 7 and 14 of each study period for the measurement of pH and concentration of electrolytes.

Results: Four horses voluntarily consumed the anionic supplement with their feed, but four horses required oral supplement administration via dose syringe. During the study period mean urine pH was lower in horses fed diets with a DCAD of 0 (6.91; SD 0.04) and ?40 (6.83; SD 0.04) mEq/kg DM compared to the control diet (7.30; SD 0.04). Compared with horses fed the control diet, mean urine pH was lower in horses fed the 0 and ?40?mEq/kg DM diets on Days 1–12 and 14 (p?<?0.05) of the study period. On Day 13 it was only lower in horses fed the ?40?mEq/kg DM diet (p?<?0.01). Urine pH was similar for horses fed the 0 and ?40?mEq/kg DM diets (p?=?0.151). The DCAD of the diet had no effect on blood pH, ionised Ca or anion gap. Mean concentrations of bicarbonate in blood were affected by diet (p?=?0.049); they were lower when horses were fed the 0?mEq/kg diet relative to the control diet on Day 14.

Conclusions and clinical relevance: The anionic supplement reduced urine pH in horses fed diets with a DCAD of 0 or ?40?mEq/kg DM compared with 85?mEq/kg DM. However as urinary pH did not fall below pH 6.5, the pH below which calcium carbonate uroliths do not form, this reduction in urine pH is unlikely to be clinically significant. The supplement was variably palatable and showed minimal promise as an effective urinary acidifier at the doses administered in this study.  相似文献   

4.
Seventeen Thoroughbred and Quarter Horse yearlings were used in a 2×2 factorial experiment to determine 1) whether adding fat (5% corn oil) to the concentrate would influence feed intake, growth and development and 2) whether time of hay feeding would influence energy metabolism on the basal and added fat diets. Yearlings were assigned at random, within breed and gender subgroups, to one of four diets: B-I, basal concentrate with Coastal Bermuda grass (Cynodon dactylon) hay fed immediately after the concentrate; B-D, basal with hay fed 3.5 hr after the concentrate; F-I, basal + fat with the hay fed immediately; and F-D, basal + fat with the hay fed 3.5 hr after the concentrate. The basal concentrate was formulated to meet or exceed NRC (1989) recommendations when fed with the hay. The basal + fat concentrate was formulated at 9.7% higher digestible energy than the basal concentrate and all of the other nutrients were increased proportionately so if the intake was reduced, the yearlings would still meet nutrient needs. The concentrates were fed individually to appetite for two 1.5-hr feeding periods daily in 1.5×3.0 m slip stalls. Hay was group fed in the paddocks at a rate of 1.0 kg/100 kg BW daily divided into two equal feedings. Animals were housed in four 9.1×34.9-m drylot paddocks with three, four, or five animals in each paddock. The mean age at the start of the experiment was 377±8 days. Weight and body measurements for withers height, heart girth, body length, and hip height were taken at the start of the experiment and at 28-day intervals for 84 days. Radiographs for bone mineral estimates were made at the start and completion of the experiment. During the final 28-day period of the feeding trial, three animals from each experimental group were randomly selected for a 24-h period of blood sampling to evaluate the effects of the diets on blood glucose and insulin.Fat addition to the concentrate reduced the daily concentrate DM (P=0.0187) and total feed DM (P=0.0021) intake. When feed intake was expressed as a function of BW, concentrate and total feed intakes were 1.33 and 2.14 kg/100 kg BW daily and were not influenced by diet (P>0.1). Colts consumed more concentrate DM (P=0.0039) and total feed DM (P=0.0022) than fillies. The yearlings gained an average of 0.60 kg/d for the 84 days. Weight gain, body measurements and bone mineral deposition were not influenced by gender or diet. Mean plasma glucose concentrations were higher (P=0.05) in yearlings consuming the basal concentrate with hay fed immediately than when hay feeding was delayed. When fat was fed, the time of hay feeding had no effect on plasma glucose concentrations (P>0.05). Plasma glucose and insulin were lowest just prior to the morning feeding and peaked two to three hours after both morning and afternoon feedings. Fat supplementation reduced plasma insulin (P=0.001). Results suggest that the addition of 5% corn oil to a yearling concentrate may reduce feed intake but will not reduce growth and development of the animal if other nutrients are supplied at concentrations that provide for the animal's daily needs. Delaying hay feeding may be advantageous to growing horses as it may allow the concentrate to move down the tract at a slower rate reducing the glucose peaks.  相似文献   

5.
When fed to horses, high-starch diets elevate plasma concentrations of interleukin-1β (IL-1β) as soon as 1 hour posteating. This increase in IL-β is possibly because of changes in intestinal pH that result from rapid bacterial fermentation of starches and sugars in the digestive tract. The purpose of this research was to investigate the effect of feeding 0.9 kg of grass hay 30 minutes before feeding a concentrate meal on the postprandial rise in IL-1β, compared with control horses receiving the same concentrate without hay first. Six mature geldings were used in a switchback design. Horses were fasted overnight before being offered a concentrate feed that provided 1.2 g/kg bodyweight of nonstructural carbohydrates. Plasma was harvested 30 minutes before hay feeding and 1, 2, 4, 6, and 8 hours postfeeding. Concentrations of IL-1β and d-lactate were analyzed by repeated measures analysis of variance. The hay-first treatment reduced (P = .034) postprandial concentrations of IL-1β at all time points compared with the control horses. An interaction between hour and treatment was detected for mean d-lactate concentrations (P = .037), with lower concentrations in hay-first fed horses at postfeeding hours 1, 2, and 4, compared with control horses. Given these findings, we believe that feeding a small amount of hay before feeding a meal of moderate starch and sugar content reduced the negative effects of rapid starch and sugar fermentation in the equine digestive tract, evidenced by reduced postprandial d-lactate and IL-1β concentrations.  相似文献   

6.
Eight weanling Standardbred horses were used to evaluate the effects on growth and plasma glucose of two differently processed diets with identical ingredients fed at a rate of 3% of body weight, as fed, daily. The daily ration was divided into two equal feedings at 7:00 am and 7:00 pm. The hay and grain diet (diet HG) consisted of 50% alfalfa hay cubes and 50% of a commercial growing horse texturized grain mix fed as is, without any further processing, with each part fed in separate containers. The completely pelleted diet (diet P) consisted of the same proportions of the hay cubes and grain mix that was ground, pelleted, and fed in a single container. Two groups of four horses were fed either diet P or diet HG for two 21-day periods such that each horse consumed each diet for 21 days. On the last day of each feeding period, 7-mL blood samples were drawn into heparinized evacuated blood tubes for determination of plasma glucose concentration. Blood samples were drawn 30 minutes before the afternoon feeding, immediately before, and every 30 minutes thereafter for 5 hours. Analysis of variance found greater (P = .027) average daily gain for horses fed diet P versus diet HG. A nonsignificant difference was seen in feed efficiency (P = .057) for horses fed diet P versus diet HG. Plasma glucose changes were compared across treatments using area under the curve analysis. No difference (P > .05) was found in the postprandial plasma glucose changes between diet treatments.  相似文献   

7.
The objective of this study was to evaluate the effects of live yeast (LY) in a high-fiber diet on nutrients digestibility in mature horses. Six Italian Standardbred mares (weight: 544 ± 14 kg; age: 15.30 ± 3.9 years) in a two-period crossover design were fed a basal diet (2.5% body weight [BW]) in a 70:30 forage:concentrate ratio with (LY) or without (CTR) the administration of 4.6 × 1010 colony forming unit (CFU)/d of Saccharomyces cerevisiae (MUCL 39885). An adaptation to the diet of 14 days, and an 18-day administration phase, with fecal collection in the last 3 days were performed for each period. Yeast was top-dressed twice a day during the concentrate meal (12:30 am and 09:00 pm). Change in BW was measured at the beginning of each experimental phase and the diet adjusted accordingly, and individual feed intake was recorded daily. Concentrate samples were collected at the beginning of each confinement period and individual hay samples were obtained for each confinement day 38 hours before fecal collection. No influence of LY was observed on BW change (P = .64), feed intake (P = .48), hay intake (P = .48), or concentrate intake (P = .47). S cerevisiae supplementation improved apparent digestibility of dry matter (64.5% vs. 60.1%, P = .03), organic matter (66.1% vs. 61.6%, P = .04), neutral detergent fiber (42.5% vs. 35.9%, P = .04), and acid detergent fiber (36.5% vs. 28.0%, P = .03) with a positive trend on crude protein (P = .08). In the present study, the administration of LY to horses significantly improved the digestion of the fiber fractions of the diet.  相似文献   

8.
Modern horse management systems tend to limit a horse's opportunity to forage. The objective of this experiment was to investigate the effect of hay net design on the rate of forage consumption when feeding horses. Eight adult horses were fed in individual stalls in a replicated Latin square design, with two horses per treatment per week. Horses were fed hay off the stall floor (control), or from one of three hay nets: large (15.2 cm openings), medium (4.4 cm openings), and small (3.2 cm openings). Horses had access to hay for two 4-hour periods each day. When horses could not consume all forage from the medium and small hay nets in 4 hours, a second study using a crossover design gave horses an unlimited amount of time to feed from the hay nets. Stopwatches were used to calculate time to consumption and dry matter intake rates (DMIR). Mean time to consumption was 3.1 and 3.4 hours for the control and large hay net, respectively, in study 1, and 5.1 and 6.5 hours for the medium and small hay nets, respectively, in study 2. Mean DMIR during the 4-hour feeding period were 1.5, 1.3, 1.1, and 0.9 kg/hr for the control, large, medium, and small hay nets, respectively; all treatments were different (P < .0001). These results demonstrate that hay nets were effective at decreasing the rate of forage consumption when feeding adult horses. Long-term studies are warranted to determine if horses will adapt to feeding from hay nets.  相似文献   

9.
The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4–10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α‐amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mares were offered a ration of air‐dried alfalfa and concentrate (70:30 as‐fed) in four subsequent periods of 14 days including 8 days of adaptation and 6 days of sampling. In each period and each meal, mares received concentrate either 30 min after (HC) or 30 min before (CH) alfalfa hay. Barley was either milled or boiled in water. Rectal samples were grabbed directly from rectum once per period. Mares subjected to CH had higher dry matter intakes than mares under HC regime. The acetate:propionate ratio (A:P ratio) in rectal content was higher with CH than HC. The AA activity was higher under CH than under HC. Mares fed boiled barley had lower rectal concentrations of VFA and propionate and a higher A:P ratio than mares fed milled barley. Furthermore, the rectal content showed a higher MCCase activity but a lower AA activity when mares were fed boiled compared with milled barley. Interactions between FS and TB were observed with respect to CMCase activity, and concentrations of propionate and valerate. In conclusion, the present results suggest that both, feeding concentrate before hay and boiling the barley, might improve the hindgut environment in Arabian mares, and that the two measures were mostly additive and sometimes even synergistic.  相似文献   

10.
Matua bromegrass hay (Bromus willdenowii Kunth) is a high quality forage, but its value for mares during gestation and lactation is not well known. Intake, rate of passage, performance, and reproduction by gestating and lactating Quarter Horse mares fed the hay was investigated. In this experiment, 12, 2- to 12-yr-old gravid mares (mean BW = 553 kg, SD = 36) were fed Matua hay (CP = 11.5%) or alfalfa hay (Medicago sativa L.) (CP = 15.4%) for variable days prepartum (mean 59.9 d; SD = 23.5) and for 70 d postpartum. Matua and alfalfa hay were fed as the roughage portion of the diet with a grain supplement. Mares, blocked by age, expected date of foaling, and BW, were assigned randomly within blocks to treatments (six mares per treatment). Forage type did not affect intake, gestation length, birth weight, number of foals, foal weight gain, day of first postpartum ovulation, cycles per conception, or pregnancy rate at 70 d. On d 1, milk from mares fed alfalfa hay contained less (P < 0.03) CP than milk from mares fed Matua hay. Milk CP decreased (P < 0.01) in all mares over time. In a separate experiment, voluntary intake and rate of passage of Matua (CP = 15.5%), alfalfa (CP = 24.9%), and Timothy (Phleum pratense L.) (CP = 4.1%) hays were determined in nine 2-yr-old pregnant mares (mean BW = 447 kg; SD = 21). Diets were 100% forage. Timothy hay did not meet CP requirements for mares. Voluntary intake of alfalfa hay was higher (P < 0.01) than Matua hay. Intake of Timothy hay was lower (P < 0.01) than the mean of alfalfa and Matua hay. Rate of passage offorage was measured by passage of Cr-mordanted fiber. Passage rate and retention time did not differ between Matua and alfalfa hay; however, the retention times of Matua and alfalfa hays were shorter (P < 0.01) than for Timothy hay. Our results indicate that Matua hay is a forage that can be used safely for mares during gestation and early lactation and for their young foals.  相似文献   

11.
Weight maintenance and blood chemistry parameters of geriatric (>20 yrs) horses and ponies housed at a farm for retired horses were compared between animals fed a 14% protein pelleted/extruded feed (ES) formulated specifically for geriatric horses versus those fed the textured sweet feed used at the facility. A total of 48 geriatric horses and 3 ponies were initially examined, 28 of which were assigned to be fed ES, the other 23 continued to be fed an 8.5% protein textured sweet feed mix (SF). Horses and ponies were fed the feeds in amounts estimated to be necessary for weight maintenance or gain according to initial body condition scores, with hay being offered free choice. The horses were weighed, assigned body condition scores and had blood drawn for complete blood counts and blood chemistry panels in December, 1992 before feed changes were initiated. The same measurements were taken on surviving horses and ponies three months after the feed changes had been made (March, 1993).For statistical analyses, data were grouped according to the animal's initial body condition score. Horses (n=17) and a pony with initial body condition scores of three or less (Group 1) which were fed ES had greater weight gain (ES: 32kg±4; SF: −9kg±7; p<.001); higher final condition scores (ES: 4.5±2; SF: 3.6±.3; p<.05) and plasma total protein (ES: 6.3 gm/dl±.2; SF: 5.2 gm/dl±.3; p<.005) in March than those fed SF (n=14). Group 1 horses fed SF experienced a decrease (p<.0001) in hematocrit (December: 41.4%±1.3; March: 34.4±1.2) and hemoglobin (December: 14.6±.4 gm/dl; March: 11.9±.3 gm/dl, p<.001), whereas those fed ES had a slight increase (p<.15) in hematocrit and no change (p>.2) in hemoglobin over the same period. Blood phosphorus was increased (December: 2.21±.08 mg/dl; March: 2.48±.07 mg/dl; p<.05) in Group 1 horses fed ES and tended (p<.15) to be higher than in Group 1 horses fed SF (March: 2.27±.12 mg/dl). In horses and the pony with initial condition scores greater than 3 (Group 2), condition scores, body weights and hematocrit did not differ (p>.2) between animals fed ES (n-9) versus SF (n=9) in December or March. However Group 1 animals fed ES experienced greater weight gains (p<.001) and increases in body condition score (p<.05) than Group 2 SF fed horses during this period. Blood phosphorus in Group 2 ES fed horses tended to increase (December: 2.3±.1 mg/dl; March: 2.6±.1 mg/dl; p<.10) and was higher (p<.01) in March than in Group 2 horses fed SF (March: 2.1±.1 mg/dl). In both groups, liver enzymes and creatinine did not differ (p>.2) between diets in March. Blood urea nitrogen (BUN) was higher in ES fed horses than the SF fed horses in March in both Group 1 (p<.02) and Group 2 (p<.07) but was within the normal range for adult horses.Horses which were fed the ES were subjectively assessed by the farm manager to have better hair coats and higher activity levels than when they had been fed textured sweet feed and relative to horses that were not fed ES. Geriatric horses, especially those unable to maintain adequate weight on standard rations in the absence of hepatic or renal disease, appear to benefit from the special formulation of ES.  相似文献   

12.
The objectives of this study were to assess the correlation between hoof surface temperature and ultrasonographic measurements of digital blood vessels in horses and to evaluate the measurements' potential as predictors for clinical lameness. Twelve 3-year-old American Quarter Horses, 6 geldings and 6 mares, with average initial body weight of 459 ± 31 kg were used. On days 0, 30, 60, and 90 of the study, horses were weighed and subjected to clinical lameness examinations. Doppler ultrasonography was used to measure diameter of the medial palmar artery in the distal left forelimb and velocity of blood flow through that artery, starting at 60 minutes after morning feeding and repeated at 30-minute intervals. Temperature measurements on the hoof were collected at 15-minute intervals beginning 75 minutes after feeding, using a digital thermographic camera. A series of bivariate linear mixed models were fitted to estimate the correlation between Doppler and temperature measurements. The within-horse and between-horse correlations between hoof surface temperature and velocity of blood flow in the distal limb through the medial palmar artery was estimated at 0.40 (P > .50) and 0.99 (P < .001), respectively. These results indicate that at the horse level, the correlation between hoof temperature and velocity of blood flow in the distal limb was very high but that the within-horse correlation was not significantly different from 0. Velocity of blood flow at 60 minutes after feeding improved model fit to the lameness data, so it was included as a model predictor for lameness.  相似文献   

13.
Minocycline is commonly used to treat bacterial and rickettsial infections in adult horses but limited information exists regarding the impact of feeding on its oral bioavailability. This study's objective was to compare the pharmacokinetics of minocycline after administration of a single oral dose in horses with feed withheld and with feed provided at the time of drug administration. Six healthy adult horses were administered intravenous (2.2 mg/kg) and oral minocycline (4 mg/kg) with access to hay at the time of oral drug administration (fed) and with access to hay delayed for 2 hr after oral drug administration (fasted), with a 7‐day washout between treatments. Plasma concentration versus time data was analyzed based on noncompartmental pharmacokinetics. Mean ± SD bioavailability (fasted: 38.6% ± 4.6; fed: 15.7% ± 2.3) and Cmax (fasted: 1.343 ± 0.418 μg/ml; fed: 0.281 ± 0.157 μg/ml) were greater in fasted horses compared to fed horses (p < .05 both). Median (range) Tmax (hr) in fasted horses was 2.0 (1.5–3.5) and in fed horses was 5.0 (1.0–8.0) and was not significantly different between groups. Overnight fasting and delaying feeding hay 2 hr after oral minocycline administration improve drug bioavailability and thus plasma concentrations.  相似文献   

14.
Five groups of horses were fed different diets of known trace mineral concentration for a minimum of six months. Copper (Cu), zinc (Zn) and manganese (Mn) concentrations were measured in livers of 125 yearling horses and kidneys of 81 yearling horses as an assessment of trace mineral status. Plasma Cu and Zn determinations were made for all horses.

Mean hepatic Cu concentrations of horses fed diets containing 6.9 to 15.2 mg Cu/kg dry matter (DM) feed were 0.27 to 0.33 μmol/g DM tissue. Plasma Cu concentrations ranged between 22.8 to 28.3 μmol/L. There was no simple mathematical relationship between plasma and hepatic Cu concentrations. Mean hepatic Zn concentrations in horses fed diets containing 25.6 to 52.2 mg Zn/kg DM feed were determined to be between 2.75 to 2.91 μmol/g DM tissue. Mean plasma Zn concentrations in groups of horses were between 11.7 to 13.5 μmol/L. Plasma Zn concentrations were not indicative of hepatic Zn concentration. Hepatic Mn concentrations ranged between 0.13 and 0.14 μmol/g DM tissue.

Renal Zn concentrations ranged between 1.55 to 1.63 μmol/g DM tissue and did not differ with diet. Mean renal Mn concentrations were 0.09 μmol/g DM tissue for all groups of horses. Renal Cu concentrations ranged from 0.36 to 0.47 μmol/g DM tissue and differed with diet.

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15.
Thousands of hectares of timothy (Phleum pretense L.) grown in the Mid-Atlantic region are infected by cereal rust mite (Abacarus hysterix) that causes discoloration and curling of leaves, decreased nutritional quality, and substantial decreases in yield. A decline in production of timothy hay can lower income for hay producers and cause horse owners to search for alternative hays. Low alkaloid reed canarygrass (Phalaris arundinacea L.) hay has potential as an alternative to timothy hay because it grows well in the Mid-Atlantic region, is believed to have a similar nutrient quality to timothy, and is not as susceptible to cereal rust mite. Eleven mature, stalled Thoroughbred geldings (549 +/- 12.1 kg) that were exercised daily were used to compare voluntary DMI and apparent nutrient DM digestibility of timothy and low-alkaloid Chiefton variety reed canarygrass hay. Horses were paired by age and BW and randomly assigned to timothy or reed canarygrass hay during a 14-d period to measure voluntary DMI followed by a 4-d period to measure apparent DM digestibility. Both hays met the minimum requirements for DE, CP, Ca, P, K, Fe, and Mn, but they did not meet the minimum requirements for Cu, Zn, and Na for horses at maintenance and averaging 550 kg of BW. Timothy hay seemed to have a lower CP concentration (14.4%) compared with reed canarygrass hay (17.1%) and a more desirable Ca:P ratio at 1.6:1 compared with 0.8:1 for reed canarygrass hay. Horses fed timothy consumed more hay (P <0.001) during the voluntary DMI period compared with horses fed reed canarygrass. Greater voluntary DMI of timothy occurred on d 1, 3, and 5 (P <0.05), but DMI was similar for other days. Apparent DM digestibility was greater in horses fed timothy hay by 9.6% compared with horses fed reed canarygrass hay (P <0.05). Horses fed timothy had greater DM digestibility of ADF (P = 0.001), NDF (P = 0.001), sugar (P = 0.05), and Ca (P = 0.001) but lower apparent DM digestibility of CP (P = 0.012) and crude fat (P = 0.004). Timothy hay was superior in voluntary DMI and apparent DM digestibility compared with low-alkaloid reed canarygrass hay fed to horses.  相似文献   

16.
Teff (Eragrostis tef) is a productive warm season annual grass. Because teff is relatively new to the horse industry in the United States, horses unaccustomed to teff hay were used in two sets of two-choice preference tests comparing teff with alfalfa hay or teff with timothy hay. A second experiment used mature mares to compare voluntary dry matter intake (VDMI) of teff hay and timothy hay. In the two-choice preference tests, horses preferred alfalfa hay and timothy hay to teff hay (P < .05). Horses preferred teff hay that was cut at an earlier stage of maturity and had lower concentrations of neutral detergent fiber and acid detergent fiber than teff hay cut at a later stage of maturity. In the VDMI experiment, four mares were fed teff hay and four mares were fed timothy hay for 17 days. Both hays had been harvested in the head stage of maturity. VDMI was measured during the last 10 days and was not different between the two groups of horses (P > .05). It was concluded that horses that are unfamiliar with teff may discriminate against it when it is offered simultaneously with alfalfa or timothy; however, if not given a choice, horses will consume approximately the same amount of mature teff as mature timothy. Additional studies are needed to compare VDMI of early maturity teff hay with other common hays.  相似文献   

17.
The influence of forage conservation method on microbial and chemical composition in forage and on colon content and faeces in horses fed with the forages was investigated. Hay (815 g DM/kg), haylage (548 g DM/kg) and silage (343 g DM/kg) was produced from the same grass crop and fed to four fistulated horses in a crossover study. Horses were sampled in right ventral colon and of faeces after a feeding period of 21 days (for each forage). Fermentation kinetics of right ventral colon was also studied on two subsequent days in each period, with sampling times immediately before and 2, 4, 8 and 12 h after the morning meal. Forage conservation method influenced microbial and chemical composition of the forages. Silage differed from haylage and hay in more variables than haylage differed from hay. However, the different forage types had similar influence on microbial and chemical composition of right ventral colon content and faeces in horses at Day 21, with the exception of counts of Streptococci which were highest when horses were fed with hay. However, interaction among forage types and sampling locations (right ventral colon and faeces) was also present for Streptococci as well as for pH. In general, pH was lower and counts of lactate utilizing and lactate producing bacteria were higher in faeces compared to right ventral colon. Fermentation kinetics in colon varied little among forage types and sampling times, and no interaction between forage types and sampling times were found, indicating that silage, haylage and hay had very similar fermentation kinetics in right ventral colon of horses. In conclusion, silage, haylage and hay produced from the same grass crop tended to produce similar responses in microbial and chemical composition in right ventral colon and faeces in horses fed with the forages.  相似文献   

18.
Growth hormone is a key component of the somatotropic axis and is critical for the interplay between nutrition, regulation of metabolic functions, and subsequent processes of growth. The objective of this study was to investigate potential relations between meal feeding concentrates differing in the glycemic responses they elicit and GH secretory patterns in young growing horses. Twelve Quarter Horse weanlings (5.4 ± 0.4 mo of age) were used in a crossover design, consisting of two 21-d periods and two treatments, a high-glycemic (HG) or low-glycemic (LG) concentrate meal, fed twice daily. Horses were individually housed and fed hay ad libitum. On the final day of each period, quarter-hourly blood samples were drawn for 24 h to measure plasma glucose, insulin, non-esterified fatty acids, and GH. Growth hormone secretory characteristics were estimated with deconvolution analysis. After a meal, HG-fed horses exhibited a longer inhibition until the first pulse of GH secretion (P = 0.012). During late night hours (1:00 AM to 6:45 AM), HG horses secreted a greater amount of pulsatile GH than LG horses (P = 0.002). These differences highlight the potential relations between glycemic and insulinemic responses to meals and GH secretion. Dietary energy source and metabolic perturbations associated with feeding HG meals to young, growing horses have the potential to alter GH secretory patterns compared with LG meals. This may potentially affect the developmental pattern of various tissues in the young growing horse.  相似文献   

19.
Plasma and urinary levels of salicylic acid were examined in Standardbred mares after administration of various feeds, containing different compositions of hay. In addition, horses were administered acetylsalicylic acid orally and methyl salicylate topically. Elevated salicylic acid levels were observed in horse urine and plasma in animals fed lucerne hay. The plasma and urinary elimination of salicylic acid exhibited a diurnal pattern which was related to the type of feed and the feeding schedule. Within 24 h after oral administration of acetylsalicylic acid, plasma and urine salicylic acid levels were consistent with residual levels observed after feeding lucerne hay. Elimination of salicylic acid was rapid and complete, with a half-life between 5 and 7 h. Topical administration of methyl salicylate (8.4 g) produced elevated urinary salicylic acid levels for 6 h. A smaller dose of methyl salicylate (3.4 g) did not elevate plasma or urine salicylic acid levels above those observed following administration of lucerne hay.  相似文献   

20.
It was hypothesized that horses exhibiting crib-biting (CB) have a greater degree of gastric mucosal damage and higher serum gastrin response to concentrate feeding than non-crib-biting (NCB) horses. Eighteen mature horses, 9 CB and 9 NCB, were used to determine prevalence and severity of gastric mucosal damage and effect of concentrate feeding on circulating gastrin. Horses were maintained on pasture with free access to hay and fed a pelleted concentrate diet twice daily. Number of crib-bites and duration of cribbing bouts were recorded in a 24-hour period. Endoscopic examinations (EE) of the squamous mucosa were performed and gastric fluid sampled after 24 to 28 hour feed removal. Following EE, horses were returned to pasture for 72 hours. Blood was collected following 12-hour feed removal (0 minutes), and at 60 and 120 minutes after consuming 1 kg of concentrate. Mean number of crib bites in 24 hours was 1,558 ± 303 with CB peaking prior to and during the afternoon feeding (3:30 PM, P < .05). There were no differences in the number or severity of ulcers, prevalence of hyperkeratosis, or baseline gastric pH between CB and NCB. Serum gastrin concentration at 60 and 120 minutes was greater (P < .05) and tended to be greater (P < .06), respectively, in CB than in NCB horses following feeding of concentrate. Crib-biting behavior in horses maintained on pasture was not associated with gastric mucosal damage; however, consumption of concentrate feed resulted in greater serum gastrin concentration in CB horses.  相似文献   

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