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1.
Sixteen Quarter Horse weanlings were used in a splitplot design experiment to determine the effects of dietary cation-anion difference (DCAD) on mineral metabolism, osteocalcin concentration and variables of growth. Horses were blocked by age and sex and then randomly allotted to two treatment groups (High or Low). Experimental diets with a DCAD of +325 (High, H) and −52 (Low, L) were formed by supplementing diet H with sodium bicarbonate and diet L with calcium chloride. The DCAD was calculated as meq (Na+K)−(Cl+S)/kg of diet DM. The 25-week trial consisted of three 72 h collection periods at 150, 240 and 330 d of age during which a complete urine collection was taken.Multiple fecal grab samples were collected to represent every 2 h post-feeding during each collection period. Venous blood samples were taken for analysis of serum osteocalcin concentration. Weekly measurements were taken to monitor skeletal growth. Representative samples of feed, feces and urine were analyzed for mineral content and apparent mineral balances were calculated by difference. Although osteocalcin concentration did not differ significantly between diets H and L at 150 and 330 d of age, it was higher (P<.05) at d 240 in horses consuming diet H versus diet L. No difference (P>.05) was detected between treatments in any skeletal growth variable measured. Phosphorus balance and digestibility did not differ significantly between treatments across d of age. However, digestibility of P was lower (P<.05) at d 240 and 330 compared to d 150 in both treatments. Horses consuming diet L experienced an increased (P<.05) urinary and a decreased (P<005) fecal excretion of Ca compared to horses consuming diet H. Apparent daily Ca balance was higher (P<.05) in horses consuming diet L than those on diet H at 240 and 330 d of age. Furthermore, Ca digestibility decreased significantly between d 150 and d 240 and 330 in horses consuming diet H. Horses consuming diet L experienced no difference (P>.05) in Ca digestibility across d of age.These findings suggest that horses consuming a low DCAD diet are able to compensate for the increased urinary excretion of Ca by enhancing intestinal Ca absorption and thereby increasing daily CA balance and digestibility.  相似文献   

2.
Sixteen Quarter Horse yearling fillies were used in a 112-day randomized block experiment to determine the comparative efficacy of alfalfa hay protein to support growth in young horses. The yearlings were divided into two groups of eight and paired according to weight and age, with one yearling from each pair randomly allotted to each diet. Group 1 was fed a diet of coastal Bermuda grass hay and concentrate. The corn-based concentrate was supplemented with soybean meal such that the total diet for group 1 contained approximately 13% CP. Group 2 was fed a diet that also contained approximately 13% CP and consisted of alfalfa hay and a similar concentrate without soybean meal. Yearlings were fed the diets in a 60:40 grain-to-hay ratio, and intakes between members of each pair were equalized. The calculated digestible energy density in both final diets was approximately 2.85 mcal/kg, and the protein:calorie ratio for both diets was approximately 45 gm/Mcal. Body weight, body length, heart girth, wither and hip heights, as well as forearm, gaskin and cannon bone circumferences were measured every 28 days. Rump fat thickness was measured ultrasonically every 28 days. Physical measures of growth were similar for horses eating each diet (P>0.05). Also, blood urea nitrogen was similar for horses eating each diet (P>0.05) and was not reflective of differences in nitrogen metabolism. The fillies fed the SBM-supplemented diet retained more nitrogen more efficiently than did fillies fed the alfalfa diet (P<0.05), and the SBM-fed fillies had higher concentrations of osteocalcin on days 14, 28, 42, and 112. It can be concluded that SBM and alfalfa proteins were equally effective in providing growth to young horses; however, the biological value of absorbed nitrogen appeared to be higher in the fillies fed the SBM-supplemented diet. also, differences in serum osteocalcin concentrations indicate that the SBM-fed fillies were experiencing a greater amount of osteoblastic activity than the alfalfa fed fillies.  相似文献   

3.
Sixteen Quarter Horse-type geldings were used to examine the response of biochemical markers of bone metabolism to forced exercise prior to and during race training. The study began when the average age of the horses was 15 months. Horses were exercised on a high-speed treadmill for 14 weeks, and were subsequently placed into race training. Serum was collected and assayed for concentrations of osteocalcin (BGP), the carboxyterminal telopeptide of type I collagen (ICTP) and the carboxyterminal propeptide of type I procollagen (PICP). When data were normalized from the onset of race training, ICTP and PICP concentrations were higher in the pre-exercised horses (P<.05 and P<.1, respectively) indicating higher rates of bone turnover. Overall, bone turnover appeared to be decreased during race training, as concentrations of PICP and ICTP were lower when compared to values seen during the pre-training Phase.  相似文献   

4.
Serum samples from 15 suckling foals, 119 days of age, of Quarter Horse and Thoroughbred breeding, that were weaned at either 140 days of age (EW) or 182 days of age (LW) were used to measure changes in vitamin K status over time and to assess the effect of age at weaning on vitamin K status. Jugular venous blood samples were collected from each foal at the start of the experiment and 21-day intervals thereafter, with the exception of a one-week interval post-weaning in both groups. The study continued for 84 days post-weaning in both groups. Serum was analyzed for total osteocalcin and hydroxyapatite binding capacity of serum osteocalcin (HABOC) which was calculated as follows: HABOC = [(total serum osteocalcin — serum osteocalcin following extraction of serum with hydroxyapatite)/total serum osteocalcin]x100. Osteocalcin's capacity to bind hydroxyapatite is vitamin K-dependant and, therefore, is used as a marker of vitamin K status. Hydroxyapatite binding capacity of serum osteocalcin increased (quadratic; P<0.01) over the experimental period regardless of weaning age, indicating an increase in vitamin K status in both weaning groups. In addition, there was a tendency for an age at weaning by time interaction (P=0.056) on serum HABOC. This tendency was due to significantly higher HABOC at 182 days of age for EW as compared to LW (P<0.05). After 182 days of age, HABOC was not different between EW and LW. Serum osteocalcin decreased (linear; P<0.01) in both weaning groups over the experimental period. In conclusion, vitamin K status increased and serum osteocalcin decreased with age. In addition, vitamin K status tended to increase at a greater rate in foals weaned early as compared to those weaned late.  相似文献   

5.
To determine to effect of feeding tall fescue hay infected with endophyte on growth rate, diet digestibility, and serum prolactin, 17 Quarter Horse yearlings were fed a diet of 60% concentrate and 40% tall fescue hay for 5 months. Diets were formulated to meet 1989 NRC recommendations for moderate growth. The dietary treatments included either non-infected (E-, n=9) or infected (E+, n=8) tall fescue hay. Field sampling determined a 52% infection rate of the E+ hay with the endophyte Acremonium coenophialum. Initially and at 29-day intervals, yearlings were weighed and measured for skeletal growth including: (1) height at the withers, (2) length of bone between knee and fetlock, (3) length of bone between hock and fetlock, and (4) the circumference of fore and rear cannon bones. Total fecal collection from the 10 geldings during the last month of the trial permitted the calculation of diet digestibility. Serum samples were taken throughout the trial to determine prolactin response to dietary treatments.The E+ fescue hay did not affect (P>.05) growth rate of yearling horses. Yearlings gained .40 and .38 kg/d when consuming the E− and E+ based diets, respectively. Geldings gained more (P<.05) than fillies. Changes in height at the wither and length and circumference of the fore and rear cannon were positive but did not differ between hay treatments or sexes.E+ fescue hay diets tended to be lower in dry matter, apparent energy, and crude protein digestibility, but values were not statistically different. Fiber digestibility was lower (P<.01) for the diet based on E+ hay. Neutral detergent fiber digestibility averaged 66.2 and 54.4% for E− and E+ diets, respectively.Acid detergent fiber digestibility averaged 78.9 and 64.5% for E− and E+ diets, respectively. Although fiber digestibility of E+ tall fescue hay was lower than E-hay, grain supplementation supportive of a moderate growth rate produced equal growth among yearling horses. Also, no differences in prolactin were apparent between the yearlings fed E− and E+ tall fescue hay.  相似文献   

6.
An experiment was conducted to determine the effect of aerobic training after a sedentary period on bone remodeling and Ca and P balance and serum concentrations in varying ages of mature horses. Eighteen stock-type geldings were blocked into three age groups (6 to 10, 11 to 15, and 16 and older years of age), within two groups of nine, with horses randomly assigned to one of two exercise treatments, exercised for 112 days (control) or idle for 56 days followed by 56 days of exercise (treated). Blood samples were taken at the beginning of period I and at 14-day intervals thereafter to determine serum concentrations of osteocalcin (OST), Ca, and P. Dorsal-palmar and lateral-medial radiographs were taken of the left third metacarpal bone on days 0, 56, 84, and 112 to monitor changes in bone density. Total fecal and urine collections were taken for 72 hours on days 0, 56, and 112. Mean serum OST concentrations were affected by treatment (P<.02), time (P<.001); and the interactions of treatment and age (P<.003), time and treatment (P<.001), and time, treatment, and age (P<.001). Overall dorsal (DBRAE), palmar (PRBAE), and medial (MRBAE) RBAE means were affected by time (P<.001), as was overall lateral (LRBAE) RBAE mean (P<.005). Overall DBRAE and PRBAE means were lower (P<.04) at day 56, and higher at day 84 (P<.02) and 112 (P<.001) as compared to day 0. Mean serum Ca concentration was affected by treatment (P<.003) and time (P<.001). Mean serum P concentration was affected by the interaction of time and treatment (P<.001). Mean apparent daily Ca balance was affected bythe interaction of time, treatment, and age (P<.03). Mean apparent daily P balance was affected by treatment (P<.02) and time (P<.001). Biochemical and radiographic data from this experiment suggest that bone remodeling as well as Ca and P balance and serum concentrations are affected by age, inactivity, and exercise in mature horses.  相似文献   

7.
Muscle biopsy samples were removed from the m gluteus medius of 47 retired running Quarter Horse (QH) mares. Horses were separated based on bloodline, past racing history and percentage Thoroughbred (TB). The bred to run and raced (BRRA) and bred to run and not raced (BRNR) groups possessed a lower percentage (P<.01) of fast-twitch low oxidative (FT) fibers (BRRA 38.6 and BRNR 36.2±2.54 respectively). These horses also possessed a higher percentage (P<.01) of fast-twitch high oxidative (FTH) fibers (BRRA 52.5 and BRNR 48.5±2.54, respectively) than not bred to run and not raced (NBNR) horses. Horses that were bred to run had higher (P<.05) FTH to FT fiber ratios (1.44) than horses that were not bred to run (.94). Successful racehorses possessed a lower percentage (P<.05) of slow-twitch (ST) fibers and a higher percentage (P<.05) of FT fibers than unsuccessful racehorses. Success or failure was determined by Speed Index. No differences (P>.05) were found in the percentage FTH fibers between successful and unsuccessful horses.  相似文献   

8.
Four mares and four geldings of Quarter Horse and Thoroughbred breeding were used in two simultaneous 4x4 Latin square experiments to study the effects of dietary cation-anion balance (DCAB), defined as meq ((Na+K)-C1)/kg dry matter, on urinary pH and mineral excretion in exercised horses. Diets consisted of a pelleted concentrate of corn, soybean meal and cottonseed hulls fed with bermudagrass hay. Treatments with DCAB of +5 (Low, L), +107 (Medium Low, ML), +201 (Medium High, MH) and +327 (High, H), meq ((Na+K)-Cl)/kg dry matter were formed by supplementing diet L with calcium chloride and ammonium chloride, diet ML with calcium chloride and diet H with sodium bicarbonate and potassium citrate (Table 1). Diet MH was not supplemented and served as the control treatment. Horses were conditioned aerobically for 6 weeks using long, slow, distance (LSD) workouts. During the experimental periods, horses were subjected to a combined exercise regimen alternating LSD with an interval-training protocol 6 days/week. There was a significant (P<.01) treatment effect on urine pH; least squares means for L, ML, MH and H were 6.73, 7.17, 7.38, and 7.92. Horses consuming diet L excreted more calcium in the urine (P<.05) than those consuming MH or H. Least squares means for daily urine calcium excretion tended to be linear across treatments and ranged from 19.66 g/day for diet L to 9.12 g/day for diet H. Urinary chloride excretion was higher (P<.05) for L than for MH or H. Horses fed diet H excreted more sodium (P<.05) in urine than horses fed the other diets. Lowering DCAB, increases urinary calcium loss; depending on the level of calcium intake, this could lead to negative calcium balance in exercising horses.  相似文献   

9.
Fifty-three Quarter Horses were put into race-training at 18 mo of age. Changes in the third metacarpal were monitored by radiographic densitometry initially at 83 days prior to the commencement of training and at days 0, 62, 104 and 244 of training. A normal increase in density of the third metacarpal due to growth and mineralization was seen from the first set of radiographs until the horses began training at day 0 (P<.001). Bone density then decreased to day 62 (P<.001), remained low through day 104 before it began to increase to day 244 (P<.005). Differences in the most optically dense portion of each cortex of the third metacarpal were compared in horses completing the study without injury and those sustaining a bone-related injury. Horses experienced fewer injuries when they had greater cortical mass in the lateral (P<.05) and medial (P<.1) aspects of the third metacarpal, relative to the palmar aspect, at the commencement of training.  相似文献   

10.
Six mature Quarter Horse-type geldings were used in a replicated 3 × 3 Latin square experiment to determine the effects of adding 5 or 10% feed-grade rendered animal fat to the concentrate diet fed to performance horses. The experiment was conducted over a 14-day pre-trial period to acquaint horses to the experimental apparatus, a 28-day conditioning period and 3 diet treatment periods of 21 days, each conducted in a Latin square arrangement. The horses were exercised on a dirt track and diet effects were evaluated during and following a submaximal exercise test (SET) on an equine treadmill. Physiological responses to the SET were determined following each experimental period. Relative to the control, the horses required 21% and 25% less of the concentrate feed (P<.05), containing 5% and 10% added fat, respectively. There was an increase (P<.05) in muscle glycogen concentration as fat was added to the diet. There were no differences due to feeding fat in nutrient digestibility or in oxygen consumption, ventilatory capacity, respiratory quotient, heart rate blood lactate or blood pH during the SET. However, there was an overall decrease (P<.05) in blood glucose and total lipid concentration, when 10% fat was added to the concentrate diet  相似文献   

11.
Thirty, 19-week-old Quarter Horses were utilized in a 112-d study to compare growth, nutrient utilization and post prandial thyroid hormone concentrations in weanling horses fed fat-supplemented or conventional diets. Concentrates were formulated to contain the same nutrient-calorie ratios and were fed with Coastal Bermuda grass hay in a 70:30 concentrate:hay ratio. Initially and at 28-d intervals the horses were weighed and measured for height, heart girth circumfer ence and subcutaneous fat thickness over the rump and ribs. Radiographs were taken of the right carpal and metacarpal phalangealjoints at the beginning and end of the experimental period for evaluation of bone density and physeal maturation. A digestion trial was conducted on each horse 10 d prior to completion of the study. On d 70, blood samples were col lected from 6 females in each treatment group over a 6-h collection period for evaluation of postprandial insulin, T4 and T3 concentrations in response to the diets. Horses in both groups consumed an average of 2.6% of body weight daily of total feed (Dry Matter). Weanlings consuming the fat-supplemented concentrate tended to have higher (P = .10) average daily weight gains (.80 vs .74 kg) and lower (P<.05) feed:gain ratios (6.3 vs 7.3) than weanlings fed the control diet. Gain in heart girth circumference was greater (P<.05) for the fat fed weanlings (20.1 cm) than the control weanlings (17.9 cm). All other linear measurements of growth were similar between treatments. There were no radiographic indications of abnormalities in the physes of horses on either treatment. Closure of the physes occurred at normal rates in foals on both treatments. Radiographic bone density was not different between treatments, and there was an expected increase in bone density in weanlings on both treatments over time. Digestibilities of protein and energy were similar between treatments, while ether extract and neutral detergent fiber digestibilities were higher (P<.05 and P<.06, respec tively) in those horses consuming the fat-supplemented diet (65.39 vs 57.67% and40.55 vs 35.62%, respectively). These data indicate that fat can be used as an energy source to support growth and development in weanling horses.  相似文献   

12.
This study examined the effects of exogenous equinesomatotropin (eST — Equigen) administration on mineral absorption and retention in two-year-old horses in race training. Sixteen Quarter Horse geldings were paired by age (ave.age=794 d), and one horse from each pair was assigned at random to either the eST treatment group or the control. The experiment was conducted over 112 days during which the horses were gentled to ride and trained on a dirt track in a regimen typical for race horses in training. At 28-day intervals, collections of total fecal and urinary output were made to determine effects on Ca, inorganic P, Mg, Cu and Zn mineral balance.Due to marginal and slightly deficient amounts (P<01)of Ca, P, Mg and Zn intake by days 84 and 112, a result of reduced feed intake to maintain a constant body condition in the presence of a decreased workload, mineral balance for the aforementioned minerals was only examined through day 56. In contrast to the previous minerals, Cu intake appeared adequate. Ca, P, Mg, Cu and Zn intake did not differ (P>.05) by treatment. The eST-treated horses increased (P<.05) Ca retention as a percent of Ca absorbed, had greater (P<.05) overall apparent efficiency of P absorption and greater (P<.05) apparent retention of P on day 56 than the control horses. The eST-treated horses had greater (P<.05) apparent Cu absorption on day 56, greater (P<.05) apparent Cu absorption efficiency on days 56 and 84, and there was a trend (P<.1) for the eST-treated horses to retain more Cu on day 56 than the control horses. Finally, the eST-treated horses retained a greater percent (P<.1) of absorbed Zn on day 56.  相似文献   

13.
Effect of age on liver enzyme activities in serum of healthy quarter horses   总被引：2，自引：0，他引：2  
Serum alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), 5'nucleotidase (5'NT), sorbitol dehydrogenase (SDH), and aspartate transaminase activities were measured in 10 clinically healthy foals, 10 yearlings, and 10 two-year-old Quarter Horses. Enzyme activities in foals at 0.5 to 3 days, 2 to 3 weeks, and 5 to 7 weeks of age were compared with enzyme activities from yearling and 2-year-old horses. Multivariate analyses of variance revealed significantly higher enzyme values in foals (P less than 0.002). This increase was mainly a result of higher ALP and GGT activities, with lesser effects due to higher SDH and 5'NT activities. Standard deviations for ALP and GGT were also larger in foals than in adult horses. The wide variation of ALP and GGT activities may limit their usefulness in the diagnosis of hepatic disease in foals. Standard deviations for serum AST, SDH, and 5'NT activities were smaller. These enzymes may be indicators of hepatobiliary disease in foals. The high serum enzyme activities in healthy foals may reflect a physiologic difference between foals and adult horses. Relative hepatic mass (as a percentage of body weight) and enzyme activity per gram of hepatic tissue are high in young animals, indicating that the high serum enzyme activities in foals are due partly to a high rate of enzyme production and release.  相似文献   

14.
Plasma concentrations of plasminogen were determined in 28 clinically normal horses, including 13 adult geldings, five non-pregnant mares, five pregnant mares and five yearlings (two fillies, three geldings). Plasminogen was quantitated by a chromogenic assay based on activation of plasmin by excess urokinase. The overall mean plasma plasminogen for these horses was 2.94 +/- 0.54 CTA units (casein units, as defined by the Committee on Thrombolytic Agents) per ml. There were no significant differences in mean plasma plasminogen values among adult geldings, non-pregnant mares, pregnant mares or yearling horses (P greater than 0.05).  相似文献   

15.
Serum bone specific alkaline phosphatase (BALP) and osteocalcin were measured in 9 Thoroughbred and 4 Quarter Horse (QH) foals. Eight were colts, and 5 were fillies. The first blood sample was collected from foals between 10 and 14 hours after birth on day 1. Blood then was collected on days 3, 6, 9, 12, 15, 18, 21, 28, 35, 42, 49, 56, 70, 84, 98, and 112 between 7:00 and 9:00 am. Serum bone metabolism marker raw data were analyzed with analysis of variance with repeated measures over time with gender and breed in the model. Average serum osteocalcin concentrations were higher for Thoroughbred than QH foals: 152.1 ± 4.6 ng/mL and 131.3 ± 6.3 ng/mL (mean ± standard error), respectively (P = .01). No overall differences were seen for gender (P = .10). However, on day 1, colts had higher osteocalcin than did fillies at 199.6 ± 30.2 ng/mL and 93.8 ± 32.4 ng/mL, respectively (P = .04). Thoroughbred foals had higher average serum BALP concentrations than did QH foals, with average values of 260.8 ± 13.4 U/L and 205.1 ± 18.5 U/L, respectively (P = .02). No gender differences were seen for serum BALP (P = .48). Serum carboxy-terminal propeptide of Type I procollagen (PICP) concentrations could not be measured in this study because the Metra Biosystems assay for PICP could not be validated.

Introduction

Bone synthesis by the osteoblast can be divided into 3 phases: proliferation, matrix development and maturation, and mineralization.1 Gene expression of type I collagen takes place during the proliferation of the osteoblast cells. The expression of bone specific alkaline phosphatase (BALP) reaches its maximum during matrix maturation and declines as matrix mineralization starts. The osteocalcin gene is expressed during matrix mineralization.When type I collagen is produced as procollagen and released into the extracellular space, the amino and carboxyterminal propeptides of type I procollagen (PINP and PICP, respectively) are cleaved off.2 Serum PICP has been shown to be a good marker for bone formation in metabolic bone diseases.3 In Thoroughbred fillies, PICP has an inverse relationship with age, with highest values found in animals less than 1 year of age.4 Serum alkaline phosphatase (ALP) has been measured in the young foal and is highest at birth, decreasing to a constant level by 2 months of age.5, 6 and 7 Serum BALP constitutes 60% to 92% of the total serum ALP in the horse and is highest in the foal.4 and 8 As the foal matures, there is an inverse relationship between age and serum BALP.4 and 9 Serum osteocalcin in foals less than 6 months of age has not been reported as having the same age-related pattern as serum BALP.10However, younger horses have higher serum osteocalcin values than mature horses.11, 12 and 13 Davicco et al14 showed plasma osteocalcin age-related changes for Thoroughbred foals with radioimmunoassay (RIA). Plasma osteocalcin was low at birth, increased to day 8, and then dropped to day 15. The objective of this study was to establish normal ranges and age-related changes in serum BALP, PICP, and osteocalcin in the foal with enzyme-linked immunospecific assays (ELISAs).

Materials and methods

Four Quarter Horse (QH; 2 fillies and 2 colts) and 9 Thoroughbred (3 fillies and 6 colts) foals were included in the study from birth through 112 days of age. Foals were born from February 5 to May 13, 1998. Mares and foals were housed on 40 acres of Bahiagrass (Paspalum notatum) pasture and fed a 15% crude protein (as fed) sweet feed. Body scores were recorded every 28 days on a scale from 1 to 9.15 Concentrate was fed to each mare at 1.5 kg/100 kg body weight daily and was increased by 20% for each body condition score below 5 and decreased by 20% for each body condition score above 5. Mares were individually fed in 3.6 × 3.6—m stalls twice daily, with foals allowed access to the mares feed. Trace mineral salt blocks were available in the pastures. Water was available at all times.Blood was collected from foals between 10 and 14 hours after birth on day 1. Blood then was collected on days 3, 6, 9, 12, 15, 18, 21, 28, 35, 42, 49, 56, 70, 84, 98, and 112 after morning feedings. Except for day 1, all blood samples were collected between 7:00 and 9:00 am. All blood samples were collected with jugular venipuncture into a glass vacutainer containing no additives or anticoagulants and were allowed to clot. Serum was separated and frozen at −20°C within 4 hours of collection. All samples were analyzed within 6 months of collection.The Alkphase-B immunoassay for the determination of BALP (Metra Biosystems, Mountainview, Calif) and the NovoCalcin immunoassay for determination of osteocalcin (Metra Biosystems), used in this study, have been previously validated in the horse.16 and 17 The Prolagen-C immunoassy for determination of the PICP (Metra Biosystems) has not been previously validated in the horse.17Serum bone metabolism marker raw data were analyzed with analysis of variance with repeated measures over time with gender and breed in the model. Analyses were performed with Statistical Analysis System with proc glm for the analysis of variances.18

Results

Average serum osteocalcin concentration for the testing period was higher for Thoroughbred than QH foals: 152.1 ± 4.6 and 131.3 ± 6.3 ng/mL (mean ± standard error), respectively (P = .01). No overall differences were seen for gender (P = .10). However, on day 1, colts had higher osteocalcin concentrations than did fillies at 199.6 ± 30.2 ng/mL and 93.8 ± 32.4 ng/mL (P = .04; Fig 1).
Full-size image (4K)
Fig. 1. Serum osteocalcin (OC) over time (mean ± standard error). A, Changes over time between breeds. B, Changes over time between gender. P < .05.
The intraassay coefficient of variation (CV) was 2.3%, 4.4%, and 10.3% for 4.7, 20.7, and 159.4 ng/mL osteocalcin serum pools. Interassay CV was 5.4%, 4.8%, and 6.1% for 2.3, 6.4, and 24.1 ng/mL osteocalcin serum pools.Thoroughbred foals had higher average serum BALP concentrations than did QH foals, with average values of 260.8 ± 13.4 U/L and 205.1 ± 18.5 U/L, respectively (P = .02). Daily serum BALP breed differences were detected only on days 12 and 112, with Thoroughbred foals having higher values than QH foals at 240.4 ± 18.4 U/L versus 168.6 ± 24.2 U/L (P = .05) and 172.3 ± 14.3 U/L versus 107.6 ± 23.2 U/L (P = .05; Fig 2).
Full-size image (4K)
Fig. 2. Serum BALP over time (mean ± standard error). A, Changes over time between breeds. B, Changes over time between genders. P < .05.
No gender differences were seen (P = .48; Fig 2). The intraassay CV was 3.6%, 2.8%, and 4.7% for the 51.9, 139.4, and 401.8 U/L BALP serum pools. Interassay CV was 5.78%, 11.8%, and 13.7% for the 15.8, 71.3, and 145.6 U/L BALP serum pools.The Prolagen-C immunoassay procedure for the determination of PICP used in this study could not be validated. Linearity for serial dilutions of serum samples could not be shown. Therefore, no PICP data are shown.

Discussion

Early age-related changes in plasma osteocalcin have been previously reported for the foal with RIA.14 Plasma osteocalcin levels were low at birth, increased to day 8, and then dropped to day 15. This study supports those trends in plasma levels of osteocalcin. However, as Hoyt and Siciliano16 observed, serum osteocalcin values determined with the immunoassay (Metra Biosystems) were higher than those observed with RIA. The antibody specificities may be different between the 2 assays. Thoroughbred foals had higher average serum osteocalcin than QH foals, which supports findings that serum osteocalcin differs among breeds.19 No gender differences had previously been reported for serum osteocalcin in horses of different ages, but when foals are stressed by weaning or exercise, gender differences were seen.12 and 20 Although no overall gender differences were seen in this study, on day 1, colts had higher serum osteocalcin than fillies. Plasma cortisol is high in the newborn foal.21 Although no serum cortisol was measured in this study, there may be different levels of cortisol or different responses to cortisol between the colts and fillies as a result of foaling. Because glucocorticoid administration results in suppressed serum osteocalcin in the horse,22 it would be of great value to understand the relationship between gender and cortisol in the neonatal foal.Serum BALP (making up most of serum ALP) values in the neonatal foal, extensively documented in this study, are in agreement with the measurements of serum ALP established in earlier reports.5, 6 and 7 Serum BALP is high at birth and decreases to a lower level by 2 months of age. Average serum BALP is higher in Thoroughbred foals than QH foals, and there are no gender serum BALP differences. No other reports for breed or gender differences concerning serum BALP in the horse have been documented. Likewise, in newborn humans, no serum BALP gender differences have been observed for the first 10 weeks of life.23Price24 and Jackson et al9 used the radioimmunoassay provided by Orion Diagnostica to determine PICP concentrations.4 and 9 Because the Metra Biosystems PICP procedure could not be validated in this study, no comparison with reported data could be made.

Conclusion

Serum BALP and osteocalcin concentrations were measured during the first 112 days of age with age, gender, and breed ranges for the foals being established when ELISA assays are used (Metra Biosystems). Because the total number of animals was small and variability of the data was large, the statistical power to detect meaningful differences for gender and breed was small. However, the data presented show trends of serum bone formation markers, some statistical differences for gender and breed, and variability of the foal during the first 112 days of age. In agreement with Price,24 a single measurement of a serum bone metabolism marker is of little clinical value, especially for the young foal where the variability is high. Because RIA ranges are typically lower than with ELISA assays for serum osteocalcin, the type of assay used should be considered when comparing serum osteocalcin levels between experiments. For use of serum markers to assess bone metabolism in the foal, the relationship of these markers with foal maturation, endocrinology, and skeletal growth needs to be resolved.  相似文献   

16.
Six Thoroughbred geldings were used in a Latin squaredesign to determine the effects of three feeding regimens and two postprandial intervals on stress parameters during rest, exercise, and recovery. Each horse was randomly assigned to one of six treatments on six sampling days. The three feeding regimens consisted of a fasting regimen in which no feed was offered, or an isoenergetic (4.1 Mcal DE) meal of either corn or alfalfa. One or 4 h after feeding, a standardized exercise test (SET) was imposed on all horses. The SET consisted of three 10-min periods each of saddling, walking to the arena, and warm-up (walking and trotting), followed by three bouts of progressively more intense galloping at heart rates of 130–140 (10 min), 150–160 (10 min), and 170–180 bpm (5 min), respectively. Blood was sampled via jugular catheters from 0630 to 1500, including the 55-min SET. Analysis of variance by repeated measures within either the 1- or 4-h protocol showed no differences between dietary treatments for glucose concentration; differences due to sampling time were shown for concentrations of glucose, lactate, cortisol, α1-acid glycoproteins (AGP), and the neutrophil to lymphocyte ratio (N:L). In both the 1- and 4-h protocols, glucose concentrations decreased precipitously in cornfed horses at the onset of the SET, but rebounded at the termination of the galloping. Plasma glucose concentrations in fasting and alfalfa-fed horses decreased slightly and then gradually increased throughout the SET. Serum cortisol and plasma lactate concentrations did not differ (P >.05) between dietary treatments, but increased concentrations were detected during the SET in both the 1- and 4-h protocols. The AGP concentration and N:L did not differ (P>.05) due to dietary treatments; however, AGP concentrations marginally increased (P<.10) from prefeeding to early recovery during the 1-h but not the 4-h protocol. The N:L increased (P<.05) in response to exercise; elevated values were detected in early recovery.  相似文献   

17.
OBJECTIVE: To determine concentrations of IgA and IgG subclasses in serum, colostrum, milk, and nasal wash samples of adult horses and foals. ANIMALS: Seven 2-year-old Welsh ponies, 27 adult mixed-breed horses, and 5 Quarter Horse mares and their foals. PROCEDURE: Serum was obtained from ponies and adult horses. Colostrum and milk were obtained from mares and serum and nasal wash samples from their foals immediately after parturition and on days 1, 7, 14, 28, 42, and 63. Nasal wash samples were also obtained from 23 adult horses. Concentrations of immunoglobulins were determined by use of inhibition ELISA. To determine transfer of maternal isotypes to foals, concentrations in colostrum and milk were compared with those in foal serum. Serum half-lives of isotypes in foals were also determined. RESULTS: IgGb was the most abundant isotype in serum and colostrum from adult horses, whereas IgA was the predominant isotype in milk. The major isotype in nasal secretions of adult horses and foals > or = 28 days old was IgA, but IgGa and IgGb were the major isotypes in nasal secretions of foals < or = 14 days old. Serum half lives of IgGa, IgGb, IgG(T), and IgA in foals were 176, 32, 21, and 3.4 days, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The early immunoglobulin repertoire of neonatal foals comprised IgGa, IgG(T), and IgA; endogenous synthesis of IgGb could not be detected until 63 days after birth. The restricted repertoire of immunoglobulins in foals may influence humoral immune responses to vaccination.  相似文献   

18.
OBJECTIVE: To determine effects of dexamethasone on insulin sensitivity, serum creatine kinase (CK) activity 4 hours after exercise, and muscle glycogen concentration in Quarter Horses with polysaccharide storage myopathy (PSSM). ANIMALS: 4 adult Quarter Horses with PSSM. PROCEDURE: A 2 x 2 crossover design was used with dexamethasone (0.08 mg/kg) or saline (0.9% NaCl) solution administered IV every 48 hours. Horses were exercised on a treadmill daily for 3 wk/treatment with a 2-week washout period between treatments. Serum CK activity was measured daily 4 hours after exercise. At the end of each treatment period, serum cortisol concentrations were measured, a hyperinsulinemic euglycemic clamp (HEC) technique was performed, and muscle glycogen content was determined. RESULTS: Mean +/- SEM serum cortisol concentration was significantly lower after 48 hours for the dexamethasone treatment (0.38 +/- 0.08 mg/dL), compared with the saline treatment (4.15 +/- 0.40 mg/dL). Dexamethasone significantly decreased the rate of glucose infusion necessary to maintain euglycemia during the HEC technique, compared with the saline treatment. Muscle glycogen concentrations and mean CK activity after exercise were not altered by dexamethasone treatment, compared with the saline treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone significantly reduced whole-body insulin-stimulated glucose uptake in Quarter Horses with PSSM after a 3-week period but did not diminish serum CK response to exercise or muscle glycogen concentrations in these 4 horses. Therefore, a decrease in glucose uptake for 3 weeks did not appear to alleviate exertional rhabdomyolysis in these horses. It is possible that long-term treatment may yield other results.  相似文献   

19.
Plasma ceruloplasmin activities and plasma Cu and Zn concentrations were determined in 215 clinically normal equids of various ages and breeds. Newborn foals, regardless of breed, were hypocupremic, compared with adolescent and mature horses. The mean plasma Cu concentration of newborn Standardbred-Thoroughbred (STD-TB) foals was 2.9 mumol/L, which was about one-sixth of plasma Cu concentrations of mature horses. Newborn draft-cross foals had higher (4.6 mumol/L) plasma Cu concentrations than did newborn STD-TB foals, but plasma Cu content was only one-fifth of the dams' concentrations. Draft-cross horses, regardless of age, had plasma Cu concentrations 15% to 40% higher than did STD-TB horses. Plasma Cu concentrations of Quarter Horse yearlings were similar to those in draft-cross yearlings. Plasma ceruloplasmin activities revealed a curvilinear relationship to plasma Cu concentrations. Plasma Zn concentrations of newborn and 1-week-old STD-TB foals were 30% to 80% higher than those for yearling and mature STD-TB horses. There were no differences between draft-cross neonates and their dams in plasma Zn concentration. Plasma Zn concentrations of neonatal and mature draft-cross horses were 22% higher than those obtained for all other equids. Age and breed of equid should be a consideration in interpretations of plasma Cu and Zn concentrations in equids.  相似文献   

20.
Coastal Bermuda grass hay was fed as the sole source of nutrients to determine comparative voluntary intake and nutrient digestibility of hay in yearling and mature horses. Yearling horses consumed dry matter at a higher (P<.10) percentage of their body weight (2.5%) than mature horses (2.0%). digestion of hemicellulose was higher (P<.05) in mature horses, but digestion of dry matter, gross energy, neutral detergent fiber and crude protein was similar between the 2 classes of horses.  相似文献   

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