Comparison of induced corpora lutea from prepuberal gilts and spontaneous corpora lutea from mature gilts: in vitro progesterone production

Prepuberal (P) gilts were induced to ovulate with pregnant mare serum gonadotropin followed 72 h later by human chorionic gonadotropin (hCG). Three P gilts and three mature (M) gilts each were ovariectomized on d 10, 14, 18, 22 and 26 (d 0 = day of hCG for P gilts and onset of estrus for M gilts). Gilts ovariectomized on d 14, 18, 22 and 26 were hysterectomized on d 6 to ensure maintenance of the corpora lutea (CL). Two to five grams of minced luteal tissue were dispersed using collagenase and hyaluronidase in HEPES buffered salt solution supplemented with glucose and bovine serum albumin. Dispersed cells were rinsed in Dulbecco's Modified Eagle Medium (DMEM), counted (ratio of large to total number of luteal cells determined) and then incubated for 1 h in DMEM. With aliquots standardized to 2.5 X 10(4) viable, large cells (greater than 25 micron diameter) were incubated in 1 ml DMEM for 2 h in the presence of either 10, 50, 100 or 1,000 ng luteinizing hormone (LH); .1, 1, 10 or 100 ng hCG; 10, 100 or 1,000 ng norepinephrine (NE) or either .75, or 1.5 mM dibutyrl cyclic adenosine monophosphate (dbcAMP). Progesterone (P4) in the medium was quantified by radioimmunoassay. Basal P4 production (no P4 stimulator added to the medium) on d 10, 14, 18, 22 and 26 for P gilts was 246 +/- 9, 66 +/- 4, 64 +/- 6, 41 +/- 3 and 69 +/- 6 ng/ml medium, respectively, and for M gilts was 281 +/- 12, 128 +/- 8, 53 +/- 4, 82 +/- 6, 101 +/- 5 ng/ml medium, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Progesterone stimulation by LH involves the phospholipase-C pathway in bovine luteal cells

Luteinizing hormone (LH)-stimulated steroidogenesis in luteal cells is known to be mediated through the activation of cyclic AMP (cAMP)-dependent protein kinase, and to be also modulated by calcium-dependent mechanisms. In the present study, we tested the hypothesis that LH stimulates progesterone (P4) production in bovine luteal cells through activation of phospholipase (PL) C by using a cell culture system. Bovine mid-luteal cells (Days 8-12 of the estrous cycle) were cultured for 24 h and then exposed to a PLC inhibitor (U-73122; 10 microM) with or without LH (10 ng/ml) for 4 h. U-73122 blocked LH-stimulated P4 production without affecting cAMP accumulation. Moreover, exposure of luteal cells to PLC increased P4 production in a dose-dependent manner. These results support the hypothesis that the luteotropic action of LH in bovine luteal cells is mediated not only by activation of adenylate cyclase but also by activation of PLC.     

Pharmacokinetics of piperacillan after intramuscular injection in red-tailed hawks (Buteo jamaicensis) and great horned owls (Bubo virginianus).

This study characterized and compared the pharmacokinetics of piperacillin after single 100 mg/kg i.m. injections in nine red-tailed hawks (Buteo jamaicensis) and five great horned owls (Bubo virginianus) over 48 hr by a modified agar well diffusion microbial inhibition assay. The mean maximum plasma piperacillin concentrations were 204 microg/ml and 221 microg/ml for the hawks and owls, respectively, and times of maximum concentrations were 15 min and 30 min, respectively. The calculated mean terminal elimination half-lives were 77 min in the hawks and 118 min in the owls. Area-under-the-curve values were 218 +/- 52 microg x hr/ml in the hawks and 444 +/- 104 microg x hr/ml in the owls. On the basis of the most common minimal inhibitory concentration (90%) for various bacterial isolates from clinical samples of 8 microg/ml, analysis of the data suggests that the maximum dosing interval for piperacillin at 100 mg/kg in medium sized raptors should be 4-6 hr.     

Pharmacokinetics of orally administered ibuprofen in African and Asian elephants (Loxodonta africana and Elephas maximus).

The pharmacokinetic parameters of S(+) and R(-) ibuprofen were determined in 20 elephants after oral administration of preliminary 4-, 5-, and 6-mg/kg doses of racemic ibuprofen. Following administration of 4 mg/kg ibuprofen, serum concentrations of ibuprofen peaked at 5 hr at 3.9 +/- 2.07 microg/ml R(-) and 10.65 +/- 5.64 microg/ml S(+) (mean +/- SD) in African elephants (Loxodonta africana) and at 3 hr at 5.14 +/- 1.39 microg/ml R(-) and 13.77 +/- 3.75 microg/ml S(+) in Asian elephants (Elephas maximus), respectively. Six-milligram/kilogram dosages resulted in peak serum concentrations of 5.91 +/- 2.17 microg/ml R(-) and 14.82 +/- 9.71 microg/ml S(+) in African elephants, and 5.72 +/- 1.60 microg/ml R(-) and 18.32 +/- 10.35 microg/ml S(+) in Asian elephants. Ibuprofen was eliminated with first-order kinetics characteristic of a single-compartment model with a half-life of 2.2-2.4 hr R(-) and 4.5-5.1 hr S(+) in African elephants and 2.4-2.9 hr R(-) and 5.9-7.7 hr S(+) in Asian elephants. Serum concentrations of R(-) ibuprofen were undetectable at 24 hr, whereas S(+) ibuprofen decreased to below 5 microg/ml 24 hr postadministration in all elephants. The volume of distribution was estimated to be between 322 and 356 ml/kg R(-) and 133 and 173 ml/kg S(+) in Asian elephants and 360-431 ml/kg R(-) and 179-207 ml/kg S(+) in African elephants. Steady-state serum concentrations of ibuprofen ranged from 2.2 to 10.5 microg/ml R(-) and 5.5 to 32.0 microg/ml S(+) (mean: 5.17 +/- 0.7 R(-) and 13.95 +/- 0.9 S(+) microg/ml in African elephants and 5.0 +/- 1.09 microg/ml R(-) and 14.1 +/- 2.8 microg/ml S(+) in Asian elephants). Racemic ibuprofen administered at 6 mg/kg/12 hr for Asian elephants and at 7 mg/kg/12 hr for African elephants results in therapeutic serum concentrations of this antiinflammatory agent.     

Further studies on anthelmintic resistance in sheep at an organised farm in arid region of Rajasthan

Faecal egg count reduction test (FECRT) and in vitro egg hatch assay (EHA) was performed on Indian Karakul (3/4 crosses of Karakul with Malpura, Marwari and Sonadi) transported from arid region campus, Bikaner, where resistance was reported in 1996. FECRT revealed that fenbendazole and levamisole were 100% effective in reducing the egg counts. LC50 value on EHA was 0.074 +/- 0.015 microg thiabendazole ml(-1). The faecal culture examination revealed the presence of Haemonchus contortus only. It was concluded that H. contortus was fully susceptible to both benzimidazole and levamisole.     

Plasma concentrations of folic acid, vitamin B12 and progesterone of cyclic bitches, bitches during pregnancy and induced abortion and bitches with pyometra

The aim of this study was to investigate the plasma concentrations of folic acid, vitamin B12 and progesterone at different stages of the sexual cycle and pregnancy, during induced abortion and in bitches with pyometra. Bitches (n = 97) were assigned to groups as follows: a) oestrous cycle (n = 42) b) pregnancy (n = 25) c) induction of abortion (n = 10 and d) pyometra (n = 20). Oestrous cycle stages were determined by vaginal inspection and cytology. Pregnancies were estimated by ultrasound (5.0 Mhz; linear transducer; Schimadzu) at days 15-25, 35-45 and 46-63 of pregnancy. Treatments for the induction of abortion were started between days 25 and 35 after mating (5 microg/kg cabergoline daily, Galastop; 5-10 microg/kg Alfaprostol every other day, Gabbrostim). Diagnosis of pyometra was confirmed by ultrasound and vaginoscopy. Folic acid and vitamin B12 concentrations did not differ among different stages of the oestrous cycle. The mean concentration of folic acid during early pregnancy (days 15-25) exceeded levels of later stages (days 46-63): 9.4 +/- 3.7 microg/ml and 4.7 +/- 1.8 microg/ml, respectively (p < 0.01). A positive correlation between folic acid and vitamin B12 was determined in pregnant dogs ( r = 0.925; p < 0.02). Before the induction of abortion, the concentration of folic acid was 9.6 +/- 5.2 microg/ml; during abortion it decreased to 5.0 +/- 3.2 microg/ml (p < 0.01). A significant correlation (r = 0.925; p < 0.02) between progesterone and folic acid was obtained in bitches with abortion. The mean concentration of folic acid in bitches with pyometra significantly differed from that of bitches at different stages of the oestrous cycle (p < 0.05). The mean concentration of folic acid was significantly lower in metoestrous bitches when compared to bitches with pyometra (p < 0.05). The decrease of serum concentrations of folic acid during pregnancy and induced abortion show that fetal growth and abortion caused higher consumption of folic acid. Concerning bitches did not show any deficiency symptoms, which is why it can be concluded that this decrease is physiological.     

Study of intragastric administration of doxycycline: pharmacokinetics including body fluid, endometrial and minimum inhibitory concentrations

The objectives of this study were to determine the pharmacokinetics and tissue concentrations of doxycycline after repeated intragastric administration, and to determine the minimum inhibitory concentrations (MIC) for equine pathogenic bacteria. In experiment 1, 2 mares received a single intragastric dose of doxycycline hyclate (3 mg/kg bwt). Mean peak serum concentration was 0.22 microg/ml 1 h postadministration. In experiment 2, 5 doses of doxycycline hyclate (10 mg/kg bwt), dissolved in water, were administered to each of 6 mares via nasogastric tube at 12 h intervals. The mean +/- s.e. peak serum doxycycline concentration was 0.32+/-0.16 microg/ml 1 h after the first dose and 0.42+/-0.05 microg/ml 2 h after the fifth dose. The mean trough serum concentrations were > 0.16 microg/ml. Highest mean synovial concentration was 0.46+/-0.13 microg/ml and highest mean peritoneal concentration was 0.43+/-0.07 microg/ml, both 2 h after the fifth dose. Highest urine concentration was mean +/- s.e. 145+/-25.4 microg/ml 2 h after the last dose. Highest endometrial concentration was mean +/- s.e. 1.30+/-0.36 microg/ml 3 h after the fifth dose. Doxycycline was not detected in any of the CSF samples. Mean +/- s.e. Vd(area) was 25.3+/-5.0 l/kg and mean t1/2 was 8.7+/-1.6 h. In experiment 3, minimum inhibitory concentrations of doxycycline were determined for 168 equine bacterial culture specimens. The MIC90 was < or = 1.0 microg/ml for Streptococcus zooepidemicus and 0.25 microg/ml for Staphylococcus aureus. Based on drug concentrations achieved in the serum, synovial and peritoneal fluids and endometrial tissues and MIC values determined in the present study, doxycycline at a dose of 10 mg/kg bwt per os every 12 h may be appropriate for the treatment of infections caused by susceptible (MIC < 0.25 microg/ml) gram-positive organisms in horses.     

Secretion of angiogenic activity and progesterone by ovine luteal cell types in vitro

In the first experiment, minced luteal tissues from cyclic ewes (n = 5) were incubated for 6 h. Media conditioned by these luteal tissue explants stimulated proliferation and migration of endothelial cells. In a second experiment, corpora lutea (CL) from superovulated ewes (n = 12) were dissociated (two ewes/dispersion) and separated into three fractions: a non-elutriated fraction containing a mixed population of luteal cells, a fraction enriched with small steroidogenic luteal cells, and a fraction containing primarily large steroidogenic luteal cells. Fractions (2 X 10(5) viable steroidogenic luteal cells per milliliter of medium) were incubated with LH in doses of 0, .1, 1, 10, and 100 ng/ml for 7 d. Conditioned media were collected on d 1, 3, 5, and 7 of incubation. Across all days of incubation, media from small luteal cells stimulated proliferation of endothelial cells. Media from large luteal cell incubations, however, secreted an endothelial mitogen only on d 7 of culture. Mixed luteal cell cultures secreted mitogenic activity on d 3, 5, and 7 of incubation, but not on d 1. Luteinizing hormone did not influence release of mitogenic activity by any luteal cell fraction. Across all days of incubation, media from large luteal cells contained more progesterone than those from small luteal cells (528 +/- 137 vs 48 +/- 16 ng/ml with no LH). Mixed (non-elutriated) and small luteal cells increased progesterone secretion in response to LH, and this response was maintained during long-term culture. Large luteal cells did not increase progesterone secretion in response to LH. Steroidogenic activity of all cell types decreased as incubation time progressed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of Amikacin in Lactating Sheep

The pharmacokinetics of amikacin (AMK) were investigated after intravenous (i.v.) and intramuscular (i.m.) administration of 7.5 mg/kg bw in 6 healthy lactating sheep. After i.v. AMK injection (as a bolus), the elimination half-life (t1/2beta), the volume of distribution (Vd,area), the total body clearance (ClB) and the area under the concentration-time curve (AUC) were 1.64 +/- 0.06 h, 0.19 +/- 0.02 L/kg, 1.36 +/- 0.1 ml/min per kg and 94.09 +/- 6.95 (microg.h)/ml, respectively. The maximum milk concentration of AMK (Cmax), the area under the milk concentration-time curve (AUCmilk) and the ratio AUCmilk/AUCserum were 1.18 +/- 0.22 microg/ml, 22.45 +/- 3.21 (micro.h)/ml and 0.24 +/- 0.02, respectively. After i.m. administration of AMK the t1/2beta, Cmax, time of Cmax (tmax) and absolute bioavailability (Fabs) were 1.29 +/- 0.1 h, 16.97 +/- 1.54 microg/ml, 1.0 +/- 0 h and 64.88% +/- 6.16%, respectively. The Cmax, AUCmilk and the ratio AUCmilk/AUCserum were 0.33 microg/ml, 1.67 (microg.h)/ml and 0.036, respectively.     

Serum cortisol and progestin concentrations in pregnant and non-pregnant Asian elephants (Elephas maximus)

Blood samples were collected during the estrous cycle (n=3), throughout gestation (n=3), and during the periparturient period (n=11) to assess serum concentrations of cortisol in pregnant and non-pregnant Asian elephants whose reproductive status was being monitored by serum progestin determination. While serum cortisol concentrations remained constant throughout gestation, progestin concentrations decreased significantly (p<0.05) in the second half of pregnancy, declining to undetectable levels by 3 days before calving. During the non-luteal phase of the estrous cycle serum progestins varied from undetectable levels to 100pg/ml (53+/-10.7pg/ml) then increased steadily during the luteal phase (322+/-207.5pg/ml). There were no significant differences between serum cortisol concentrations during the luteal and those of the non-luteal phase (p>0.05). The mean cortisol concentration during the estrous cycle was about twice that during pregnancy (p>0.05). No substantial changes in maternal cortisol were found during the course of pregnancy or the periparturient period.     

Plasma concentrations of luteinizing hormone and adrenocorticotropic hormone in blood collected during the luteal and follicular phases of the estrous cycle in cows.

Luteinizing hormone (LH) and ACTH concentrations were measured in plasma from 7 cows to determine whether ACTH secretion changes with the phase of the estrous cycle, and to determine whether any ACTH peaks are associated with LH peaks. Blood was collected every 5 minutes for 190 minutes during the luteal and follicular phases of the estrous cycle. Radioimmunoassays were used to measure ACTH and LH in plasma. Mean concentration of ACTH in all cows did not differ significantly between luteal (35.1 +/- 8.0 pg/ml) and follicular (37.5 +/- 9.4 pg/ml) phases of the estrous cycle. Mean concentration of luteal-phase LH of all cows (2.0 +/- 1.1 ng/ml) was significantly (P less than 0.01) lower than mean concentration of follicular-phase LH (5.4 +/- 1.6 ng/ml). Frequency of peaks in ACTH concentration was low during the sampling period. Mean number of luteal-phase ACTH peaks (0.29 +/- 0.49) was not significantly different from that of follicular-phase samples (0.43 +/- 0.530). Unlike ACTH, mean frequency of LH peaks was significantly (P less than 0.05) higher in plasma from cows in the follicular phase of the estrous cycle (2.9 +/- 0.7), compared with that from cows in the luteal phase (0.29 +/- 0.49).     

Progesterone production by cultured luteal cells in the presence of bovine low- and high-density lipoproteins purified by heparin affinity chromatography.

The objectives of this study were to separate plasma lipoprotein particles based on the presence (low-density lipoproteins; LDL) or absence of apolipoprotein B (high-density lipoproteins; HDL) and to compare the abilities of bovine LDL and HDL to stimulate progesterone production by bovine luteal cells in culture. Plasma lipoproteins were isolated by ultracentrifugation and separated into LDL and HDL by heparin affinity chromatography. Luteal cultures were treated with LDL or HDL cholesterol for 48 h on d 3 of the culture (d 0 = day of dissociation). Progesterone production by luteal cells increased in a dose-dependent manner with increasing concentrations of either LDL or HDL cholesterol. There were no differences in the ability of LDL or HDL cholesterol to stimulate luteal cells to produce progesterone. Because LDL and HDL were equally potent, and experiment was designed to investigate the ability of modified LDL or reconstituted particles without apolipoproteins to stimulate progesterone production. Stimulation of luteal cell progesterone production by lysine-modified LDL was 70% of unmodified LDL. Progesterone production in the presence of phosphatidylcholine liposomes or BSA containing cholesterol was 50 and 108% of that obtained with HDL or LDL. Evidence indicated that apolipoprotein-free particles that contained free cholesterol but not cholesterol esters stimulated luteal cells to produce progesterone.     

Influence of a PGF2alpha-analogue, etiproston tromethamine, on the functional corpus luteum of dogs

To induce luteal regression-related abortion/delivery and treat pyometra in dogs, various PGF2alpha-analogues (PGAs) are administered, but a PGA most appropriate for clinical application in dogs, with a low incidence of side effects, is being investigated. In this study, we compared the effects of etiproston tromethamine (PGA-E), which has not been investigated in dogs, with those of cloprostenol (PGA-C), which is routinely used in dogs. A single dose of PGA-E at 100, 200, 400 or 800 microg or PGA-C at 12.5, 25, 50 or 100 microg was administered to beagles (n=5 per group) 25 days after ovulation, when the corpus luteum was in the functional phase. We compared the state of luteal regression by measuring plasma progesterone levels. As side effects, the incidences of salivation, vomiting, tachypnea, diarrhea and the drop in body temperature were investigated. In the 400-microg and 800-microg groups treated with PGA-E, the mean intervals from administration until luteal regression were 18.6 days and 31.2 days, respectively. In the dogs treated with 50 microg or more of PGA-C, luteal regression was noted 2 days after administration. The above side effects were observed for 3 hr after administration of PGA-E/PGA-C. In the dogs treated with 800 microg of PGA-E, the mean body temperature was 36.7 degrees C 4 hr after administration; hypothermia persisted. PGA-E may be less useful than PGA-C for promoting luteal regression in dogs in clinical application.     

Endocrine patterns in two strains of Japanese black cattle with growth retardation

Endocrine patterns were compared in 2 strains of Japanese black cattle with growth retardation; MHO- and HSK-paternal strains (MHO and HSK cattle, respectively). MHO cattle (n=8) displayed lower serum concentrations of insulin-like growth factor-1 (IGF-1), triiodothyronine (T3), thyroxine (T4), and cortisol (31.1+/-20.7 ng/ml, 73.9+/-51.9 ng/dl, and 2.9+/-2.9 microg/dl, 1.3+/-0.7 microg/dl, respectively) than those in both HSK cattle (n=5) (64.9+/-47.6 ng/ml, 97.8+/-40.7 ng/dl, 4.1+/-2.1 microg/dl and 1.8+/-1.1 microg/dl, respectively), and the controls (n=6) (314.7+/-197.2 ng/ml, 140.2+/-21.3 ng/dl, 5.8+/-1.7 microg/dl, and 3.0+/-1.4 microg/dl, respectively). The area under the concentration curve of growth hormone (GH-AUC 0-600 min) in MHO cattle (22210+/-18951 ng.min/ml) tended to be greater than those in HSK (7887+/-6340 ng.min/ml) and the controls (2811+/-1275 ng.min/ml). MHO cattle showed a high GH-AUC0-600 min in contrast to a low serum IGF-1 concentration, as well as lower serum T3, T4, and cortisol concentrations. HSK cattle exhibited the same secretory patterns, but much more moderately. Growth retardation in Japanese black cattle exhibits some variations based on pedigree.     

Pharmacokinetics of erythromycin estolate and erythromycin phosphate after intragastric administration to healthy foals

OBJECTIVE: To determine pharmacokinetics and plasma concentrations of erythromycin and related compounds after intragastric administration of erythromycin phosphate and erythromycin estolate to healthy foals. ANIMALS: 11 healthy 2- to 6-month-old foals. PROCEDURE: Food was withheld from foals overnight before intragastric administration of erythromycin estolate (25 mg/kg of body weight; n = 8) and erythromycin phosphate (25 mg/kg; 7). Four foals received both drugs with 2 weeks between treatments. Plasma erythromycin concentrations were determined at various times after drug administration by use of high-performance liquid chromatography. Maximum plasma peak concentrations, time to maximum concentrations, area under plasma concentration versus time curves, half-life of elimination, and mean residence times were determined from concentration versus time curves. RESULTS: Maximum peak concentration of erythromycin A after administration of erythromycin phosphate was significantly greater than after administration of erythromycin estolate (2.9 +/- 1.1 microg/ml vs 1.0 +/- 0.82 microg/ml). Time to maximum concentration was shorter after administration of erythromycin phosphate than after erythromycin estolate (0.71 +/- 0.29 hours vs 1.7 +/- 1.2 hours). Concentrations of anhydroerythromycin A were significantly less 1 and 3 hours after administration of erythromycin estolate than after administration of erythromycin phosphate. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma concentrations of erythromycin A remained > 0.25 microg/ml (reported minimum inhibitory concentration for Rhodococcus equi) for at least 4 hours after intragastric administration of erythromycin phosphate or erythromycin estolate, suggesting that the recommended dosage for either formulation (25 mg/kg, q 6 h) should be adequate for treatment of R equi infections in foals.     

Insulin-like growth factor (IGF)-I and IGF binding proteins-2, -3, -4, -5 in porcine corpora lutea during the estrous cycle; evidence for inhibitory actions of IGFBP-3

In this study we measured protein concentrations of insulin-like growth factor (IGF)-I and IGF binding proteins (IGFBPs) 2-5 in porcine corpora lutea (CLs) throughout the estrous cycle (Experiment 1), and examined the effects of IGFBP-3 and IGFBP-3 antibody (AB) on luteal progesterone (P4) secretion in vitro (Experiment 2). For Experiment 1, (CLs) and serum were collected on days (D) 4, 7, 10, 13, 15 and 16 of the estrous cycle (n = 5 animals per day). IGF-I was extracted from CLs and sera, and measured by radioimmunoassay (RIA). IGFBPs were measured in CLs by ligand blots. For Experiment 2, CLs (from Experiment 1) were enzyme dissociated and luteal cells cultured (24 h) in Medium 199 (M199) containing (0-500 ng/ml) IGFBP-3 (+/-IGF-I; 100 ng/ml), or (0-10 microg/ml) IGFBP-3 AB. P4 in media was measured by RIA. In Experiment 1, luteal IGF-I concentrations (ng/g tissue) were maximal on day 4 and gradually decreased thereafter. Serum IGF-I concentrations (ng/ml) were highest on days 4 and 7, compared with days 10-15. Peak levels of luteal IGFBP-3 were also seen on days 4 and 7 of the cycle. Luteal IGFBP-2 concentrations showed a tendency to increase on day 16 (P < 0.05 versus day 10), but no significant changes in IGFBP-4 or -5 were seen. In Experiment 2, IGFBP-3 (w IGF) inhibited the steroidogenic actions of IGF-I, but had no significant actions alone (IGFBP-3 w/o IGF). Finally, IGFBP-3 AB stimulated P4 secretion on days 4 and 7, but not on days 10-16. We conclude that IGFBP-3 inhibits IGF-I actions in the porcine CL.     

Use of milk progesterone enzyme immunoassay for differential diagnosis of follicular cyst, luteal cyst, and cystic corpus luteum in cows

In 160 cows with ovarian cysts as determined by rectal palpation, differentiation was made of follicular cyst, luteal cyst, and cystic corpus luteum on the basis of milk progesterone concentrations estimated by an enzyme immunoassay before and at 10 days after cows were treated with gonadotropin-releasing hormone. Cows having a progesterone concentration in skim milk less than 1.0 ng/ml were considered to have follicular cysts and those with concentrations of 1.0 ng/ml or higher were regarded as the cases of luteal cyst or cystic corpus luteum. Luteal cyst was characterized by progesterone values remaining high in the cows for 10 days after treatment, and cystic corpus luteum was characterized by a decrease in progesterone concentration after cows were treated. By the rectal palpation procedure it was impossible to differentiate luteal cyst and cystic corpus luteum from follicular cyst. The frequencies of follicular cyst, luteal cyst, and cystic corpus luteum were 65%, 19%, and 16%, respectively. Of 104 cows with follicular cysts as defined by milk progesterone assay result, 73 (70%) responded to the treatment with gonadotropin-releasing hormone, the milk progesterone concentration increasing from 0.7 +/- 0.2 ng/ml (mean +/- SD) to 1.8 +/- 1.1 ng/ml. The accuracy of rectal palpation 10 days after treatment for judgment of luteinization of follicular cyst confirmed by milk progesterone analysis was only 30% (48 cows of 160).     

A Pharmacokinetic Comparison of Meloxicam and Ketoprofen following Oral Administration to Healthy Dogs

Ketoprofen (KTP) and meloxicam (MLX) are non-steroidal anti-inflamatory drugs used extensively in veterinary medicine. The pharmacokinetics of these drugs were studied in eight dogs following a single oral dose of 1 mg/kg of KTP as a racemate or 0.2 mg/kg of MLX. The concentrations of the drugs in plasma were determined by high-performance liquid chromatography (HPLC). There were differences between the disposition curves of the KTP enantiomers, confirming that the pharmacokinetics of KTP is enantioselective. (S)-(+)-KTP was the predominant enantiomer; the S:R ratio in the plasma increased from 2.58 +/- 0.38 at 15 min to 5.72 +/- 2.35 at 1 h. The area under the concentration time curve (AUC) of (S)-(+)-KTP was approximately 6 times greater than that of (R)-(-)-KTP. The mean (+/- SD) pharmacokinetic parameters for (S)-(+)-KTP were characterized as Tmax = 0.76 +/- 0.19 h, Cmax = 2.02 +/- 0.41 microg/ml, t1/2el = 1.65 +/- 0.48 h, AUC = 6.06 +/- 1.16 microg.h/ml, Vd/F = 0.39 +/- 0.07 L/kg, Cl/F = 170 +/- 39 ml/(kg.h). The mean (+/- SD) pharmacokinetic parameters of MLX were Tmax = 8.5 +/- 1.91 h, Cmax = 0.82 +/- 0.29 microg/ml, t1/2lambda(z) = 12.13 +/- 2.15 h, AUCinf = 15.41 +/- 1.24 microg.h/ml, Vd/F = 0.23 +/- 0.03 L/ kg, and Cl/F = 10 +/- 1.4 ml/(kg.h). Our results indicate significant pharmacokinetic differences between MLX and KTP after therapeutic doses.     

Single daily intramuscular injections of low quantities of recombinant ovine interferon-tau extends luteal life-span in Angora goats

The objective of this study was to determine whether single, daily intramuscular injections of low amounts of ovine interferon-tau (ovIFN-tau) would extend luteal life-span in nonpregnant Angora goats. Female goats were assigned randomly to receive a single daily injection of 1) PBS (control; n = 11), 2) 125 microg/d ovIFN-tau (n = 11), or 3) 500 microg/d ovIFN-tau (n = 11) from d 14 to 20 after estrus. Luteal life-span was defined as the number of days from the synchronized estrus until serum progesterone (P4) declined (< 0.5 ng/mL) and was of normal duration in controls (19.4 +/- 0.3 d) but was increased (P < 0.05) in goats receiving 125 microg/d (23.2 +/- 1.3 d) and 500 microg/d (25.5 +/- 1.2 d) ovIFN-tau. Injection of either ovIFN-tau dose caused an initial decrease (P < 0.05) in serum P4 concentrations relative to controls but did not differ from controls thereafter. Rectal temperatures increased (P < 0.05) following ovIFN-tau treatment until d 18 for goats given the lower dose and throughout the treatment period for those given 500 microg/d. In summary, injections of as little as 125 microg/d of ovIFN-tau extended luteal life-span in goats. This dose caused a transient reduction in serum P4 concentrations and induced hyperthermia.     

The effect of diet type on the plasma disposition of triclabendazole in goats

The effect of two different diet types (concentrate feed+hay and grazing) on the pharmacokinetic profiles of triclabendazole following oral administration in goats was investigated. A total of 12 goats were randomly allocated into two groups which were either indoor and fed concentrate + hay ration (housed group) or were grazing on pasture (grazing group). Triclabendazole was administered orally to animals in two groups at 10 mg/kg bodyweight. Blood samples were collected from 1 h to 192 h post-treatment and analyzed by high performance liquid chromatography (HPLC). Feeding with different diets significantly effected the plasma disposition of triclabendazole sulphoxide. Maximum plasma concentration (C(max): 13.22+/-2.81 microg/ml), time to reach maximum plasma concentration (t(max): 18.4+/-2.19 h), area under the curve (AUC: 613+/-137 microg h/ml), half-life (t(1/2): 24.77+/-1.94 h) and mean resident time (MRT: 40.22+/-4.36 h) of triclabendazole sulphoxide in housed group were significantly different from those of grazing group (C(max): 10.17+/-1.51 microg/ml, t(max): 14.0+/-2.19 h, AUC: 406+/-98 microg h/ml), t(1/2): 16.16+/-1.17 h and MRT: 34.48+/-4.40 h). It is concluded that anthelmintically more active sulphoxide metabolite has higher plasma concentration when triclabendazole is administered to goats fed with concentrate feed + hay compared to grazing goats.