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PubMed2002

Fasting-induced suppression of pulsatile luteinizing hormone secretion is related to body energy status in ovariectomized goats.

The effect of energy status on the response of luteinizing hormone (LH) pulse frequency to acute short-term energy deficiency created by fasting in estradiol-treated ovariectomized Shiba goats was studied in two experiments. In experiment 1, eight goats whose mean body weight (BW) was 25.6 +/- 5.8 (mean +/- S.D.)kg were fed 500 g hay cubes daily for 1 week. Then they were fasted for 3 days. Blood samples were collected for 4 h at 6 min intervals on the last day of feeding, first, second and third day of fasting for LH analysis. The goats were divided into light (<24 kg, n = 4) and heavy (> or =24 kg, n = 4) groups for data analysis. There was no difference in LH pulse frequency between the last day of feeding and each day of fasting in the heavy group. LH pulse frequency was significantly (P < 0.05) suppressed on the second day (3.3 +/- 1.3 pulses/4 h) and on the third day (2.3 +/- 1.9 pulses/4 h) relative to the day prior to fasting (4.8 +/- 1.5 pulses/4 h) in the light group. In experiment 2, BW plus a body mass index (BMI (body weight (kg)/withers height (m)/body length (m))/10 [corrected]) were measured to define energy status. Nine goats (BW, 25.6 +/- 5.8 kg) were fed 500 g hay cubes daily for a week and then fasted for 3 days. Then they were divided into two groups offered either a maintenance (n = 4) or a restricted (n = 5) level of feeding for 4 weeks. The restricted level of feeding was 30% of maintenance requirement based on the BW recorded weekly. The feeding level was then adjusted to maintain BW for a further week followed by 3 day fasting for restricted animals. Blood samples were collected for 6 h at 10 min intervals on the day prior to fasting and on third day of fasting before and after the dietary manipulation. BW (26.6 +/- 2.2 to 26.8 +/- 3.8 kg) and gBMI (8.4 +/- 0.4 to 7.8 +/- 0.3) remained constant over the period prior to fasting for the maintenance animals but were significantly lower (P < 0.05) after 4 weeks for the restricted goats (BW, 26.3 +/- 2.1 to 21.5 +/- 2.4 kg; gBMI, 8.4 +/- 0.9 to 6.9 +/- 0.7). There was no significant difference in the LH pulse frequency between feeding and fasting day in both sampling periods in the maintenance group. In the restricted group, LH pulse frequency was not suppressed by fasting in the first sampling period (6.8 +/- 2.9 to 5.2 +/- 2.5 pulses/6 h), whereas it tended to be suppressed (4.8 +/- 3.1 to 1.6 +/- 2.3 pulses/6 h; P < 0.06) and was significantly (P < 0.05) correlated to body weight (r = 0.70) and gBMI (r = 0.81) after the dietary manipulation. These results suggest that the suppressive effect of short-term energy restriction (fasting) on pulsatile LH secretion is related to body energy status.

Animals↗

PubMed1999

Oral administration of peptidergic growth hormone (GH) secretagogue KP102 stimulates GH release in goats.

To assess the oral activity of KP102 (also known GHRP-2) on growth hormone (GH) release in ruminant animals, 5 or 10 mg/kg body weight (BW) of KP102 dissolved in saline was orally administered twice at 2 hr-intervals to either 1- or 3-mo-old goats (n = 5-6). Plasma GH concentrations in the 1-mo-old goats were elevated at 15 min after the first administration of both 5 and 10 mg/kg BW of KP102. Significant elevation of GH concentrations continued until 180 min after 10 mg/kg BW of KP102, whereas the elevated GH levels after the administrations of 5 mg/kg BW of KP102 subsided to basal concentrations within 90 min. The second administration of 10 mg/kg BW of KP102 failed to elevate the GH concentration, but 5 mg/kg BW of KP102 abruptly stimulated GH release. Plasma GH concentrations in the 3-mo-old goats were also significantly elevated after the administration of both 5 and 10 mg/kg BW of KP102. The plasma GH responses to 5 and 10 mg/kg BW of KP102 were almost identical. The elevated GH levels after the first administration of KP102 tended to be maintained throughout the experiment, and a transient increase in plasma GH levels was observed after the second administration. However, the stimulatory effect of KP102 on GH release in the 3-mo-old goats was small and less abrupt than that in the 1-mo-old goats. The concentrations of insulin-like growth factor-I were not increased by KP102 during the brief sampling periods used in this experiment. These results show that the oral administration of the peptidergic GH secretogogue KP102 stimulates GH release in a ruminant species, and that the oral activity of KP102 on GH release is modified by the age.

Aging↗

PubMed1995

Dehorning the adult goat.

Although goats are ideally disbudded as infants, occasionally they are not. Goats grow horns much more rapidly than most owners realize and use these horns on other goats and, occasionally, people. Dehorning adult goats is not as easy as dehorning cattle. The techniques for tranquilizing, anesthetizing, and dehorning adult goats is described and aftercare is discussed.

Anesthesia↗

PubMed2003

Influence of albendazole on the disposition kinetics and milk antimicrobial equivalent activity of enrofloxacin in lactating goats.

The pharmacokinetics of single intravenous and intramuscular administrations and milk antimicrobial equivalent activity of enrofloxacin at a dose of 5 mg per kilogram body weight were studied in clinically healthy lactating goats which were either not treated or had received 7.5 mg per kilogram body weight of albendazole orally. The concentrations of enrofloxacin in serum and milk were determined using microbiological assay. Following intravenous injection, enrofloxacin antimicrobial equivalent activity versus time data in serum was described by a two-compartmental open model. Albendazole treatment significantly decreased the elimination half-life (t(1/2beta)) (P>or=0.05) and the mean residence time (MRT) (P>or=0.05), whereas, the rate of enrofloxacin return to central compartment from peripheral tissue (K(21)) was significantly increased (P>or=0.01). In contrast, the volumes of distribution V(d(area)) and V(d(SS)) were significantly decreased (P>or=0.01 and P>or=0.05, respectively) in albendazole-treated goats. After intramuscular injection, enrofloxacin was rapidly absorbed in control and albendazole-treated lactating goats with absorption half-lives (t(1/2ab)) 0.43 and 0.39 h, respectively. The mean peaks of serum concentration (C(max)) were 0.68 and 0.65 mcg ml(-1) attained at (t(max)) 1.08 and 1.12 h, before and after albendazole dosing, respectively. The elimination half-life (t(1/2el)) and (MRT) following intramuscular injections were also shorter in the albendazole-treated lactating goats. The systemic bioavailability of enrofloxacin was significantly decreased from 110.16 to 84.38% in albendazole-treated lactating goats. Concomitant administration of albendazole with enrofloxacin resulted in significant alterations in the disposition kinetic of enrofloxacin and significant decrease in enrofloxacin concentrations in milk. Consequently, the interaction between albendazole and enrofloxacin could be of clinical significance and may require monitoring and adjustment of enrofloxacin dosage.

Administration, Oral↗

PubMed2003

[Use of goat's milk in patients with cow's milk allergy].

BACKGROUND: Several epidemiological studies estimate that cow's milk allergy affects approximately 3-5 % of infants in industrialized countries. Infant formulae based on soy protein or hydrolysates free of cow's milk protein guarantee adequate nutritional development, although they may be inadequate for older patients. OBJECTIVE: To evaluate the possibility of using goat's milk in these patients by investigating possible cross-reactivity between both proteins in vivo and in vitro. METHODS: Twelve patients with cow's milk allergy were tested for tolerance to goat's milk protein through radioallergosorbent assay (RAST), specific IgE, skin prick and challenge tests. RESULTS: Only 25 % of the patients showed adequate immediate and late oral tolerance and had negative results of immunological tests for adverse reactions. CONCLUSIONS: The use of goat's milk cannot be recommended to patients with cow's milk allergy without investigation of possible tolerance by a specialist. For the 25 % of patients that tolerate goat's protein, goat's milk can be a excellent substitute in children older than 2 years old.

Animals↗

PubMed2003

Effect of dietary inclusion of goat milk on the bioavailability of zinc and selenium in rats.

The effects of dietary inclusion of freeze-dried goat and cow milk on the utilization of zinc and selenium, and on the metabolic fate of zinc, were studied in transected (control) and resected rats (resection of 50% of the distal small intestine). Intestinal resection reduced the apparent digestibility coefficient and zinc retention in the cow milk diet, whereas these biological indices were similar in transected (control) and resected rats with standard (without milk) and goat milk diets. The apparent digestibility coefficient and retention of selenium were not affected by intestinal resection in the animals fed with the three diets studied. In transected (control) and resected rats, the apparent digestibility coefficient and retention of zinc and selenium were higher for the goat milk diet than for the other two diets. Zinc deposits in the organs, expressed as microg/g dry weight were in order of decreasing concentrations: femur, testes, sternum, liver, kidney, heart, spleen, longissimus dorsi muscle and brain. Deposits were greatest with the goat milk diet, followed by the standard diet and were lowest for the rats given the cow milk diet, both for transected (control) and resected animals. We conclude that consumption of the goat milk diet produces a greater bioavailability of zinc and selenium and a greater deposit of zinc in key organs, for both the transected (control) and the resected rats, with respect to the standard diet and the cow milk diet.

Animals↗

PubMed2004

Strong phylogeographic relationships among three goat breeds from the Canary Islands.

We partially sequenced the mitochondrial D-loop region in 47 individuals from eleven Spanish and foreign goat breeds. Phylogenetic analysis of these sequences allowed us to identify a particular D-loop haplotype shared by individuals from the Palmera, Majorera and Tinerfeña Canarian breeds. Genotyping of 281 goats from 17 different breeds by PCR-Hpall RFLP evidenced that the geographical distribution of this haplotype is restricted to the Canary Islands. This ancestral mitochondrial haplotype might originate in the domestic goat herds brought by the native Canarian inhabitants approximately 3000 years ago. Although we observed other miscellaneous D-loop haplotypes in the Palmera, Majorera and Tinerfeña breeds, any of them allowed us to group individuals from these three populations in a single cluster, a feature that suggests that these haplotypes might have diverse origins. The remarkable degree of phylogeographic structure of the Canary goat breeds with regard to other Spanish and foreign populations might be attributed to the isolation of these breeds in the Canary Islands for approximately 2500 years, without exposure to the migratory movements and commercial trading events that probably affected the genesis of most domestic goat breeds worldwide. The Canarian D-loop haplotype can be efficiently genotyped by using DNA isolated from milk and cheese samples, which paves the way for the future establishment of a Canary breed identity test for these dairy products.

Animals↗

PubMed1985

Suppression of Trypanosoma congolense, T. vivax and T. brucei infection rates in tsetse flies maintained on goats immunized with uncoated forms of trypanosomes grown in vitro.

Significant suppression in the incidence of cyclical development of Trypanosoma congolense, T. vivax and T. brucei occurred in Glossina morsitans centralis maintained on goats immunized with in vitro-propagated uncoated forms of T. congolense, T. vivax and T. brucei, respectively. This was observed when tsetse given a T. congolense-infected feed were subsequently maintained on uninfected immunized goats and also when uninfected tsetse were fed on immunized goats infected with T. congolense, T. vivax and T. brucei. Suppression of infection rates in tsetse was trypanosome species specific, but was independent of the trypanosome stock used for immunization of goats. These findings were reflected in antibody responses to uncoated trypanosomes, as measured by immunofluorescence and the solid-phase immunoradiometric binding assay. Thus, antibody from goats immunized with uncoated trypanosomes of one species exhibited minimal reactivity with uncoated forms of other species of trypanosomes, but showed high levels of activity with uncoated forms of the same or unrelated stocks of the same species. However, in view of the range of hosts upon which tsetse feed, it is open to question whether the use of a vaccine which suppresses trypanosome infection rates in tsetse would have any significant effect in the field.

Animals↗

PubMed2000

Prevalence of antibodies to Brucella spp. in cattle, sheep, goats, horses and camels in the State of Eritrea; influence of husbandry systems.

Samples from 2427 cattle, 661 goats, 104 sheep, 98 camels and 82 horses were screened for brucella infections by the Rose Bengal Test and positive reactors confirmed by the complement fixation test. In cattle, the highest individual seroprevalence was in dairy herds kept under the intensive husbandry system, with an individual prevalence of 8.2% and unit (herd) seroprevalence of 35.9%. This was followed by the pastoral husbandry system in the Western Lowlands with 5.0% individual but a higher unit (vaccination site) prevalence of 46.1%. The lowest was in the mixed crop-livestock system in the Southern Highlands with individual 0.3% and unit (village) prevalence of 2.4%. In sheep and goats, no positive animals were detected in the mixed crop-livestock areas. In the Eastern Lowlands individual prevalences of 3.8% (goats) and 1.4% (sheep) and unit prevalence of 33.3% (goats) and 16.7% were found, while 14.3% of individual goats and 56.3% of the units in the Western Lowlands were positive. No positive horses were found. The present study documents the first serological evidence of Brucella spp. infection in camels (3.1%) in Eritrea.

Animal Husbandry↗

PubMed1999

Identification of cell types in the developing goat mammary gland.

The goat was chosen as the model system for investigating mammary gland development in the ruminant. Histological and immunocytochemical staining of goat mammary tissue at key stages of development was performed to characterize the histogenesis of the ruminant mammary gland. The mammary gland of the virgin adult goat consisted of a ductal system terminating in lobules of ductules. Lobuloalveolar development of ductules occurred during pregnancy and lactation which was followed by the regression of secretory alveoli at involution. The ductal system was separated from the surrounding stroma by a basement membrane which was defined by antisera raised against laminin and Type IV collagen. Vimentin, smooth-muscle actin and myosin monoclonal antisera as well as antisera to cytokeratin 18 and multiple cytokeratins stained a layer of myoepithelial cells which surround the ductal epithelium. Staining of luminal epithelial cells by monoclonal antibodies to cytokeratins was dependent on their location along the ductal system, from intense staining in ducts to variable staining in ductules. The staining of epithelial cells by monoclonals to cytokeratins also varied according to the developmental status of the goat, being maximal in virgin and involuting glands, lowest at lactation and intermediate during gestation. In addition, cuboidal cells, situated perpendicular to myoepithelial cells and adjacent to alveolar cells in secretory alveoli, were also stained by cytokeratin monoclonal antibodies and antisera to the receptor protein, erbB-2, in similar fashion to luminal epithelial cells. These results demonstrate that caprine mammary epithelial cell differentiation along the alveolar pathway is associated with the loss of certain types of cytokeratins and that undifferentiated and secretory alveolar epithelial cells are present within lactating goat mammary alveoli.

Animals↗

PubMed2000

Production of biologically active human granulocyte colony stimulating factor in the milk of transgenic goat.

We have developed a transgenic female goat harboring goat beta-casein promoter/human granulocyte colony stimulating factor (G-CSF) fusion gene by microinjection into fertilized one-cell goat zygotes. Human G-CSF was produced at levels of up to 50 microg/ml in transgenic goat milk. Its biological activity was equivalent to recombinant human G-CSF expressed from Chinese hamster ovary (CHO) cell when assayed using in vitro HL-60 cell proliferation. Human G-CSF from transgenic goat milk increased the total number of white blood cells in C57BL/6N mice with leucopenia induced by cyclophosphamide (CPA). The secreted human G-CSF was glycosylated although the degree of O-glycosylation was lower compared to CHO cell-derived human G-CSF.

Animals↗

PubMed2002

Chemical evaluation and digestibility of cocoa (Theobroma cacao) byproducts fed to goats.

A study was undertaken to evaluate and compare the chemical composition of the cocoa byproducts CPH (cocoa pod husk), CS (cocoa shell) and CD (cocoa dust), and to establish a rational use of CS and CD in the diets of growing goats. CD had a high crude protein (CP) content of 15.9%, while CS and CPH had 13.8% and 6.7%, respectively. The byproducts were high in crude fibre (CF) content. Among the byproducts, CD had the highest ether extract value (22.0%). Fifteen growing goats, 18-20 months of age, with pre-experimental body weights of 20.9 +/- 0.33 kg, were randomly allotted to three diets in growth studies. In diet 1, dried brewers' grain (DBG) served as the control, while the other two diets had CS or CD plus DBG. The dry matter intake (DMI) was 570, 530 and 486 g/head per day for the control, CS + DBG and CD + DBG diets, respectively. The growth rate differed significantly among the goats offered the diets (p < 0.05). Dry matter (DM), crude protein (CP), crude fibre (CF), organic matter (OM) and gross energy (GE) digestibility were significantly higher (p < 0.05) in the goats on the control diet than in those on CS + DBG or CD + DBG. The DM, CP and OM in the CS + DBG diet were more digestible (p < 0.05) than those in the CD + DBG diet. The inclusion of DBG in the CS and CD diets improved their use by the goats.

Animal Feed↗

PubMed2003

Comparative plasma pharmacokinetics and tolerance of florfenicol following intramuscular and intravenous administration to camels, sheep and goats.

Florfenicol, a monofluorinated analogue of thiamphenicol, has a broad antibacterial spectrum. The pharmacokinetics of florfenicol was studied following a single intravenous (i.v.) or intramuscular (i.m.) injection at a dose of 20 mg/kg body weight in healthy male camels, sheep and goats. The concentration of florfenicol in plasma was determined using a microbiological assay. Pharmacokinetic analysis was performed using a two-compartment open model. Following i.m. administration, the maximum plasma concentration of florfenicol (Cmax) reached in camels, sheep and goats was 0.84 +/- 0.08, 1.04 +/- 0.10 and 1.21 +/- 0.10 microg/ml, respectively, the the time required to reach Cmax (t(max)) in the same three respective species was 1.51 +/- 0.14, 1.44 +/- 0.10 and 1.21 +/- 0.10 h. The terminal half-life (t(1/2)beta) and the fraction of the drug absorbed (F%) in camels, sheep and goats were 151.3 +/- 16.33, 137.0 +/- 12.16 and 127.4 +/- 11.0 min, and 69.20% +/- 7.8% , 65.82% +/- 6.7% and 60.88% +/- 5.9%, respectively. The MRT in the same three respective species was 4.01 +/- 0.45, 3.42 +/- 0.39 and 2.98 +/- 0.32 h. Following i.v. administration, the terminal half-life (t(1/2)beta) and total body clearance (Clbeta) in camels, sheep and goats were 89.5 +/- 9.2, 78.8 +/- 8.3 and 71.1 +/- 8.9 min and 0.33 +/- 0.04, 0.30 +/- 0.03 and 0.27 +/- 0.03 L/h per kg, respectively. The area under the curve (AUC(0-infinity)) and the mean residence time (MRT) in the same three respective species were 60.61 +/- 6.98, 62.45 +/- 6.56 and 74.07 +/- 7.85 microg/ml per h, and 2.71 +/- 0.31, 2.34 +/- 0.25 and 2.11 +/- 0.23 h. These data suggest that sheep and goats absorb and clear florfenicol to a broadly similar extent, but the rate and extent of absorption of the drug tends to be higher in camels. Drug treatment caused no clinically overt adverse effects. Plasma enzyme activities and metabolites indicative of hepatic and renal functions measured 1, 2, 4 and 7 days following the drug treatment were within the normal range, indicating that the drug is safe at the dose used.

Animals↗

PubMed2025

16S rRNA and Metagenomic Datasets of Gastrointestinal Microbiota in Fetal and 7-Day-Old Goat Kids.

The perinatal period (from late gestation to the neonatal stage) in ruminants is a critical phase for fetal organ maturation, where ecological succession of gastrointestinal microbial communities significantly impacts livestock production efficiency. However, research remains insufficient regarding the distribution patterns and functional annotation of microbial communities across different gastrointestinal compartments during this period. This study characterized early microbiota dynamics in Hutianshi Goats using 16S rRNA sequencing (4 fetal goats at 90 ± 10 gestational days) and metagenomics (3 7-day-old goat kids). The fetal goat group generated 852,694 valid reads, yielding 688,277 high-quality reads after chimera removal for downstream analysis. The 7-day-old goat kids group produced 1,081,588,182 final valid reads, after data processing and assembly, 8,561,345 contigs were generated. Gene prediction identified 6,095,352 genes. Multi-database annotations (NR, KEGG, CAZy, etc.) revealed functional potential and antimicrobial resistance traits. The public release of this dataset facilitates academic understanding of microbial community dynamics and host-microbe interactions during this developmental stage, providing both theoretical foundations and data resources for ruminant developmental biology and precision breeding regulation.

Animals↗

PubMed1995

The primary elastase inhibitor (elastasin) and trypsin inhibitor (contrapsin) in the goat are serpins related to human alpha 1-anti-chymotrypsin.

Two primary serine proteinase inhibitors in goat plasma have been isolated and characterized. The N-terminal sequence analysis of the purified proteins revealed that they are closely related to each other and are highly homologous to human alpha 1-anti-chymotrypsin rather than alpha 1-proteinase inhibitor. However, despite structural similarities the inhibitory specificity of the goat inhibitors differed from each other and from that of anti-chymotrypsin. In contrast with human anti-chymotrypsin, one of the goat inhibitors was shown to be a strong and specific inhibitor of trypsin (k(ass.) = 1.9 x 10(6) M-1.s-1), whereas the other was an efficient inhibitor of neutrophil elastase (k(ass.) = 1.5 x 10(6) M-1.S-1). Differences in the inhibitory specificity of each protein could readily be attributed to the amino acid sequence within the reactive site region. The trypsin inhibitor with an assumed arginine residue at the P1 position of the reactive-site peptide bond is referred to as 'contrapsin', and indicates that the occurrence of contrapsins is not restricted to rodents. In contrast, the inhibitory specificity, resistance to oxidative and proteolytic inactivation and the presence of a P1 leucine residue in the elastase inhibitor is unique among inhibitory serpins that have been characterized to date. Because this serpin is apparently the major elastase inhibitor in goat plasma, it is likely to be involved in the control of goat neutrophil elastase. Therefore, we suggest the name 'elastasin', and extend it to any other anti-chymotrypsin related serpins possessing neutrophil-elastase- inhibitory activity.

Amino Acid Sequence↗

PubMed1975

Effect of liver failure on the response of ventilation and cerebral criculation to carbon dioxide in man and in the goat.

1. The acid-base state of arterial blood and cerebrospinal fluid, and the ventilatory response to CO2, were measured in twelve patients with liver disease. The CO2 response was also measured in eight goats before and after the experimental production of liver failure. Arterial PCO2 and pH, cerebral blood flow and the cerebral metabolic rate for oxygen were also measured in four of the goats while they breathed air and various CO2-enriched gas mixtures. 2. Liver failure was accompanied by a respiratory alkalosis in both the patients and in the goats. Decreased PCO2 and increased pH occurred in the cerebrospinal fluid and in the arterial blood of the patients. 3. The slope of the ventilatory response to CO2 was reduced when liver failure was severe, in patients and goats alike. In addition there was a reduction in the extrapolated PCO2 at zero ventilation, even when liver failure was mild. 4. Cerebral blood flow and metabolic rate were consistently reduced in the goats during liver failure. There was also less cerebral vasodilatation and a greater reduction in cerebral metabolism during experimental hypercapnia when these animals were in liver failure. 5. The decreases in the ventilatory and cerebral circulatory responsiveness to CO2 indicate that the brain is less well defended against hypercapnia in liver failure, and these changes are especially unfavourable as cerebral function deteriorates when the PCO2 is increased.

Adult↗

PubMed1976

Effect of liver failure on the ventilatory response to hypoxia in man and the goat.

1. The ventilatory responses to transient and steady-state hypoxia were measured in ten patients with hepatic cirrhosis and in ten healthy control subjects. Successive measurements of these responses were also obtained in six goats before and after the experimental production of liver failure. Changes in the effect of steady-state hypoxia on the ventilatory response to hypercapnia were evaluated by successive studies in another goat. 2. In spite of a respiratory alkalosis during liver failure, the response to transient hypoxia was greater in the patients than in the control subjects. This response was increased after the onset of liver failure in all the goats. 3. In healthy humans and goats the responses to transient and steady-state hypoxia were similar in magnitude. During liver failure there was a disparity between the size of these responses, since the ventilatory increment evoked by steady-state hypoxia was unchanged in spite of the increase in response to transient hypoxia. Steady-state hypoxia consistently enhanced the ventilatory response to hypercapnia in a healthy goat, but frequently depressed the response to hypercapnia during liver failure. 4. The findings suggest that liver failure heightens the sensitivity of the peripheral chemoreceptors to the hypoxic stimulus, but may increase the tendency of the medullary centres to become depressed in hypoxia.

Adult↗

PubMed2002

Serum pharmacokinetics and tissue and milk residues of oxytetracycline in goats following a single intramuscular injection of a long-acting preparation and milk residues following a single subcutaneous injection.

Separate groups of goats were used to determine drug depletion patterns in serum (n=10), tissue (n=20) and milk (n=8) following a single intramuscular (i.m.) dose of 20 mg/kg of a long-acting oxytetracycline (OTC) formulation (Liquamycin LA-200). Milk residues were also determined following a subcutaneous (s.c.) administration of the same product at the same dose. Serum samples were taken for 24 h post-treatment and tissues (fat, liver, kidney, muscle and injection site) collected at 4, 7, 14, 21 and 28 days following injection. Milk from lactating goats was collected every 12 h for 8 days following both the i.m. and s.c. treatments utilizing an intervening 5-week washout period. Residues in serum and tissue were measured using a microbial inhibition assay, while milk residues were measured using both a microbial inhibition assay and a validated HPLC method. The serum pharmacokinetic parameters of OTC in goats were determined, with a mean AUC=67.4 microg h/mL, mean terminal half-life=14.4 h, and apparent clearance=0.33 L/kg h. Tissue half-lives could not be determined with confidence because the collection times provided only two points at which residues could be measured for most tissues. Oxytetracycline residues in all goat tissue samples measured less then cattle tissue tolerance by 96 h postdosing. One-compartment model describing milk depletion data for i.m. and s.c. dosing had terminal slope half-lives of 20.1 and 36.1 h, respectively. By 96 h post-treatment none of the milk samples contained OTC residues in excess of the cattle milk tolerance (0.3 p.p.m.). For both milk and tissue, the upper-bound 99% confidence intervals for the samples taken from goats 96 h postdosing were lower than approved cow milk and tissue tolerances.

Animals↗