Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism     

AR RABIEE  KL MACMILLAN  F SCHWARZENBERGER  D THALLER  MJ RATHBONE  TE TRIGG 《Australian veterinary journal》2001,79(10):690-694

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.  相似文献   

BOOK REVIEW     

KL Stafford 《Australian veterinary journal》2005,83(8):505-505

  相似文献   

Theileria orientalis: a review     

JG Watts  MC Playford  KL Hickey 《New Zealand veterinary journal》2016,64(1):3-9

Theileria orientalis (also known historically as T. sergenti and T. buffeli) is responsible for benign or non-transforming theileriosis, and exerts its major effect through erythrocyte destruction. The life cycle of T. orientalis is essentially similar to that of other Theileria species, except that the schizonts do not induce transformation and fatal lymphoproliferation. The pathogenesis of anaemia as a result of infection is not clearly established and may be multifaceted. Clinical signs of weakness, reluctance to walk and abortion are early but non-specific indications of disease, particularly if accompanied by a history of cattle being moved. Physical examination may reveal pallor (pale eyes, vaginal mucosa), pyrexia, and elevated heart and respiratory rates. T. orientalis is an economically important parasite of cattle in New Zealand, Australia and Japan, especially where naïve animals are introduced into an endemic area or in animals under stress. Increased awareness of the risks posed by the parasite is required to enable management practices to be implemented to minimise its impact.  相似文献   

Tests of anthelmintic activity (utilizing experimental challenge) against the migratory stages of Strongyloides ransomi in pigs     

S E Leland  G E Combs 《American journal of veterinary research》1965,26(113):932-938

  相似文献   

Development of an assay to determine the bioavailability of potassium in feedstuffs for the young pig     

N R Combs  E R Miller  P K Ku 《Journal of animal science》1985,60(3):709-714

A series of four trials was conducted to verify the published requirement of .26% total K in the diet and to identify response variables useful in an assay of the bioavailability of K in feedstuffs for the young pig. Purified diets were supplemented with K at four levels as KC2H3O2 in three trials and as KHCO3 in the fourth trial. In the first three trials, the requirement was estimated by least-squares analysis of a linear-plateau response of average daily gain. Additional measures in each trial were taken for linear response to dietary K levels. The three estimates of K requirement obtained were .30, .33 and .26% total K in the diet. These three estimates were not found to be inconsistent with the published value of .26% total K in the diet. Various urinary and hematological measures also were examined during the four trials for linear response to dietary K levels. Plasma K was the only hematological response to show a significant linear relationship to dietary K levels. Urinary K concentrations and daily excretion showed a highly significant linear response to dietary K levels. Based on these results, a K bioavailability assay using urinary K measures as the primary response variable and plasma K as the secondary response variable seems the most promising.  相似文献   

Luteoma in two mares treated by ovariectomy     

E. Combs  T. Beachler  J. R. Troy  A. Olds-Sanchez  J. M. Howard  A. Fales-Williams  M. Yaeger  D. M. Tatarniuk 《Equine Veterinary Education》2022,34(8):e318-e322

A 15-year-old Paint mare (Case 1) and a 15-year-old Arabian mare (Case 2) were presented for aggressive and undesired behaviour. Reproductive evaluation revealed, initially, an enlarged ovary with a smaller/normal sized contralateral ovary in each case. Granulosa cell tumour (GCT) panel testing revealed elevated inhibin B in both cases and elevated anti-Mullerian hormone (AMH) levels only in Case 1 determined from currently established reference ranges. Based on a presumptive diagnosis of GCT, bilateral standing ovariectomy was elected for both mares. In each case neoplastic tissue consistent with luteoma was detected only on histological examination in the smaller/normal sized left ovary; the right ovary appearing normal. Long-term follow-up was performed 1 year and 5 years post-operatively by telephone. The owners were satisfied with the outcome and each patient demonstrated resolution of aggressive stallion-like behaviour. Each case returned to the owners' intended use. In conclusion, luteoma should be considered as a differential diagnosis for ovarian neoplasms in horses related to behavioural abnormalities, even in normal-sized ovaries.  相似文献   

Efficacy of vaginal spaying and anabolic implants on growth and carcass characteristics in beef heifers   总被引：2，自引：0，他引：2  

M J Garber  R A Roeder  J J Combs  L Eldridge  J C Miller  D D Hinman  J J Ney 《Journal of animal science》1990,68(5):1469-1475

Ninety crossbred beef heifers averaging 260 kg were blocked by weight and allotted randomly to 15 pens of six heifers each, with three replicates per treatment. The treatments were spayed heifers (S); intact heifers (I); S + Synovex-H7 (SH); I + Synovex-H (IH); and S + Synovex-S7 (SS). The heifers were spayed vaginally with a Willis instrument; intact heifers were rectally palpated for reproductive soundness. Heifers were fed a growing diet (55 d), re-implanted and subsequently fed a finishing ration (73 or 101 d). All heifers were observed for estrus daily at approximately 0600 and 2000 until d 69. A jugular vein blood sample was obtained from each heifer on d 48, 55, 62 and 69 for blood progesterone analysis. Results of blood progesterone analysis and reproductive tract examination indicated that two spayed heifers were incompletely spayed, a 96% success rate. The SH and SS heifers continued to exhibit estrous behavior despite being successfully spayed. Heifers implanted with Synovex-H had greater (P less than .01) ADG and were more efficient (P less than .03) than nonimplanted heifers. The SS heifers had greater ADG (P less than .05) during the finishing phase than SH heifers, but no advantage of SS over SH was apparent during the growing phase. The overall ADG response to implantation was fourfold greater (P less than .07) in the spayed heifers than in the intact heifers (32 vs 8%). Heifers implanted with Synovex-H had greater adjusted hot carcass weight (P less than .02) and ribeye area (P less than .002) than nonimplanted heifers. For adjusted live weight and ribeye area, the response to implantation was approximately threefold greater in the spayed heifer than the intact heifer. These results demonstrate that spaying and implanting heifers can increase rates and efficiency of gain even though behavioral estrus is not eliminated.  相似文献   

Fat supplementation of diets containing a high level of oats for growing-finishing swine.     

R O Myer  G E Combs 《Journal of animal science》1991,69(12):4665-4669

Two 2 x 2 factorial arrangement trials were conducted to evaluate the effectiveness of fat supplementation in improving the energy value of diets containing a high level of a fibrous feedstuff (oats) for growing-finishing swine. Corn-soybean meal-based diets were used that contained either 0 or 40% ground oats and either 0 or 3% added fat. Each trial used 120 pigs (27 kg) with each treatment assigned to five pens of six pigs each. Growing diets (.80% lysine for basal diet) were given from 27 to 55 kg live weight and finishing diets (.64% lysine) from 55 to 102 kg. Diets were formulated to a constant calculated ME to lysine ratio within the growing and finishing phases. Apparent digestibilities of DM and energy were determined for the growing and finishing diets by the indigestible marker (chromic oxide) method. The inclusion of oats in the diets resulted in poorer (P less than .01) feed conversion efficiency and reduced (P less than .01) apparent DM and energy digestibilities. The addition of fat improved (P less than .01) feed conversion efficiency but had no effect (P greater than .10) on DM or energy digestibility. The improvements noted for feed conversion efficiency were similar (P greater than .10) regardless of the dietary oat content. The 3% dietary fat supplementation was equally effective in improving feed conversion efficiency whether the diets did contain or did not contain ground oats for growing-finishing swine.  相似文献   

The AK Sutherland Oration     

KL HUGHES 《Australian veterinary journal》1995,72(10):361-363

  相似文献   

Naphthalophos combinations with benzimidazoles or levamisole as effective anthelmintics for sheep     

NA COOPER  PF ROLFE  JE SEARSON  KL DAWSON 《Australian veterinary journal》1996,74(3):221-224

Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option.  相似文献