Assessment of the Intensity of Behavioural Traits and Ovulation between Synchronized and Non-synchronized Cows

Thirty cyclic, non-suckled Brahman cows were divided into three groups, all of which were synchronized sequentially with CIDR-B and observed continuously for 100 h to determine different behavioural oestrus signs. Twenty-four hours after implant withdrawal, all synchronized cows in the group, together with all other cows displaying oestrus, were subjected to intensive ultrasonographic observations (every 6 h for 120 h) to pinpoint the moment of ovulation. In the first group, oestrus and ovulation response was 60% (6/10), in the second 44% (4/9) showed oestrus and six ovulated, and in the third group oestrus and ovulation were 80% (8/10). Significant differences were observed between the second and third groups (p < 0.05). No differences were observed in the duration of oestrus, time when oestrus was displayed after implant withdrawal, time of ovulation and onset of oestrus, end of oestrus to ovulation, and intensity of oestrus on a point scale. The relationship between duration of oestrus and time of ovulation was r(2) = 0.16. Ovulation, on average, was 32.1 +/- 14.5 h after the onset of oestrus, 22.3 +/- 16.5 h after the end of oestrus, and 91.8 +/- 16.7 after implant withdrawal, although no significant differences were observed. One non-synchronized animal showed oestrous activity in the second group but failed to ovulate. In the third group, 8 animals showed oestrus, 4 with high concentrations of progesterone. Of the other four one ovulated. In conclusion, oestrous behaviour is not necessarily the best marker to predict the time when ovulation takes place due to variation in the length of the oestrous period and the possible integration of non-ovulatory animals into sexually active groups.     

Efficacy of toltrazuril in broilers and development of a laboratory model for sensitivity testing of Eimeria field isolates

(1) The efficacy of toltrazuril (Baycox) against coccidiosis was established on a broiler farm in an intermittent application during five consecutive growing periods. Treated birds were fed a broiler ration without anticoccidials. The efficacy of Baycox was compared with the nicarbazin-salinomycin shuttle. It was concluded that Baycox retarded the onset of Eimeria infection for several weeks. During the fifth rearing period coccidiosis problems emerged on the farm in all birds during medication, suggesting development of resistance. (2) During a laboratory experiment the efficacy of Baycox was studied in birds after inoculation with different numbers of oocysts at 7, 10 or 15 days of age. Baycox was applied at 10 and 11 days of age. In all cases medication with Baycox protected birds from coccidiosis during a period of at least 7 days. This effect of Baycox could be due to the long-existing tissue levels of the product and its metabolites as well as its specific effect on the second generation of schizonts. (3) In another laboratory experiment coccidia obtained from field trials were tested for sensitivity to Baycox in conjunction with two strains obtained from farms were coccidiosis emerged during application. The inoculation model developed in this study was used for sensitivity testing. One of the Eimeria strains tested was resistant to the product, one strain was tolerant and the remaining two strains, including the control strain, were fully sensitive to Baycox.     

Een waarneming over het voorkomen van fysiologische rassen van het aardappel cystenaaltje,welke zich sterk kunnen vermeerderen in resistente nakomelingen vanSolanum tuberosum subsp.andigena

Ohne Zusammenfassung

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With a summary: A record of the existence of physiologic races of the potato root eelworm, which multiply vigorously in resistant progy, of Solanum tuberosum subsp. andigenum

     

Control of tent caterpillars (Malacosoma neustrium) withBacillus thuringiensis in the city of Amsterdam

Summary Laboratory experiments comparing the effect of dusts of Derris powder with dusts of products, based onBacillus thuringiensis, indicated a higher toxicity to Tent Caterpillars (Malacosoma neustrium) of the latter group. As, moreover, these dusts are harmless to man and higher animals, and even have a very specific action to insects, the use of the products is to be preferred above the use of Derris dust. The bacterial dusts are already used for some time in outdoor experiments, and it is proposed to use these dusts on a large scale in coming years.The insecticides are killing through their specific action the nuisant caterpillars only, and are therefore appreciable also because of recreation and nature conservation.Samenvatting De iepen langs de grachten in de stad Amsterdam worden periodiek aangetast door ringelrupsen (Malacosoma neustrium). Jaarlijks worden de bomen bestoven met een Derris-stuifmengsel. Deze bestrijding heeft nadelen, daar Derrispoeder giftig is voor vissen, nuttige insekten en andere levende organismen.Vergelijkende proeven in het laboratorium met Derris-stuifmengsel en preparaten op basis vanBacillus thuringiensis hadden tot resultaat, dat bij de gegeven concentraties de bacterie-poeders een iets betere werkzaamheid vertoonden dan Derris (tabel 1). Daar deze poeders bovendien geen gevaar opleveren voor mensen en huisdieren, en zelfs tegenover insekten zeer specifiek werken, verdient het gebruik van deze poeders de voorkeur boven dat van Derris.Vooral uit een oogpunt van natuurbescherming zijn in deze omstandigheden de preparaten, gebaseerd opBacillus thuringiensis, de beste bestrijding van deze insektenplaag in een grote stad.Proeven in de straten van Amsterdam metBacillus thuringiensis-poeder zijn tevens reeds enige jaren genomen. Zij worden in de komende jaren op grotere schaal voortgezet.Dit onderzoek geschiedde onder aspiciën van de Werkgroep voor Harmonische Insektenbestrijding T.N.O.     

Rectal tears in the horse: two case reports

Rectal tears occur incidentally and often have a poor prognosis. Early recognition of the problem and adequate therapy determine the outcome. The history, clinical examination, therapy, and outcome of two horses with grade IIIb and grade IV rectal tears are discussed.     

TB diagnosis in non-human primates: comparison of two interferon-gamma assays and the skin test for identification of Mycobacterium tuberculosis infection

To examine the effect of recombinant bovine interferon-gamma (rbIFN-gamma) on cattle persistently infected with bovine leukemia virus (BLV), BLV-infected cattle were inoculated intraperitoneally with IFN-gamma. All cattle were febrile after inoculation with IFN-gamma and then recovered within 48 h. Flow cytometric analysis showed that the numbers of CD4+ and CD8+ T cells were decreased for 2-3 days and then their numbers were recovered. The number of gammadelta T cells increased after the fever. In contrast, the number of IgM+ lymphocytes remained low for about 1 week. Moreover, the numbers of syncytia produced by peripheral blood lymphocytes decreased and remained low compared to that before IFN-gamma administration. These results suggest that IFN-gamma induces the up-regulation of gammadelta T cells, decreases the number of IgM+ lymphocytes and suppresses the growth of BLV in BLV-infected cattle in vivo.     

Progestagen supplementation during early pregnancy does not improve embryo survival in pigs

Progesterone supplementation during early pregnancy may increase embryo survival in pigs. The current study evaluated whether oral supplementation with an analogue of progesterone, altrenogest (ALT), affects embryo survival. A first experiment evaluated the effect of a daily 20-mg dosage of ALT during days 1-4 or 2-4 after onset of oestrus on embryo survival at day 42 of pregnancy. A control group (CTR1) was not treated. The time of ovulation was estimated by transrectal ultrasound at 12-h intervals. Altrenogest treatment significantly reduced pregnancy rate when start of treatment was before or at ovulation: 25% (5/20) compared to later start of treatment [85% (28/33)] and non-treated CTR1 [100% (23/23)]. Altrenogest treatment also reduced (p < 0.05) number of foetuses, from 14.6 ± 2.6 in CTR1 to 12.5 ± 2.5 when ALT started 1-1.5 days from ovulation and 10.7 ± 2.9 when ALT started 0-0.5 days from ovulation. In a second experiment, sows with a weaning-to-oestrous interval (WOI) of 6, 7 or 8-14 days were given ALT [either 20 mg (ALT20; n = 49) or 10 mg (ALT10; n = 48)] at day 4 and day 6 after onset of oestrus or were not treated (CTR2; n = 49), and farrowing rate and litter size were evaluated. Weaning-to-oestrous interval did not affect farrowing rate or litter size. ALT did not affect farrowing rate (86% vs 90% in CTR2), but ALT20 tended to have a lower litter size compared with CTR2 (11.7 ± 4.1 vs 13.3 ± 3.1; p = 0.07) and ALT10 was intermediate (12.3 ± 2.9). In conclusion, altrenogest supplementation too soon after ovulation reduces fertilization rate and embryo survival rate and altrenogest supplementation at 4-6 days of pregnancy reduces litter size. As a consequence, altrenogest supplementation during early pregnancy may reduce both farrowing rate and litter size and cannot be applied at this stage in practice as a remedy against low litter size.