Multiple use of progesterone releasing intravaginal devices for synchronisation of oestrus and ovulation in cattle

Experiments were conducted to investigate the possibility of using progesterone releasing intravaginal devices (PRIDs) more than once, for the purpose of synchronising oestrus and ovulation in dairy cows. In an initial study, PRIDs were inserted into 6 ovariectomised cows for 12 days on 3 separate occasions and blood samples were collected for progresterone assay. After removal, 3 PRIDs were sterilised by autoclaving and the other 3 by gassing with ethylene oxide. After PRID insertion progesterone concentration in plasma rose rapidly. Autoclaved PRIDs which were reused once and then twice, maintained blood progesterone profiles which were comparable to the release of progesterone from a new PRID. This was not the case when PRIDs were re-used after gas sterilisation. In a second study, PRIDs were inserted into 41 dairy cows for 9 days and an injection of prostaglandin F2o was given one day before PRID removal. Onset of oestrus was determined by observation at intervals of 3 h for 30 min and time of ovulation was determined by endoscopy approximately 30 h after onset of oestrus. PRIDs were autoclaved after removal and re-used twice. In cows which received new PRIDs, 85% came into oestrus between 30 and 60 h after removal. When PRIDs were used for the second time, 100% of cows showed oestrus within 30 to 60 h. When PRIDs were used for the third time the interval between PRID removal and onset of oestrus was highly variable. Only 29% of cows showed oestrus within 30 to 60 h whereas 59% showed oestrus between 12 and 42 h after PRID removal. The distribution in estimated time between PRID removal and ovulation followed closely the distribution of onset of oestrus for each insertion of PRIDs. The synchrony of ovulation was most concentrated for the second use of PRIDs and least for the third use. A few cows did not follow the general pattern of response. Indications that the PRID may be used more than once for synchronising oestrus and ovulation in the dairy cow, and the adoption of a 9-day PRID insertion interval in any synchronisation schedule should result in a significant reduction in the cost of this technology.     

Oestrous cycles, oestrus and ovulation of the zebu in the Mexican tropics

The length of the oestrous cycle, oestrus and the time of ovulation were assessed in 20 adult, non-lactating zebu cows over 53 consecutive days of observation. Oestrus was detected at 30-minute observation periods daily. Peripheral blood samples were collected twice weekly for progesterone determination. To measure the length of the synchronised oestrous period, 10 cows with a palpable corpus luteum were injected with prostaglandin F2 alpha and continuously observed for 96 hours. Two cows at a time were exposed to a bull with a deviated penis for five minutes every three hours during this period. To measure the length of the natural oestrus, eight of the 10 cows from the previous experiment were continuously observed from day 21 after prostaglandin injection. They were kept during the daytime in a field with two teaser bulls and at night in a cattle pen where they were exposed to a teaser bull every three hours. Oestrus was considered to occur when the cow stood to be mounted. Ovulation was detected by rectal palpation every three hours in five cows starting six hours after receptivity commenced until ovulation took place. The length of the oestrous cycle was 20.1 +/- 1.9 days; 20 per cent of the animals did not show oestrus although their progesterone levels demonstrated that they were cycling. Two cows showed oestrus following prostaglandin F2 alpha injection although they were cycling as revealed by serum progesterone. Five animals showed behavioural oestrus around 118 hours after injection and following their release. Oestrus duration was 15.3 +/- 6.0 hours and ovulation occurred 28.2 +/- 5.0 hours after the start of the period of sexual receptivity.     

Fertility in zebu cattle (Bos indicus) after prostaglandin administration and artificial insemination.

A total of 137 cycling zebu cows, each receiving a single dose of prostaglandin PGF(2alpha)were used in an oestrus synchronization programme on three different farms. Of the cows on the three farms, 60.6 and 90.5% showed overt oestrus and luteolysis, respectively. Pregnancy rate to fixed time inseminations following single injection of PGF(2alpha)was 61.4% for farm 1, significantly higher than the values of 45.7 and 46.9% for farms 2 and 3, respectively. The pregnancy rates to second service of rebred cows were 53.3, 50.0 and 50.0% for the three farms, respectively, with no significant differences between each.Fertility classification of the cows based on progesterone (P(4)) concentration showed that 6.6% of cows on the three farms were incorrectly diagnosed as having corpora lutea; 2.9% of them had incomplete luteolysis and 5.1% may have lost their embryos between days 21 and 45 post-insemination. The pregnancy rate was 10% higher in the rainy season than in the dry season. Cows with body condition scores of 3 and 4 had a higher overall pregnancy rates than those with a body condition score of 2. The findings of this study further confirm the luteolytic efficacy of prostaglandin in inducing oestrus in zebu cattle and indicate that the nutritional status of the cows must be satisfactory before embarking on oestrus synchronization programmes.     

Conception rates in cows after various synchronisation techniques using progesterone releasing intravaginal devices

The effects of different treatments for oestrus synchronisation on the incidence of oestrus and fertility levels in dairy cows were studied in 2 experiments. In Experiment 1, 200 lactating cows were allotted to 5 groups and the treatments imposed were either; 1: Untreated controls, 2: An injection of 0.5 mg of cloprostenol followed 13 days later by a progesterone releasing intravaginal device (PRID) inserted for 12 days, 3: A PRID, with a capsule containing 10 mg of oestradiol benzoate (ODB) attached, inserted for 12 days, 4: A PRID inserted for 12 days with 0.5 mg of cloprostenol administered 24 h before PRID removal or, 5: As for 4 but 14 days after fixed-time insemination a second PRID was inserted for 12 days. Treated cows were inseminated 56 h after PRID removal and at an observed oestrus during the subsequent 30 days. The control group was inseminated at an observed oestrus during this 30-day period. For treatments 2, 3, 4 and 5, respectively, the percentage of cows showing oestrus by 60 h after PRID removal was 70, 40, 67 and 43 and conception rates to the fixed time insemination were 34, 33, 49 and 29%. Calving rates of cows inseminated at an observed oestrus during a 30-day period were 70, 75, 70, 83 and 82% for treatments 1, 2, 3, 4 and 5, respectively. In Experiment 2, 60 lactating cows were divided into 2 groups and the treatments imposed were either 1: An injection of 0.5 mg of cloprostenol followed 13 days later by a PRID inserted for 12 days or 2: As for 1 but 14 days after fixed-time insemination a second PRID was inserted for 12 days. Treated cows were inseminated 56 h after PRID removal and at an observed oestrus over a period from the first insemination to 6 days after removal of the second PRID. For treatments 1 and 2, respectively, 73 and 71% of cows showed oestrus by 60 h after removal of the first PRID and 40% and 46% conceived to the fixed time insemination. The conception rates to inseminations over the treatment period were 73 and 70% for treatments 1 and 2, respectively. None of the treatments resulted in conception rates which were lower than those of control cows provided that treated cows were reinseminated at observed oestrus. Treatment 4 provided the most practicable technique for oestrus synchronisation.     

Relationship between ticks and zebu cattle in southern Uganda

Summary Tick populations were observed on zebu(Bos indicus) cattle over a period of 2 years at Entebbe, Uganda where the climate was thought to be highly favourable for the free-living stages of ticks. Collections of all instars of ticks were made from the body surfaces of the cattle at intervals of between 1 and 5 weeks. The species recorded in order of decreasing abundance wereRhipicephalus appendiculatus, Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositus andHyalomma marginatum rufipes. The rankings of the cattle based on burdens of any particular species of tick were always correlated with their rankings for other species; animals that carried more adult stages of a species also carried more of its immature stages. There were more adult males than females ofR. appendiculatus, A. variegatum andR. e. evertsi even when the cattle had had all ticks removed 1 week previously; several possible mechanisms are suggested to explain the biased sex ratio. It is concluded that there is promise for improvement in control of 3-host ticks by increasing the resistance of herds of zebu cattle by culling or selective breeding.

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Relacion Entre Garrapatas Y Ganado Cebu En El Sur De Uganda

Resumen Se observaron las poblaciones de garrapatas en ganado cebú (Bos indicus) en Entebe, Uganda, donde el clima parecía favorecer a los estados libres de las garrapatas. Las observaciones duraron dos años. Las colecciones de los estadios larvales se realizaron con intervalos de 1 a 5 semanas. Las especies identificadas en orden numérico decreciente fueronRhipicephalus appendiculatus, Amblyommavariegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositu andHyalomma marginatum rufipes. Los rangos del ganado basados en la carga de garrapatas de una especie en particular, tuvieron correlación en rangos para otras especies en los animales que tuvieron una carga mayor de etapas maduras de una especie se observaron tambie más ejemplos de las etapas no maduras. Hubo más machos adultos que (hembras deR. appendiculatus, A. variegatum yR. e. evertsi aun cuando todas las garrapatas del ganado habían sido removidas 1 semana previamente; se sugieren varios mecanismos para explicar este fenómeno. Se concluye que existe una posibilidad para controlar garrapatas de 3 huéspedes, incrementando la resistencia de ganado cebú mediante selección y cruzamiento de animales resistentes.

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Relation Entre Les Tiques Et Les Zebus Dans Le Sud-Est De L'Ouganda

Résumé Des populations de tiques ont été observées sur des zébus (Bos indicus) pendant 2 ans à Entebbe, en Ouganda où le climat est connu pour être très favorable aux stades libres des tiques. Des collections de tous les stades de tiques présentes sur le corps des animaux ont été faites à des intervalles allant de 1 à 5 semaines. Les espèces suivantes ont été recueillies dans l'ordre d'abondance décroissante:Rhipicephalus appendiculatus, Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus, Rhipicephalus compositus etHyalomma marginatum rufipes. Le classement du bétail basé sur la charge en une espèce de tique a toujours été en corrélation avec la charge dans les autres espèces de tiques. Les animaux porteurs du plus grand nombre d'adultes d'une espèce étaient également porteurs du plus grand nombre de stades préimaginaux. Il y avait beaucoup plus de mâles que de femelles deR. appendiculatus, A. variegatum etR. e. evertsi même lorsqu'on avait prélevé toutes les tiques sur le bétail une semaine auparavant. Plusieurs mécanismes possibles sont suggérés pour expliquer le déséquilibre dans le pourcentage des sexes. La conclusion porte sur les promesses d'amélioration de la lutte contre les tiques trixènes par l'accroissement de la résistance des troupeaux de zébus par élevage sélectif.

     

AcuteTrypanosoma vivax infection of ethiopian cattle in the apparent absence of tsetse

Summary Investigations of acute trypanosomiasis in a group of 1,200 cattle provided strong evidence for mechanical transmission by haematophagous flies other than tsetse. Although recently introduced cattle may have had previous contact with tsetse flies the incident occurred in an area remote from their known range. Mortality exceeded 6% before the outbreak was controlled by chemotherapy. Mechanically transmittedTrypanosoma vivax infection may be of widespread occurrence in eastern Ethiopia.

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Infeccion Aguda PorTrypanosoma Vivax En Ganado Etiope En La Ausencia Aparente De Tsetse

Resumen La investigación sobre tripanosomiasis aguda, en un grupo de 1.200 animales, proporcionó evidencia de transmisión por moscas hematófagas diferentes a la tsetse. El incidente ocurrió en un área remota del habitat de la tsetse, aunque un grupo de ganado recientemente introducido, pudo tener algun contacto previo con éstas últimas. La mortalidad excedió el seis por ciento, antes que el brote se controlara. La transmisión puramente mecánica de la tripanosomiasis en Etiopía, podría tener más importancia que la que actualmente se le da.

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Infection Aigue ATrypanosoma Vivax Chez Les Bovins Ethiopiens Malgre L'Absence Apparente De Tse-Tse

Résumé Les recherches des signes de la Trypanosomiase aiguë conduites dans un groupe de 1200 bovins ont apporté la preuve certaine de la transmission mécanique de la maladie par d'autres insectes hématophages que la tsé-tsé. Bien que du bétail récemment importé ait pu déjà être en contact avec ce vecteur, la maladie est apparue dans une région éloignée de sa zone habituelle. La mortalité a dépassé 6 p. 100 avant que le foyer n'ait pu être contrôlé par la chimiothérapie. La transmission mécanique de l'infection àT. vivax est probablement largement répandue dans l'Est éthiopien.

     

Effects of copper and cobalt treatment of cattle in the ethiopian rift valley

Summary The effects of treatment of young Borana-type zebu cattle with copper and cyanocobalamin by injection are described. Cattle receiving copper gained a mean of 9.18 kg more than cobalt treated and control cattle over a 23-week period of the dry season. Anaemia was not present initially nor in control animals and blood parameters, with the exception of serum copper content, were unaffected by treatment. Serum copper contents were low initially in all cattle and, although increased in the copper treatment group, remained below normal levels.

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Effectos Del Tratamiento Con Cobre Y Cobalto Del Ganado En El Valle De Rift En Etiopia

Resumen Se describen los efectos del tratamiento de ganado Cebú Borana con cobre y cianocobalamina. El ganado que recibió inyecciones de cobre ganó un promedio de 9.18 kg más que el ganado tratado con cobalto y los controles, durante un período de 23 semanas en la estación seca. Los animales tratados no tenían anemia y los parámetros sanguíneos, con la excepción del contenido sérico de cobre, no variaron con el tratamiento. El contenido sérico de cobre fué bajo en todos los animales en experimentación y aunque aumentó en los tratados, siempre se mantuvo por de bajo de los limites normales.

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Effets Du Traitement Au Cuivre Et Au Cobalt Sur Le Betail De La Vallee Du Rift En Ethiopie

Résumé Les effets du traitement au cuivre et à la cyanocobalamine en injection sur de jeunes zébus Borana sont décrits. Au cours d'une période de 23 semaines pendant la saison sèche, le bétail recevant du cuivre a gagné en moyenne 9,18 kg de plus que celui traité au cobalt et que le bétail témoin. Au début il n'y avait pas d'anémie chez les animaux traités pas plus que chez les animaux témoins et les paramètres sanguins, exception faite du cuivre présent dans le sérum, n'étaient pas affectés par le traitement. Initiallement les dosages de cuivre étaient faibles chez tout le bétail et bien qu'ils aient augmente dans le groupe recevant un traitement au cuivre, ils sont restés en dessous des taux normaux.

     

Maintaining zebu maure cattle in a tsetse infested area of Mali

Summary A study was initiated to evaluate two trypanocidal drugs, the prophylactic isometamidium chloride (Trypamidium) and the curative diminazene aceturate (Berenil) as to their potential for long-term maintenance of zebu cattle in a tsetse infested area of Mali. Trypamidium was administered quarterly and Berenil was administered only as animals were found to be positive for trypanosomes. During the 21-month study trypanosomiasis was the most frequently encountered disease in the cattle in the Berenil treatment group with an average of 5·5 reinfections. The predominant trypanosome species encountered wasTrypanosoma vivax and the most important vector wasGlossina palpalis gambiensis. The results indicate that, even though the direct costs for drugs under the two maintenance regimens were almost identical, the use of Trypamidium resulted in a significantly greater annual weight gain, prevented death loss due to trypanosomiasis and resulted in a herd with a greater market value.

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Mantenimiento De Ganado Cebu Maure En Una Zona Infestada Por Moscas Tsetse

Resumen Se evaluaron dos drogas contra la tripanosomiasis en Mali. Una profiláctica, Trypamidium, y la otra curativa, Berenil. El Trypamidium (cloruro de isometamidium) se aplicó cada tres meses y el Berenil solo cuando los animales se encontraron positivos. Durante los 21 meses del estudio, tripanosomiasis fue la enfermedad más comunmente encontrada en el grupo tratado con Berenil, con un promedio de reinfección de 5·5. Los tripanosomas predominantes fueron elTrypanosoma vivax y el vector más importante laGlossina palpalis gambiensis. Los resultados del estudio indican que aunque el costo de las drogas para los dos grupos fue casi idéntico, el uso del Trypamidium resultó en un aumento significativo de peso de los animales tratados, previniendo muertes por tripanosomiasis.

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Maintien De Bovins Zebu Maure Dans Une Region Du Mali Infestee De Glossines

Résumé Une étude fut entreprise pour évaluer deux médicaments trypanocides, le chlorure d'isometamidium (Trypamidium) à titre préventif et l'acéturate de diminazène (Bérénil) à titre curatif, en ce qui concerne leur valeur potentielle pour le maintien à long terme de bovins zébu dans une zone infestée de glossines au Mali. Le Trypamidium était infecté tous les trois mois et le Bérénil seulement lorsque les animaux s'avéraient porteurs de trypanosomes. Pendant les 21 mois de l'étude, la trypanosomose a été la maladie la plus fréquemment rencontrée dans le groupe traité au Bérénil avec en moyenne 5,5 réinfections. L'espèce trypanosomienne prédominante étaitT. vivax et le vecteur le plus importantGlossina palpalis gambiensis. Les résultats montrent que, bien que le coût direct des médicaments dans les deux régimes de maintien ait été presque identique, l'emploi du Trypamidium a engendré un gain de poids annuel significativement plus grand, a prévenu les mortalités dues à la trypanosomose et conduit à un troupeau de valeur marchande plus élevée.