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PubMed2001

A possible role of neuropeptide Y as a mediator of undernutrition to the hypothalamic gonadotropin-releasing hormone pulse generator in goats.

To understand central mechanisms for nutritional infertility, the activity of the GnRH pulse generator was directly assessed in ovariectomized (OVX) goats under several experimental conditions by recording characteristic increases in the multiple-unit activity (volleys). When estradiol (E(2))-treated animals were fasted for 4-5 days, the activity of the GnRH pulse generator was gradually suppressed, and the volley interval at the end of fasting was significantly prolonged, compared with that during the feeding period (67.4 vs. 49.3 min, n = 5, P < 0.01). On the other hand, such a significant effect on the pulse generator was not observed in OVX goats. In the second experiment, the animals received a bolus intracerebroventricular injection of several doses (0, 2, 5, and 20 microg/400 microl) of neuropeptide Y (NPY). Exogenous NPY dose-dependently inhibited the pulse generator activity. At the highest dosage, the 1st posttreatment volley interval was significantly longer than that of the pretreatment (112.4 vs. 32.6 min, n = 5, P < 0.01) in OVX goats. The suppressive effect of NPY was similarly observed in OVX+E(2) goats. Further, when NPY was infused (10 microg/200 microl.h for 6 h) into OVX goats, the activity of the GnRH pulse generator was almost completely inhibited during the infusion period. Hypothalamic sites responding to fasting were immunohistochemically evaluated using an antibody for Fos in castrated goats. Fos-immunoreactive neurons were found in areas adjacent to the third ventricle. Double-labeling immunohistochemistry revealed that a subpopulation of NPY neurons in the arcuate nucleus was activated in response to fasting. These results demonstrate that: 1) the activity of the GnRH pulse generator is suppressed by fasting in the presence of E(2); 2) exogenous NPY inhibits the activity of the GnRH pulse generator regardless of the presence of E(2); and 3) several hypothalamic neurons or regions, including those containing NPY in the arcuate nucleus, are activated by fasting. Collectively, these observations suggest that NPY acts as a mediator of undernutrition to the GnRH pulse generator.

Animal Nutritional Physiological Phenomena↗

PubMed2005

Immunolocalization of steroidogenic enzymes in the corpus luteum and placenta of the Japanese Shiba goat.

In this study, we performed immunohistochemistry of cholesterol side-chain cleavage cytochrome P450 (P450scc), 3beta-hydroxysteroid dehydrogenase (3betaHSD), cytochrome 17alpha-hydroxylase P450 (P450c17), and cytochrome P450 aromatase (P450arom) in the corpus luteum and placenta of Shiba goats. The aim was to clarify the steroidogenic capability of the corpus luteum and placenta of Shiba goats. Ovaries containing corpora lutea were obtained from four adult Shiba goats during the luteal phase (day10; n=2) and pregnancy (90 and 120 days of gestation). Placenta was obtained from one Shiba goat on day 120 of gestation. The sections of the ovaries and placentae were immunostained using the avidin-biotin-peroxidase complex method (ABC) with polyclonal antibodies generated against steroidogenic enzymes of mammalian origin. All luteal cells expressed P450scc, 3betaHSD, P450c17 and P450arom. The distribution of P450scc, 3betaHSD, P450c17 and P450arom were not different during the luteal phase and pregnancy. P450arom showed a weak positive staining in late pregnancy (120 days). In addition, immunoreactions for P450c17 and P450arom were observed in syncytiotrophoblast of the placenta of one Shiba goat. These results indicate that, in Shiba goats, corpus luteum is not only an important source of progesterone but also has the ability to synthesize androgen and estrogen during the luteal phase and pregnancy. Also the placenta has the ability to synthesize androgen and estrogen in late pregnancy.

17-Hydroxysteroid Dehydrogenases↗

PubMed2004

Body growth and plasma concentrations of metabolites and metabolic hormones during the pubertal period in female Shiba goats.

It has been shown in various species that the onset of puberty is closely associated with body growth and nutritional state rather than age. The present study was conducted to determine the timing of puberty and to clarify body growth and metabolic changes around the pubertal period in female Shiba goats. Blood samples were collected between 10 to 38 weeks of age from 12 female goats, and plasma concentrations of progesterone, metabolites (glucose, nonesterified fatty acid, ketone body and acetic acid) and metabolic hormones (insulin and insulin-like growth factor-I (IGF-I)) were analyzed. Physical parameters (body weight, withers height and body length) were also measured at the blood sampling. The week when plasma progesterone concentrations first exceeded 1.0 ng/ml was designated as the onset of puberty. The results showed that the average age of the onset of puberty was 27.0 +/- 0.9 (mean +/- SEM) weeks in female Shiba goats. When the goats reached puberty, the average values of body weight and goat body mass index ((body weight (kg)/withers height (cm)/body length (cm)) x 10(3)) were 12.2 +/- 0.5 kg and 5.7 +/- 0.2, respectively. No particular change associated with puberty was apparent for plasma concentrations of the metabolites examined. Plasma insulin concentrations were maintained at lower levels until the onset of puberty, and then they began to gradually increase. Plasma IGF-I concentrations began to gradually increase 1 to 4 weeks before the onset of puberty and this increase continued throughout the peripubertal period. These results imply that IGF-I acts as a peripheral nutritional signal to trigger the onset of puberty in Shiba goats.

Acetic Acid↗

PubMed1981

Studies on hybridization between a Barbary ram (Ammotragus lervia) and domestic ewes (Ovis aries) and nanny goats (Capra hircus).

Six nanny goats and 9 ewes were inseminated with Barbary semen and 4-5 days after insemination 16 hybrid embryos were recovered: 14 were transferred to ewes or nanny goats. Survival of embryos was monitored by return to service after transfer, peripheral plasma progesterone values and by examination at laparotomy. None of the Barbary ram x ewe embryos transferred to 4 ewes and 4 nanny goats or the Barbary ram x nanny goat embryos transferred to ewes survived. Of the 4 nanny goat recipients of Barbary rm x nanny goat embryos one had a resorbed fetus at 7 weeks after transfer, one was pregnant at 7 weeks but failed to produce a young and a third produced a healthy male 155 days after the transfer oestrus. The karyotype of the hybrid was 2n = 59XY, characterized by a single metacentric chromosome.

Animals↗

PubMed1975

Concentrations of prolactin in serial blood samples from goats before, during and after milking throughout lactation.

Two experiments are described in which prolactin was measured in (a) serial blood samples taken at monthly intervals (April-November) from six lactating goats before, during and after milking and (b) in similar blood samples taken on days 2, 7 and 12 after parturition. The quantity of prolactin released at milking (April-August) varied both between goats and within the individual goat. No correlation was found between the duration of milking and the quantity of prolactin released into the circulation (r equals minus 0-24, P greater than 0-1) or the average concentration of prolactin found at milking (April-August) and the average daily milk yield of the individual goat (r equals minus 0-57, P greater than 0-1). No evidence was found for a release of prolactin conditioned by events normally preceding milking. The results showed a correlation between the average concentration of prolactin released at milking each month and the average milk yield of the six goats (r equals 0-67, P smaller than 0-05). The physiological significance of this correlation is discussed. No correlation was found between the average concentration of prolactin released during early lactation and the average milk yield of the goats (r equals 0-36, P greater than 0-1).

Animals↗

PubMed1975

Seasonal factors affecting the release of prolactin in goats in response to milking.

An investigation has been carried out in goats of the possible seasonal factors which might influence the autumn decline in the average concentration of prolactin released at milking. Serial blood samples were taken during milking, once a month between August and December 1972, from groups of mated, non-mated and ovariectomized goats and also from goats maintained in summer light conditions (17 h light: 7 hr darkness). Since high levels of progesterone occur in the circulation during the major part of the oestrous cycle and pregnancy in the goat, the same sampling procedure was carried out earlier in the year (June-August) in animals which had been implanted with progesterone tablets. Although high levels of progesterone in the circulation inhibited the release of prolactin at milking, oestrus, mating and pregnancy were not found to be responsible for the fall in prolactin levels in the blood in the autumn. In each of these cases the concentration of prolactin released at milking decreased uniformly between August and October. Housing goats in summer lighting conditions, however, maintained the release of prolactin at milking at a consistently high level from August until December, but had no effect on the milk yield which declined in a manner similar to that of the control animals. It is concluded that daylength is the predominant factor governing the autumn decline in the concentration of prolactin released at milking and that the decline is not the major cause of the fall in milk production during late lactation in goats.

Animals↗

PubMed1979

Mammary growth during pregnancy in hypophysectomized or bromocriptine-treated goats.

Mammogenesis in primiparous hypophysectomized goats has been assessed between days 60 and 120 of gestation and compared with that found in untreated goats and goats treated with 5 mg bromocriptine/day. There were fivefold increases in the weight of lobulo-alveolar tissue in the hypophysectomized and bromocriptine-treated goats and a tenfold increase in the untreated goats. Histological examination of the mammary glands at 120 days showed normal structure, and determinations of lactose, lactose synthetase, cytosol enzymes, protein, DNA and RNA indicated qualitatively normal initiation of milk synthetic capabilities in both the hypophysectomized and bromocriptine-treated goats. Bromocriptine treatment lowered the plasma concentration of placental lactogen as well as that of prolactin. The results indicate that placental lactogen has important mammogenic effects during pregnancy.

Animals↗

PubMed1985

Thyroxine concentrations and secretion rates in relation to pregnancy, lactation and energy balance in goats.

Plasma thyroxine (T4) concentrations were measured during pregnancy and lactation in goats on diets with different energy concentrations to study the role of T4 secretion in metabolic adaptation to pregnancy and lactation. Thyroxine distribution space (the volume of fluid required to dissolve the total pool of circulating T4 at a concentration equal to that in the plasma) and secretion rates were determined by using 125I-labelled T4 at different stages of lactation and pregnancy. Plasma concentrations of T4 increased during lactation and reached maximum levels 4-5 months after giving birth. They then remained fairly constant for the following 2-3 months until the goats became pregnant again. Thyroxine concentrations decreased slightly during pregnancy and showed a sudden drop at the onset of lactation. Minimum concentrations were observed during the first 2-3 weeks of lactation after which time concentrations increased slowly. Average concentrations for goats on a low-energy diet were consistently lower than those in goats on a high-energy consistently lower than those in goats on a high-energy diet. The mean secretion rate was 10.4 nmol day-1 kg body wt-0.75. The distribution spaces were much lower than the total extracellular space. The average distribution space in non-pregnant and pregnant goats was 11 and 5.3% of the body weight respectively. The decrease in T4 secretion rate and T4 distribution space during pregnancy is considered to be part of a homeorhetic adaptation to the condition. The drop in T4 secretion rate at the onset of lactation appears to be a homeostatic adaptation to a decreased fuel supply, similar to the situation with fasting or energy malnutrition.

Animals↗

PubMed2003

Ovarian and hormonal response of female goats to active immunization against inhibin.

This study was conducted to evaluate the effect of active immunization against inhibin on hormonal levels and the ovulation rate in goats. Ten adult Shiba goats (Capra hircus) in two groups were used in this study. The first group was injected with inhibin vaccine (immunized, n=5) and the second group was injected with Freund's adjuvant (control, n=5) followed by three booster injections at 4-week intervals. After the third booster injection, three consecutive periods of oestrus were induced using prostaglandin F(2alpha) at intervals of 11 days. Blood samples were collected at 2-6 h intervals and the ovaries were monitored using B-mode ultrasonography. All inhibin-immunized goats generated antibodies that bound (125)I-labelled bovine inhibin and their FSH concentrations were significantly higher than corresponding values in the control group. Also, inhibin-immunized goats had significantly higher preovulatory oestradiol-17beta (P<0.01) and higher concentrations of progesterone in the luteal phase (P<0.05). Immunization of goats against inhibin resulted in a significant (P<0.01) increase in ovulation rate (control: 1.7+/-0.3 vs immunized: 7.6+/-1.1). These results demonstrate that active immunization against inhibin enhances ovarian follicular development and ovulation rate by promoting an increase in pituitary FSH secretion. Therefore, immunization against inhibin may be a useful alternative to the conventional approach of superovulation in goats.

Animals↗

PubMed2006

A model of spontaneous periodontitis in the miniature goat.

BACKGROUND: The pathogenesis and progression of periodontal disease have been extensively studied through the use of animal models. However, no animal model has yet been established that is precisely similar to periodontitis in humans. In the present study, we examined the use of Shiba goats as a model for spontaneous periodontitis. METHODS: Thirty-four Shiba goats (seven males and 27 females, aged 10 to 98 months) were used. We examined periodontitis in Shiba goats clinically, histopathologically, and microbiologically. RESULTS: The mean probing depth (PD) of the 68 teeth examined was 2.7 +/- 0.8 mm. The incidences of PD > or =3 and 4 mm were 46.4% and 22.1%, respectively. The incidence of bleeding on probing in 68 sites and in 34 animals was 60.7% and 73.5%, respectively. The formation of vertical alveolar bone defects and downgrowth of gingival epithelial cells were found in the areas of periodontitis. The prevalence of Tannerella forsythensis, Campylobacter rectus, Fusobacterium necrophorum, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans in subgingival plaque by polymerase chain reaction was 46.4%, 28.5%, 28.5%, 17.8%, and 3.5%, respectively. These percentages were increased in subgingival plaque from PD > or =3 mm. CONCLUSIONS: The clinical, histopathological, and microbiological features of spontaneous periodontitis in Shiba goats were somewhat similar to those in human periodontitis. Moreover, there are some advantages of using the Shiba goat; the size of the oral cavity is suitable for periodontal treatment, and handling and housing are relatively easy. Therefore, these results suggest that the Shiba goat is a useful animal model for human periodontitis.

Animals↗

PubMed1990

Comparative utilization of warm- and cool-season forages by cattle, sheep and goats.

The quality of different classes of forage hay (C3, C4 grasses and legumes) was determined in intake and digestibility trials with mature cattle, sheep and goats. For all nine hays, DM and NDF digestibility by cattle and goats was higher (P less than .05) than by sheep, with no differences due to forage class. Cattle had a higher (P less than .01) DM intake than sheep or goats averaged across forage (92.6 vs 65.8 and 68.6 g/kg BW.75); hay intake was highest on legume, with no difference between C3 and C4 grasses. Mean NDF intake by cattle was greater than by sheep or goats (58.7 vs 39.6 and 42.6 g/kg BW.75); NDF intake for all animal species decreased in the order C4 grass greater than C3 grass greater than legume. Particle passage rates did not differ (P greater than .05) with forage class but were higher (P less than .02) for sheep and goats than for cattle. Prefeeding ruminal DM fill values, determined by emptying, were 10.6, 15.0 and 19.9 g/kg BW1.0 for alfalfa, orchardgrass and switchgrass hays fed to cattle, and 11.2, 11.3 and 16.5 g/kg BW1.0 for the same hays fed to sheep. Estimated turnover times for DM and NDF were shorter (P less than .05) for sheep than for cattle; DM turnover was longer for switchgrass than for alfalfa and orchardgrass, with no forage differences in NDF turnover between these two animal species. Results show that goats were superior to sheep in NDF digestion.

Animal Feed↗

PubMed1999

Adrenocortical response to ACTH in Angora and Spanish goat wethers.

Angora goats do not cope well with stress compared with goats of other breeds. Our hypothesis that this involves subclinical primary hypoadrenocorticism associated with low cortisol release in response to ACTH stimulation was tested by measuring adrenocortical response (plasma cortisol) in six Spanish (37 +/- 2 kg BW) and six Angora wethers (39 +/- 3 kg BW) under simulated acute and chronic ACTH challenges. In Exp. 1 (acute ACTH challenge), wethers were dosed i.v. with high (2.5 IU/kg BW) or low (.4 IU/kg BW) quantities of ACTH. In Exp. 2 (chronic ACTH challenge), ACTH at the rate of .015 IU/(kg BW x min) or saline (.15 M NaCl) was infused i.v. at 15 mL/h for 6 h. The mean baseline plasma cortisol concentration before ACTH stimulation was similar (P > .05) between Angora and Spanish goats in Exp. 1 (averaged over days) and in Exp. 2. The cortisol concentration response area (ng/ (mL x min) x 10(-3)) above the baseline was similar (P > .05) between Angora and Spanish goats during low (7.6 +/- .5 and 9.0 +/- 1.7, respectively) and high (12.8 +/- 1.0 and 16.0 +/- 1.8, respectively) levels of acute ACTH challenge (Exp. 1) and during chronic ACTH challenge (45.1 +/- 5.9 and 41.8 +/- 7.3, respectively; Exp. 2). In conclusion, these data indicate that, under the conditions of this study, adrenocortical responsiveness to ACTH stimulation is not different between Angora and Spanish goat wethers and, thus, may not contribute to stress susceptibility in Angora goats.

Adrenal Cortex↗

PubMed2001

Growth and slaughter traits of Boer x Spanish, Boer x Angora, and Spanish goats consuming a concentrate-based diet.

The number of Boer crossbred meat goats has been increasing rapidly, although how their growth and slaughter traits compare with those of Spanish goats and influences of maternal genotype have not been thoroughly evaluated. This information would be useful to achieve optimal meat goat production systems and yield of goat products desired by consumers. Therefore, postweaning growth (9 to 24 wk of age) and slaughter traits (212 +/- 5.0 d of age) of Boer x Spanish, Spanish, and Boer x Angora wethers (n = 16, 18, and 18 for growth measures, respectively, and n = 6 per genotype for slaughter traits) consuming a concentrate-based diet were compared. Over the 16-wk performance period, ADG, DMI, and ADG:DMI were greater (P < 0.05) for Boer crossbreds than for Spanish goats (ADG: 154, 117, and 161 g; DMI: 646, 522, and 683 g/d; ADG:DMI: 263, 235, and 261 g/kg for Boer x Spanish, Spanish, and Boer x Angora, respectively). Dressing percentage (46.3, 47.3, and 47.0% of BW; SE = 1.21) and quality grade score (11.17, 9.67, and 11.17 for Boer x Spanish, Spanish, and Boer x Angora, respectively; SE = 0.66 [12 = Choice+; 11 = Choice; 10 = Choice-; 9 = Good+]) were similar among genotypes. Weights of some noncarcass components were greater for Boer crossbreds than for Spanish goats, but relative to empty BW, noncarcass component weights were similar among genotypes. Concentrations of moisture, ash, fat, and protein in carcass and noncarcass components did not differ among genotypes. Contributions to the carcass of different primal cuts were similar among genotypes, and there were few differences in concentrations of separated lean, bone, and fat in primal cuts. In conclusion, when consuming a concentrate-based diet, early postweaning growth rate was similar between Boer x Spanish and Boer x Angora wethers and greater for Boer crossbreds than for Spanish wethers. Slaughter traits were primarily related to differences in final BW.

Animals↗

PubMed2002

Effects of N-methyl-D,L-aspartate on LH, GH, and testosterone secretion in goat bucks maintained under long or short photoperiods.

Photoperiod modulates reproduction in goats. We tested the hypothesis that the excitatory glutamatergic tone is reduced in the photoinhibited goat. The objectives of this study were to determine the effect of photoperiod and glutamatergic stimulation on LH, GH, and testosterone (T) secretion in goat bucks. Eight mature, intact bucks were used in two simultaneous 4 x 4 Latin square designs. Variables were two photoperiod regimens (short day; SD, 10 h light:14 h dark, n = 4; vs long day; LD, 16 h light:8 h dark, n = 4) and four doses of N-methyl-D-L-aspartate (NMA; 0, 1, 2 and 4 mg/kg BW, i.v.). Venous blood was obtained for 2 h before and after NMA injection, followed by GnRH injection and then a final 1 h of sampling. Injection of NMA increased (P < 0.002) LH secretion within 20 min. This increase was sustained for 120 min, but the response was most pronounced in LD goats. The increase in mean LH was associated with a concomitant dose-dependent increase in pulse frequency (P < 0.006). However, NMA treatment had no effect (P > 0.10) on LH pulse amplitude. The release of LH after injection of GnRH was not affected by photoperiod. Exposure of bucks to LD reduced T secretion relative to that of SD bucks (P < 0.01). However, GH secretion was enhanced in LD bucks (P< 0.001). The response of GH to NMA was dependent on photoperiod history. A highly significant immediate and sustained increase (P < 0.001) was observed in LD but not in SD bucks within 10 min. Overall, a dose-dependent increase (P < 0.01) in T secretion was stimulated by NMA in both LD and SD bucks. These results indicate that NMA receptors may be involved in the regulation of LH, GH, and testosterone secretion in the goat. Furthermore, length of day influences GH secretion in the goat and NMA receptor activation had divergent effects on the secretion of this hormone.

Animals↗

PubMed1986

Dynamics of digestion in cattle, sheep, goats and deer.

Four experiments were conducted to study factors affecting digestibility of forages in cattle, sheep, goats and white-tailed deer. In a series of digestion trials (Exp. 1), the dry matter digestibility of a moderately high fiber diet was greater in cattle than in deer. Digestibilities of the diet in sheep and goats were intermediate and not different from either extreme. In a second series of trials (Exp. 2), relative organic matter digestibilities were for goats more than sheep more than deer. However, in Exp. 2, intake in goats was very low and digestibility appeared to be positively related to retention time and inversely related to turnover rate. Results of three trials (Exp. 3) suggested that rate of digestion was related more to diet than to the animal species consuming the diet. In grazing animals (Exp. 4), goats digested a smaller percentage of consumed material than either cows or sheep during three of four seasons even though diets were of similar in vitro digestibility. This difference was related to a faster turnover and shorter retention time in goats. These data support the concept that there are species differences in gastrointestinal dynamics which may be which may be important determinants of adaptability to grazing conditions.

Animal Feed↗

PubMed1992

Metabolism of antipyrine and sulphadimidine in dwarf goats: effects of the enzyme-inducing agents phenobarbital, troleandomycin and rifampicin.

1. Antipyrine (AP) and sulphadimidine (SDD) plasma elimination and metabolite formation were studied in dwarf goats before and after treatment with phenobarbital (PB), triacetyloleandomycin (TAO), and rifampicin (RIF). 2. PB treatment significantly increased AP plasma clearance in both male and female goats. With SDD, only male goats were studied, which showed a significant increase of SDD plasma clearance following PB treatment. 3. After PB treatment, partial clearance values of four AP metabolites, 3-hydroxymethylantipyrine (HMA), norantipyrine (NORA), 4-hydroxyantipyrine (OHA) and 4,4'-dihydroxyantipyrine (DOHA), were significantly increased. This induction effect was different for the individual metabolites and also showed sex-dependency. 4. In PB-induced male goats the formation of the hydroxylated SDD metabolites, 6-hydroxymethyl-SDD and 5-hydroxy-SDD, was significantly increased. 5. After TAO treatment, female goats showed a slightly reduced AP plasma clearance and a decreased partial clearance of two AP metabolites, HMA and DOHA. There was no effect on SDD plasma elimination or metabolite excretion. 6. In male goats, RIF had no effect on plasma elimination of AP and SDD. With SDD, it decreased the urinary excretion of the unchanged drug and its N4-acetylated metabolite. 7. Induction/inhibition studies of drug metabolism in food-producing animal species are desirable to gain more insight into the regulation of enzymes involved in the metabolism of xenobiotics.

Animals↗

PubMed1979

The structure of goat hemoglobins. V. A fourth beta chain variant (beta-D-Malta; 69 Asp is replaced by Gly) with decreased oxygen affinity and occurring at a high frequency in Malta.

During a survey of hemoglobin types in goats in the Republic of Malta a variant (Goat Hb D-Malta) was discovered which differs from normal goat Hb A by the substitution of an aspartyl residue in position beta 69 (E13) by a glycyl residue. The gene frequency of the beta D allele was 0.255; 29 homozygous Hb D goats were present among 327 animals sampled. Homozygous Hb D goats also produce Hb C, whose beta chains are the product of a non-allelic beta C structural gene. Goat Hb D-Malta has a distinctly decreased affinity for molecular oxygen.

Amino Acid Sequence↗

PubMedDate not supplied

Growth profiles and articular cartilage characterization in a goat model of Legg-Calve-Perthes disease.

Numerous animal species, including the goat, have been evaluated as potential models for human Legg-Calve-Perthes disease (LCPD). These models disrupt the vasculature of the femoral head, causing it to collapse, and therefore do not mimic all the clinical patterns of the human disease. Baseline data regarding the weight and femoral length in the growing goat are not available. This study characterized the goat's normal growth for comparison with that of humans. The growth aberrations in the proximal femur created by surgically ablating the capital physis were described and compared with the aberrations observed in human LCPD cases. Age, weight, and femoral length (test and control) data were obtained for goats approximately 1 to 14 months of age. At 4 months of age, a craniolateral surgical approach was used to expose the cranial lateral capital physis so that it could be cauterized. Postoperative radiographs were evaluated by graphic analysis to assess the resultant changes in the morphology of the proximal femur. The articular cartilage of the femoral head and acetabulum was evaluated mechanically, using indentation testing, to determine the apparent modulus of elasticity, and histopathologically regarding its thickness and proteoglycan content. The proximal femurs of goats and humans exhibit similar morphology and growth patterns. There was a positive correlation between age, weight, and femoral lengths in the goat. The surgical procedure was effective in ablating the capital femoral physis as indicated by shorter femoral lengths and fragmented, flattened, and mushroomed femoral heads. The histopathological data revealed that the articular cartilage was significantly thicker in the operated hip joints at the ventrocaudal and cranial acetabula and the dorsal and ventral femoral heads. The test cartilage exhibited significantly less positive staining for proteoglycans in the dorsocaudal and the cranial acetabula as well as the ventral femoral head. The apparent modulus of elasticity, of the test cartilage was significantly lower than the control value at the dorsocaudal acetabulum. These data show that the surgical procedure produced morphological changes that mimic those in human LCPD. The increased thickness of the articular cartilage of the LCPD femoral head may account for the articular degeneration observed in older patients with LCPD, as increased cartilage thickness is associated with decreased tissue quality.

Animals↗