British Veterinary Journal

Published by Elsevier
Print ISSN: 0007-1935
The effects of a moderately low calcium diet (55 g/day) relative to one providing 120 g Ca/day were studied in 11 dairy cows during the last two weeks before and first week after parturition. The moderately low calcium diet was first fed to all the cows approximately five weeks before calving. The dietary calcium intake of five of these animals was increased to 120 g Ca/day five to 14 days before parturition. Although there were no instances of clinical parturient paresis in any of the cows the fall in plasma calcium concentration around and at parturition was significantly greater in those cows fed the high calcium diet prepartum than in those fed the low calcium diet. The prepartum plasma concentrations of 1,25-dihydroxycholecalciferol tended to be higher in the cows fed the lower calcium diet, although not significantly so. In contrast, these concentrations one day after parturition were higher in the high calcium group.It is concluded that a moderately low calcium diet fed to cows during the last five weeks of pregnancy reduces the likelihood of parturient paresis.
Extensive chemical modification and biological testing of benzenesulphonamides resulted in the selection of 4-amino-6-trichloroethenyl-1,3-benzenedisulphonamide as the most promising fasciolicide in this series. Dosages of 10 and 15 mg/kg were 97 and 92% effective against immature liver flukes in calves and sheep respectively. Mature flukes in both sheep and cattle were removed by a single dose of 3 · 75 mg/kg.
The results of an investigation of the incidence and cause of death amongst 2488 sows in 106 herds in Essex are reported. The annual mortality rate was approximately 4 per cent. The principal causes of death were complications of parturition, cystitis and nephritis, endocarditis and acute haemorrhage. Bacterial infection played an important part in the diseases leading to the death of over 40 per cent of the sows examined.
Eleven animal species (cattle, sheep, goat, camel, pig, horse, dog, chicken, pigeon, duck and guinea-fowl) kept under different management systems in northern Nigeria were screened for antibodies against three serogroups of Yersinia enterocolitica using the tube agglutination test. Only animals serologically negative for brucellosis were used. Of 688 animals tested 248 (36·0%) were seropositive for antibodies against either serogroups 0:3, 0:8 or 0:12,26 using a cut-off point for definition of sero-positive of . The highest antibody prevalence was detected in polo horses (67·5%) and the lowest in pigeons (6·7%). In all species tested, antibodies against 0:3 were most prevalent with 203 (29·5%) being seropositive. For serogroups 0:12,26 and 0:8, 11·6 and 7·0%, respectively were seropositive. The highest positivity rate to serogroup 0:3 was detected in guinea-fowls (55·6%), to serogroup 0:8 in pigs (22·6%) and to 0:12,26 in horses (43·8%). Antibody titre of was most frequently encountered although titres of or above were detected in 54 of 203 seropositive animals for serogroup 0:3, 14 of 54 for 0:8 and 12 of 80 for 0:12,26.The most common multiple antibodies found were to serogroups 0:3 and 0:12,26 in 26 (10·5%) of 248 seropositive animals.It was concluded that Y. enterocolitica infection by the three serogroups tested was widespread in domesticated animals in Nigeria. With relatively high antibody titres () suggestive of recent infection coupled with the fact that serogroups 0:3 and 0:8 are known human pathogens, meat and milk products from infected animals could be a health hazard to consumers.
An in-vitro system was devised for the culture of porcine embryos from: 1.(a) the late primitive streak/early neural folds ( to 13-day) stage to neural fold closure and early differentiation of the cephalic region (16 days);2.(b) the 15 to -day stage to the first appearance of tail and limb buds.The embryos were cultured in 30-ml bottles on a roller apparatus, and a chemically-defined medium supplemented with pig serum was used.Two different gas phases, 5% CO2 with 95% O2, and 5% CO2 in air were tested, and for both early ( to 13-day) and later (15 to -day) stage embryos the 5% CO2 in air was found to give the best results. With the early embryos growth over a 96 h period in vitro was similar to that which occurs in vivo. However, with the later embryos, growth, as reflected by size and morphology, was not as good as that in vivo except possibly during the initial 48 h in culture.
Analyses were made of respiratory, acid base and blood gas values in 5 Percheron foals anesthetized when 1 to 21 days old. There was a mean Pa(O2) of 60 mm Hg in conscious newborn foals compared with 75.5 mmHg in their dams (P<0.01). The Aa P(O2)difference was smaller in foals 15 to 21 days old, than in foals 1 to 3 days old (P<0.05). Under Na pentobarbitone anesthesia, the mean Pa(O2) decreased significantly in both newborn and older foals to 49.7 mmHg and 52.4 mmHg respectively (P<0.01). Under halothane and O 2 anesthesia, gross Aa P(O2) differences were observed in both newborn and older foals amounting to 55.5% and 57.0% of PA(O2) respectively. PA(CO2) increased to values close to 60 mmHg (P<0.01). Oxygenation improved in 3 newborn foals transferred to a T piece anesthesia system. Correlation of alveolar dead space with the magnitude of the right to left shunt expressed as a percentage of PA(O2) (P<0.001) suggests that in newborn foals, the alveolar dead space is largely due to right to left shunt effect, and to non perfused alveoli. The ventilation equivalent for oxygen (VE(O2) was significantly greater in older foals. The above findings are discussed in relation to cardiopulmonary function in the horse.
This paper records the post-mortem findings of 132 wild birds found dead or dying.Thirty-three per cent of the birds died of infectious diseases, 27% were poisoned, 16% had traumatic injuries, 2% were severely infested with parasites and in 9% no diagnosis was reached. The remaining 13% died of miscellaneous causes. These results are similar to those reported by McDonald (1965), Jennings (1961) and Keymer(1958).
Under field conditions a 97.8% success rate was achieved for caesarean operations performed on ewes with live or freshly dead lambs present in utero. Where lambs were in moderate to advanced stages of autolysis and emphysema the survival rate of the dam was 57.1%. Neither the presence of a vaginal prolapse nor abortion appeared to have an influence on the survival rate of the ewe. Interference and trauma to the posterior reproductive tract prior to veterinary examination reduced the success rate of cases. Ewes with a history during gestation of a prolapsed vagina were 10 times more likely to require a caesarean operation to correct the dystocia than normal ewes. A range of haematological variables failed to give an accurate prognostic guide to the outcome of surgery. A caesarean operation is recommended in preference to euthanasia of a ewe that could have been considered a poor-risk surgical case. Fetotomy was not possible in cases where emphysematous lambs were present in utero.
In artificially inseminated cows (AI on day 1) peak concentrations of oestradiol-17 beta in defatted milk occurred at median times of day 0 during the pre-ovulatory period, days -5 to 2, and day 6 during the post-ovulatory period, days 2-15. Median peak concentrations during these periods were approximately 5 pg/ml and 3 pg/ml respectively. There were no significant differences in the timing or magnitude of oestradiol-17 beta concentrations between cows that became pregnant to the AI and those that entered normal length oestrus cycles immediately after AI.
Fourteen cases of bovine spongiform encephalopathy (BSE) were diagnosed on the basis of clinical examination in a closed herd of British Friesian cows during a 9-month period from October 1987 until June 1988. The diagnosis was confirmed on histopathological examination of brain tissue from five of the six samples submitted. The main presenting clinical signs were of altered behaviour: apprehension, anxiety and hyperaesthesia. One cow was euthanized after a short period of recumbency; the remaining 13 cows were slaughtered on humane or economic grounds. No protein of animal origin had been fed to either heifers or cows in this herd during the past 5 years and there had been no direct contact with sheep. The epidemiology of BSE in this report suggests that, if the postulate of Morgan (1988) is correct, infection is ingested within the first 6 months of life and there then follows a 4-5-year period before clinical signs appear.
M&B 15,497 (ethyl 6-n-decyloxy-7-ethoxy-4-hydroxyquinoline-3-carboxylate) was tested against laboratory strains of six species of chicken Eimeria, and against a total of eighty-four field isolates of Eimeria. All the infections were completely controlled (as measured by oocyst production, lesions or deaths) by M&B 15,497 at a dietary concentration of 0 004 per cent w./w. In two weight gain experiments in infected birds, M&B 15,497 at 0.004 per cent was effective in controlling deaths and weight gain depression against a mixed infection of Eimeria. Compatibility studies showed that there was no obvious incompatibility between M&B 15,497 and furazolidone, Oxytetracycline, chlortetracycline or spiramycin.
The data presented show that M&B 15,497 (ethyl 6-n-decyloxy-7-ethoxy-4-hydroxyquinoline-3-carboxylate) is non-toxic to cockerels and pullets at doses equivalent to at least eighty times the effective dose for the control in chickens of infections with Eimeria. The contamination with M&B 15,497 of laying birds’ feed does not produce any effect on egg shell colour or internal egg quality.
Colostrum deprived specific pathogen-free (S.P.F.) and conventionally reared minimal disease growing pigs have been experimentally infected with H. rubidus infective larvae. Infection doses have ranged from 3000-150,000 larvae administered as one dose; previously infected animals have also been reinfected. Animals have been maintained in metabolism crates on diets containing 16 per cent and 13 per cent crude protein, and the following indices recorded: liveweight gains, nitrogen retention, food conversion efficiencies and apparent digestibility.
Explant cultures of gill arches and rakers were established to evaluate the attachment and colonization characteristics as well as the cytotoxic effects of the piscine bacterium, Mycoplasma mobile 163 K on piscine gill epithelium. Light, scanning and transmission electron microscopy were applied in this study and revealed heavy colonization of mycoplasmas on gill rakers, resulting in severe tissue damage of the gill epithelium. The complications for the function of the gills during breathing, the mechanisms of cytotoxicity, and the validity of this newly-established in vitro model are discussed in detail. In addition, anatomical specialities designated as spikes were identified on the inner surface of the gill rakers from trout; these could be used in the differentiation of fish.
Sodium, potassium, inorganic phosphate and calcium, together with the hormones 17 β-oestradiol and progesterone, were measured in 16 sheep suffering from vaginal inversion and prolapse ante partum (ap) from the time of admission to the clinic up to 24 h post partum. For control purposes the same parameters were measured in six animals having normal pregnancy and parturition. The animals with vaginal prolapse ap showed significantly lower calcium concentrations together with elevated 17 β-oestradiol and progesterone concentrations until shortly before giving birth. Intra and post partum, the hormone patterns were virtually identical in the two groups of animals, whereas the calcium levels remained depressed throughout the entire period of the study in the animals with vaginal prolapse. Possible causes for the hormonal imbalances and the derangements in calcium metabolism are discussed.
Four milked and four suckled post-partum Friesian cows were used to study LH and oestradiol-17β secretion over the transition from parturition to the resumption of ovarian activity. Plasma samples were collected every 6 h over the first 30 to 40 days post partum and at 15 min intervals for 24 h periods on four occasions at approximately weekly intervals.There were no differences between milked and suckled cows in either duration of the post partum acyclic period or in LH and oestradiol-17β secretion.In cows remaining acyclic for 20 to 40 (mean 28·0 ± 3·5) days post partum compared with those acyclic for 80 to 130 (mean 107·3 ± 13·5) days, LH levels were slightly higher (1·20 ± 0·12 and 0·96 ± 0·10 ng/ml respectively), mean plasma oestradiol-17β levels were higher (1·40 ± 0·13 and 0·80 ± 0·19 pg/ml respectively) and there were significantly more LH episodes (mean 7·50 ± 0·84, range two to h and 4·75 ± 0·64, range two to eight/24 h respectively).Plasma oestradiol-17β concentrations often increased following LH episodes, but a significant temporal relationship was not consistently detected. The resumption of ovarian activity was preceded by an increase in basal LH concentrations, the appearance of frequent episodes of LH and enhanced oestradiol-17β secretion.
The concentration of unconjugated oestradiol-17α was measured in faeces of 21 non-pregnant animals and of 39 cows and heifers between the 10th and 25th week of gestation. After the 14th week of gestation all pregnant animals secreted significantly more oestradiol-17α in the faeces than non-pregnant animals. This is a possible method therefore for the confirmation of pregnancy not only in cows but also in heifers.
Friesian steers were implanted with commercial preparations of anabolic steroids containing either an androgen, trenbolone acetate, or an oestrogen, oestradiol-17β, or as a combined implant. The residues of trenbolone in tissues taken at slaughter were determined by radioimmunoassay techniques. The concentration of trenbolone in liver, muscle, kidney and fat was less than 0.5 parts/10⁹ at 63 days after implantation. The concentrations of trenbolone and oestradiol-17β in plasma were measured for six months. The levels of trenbolone were highest immediately after implantation but declined quickly to levels much less than 1 part/10⁹ and persisted at these levels for up to five months following implantation. The concentration of oestradiol-17β in plasma following oestrogen implantation showed two distinct patterns. If the oestradiol-17β was implanted alone the initial levels were high but fell to the levels present in controls four to six weeks after treatment. On the other hand the concentrations of oestradiol-17β in the animals receiving combined implants maintained a constant level of 0.05 to 0.1 parts/10⁹ for almost five months after implantation.
Two ‘hyena’ heifers and two control heifers were simultaneously investigated using daily blood sampling in order to assay LH, oestradiol-17β, testosterone, progesterone and 17-hydroxyprogesterone in peripheral plasma. One ‘hyena’ and both control animals were seen in oestrus and hormonal patterns showed evidence of cyclic ovarian activity. No different patterns between those females emerged. The plasma concentrations of LH, oestradiol-17β and testosterone of the ‘hyena’ heifer which had no oestrous cycle were not significantly different from those of the other animals, and the progestagen levels remained at low and normal values as expected in non-cycling females. Therefore no impairments of the LH and of the steroid patterns were observed in the ‘hyena’ heifers.
Field experiments in horses with the recently synthesized anthelmintic mebendazole are described. Faecal egg counting techniques were used. In one group, strongyle eggs were cultured and grown in order to identify their species. A high success rate was achieved and palatability was good. No side effects or mortality occurred.
The patterns of change in concentrations of progesterone and oestradiol-17β were similar in defatted milk from cows which conceived (n = 17) and in those which did not conceive (n = 24). However, relative to oestrus and ovulation most unsuccessful inseminations were performed at different times from successful inseminations. When 46 cows were examined by ovarian palpation, 18 of 21 cows (86%) which conceived had a follicle present on the day of insemination which had ovulated by the next day. However, only 26 of the 46 cows (57%) were inseminated at this time when optimum conception rates could be expected. Plasma progesterone concentrations in the 46 animals increased at different rates depending on whether or not there was a follicle on the ovary at insemination. It was concluded that the failures to conceive were due to errors in the timing of insemination rather than to hormonal or ovarian asynchronies.
Changes in plasma progesterone and oestradiol-17 beta in yaks during pregnancy and the periparturient period of yaks and in milk during the first month of pregnancy were analysed. The profiles of progesterone were similar for pregnant and non-pregnant yaks within 14 days following oestrus (P > 0.05), but the concentration was significantly higher on day 19 (P < 0.05) and in pregnant yaks tended to increase gradually thereafter. The plasma progesterone decreased rapidly on day 120 (P < 0.05), then increased to reach its maximum of 15.5 (SD 3.74) ng ml-1 on day 210; declined again 20 days before parturition and resumed the same levels at parturition as during mating (P > 0.05). The oestradiol-17 beta levels in plasma and milk increased gradually from day 23 after conception, decreased abruptly on day 60 (P < 0.05), then increased to reach their maximum at parturition of 551.4 (SD 70.86) pg ml-1. The oestradiol decreased again after parturition to the same level as during mating (P > 0.05).
Vaginal exfoliative cytology was studied in five normal cyclical Friesian cows over 10 oestrous cycles each. Oestrus was assessed by the use of KaMaR heat mount detectors, whilst progesterone concentrations were measured in the peripheral blood using radioimmunoassay. Apart from oestrus, the exfoliative cytology was not consistent in appearance and did not appear to be influenced directly by the changes in endogenous ovarian steroid hormones. Four of the cows were subsequently ovariectomized and the vaginal exfoliative cytology monitored before and after the administration of 2 g of progesterone in a slow release vehicle and, following a rest period, after the administration of 12.5 mg oestradiol benzoate in oil. Peripheral progesterone and oestradiol-17 beta concentrations were measured in the peripheral plasma. Although the total number of epithelial cells increased after both hormone treatments no specific changes were observed.
Concentrations of oestradiol-17 beta and progesterone in defatted milk have been used to study the post-partum restoration of ovarian function in 52 autumn-calved dairy cattle. In 32 cows the first preovulatory peaks in oestradiol-17 beta concentration (indicative of imminent ovulation) were less than or equal to 15 days and in 49 cows less than or equal to 49 days post partum. Delay to first ovulation was mainly due, not to failure of ovarian secretion of oestradiol-17 beta at preovulatory level, but to failure of oestradiol-17 beta at this level to exert its normal preovulatory function. Longer intervals to first ovulation were associated with longer intervals from calving to the clearance of placental oestradiol-17 beta, high peak milk yields and high body weight losses, suggesting that in high-yielding dairy cows these factors (themselves inter-related) may be associated with others, which are the immediate cause of the inhibition of the normal, preovulatory function of oestradiol-17 beta. Forty-eight per cent of cows had short, first ovulation cycles. Ovarian function, comprising oestradiol-17 beta secretion at preovulatory level, normal preovulatory function of oestradiol-17 beta and normal corpus luteum progesterone secretion were almost fully restored in this herd by the 49th day post partum.
High-pressure liquid chromatography (HPLC) has been used to separate oestradiol-17β, oestradiol-17α and oestrone. Oestrogens were extracted from defatted cows' milk collected one day before oestrus, using Sepharose coupled to antiserum having high specificity for oestradiol-17β. Recovery of 83% of [3H]oestradiol-17β added to the milk was obtained. Extracts were submitted to radioimmunoassay (RIA) using oestradiol-17β antisera of both high and relatively low specificity. Other portions were chromatographed (HPLC) and fractions having the retention times of oestradiol-17β, oestradiol-17α and oestrone were assayed (RIA) using the oestradiol-17β antiserum of relatively low specificity.Evidence from HPLC is now added to that from RIA in support of the presence of oestradiol-17β and oestrone in milk. It is further concluded that the analytical procedure consisting of extraction of oestrogens from defatted cows' milk collected around oestrus with Sepharose coupled to the oestradiol-17β antiserum G510/6 followed by RIA of the extract with this antiserum is highly specific for oestradiol-17β, as well as being a sensitive and convenient method.
Concentrations of oestradiol-17β and progesterone in plasma and defatted milk of British Friesian dairy cattle were measured by radioimmunoassay in samples taken daily for 23 to 35 days from five early post-partum cows (two of which were ovariectomized within 24 to 48 h of calving) and from three cows with regular oestrous cycles.During the first five to 10 days post partum, in both the intact and ovariectomized cows, progesterone levels in plasma and defatted milk were basal (< 0·3 ng/ml). Oestradiol-17β levels fell from > 15 pg/ml to < 1 pg/ml, presumably due to clearance of placental oestradiol-17β following cessation of production at calving. They then rose to a pre-ovulatory peak in the intact cows (about 13 days post partum) and a post-ovulatory peak six days later. Concentrations of progesterone were typical of those known to occur in plasma and defatted milk during the oestrous cycle. Similar oestradiol-17β and progesterone levels were found during later oestrous cycles. In the ovariectomized cows steroid levels remained basal after the first oestradiol-17β post-partum fall.Concentrations of oestradiol-17β and progesterone in plasma and defatted milk throughout these various periods were highly correlated (r = 0·76 and 0·90 respectively). Mean levels of oestradiol-17β and progesterone in defatted milk were respectively 66% and 52% of those in plasma; they reflect changes in plasma during the post-partum, anovulatory period and oestrous cycles, and may be used in studies of bovine ovarian function.
Concentrations of oestradiol-17 beta and progesterone in plasma and milk of the yak before the first oestrus at the beginning of the breeding season and during normal and short oestrus cycles were measured by radioimmunoassay (RIA). Both oestradiol-17 beta and progesterone were maintained at stable, low levels before the first oestrus. However, oestradiol-17 beta showed a peak, similar to that on the day of oestrus (P > 0.05), about 6 days before the first oestrus and a small progesterone peak was seen 2 days before it. There were three peaks of oestradiol-17 beta in plasma and milk on the day of oestrus [24.57 (SD 11.35) pg ml-1 and 97.84 (SD 26.02) pg ml-1 respectively], and on days 5 and 14 of the cycle. Progesterone levels in plasma and milk were low during oestrus but peaks were seen on day 15 [5.23 (SD 1.02) ng ml-1 and 20.44 (SD 3.64) ng ml-1 respectively]. The patterns of oestradiol-17 beta and progesterone during the short cycle were similar to those during the normal cycle (P > 0.05), but the values were lower. The levels of oestradiol-17 beta and progesterone in milk were about 3 or 4 times higher than those in plasma before the first oestrus, and about 4 or 5 times higher during the normal cycle.
Pre-ovulatory peaks in oestradiol-17 beta concentrations were observed on days 1 or 2 and post-ovulatory peaks between days 4 and 7, both in jugular venous plasma and defatted milk, day 1 being the day of the onset of oestrus in the goats. Mean values of the magnitudes of these concentration peaks and of their timing (relative to oestrus) during the oestrus cycle did not differ significantly (P greater than 0.05) from those when the goats were mated and became pregnant. Pre-ovulatory oestradiol-17 beta peaks were invariably greater than the corresponding post-ovulatory peaks, as were peak concentrations in plasma relative to those in defatted milk collected on the same day. Mean intervals between the pre- and post-ovulatory peaks in oestradiol-17 beta concentrations were respectively 4.2 days for plasma and 4.0 days for defatted milk. Concentrations of oestradiol-17 beta in jugular venous plasma and defatted milk were strongly correlated: rank correlation coefficients for the three goats studied were 0.871, 0.668 and 0.739. It is suggested that in goats, as in cattle, ovarian follicular oestradiol-17 beta secretion approaching pre-ovulatory level is restored by 4 days after oestrus and its rapid decline after this time may be due to the inhibitory influence of the rapidly rising plasma progesterone concentration.
Six aged Merino ewes were used in an experiment in which five were infused with 4.7% Na2EDTA solution intravenously for 18 h at a rate designed to produce hypocalcaemia and maintain recumbency, and five with 0.9% sodium chloride solution at the same rate for the same period (four were infused at different times with both solutions). Blood samples were collected every 3 h and determinations made of plasma Ca, Na, K, Mg, and inorganic P (PiP), erythrocyte Na, K and Mg, and PCV. Three of the hypocalcaemic sheep took 36-64 h to regain their feet. Plasma Ca and K, and erythrocyte Na showed significant (all P less than 0.01) decreases in the group infused with Na2EDTA compared with the group infused with saline while PCVs were significantly (P less than 0.01) greater in the former group. The sheep model used could be suitable for the study of the effects of prolonged hypocalcaemia and recumbency in cows.
This study was conducted throughout the year 1968, with the object of determining the incidence of D. dendriticum infection in sheep of different ages, and of identifying the first and second intermediate hosts (land snails and ants respectively) at two places which are representative of South Marmara geographic region: Karacabey State Farm, Bursa, and Kumkale State Farm, Canakkale. The mean infection rate in sheep one year old or more was 64 per cent at Karacabey and 74 per cent at Kumkale, being higher in older sheep. In lambs born in winter 1967–1968, the first eggs of D. dendriticum were observed in the faeces in August 1968 at Karacabey and November 1968 at Kumkale. These observations indicate that lambs began to acquire their infections during the period May and June.
Lambs were administered heavy doses of infective larvae of Ostertagia ostertagi. Those autopsied 29 days after infection had some worms while others autopsied at the 57th day had no worms. The vulval flap was absent in female worms and eggs were not detected in the faeces of the lambs. The sheep is considered to be an unsuitable host for O. ostertagi.
Thirty cows presenting with lameness and persistent serological reactions to Brucella abortus had chronic granulomatous arthropathy of the femorotibial and occasionally other joints. Attempts to culture Brucella or other pathogens gave negative results but organisms of Brucella morphology were seen in fluorescent antibody-stained cryostat sections of synovial tissue. The synovial fluids contained high titres of antibodies to B. abortus and Yersinia enterocolitica O:9 and had elevated total protein and immunoglobulin concentrations showing an oligoclonal electrophoretic profile. Immune complexes and rheumatoid factor were detected in some of the fluids.
A smooth phage-resistant variant of Brucella abortus strain 19 was avirulent for guinea-pigs and induced a low grade serological response. Organisms recovered from the spleens of inoculated guinea-pigs were smooth and phage-resistant on primary isolation but on subculture released phage and underwent dissociation to non-smooth forms.
Attempts to reproduce in calves the arthropathy associated with Brucella abortus strain 19 (S19) vaccination by direct intra-articular injection of S19 or virulent Brucella cells were unsuccessful. Intra-articular injection of rabbits and a calf with immune complexes isolated from the synovial fluid of a field case produced clinical and histological signs of arthropathy accompanied by the development of rheumatoid factor.
Beckett and MacDiarmid (1985) reported on the experimental vaccination of adult cattle in three brucellosis-free dairy herds with reduced dose Brucella abortus strain 19 ( of standard dose). This communication reports the subsequent testing history of the three herds in the four years following vaccination.
Three dairy herds accredited free from brucellosis and comprising 307 animals were vaccinated with a reduced dose of Brucella abortus strain 19 (S19). Vaccination was carried out when the cows were three to five months pregnant. Thirty-eight of 252 (15%) cows developed positive complement fixation titres (1:8 or greater) which persisted for 12 months or more. At least eight aborted as a result of vaccination. The occurrence of persistent titres was significantly lower in cows which had previously been vaccinated as calves.It was concluded that vaccination of adult cattle with reduced dose S19 should not be used in uninfected herds because of the resultant interference with serological and milk ring agglutination tests.
Leukograms from acute field cases in the parasitaemia stage of Babeusa equi infection were analysed. These were compared to leukograms from two 12-year-old horses, which were clinically normal and serologically negative to equine piroplasmosis before being inoculated with infected B. equi blood.
The agar gel precipitin test was used to study the antigens of Theileria parva. Fractions were prepared from pre- and post-infection blood and lymph glands from the same ox. Antisera were prepared on cattle by inoculating post-infection fractions prepared from blood and spleen in Freund’s adjuvant. At least four specific precipitin bands were observed; the antigens associated with at least two of the bands were heat labile and the remainder heat stable. A number of the antigens in the blood and spleen were common.
Top-cited authors
Donald M. Broom
  • University of Cambridge
Andrew James Higgins
  • Animal Health Trust
Stephen Wotton
  • University of Bristol
Peter Lees
  • Royal Veterinary College
J. J. Vermunt
  • James Cook University