Uterine prolapse in Southland ewes

Extract

During the spring of 1997, there has been a high prevalence of “bearings” (vaginal prolapse) on a number of farms in Southland. No doubt other regions of New Zealand have had similar problems.     

Leptin infusion during the early luteal phase in ewes does not affect progesterone production

Infusion of leptin during the ovine follicular phase has been shown to increase progesterone secretion during the subsequent luteal phase. In this study, we have assessed the effects of infusing leptin during the early luteal phase. Infusion of leptin (2.5 microg/h) into the ovarian artery of ewes with ovarian autotransplants (n=5) on day 3 of the luteal phase for 12h did not affect progesterone estradiol or LH concentrations compared to control ewes (n=5). These results suggest no direct effect of leptin on ovarian function at this stage of the estrous cycle.     

Comparative efficiency of oestrus synchronization in sheep with progesterone/eCG and progesterone/GnRH during breeding and non-breeding season

The present study compared the occurrence of oestrus behaviour and ovulation in response to the insertion of CIDR devices plus a classical treatment with equine chorionic gonadotrophin (eCG; single dose at CIDR removal) or alternative treatments with gonadotrophin-releasing hormone (GnRH, either in a single dose at 56 hr after CIDR removal, or in one dose at CIDR insertion and another dose at 56 hr after CIDR removal). The appearance of oestrus behaviour during reproductive season ranged between 84% and 95% and all females showing oestrus signs had subsequent ovulations. The response, during seasonal anoestrus, was similar in the group treated with eCG, but less than half of the females in the groups treated with GnRH showed oestrus signs in response to the treatment, although more than 80% of them showed resumption of ovulatory activity after the treatment. In conclusion, protocols based on GnRH administration offer similar yields to eCG-based protocols during the reproductive season but occurrence of oestrus in response to GnRH-based treatments is highly compromised during seasonal anoestrus.     

Estrous synchronization in ewes: The use of progestogens and prostaglandins

ABSTRACT

This review summarizes the first principles, hormone types, and applied research related to the synchronization of estrus in ewes. The hormones used to induce synchronization include progestogens, such as medroxyprogesterone acetate (MAP), fluorogestone acetate (FGA), a controlled internal drug-releasing (CIDR) device, progesterone (P₄), norgestomet, and prostaglandins. These are usually combined with gonadotropins. Research on these hormones indicates that CIDR, MAP, and FGA can be regarded as equally effective for induction of estrus in ewes. Prostaglandins are a suitable alternative for estrous synchronization especially considering that progestogens may have negative effects on the functionality of ovulatory follicles. Artificial insemination, embryo transfer, and the acceleration of herd genetic trait improvement are among the potential practical applications of synchronous estrus in ewes.     

Efficacy of a continuous, multiagent chemotherapeutic protocol versus a short-term single-agent protocol in dogs with lymphoma

OBJECTIVE: To compare response rates and remission and survival times in dogs with lymphoma treated with a continuous, multiagent, doxorubicin-based chemotherapeutic protocol or with a short-term single-agent protocol incorporating doxorubicin. DESIGN: Nonrandomized controlled clinical trial. ANIMALS: 114 dogs with lymphoma. PROCEDURES: Dogs were treated with a chemotherapeutic protocol consisting of L-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate, and prednisolone (n=87) or doxorubicin alone (27). RESULTS: 63 of 86 (73%) dogs treated with the multiagent protocol (data on response was unavailable for 1 dog) and 14 of 27 (52%) dogs treated with the single-agent protocol had a complete remission. Dogs with lymphoma classified as substage相似文献   

The effect of progesterone impregnated sponges on fertility in anoestrous ewes

Progestagen impregnated sponges have been widely used for the induction and synchronization of oestrus in the ewe. We report here a study of the use of the natural hormone, progesterone, administered on sponges in order to induce oestrus in anoestrous ewes. A linear increase in fertility was observed when the progesterone dose was increased from 500 to 1000 mg. A similar quantity of progesterone (250 mg) was absorbed by the ewes regardless of the dose administered in the range 500 to 1200 mg. Sixty eight per cent lambing of treated ewes was achieved using sponges impregnated with 1000 mg progesterone. Optimum fertility appeared to be governed by adequate absorption of the hormone at a rapid initial rate, and this was ensured at the higher doses of progesterone.

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Kurzfassung Progestagen-getränkte Schwämme wurden zur Herbeiführung und Synchronisierung der Brunst bei Schafen weitgehend benutzt. Eine derartige Behandlung der Tiere kann zu einer geringeren Fruchtbarkeit, als sie unter natürlichen Zuchtbedingungen im Herbst besteht, führen. Die Wirkung von zunehmenden Dosen der verabreichten synthetisch hergestellten Progestagene auf die anschliessende Fruchtbarkeit der Schafe ist gut dokumentiert. Mehrere Verfasser haben den Restgehalt an SC-9880 gemessen, der auf den Schwämmen nach ihrer Entfernung von den Schafen, die zur Herbeiführung und Synchronisierung der Brunst behandelt worden waren, verblieb. Sie stellten eine lineare Zunahme der Frunchtbarkeit mit der verabreichten Dosis bei SC-9980 fest; bei höheren Dosen (30 bis 50 mg) wurde eine verlangsamte Progestagen-absorption von den Schwämmen beobachtet. Die Forscher berichteten, dass die Frucktbarkeit nicht-brünstiger Schafe bei Dosen von SC-9880 von über 30 mg bei 38 bis 67% Lammen liegen kann.Hier wird eine Untersuchung des natürlich vorkommenden Hormons Progesteron und seiner Verabreichung auf Schwämmen zur Herbeiführung der Fruchtbarkeit bei nicht-brünstigen Schafen beschrieben. Auch bei dieser Untersuchung wurde eine lineare Zunahme der Frucktbarkeit bei zunehmenden Dosen des verabreichten Progesterons beobachted. Ein Schwellenwert von Progesteron (250 mg) wurde von den Schafen unabhängig von der verabreichten Dosis im Bereich von 500 bis 1200 mg absorbiert. Bei den behandelten Schafen (mit 1000 mg imprägnierte Schwämme) wurde ein Ergebnis von 68% Lammen erzielt. Eine optimale Fruchtbarkeit wird anscheinend bei einer anfänglich schnellen, angemessenen Absorption des Hormons erzielt und diese Faktoren waren bei höheren Dosen von Progesteron gegeben.

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Resume On a largement utilisé la technique des éponges impregnées de progestagène pour induire et synchroniser l'oestrus chez les brebis. Un tel traitement peut entraîner un taux de fertilité inférieur à celui obtenu dans des conditions normales de reproduction en automne. L'effet de l'augmentation des doses de progestagène synthetique administrées sur la fertilité ultérieure des brebis a fait l'objet de nombreuses études. Plusieurs auteurs ont etudié les niveaux résiduels de SC-9880 sur les éponges après leur retrait des brebis qui avaient été traitées en vue de l'induction et de la synchronisation de l'oestrus. Ils ont constaté une progression linéaire de la fertilité en fonction des doses de SC-9880 administrées et un ralentissement de l'absorption du progestagène contenu les éponges aux doses les plus elevées utilisées (30 a 50 mg). Ces chercheurs ont signalé que la fertilité des brebis pendant l'anoestrus pouvait aller de 38 a 67% d'agnelage aux doses de SC-9880 supérieures à 30 mg.Le présent rapport a pour objet l'étude de l'hormone naturelle, la progestérone, administrée au moyen d'éponges pour induire l'oestrus chez les brebis en période l'anoestrus. Dans la présente étude, on a également observé une augmentation linéaire de la fertilité avec l'augmentation de la dose de progestérone administrée. On a constaté chez les brebis une valeur limite d'absorption de progestérone (250 mg), quelle que soit la dose administrée allant de 500 a 1200 mg. On a obtenu 68% d'agnelage chez les brebis traitées au moyen d'éponges impregnées de 1000 mg de progestérone. La fertilité optimale semble dépendre de l'absorption adéquate de l'hormone à un taux initial élevé, condition qui se trouve remplie en administrant des doses élevées de progestérone.

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Riassunto Le spugne impregnate di progesterone sono comunemente utilizzate per indurre e sincronizzare l'estro della pecora. Un simile procedimento rischia tuttavia di rendere l'animale meno fecondo rispetto alle condizioni di riproduzione naturale nella stagione autunnale. Gli effetti che dosi crescenti di preparati progestogeni producono sulla fecondità delle pecore sono del resto ampiamente documentati. Analizzando i residui di SC-9880 che restano sulle spugne rimosse dal corpo della pecora, diversi autori sono giunti alla conclusione che esiste un incremento lineare della fecondità se si somministrano le dosi sotto forma di SC-9880. La stessa indagine evidenzia inoltre un minore assorbimento di sostanza progestagena dalle spugne se si utilizzano dosi massime comprese fra 30 e 50 mg. I ricercatori affermano che le pecore in anestro hanno parti in una percentuale compresa fra il 38 e il 67% se ricevono dosi di SC-9880 superiori ai 30 mg.La presente ricerca riguarda la somministrazione mediante spugne di progesterone naturale per indurre l'estro nelle pecore in anestro. Essa dimostra che dosi crescenti di progesterone conducono ad un incremento lineare della fecondità. Esiste un tetto massimo di assorbimento del progesterone (250 mg) anche con dosi di somministrazione comprese fra i 500 e i 1200 mg. Il 68% dei parti delle pecore trattate si ha con spugne impregnate con 1000 mg di progesterone. La fecondità ottimale sembra dipendere da un adeguato ed inizialmente rapido assorbimento dell' ormone, ottenibile con dosi massime di somministrazione.

     

Effect of progesterone supplementation on pregnancy and embryo survival in ewes

Two hundred eighteen ewes were used in experiments 1) to develop a progesterone supplementation regimen capable of sustaining serum concentrations of progesterone at about 2.0 ng/ml for a period of 50 d (Exp. 1) and 2) to determine the effects of progesterone supplementation (d 6 to 50 after mating) on pregnancy and embryo survival rates in mated ewes (Exp. 2). In ovariectomized ewes in Exp. 1, s.c. administration of four cylindrical (9.5 x 60 mm) silastic implants, containing 20% (1.1 g) progesterone by weight, sustained mean serum concentrations of progesterone of 1.9 +/- .07 ng/ml compared with 1.03 +/- .05 ng/ml in ewes bearing two implants. In Exp. 2 each ewe (n = 159) was mated to two fertile rams at a spontaneous estrus (d 0) during mid-breeding season. Mean ovulation rate, determined on a subgroup of 46 ewes, was 1.45 +/- .05. On d 6, ewes were assigned randomly to control (two implants containing no progesterone) or progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (3.50 +/- .06) than in control (2.65 +/- .05) ewes. Pregnancy rates (86% and 83%) and calculated embryo survival rates (77% and 78%) were similar (P greater than .05) for the control and progesterone-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fertility following synchronization of oestrus in romney,corriedale and merino ewes

Attempts were made to recover and serologically identify Yersinia pseudotuberculosis from the faeces of groups of nine to twenty clinically healthy cattle eight to thirteen months old on each of 50 farms in the northern part of New Zealand.

Yersinia pseudotuberculosis was recovered from 134 (26.3%) of 509 faeces samples from cattle on 42 (84%) farms and from nine often samples on two of these farms. Serotypes I, II, and III were identified, of which serotype III was by far the most common and accounted for 125 (93.2%) of the 134 isolates.

Because of the common occurrence and widespread distribution of Y. pseudotuberculosis it is suggested that the clinical significance of isolation of this micro-organism from faeces samples or intestinal contents should be treated with caution.     

Uterine activity in cows during the oestrous cycle, after ovariectomy and following exogenous oestradiol and progesterone

Uterine activity was monitored in three, 2-year-old nulliparous Ayrshire heifers using intrauterine balloon-tipped catheters and pressure transducers during the oestrous cycle, after ovariectomy and following the intravenous infusion of progesterone and oestradiol-17 beta. During the oestrous cycle uterine activity, as measured by the frequency and amplitude of contractions, was greatest around oestrus and declined during the luteal phase of the cycle; there was a close correlation with peripheral progesterone concentrations. In two animals after bilateral ovariectomy spontaneous uterine activity persisted, whilst in the third animal the uterus was quiescent. In the first two heifers intravenous progesterone infusions reduced the spontaneous uterine activity, eventually completely abolishing it. There was evidence of a dose response effect at the two infusion rates. Oestradiol benzoate infusions initially inhibited spontaneous uterine activity before stimulating contractions with some evidence of a dose relationship. As demonstrated in normal cyclical and steroid-infused animals, uterine activity appears to be under the influence of both hormones although the influence of progesterone is greater.     

Effects of melatonin and progesterone administered to ewes in spring and summer

Melatonin (MEL) was evaluated for effects on LH, prolactin (PRL) and fertility in spring (Exp. 1, 2) and summer (Exp. 3 to 5). In Exp. 1, 17 ovariectomized ewes bearing estradiol implants were fed 3 mg MEL or vehicle for 44 d beginning May 1. Melatonin decreased (P less than .001) PRL levels but had no effect on LH secretion and response to GnRH. In Exp. 2, 12 ewes each received a 40-d MEL ear implant or a sham implant on March 31. Progesterone-releasing pessaries (CIDR) were applied for 12 d and were withdrawn concomitant with ram joining on May 7. Neither treatment stimulated follicular development or induced estrus or ovulation. Exp. 3 and 4 were contemporary 2 x 2 factorial trials with 24 ewes at each of two locations. Melatonin implants were administered on June 29 and CIDR on July 22. The CIDR were removed and rams (Exp. 3, vasectomized; Exp. 4, fertile) were joined on August 3. Days from introduction of rams to estrus were reduced (P less than .05) by CIDR but not by MEL. All ewes lambed in Exp. 4, and days to estrus and conception were reduced (P less than .001) by CIDR but not by MEL. Exp. 5 was designed like Exp. 4 except that MEL implants were inserted June 20 and rams were joined August 8. Intervals from introduction of rams to estrus were reduced (P less than .01) by both MEL and CIDR treatments.(ABSTRACT TRUNCATED AT 250 WORDS)