Seasonal comparisons of anthelmintic activity of levamisole pour-on in cattle in the USA

Anthelmintic activity of a pour-on formulation of levamisole, applied during warm weather (16 degrees to 36 degrees C) at 10 mg/kg bodyweight, was evaluated in groups of naturally parasitised calves. This activity was compared to that obtained in similar groups of calves treated in the winter (-4 degrees to +7 degrees C). Controlled efficacy of the pour-on formulation was determined for each season by comparing mean worm burdens in treated calves sacrificed seven to nine days after treatment to non-treated controls. In these trials, burdens of Bunostomum phlebotomum, Cooperia species, Haemonchus placei, Nematodirus species, Oesophagostomum radiatum, Ostertagia ostertagi and Trichostrongylus axei in treated calves were reduced by 83.3 to 100 per cent in the summer and 89.2 to 100 per cent in the winter. Field investigations at nine locations across the USA compared changes in faecal egg counts for cattle treated and evaluated during warm summer months (27 degrees to 36 degrees C) to those treated during cold winter months (-18 degrees to +10 degrees C). Overall, faecal egg counts were reduced by 90.2 per cent in the summer trials and 94.0 per cent in the winter trials. The results of these trials indicate that there is no seasonal variation in the anthelmintic activity of this pour-on formulation of levamisole.     

Distribution Et Écologie de Quelques MammifèRes de L’est du Congo

1. C. kraussi in the Swartkops river estuary in South Africa has a major breeding period in winter-spring (May-July/August) and a minor breeding period in summer (November-January).

2. A maximum of 43 per cent of ovigerous mature females was recorded. Females in the 8 and 9 mm carapace-size classes make the major contribution to the breeding effort.

3. Recruitment is very marked with 60-80 per cent of the population consisting of juveniles at times.

4. Both sexes live for about two years. Females hatching in winter-spring may breed first in summer at an age of about 16-18 months and then again in the following winter at an age of about two years. Females hatching in summer breed first in winter at an age of about 18 months and some in the following summer at an age of about two years.

5. Breeding and growth in C. kraussi is compared with that in other known callianassids, and discussed in relation to estuarine eco-systems and conservation measures.     

Effect of whole herd anthelmintic treatment on milk production of dairy cows

Fifteen of 29 commercial dairy herds were given a series of anthelmintic treatments. The remaining herds were untreated to provide a measure of seasonal variation. In the treated herds all milking cows were treated once in the summer and the autumn and three times at monthly intervals in late winter and early spring. Any other animals grazing the same area were similarly treated. No herds had been treated with anthelmintics in the preceding year and mean herd lactations for that year were used as covariate corrections. This experimental design had the potential to detect differences in production of the order of 5 X 7 per cent (P = 0.05). Although levels of subclinical parasitism were low, anthelmintic treatment increased milk fat production by 10.8 kg (8.3 per cent) in heifers. Average response in mature cows was much smaller (3.1 per cent) and not significant. Apparent milk fat responses in individual herds were variable with no relationship to level of production in the previous year.     

Hair coat characteristics and postweaning growth of Hereford and Angus cattle

Mid-rib hair coat samples (n = 577) were obtained from 9- to 10-mo-old Hereford and Angus bulls and heifers to examine diet and breed differences in hair coat characteristics and their relationship to 168-d postweaning gain. Each sample was cleaned and subdivided into guard hairs and undercoat. Dependent variables included the number, weight, length, diameter and percentage of medullation of guard hairs and undercoat. Sources of variation included breed, sire nested within breed, year (1965 or 1966), sex of calf, diet fed during the postweaning gain test (2 parts rolled grain:1 part chopped hay vs all chopped hay) and the linear regression on age of calf as a covariate. Factor analysis was used to transform the 10 hair coat variables into a set of four factors that accounted for 71% of the total variance of the original variables. Angus cattle tended to have shorter, less medullated coats (Factor 1), shorter, larger diameter undercoat hairs and guard hairs with less medullation than Herefords. Sire within breed differences existed for weight, length, and diameter of both types of hairs and all four factors. Compared with the medium-energy-diet, the high-energy diet reduced hair weight per unit of surface area, undercoat number and guard hair medullation. Undercoat density (Factor 3) was reduced by the higher-energy diet (P less than .001), whereas guard hair density (Factor 2) was not changed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Expression analysis of the type I keratin protein keratin 33A in goat coat hair

The coat of a goat, like that of many mammalian species, consists of an outer coat of coarse hairs and an under coat of fine, downy hairs. The coarse guard hairs are produced by primary follicles and the finer cashmere hairs by secondary follicles. We previously reported that hair keratins are components of cashmere hair, and proteomic analysis revealed that their expression is elevated in winter coat hair. To determine detailed characterization, we have cloned keratin 33A gene, a major highly expressed keratin in winter, and then analyzed the expression of goat hair coat. By Western analysis, we detected that keratin 33A protein is expressed only in hair coat among the various goat tissues. Moreover, the expression level in winter has increased in cashmere high‐producing Korean native breed, whereas the expression levels between summer and winter had not changed in cashmere low‐producing Saanen. In addition, by immunohistochemistry we determined that keratin 33A is localized in the major cortex portion of cashmere fiber. These results confirm that keratin 33A is a structural protein of goat cashmere hair fiber.     

Stochastic Simulation Model Comparing Distributions of STEC O157 Faecal Shedding Prevalence Between Cattle Vaccinated With Type III Secreted Protein Vaccines and Non‐Vaccinated Cattle

Pens of cattle with high Escherichia coli O157:H7 (STEC O157) prevalence at harvest may present a greater risk to food safety than pens of lower prevalence. Vaccination of live cattle against STEC O157 has been proposed as an approach to reduce STEC O157 prevalence in live cattle. Our objective was to create a stochastic simulation model to evaluate the effectiveness of pre‐harvest interventions. We used the model to compare STEC O157 prevalence distributions for summer‐ and winter‐fed cattle to summer‐fed cattle immunized with a type III secreted protein (TTSP) vaccine. Model inputs were an estimate of vaccine efficacy, observed frequency distributions for number of animals within a pen, and pen‐level faecal shedding prevalence for summer and winter. Uncertainty about vaccine efficacy was simulated using a log‐normal distribution (mean = 58%, SE = 0.14). Model outputs were distributions of STEC O157 faecal pen prevalence of summer‐fed cattle unvaccinated and vaccinated, and winter‐fed cattle unvaccinated. The simulation was performed 5000 times. Summer faecal prevalence ranged from 0% to 80% (average = 30%). Thirty‐six per cent of summer‐fed pens had STEC O157 prevalence >40%. Winter faecal prevalence ranged from 0% to 60% (average = 10%). Seven per cent of winter‐fed pens had STEC O157 prevalence >40%. Faecal prevalence for summer‐fed pens vaccinated with a 58% efficacious vaccine product ranged from 0% to 52% (average = 13%). Less than one per cent of vaccinated pens had STEC O157 prevalence >40%. In this simulation, vaccination mitigated the risk of STEC O157 faecal shedding to levels comparable to winter, with the major effects being reduced average shedding prevalence, reduced variability in prevalence distribution, and a reduction in the occurrence of the highest prevalence pens. Food safety decision‐makers may find this modelling approach useful for evaluating the value of pre‐harvest interventions.     

Pharmacokinetics and urinary excretion of sulphadimidine in sheep during summer and winter

Pharmacokinetics and urinary excretion of sulphadimidine were investigated in sheep during summer and winter seasons. Average minimum and maximum environmental temperature in the summer ranged from 22.6 to 40.2 degrees C and in winter from 4.5 to 21.1 degrees C. The determination of plasma volume, plasma protein and packed cell volume during summer and winter revealed a significant decrease in plasma volume and a significant increase in plasma protein in the summer indicative of haemoconcentration. Packed cell volume did not differ significantly between the seasons. The pharmacokinetics of sulphadimidine were determined following a single intravenous injection (100 mg/kg) in summer and winter. Zero time plasma concentration of the drug was higher during summer than in winter. The elimination half-life of the drug was similar in summer and winter, but the apparent volume of distribution was lower in summer. Likewise, total body clearance was significantly lower in summer. Based on these studies a satisfactory intravenous dosage regimen might consist of 86 and 100 mg/kg for priming and 78 and 88 mg/kg as maintenance doses during summer and winter, respectively, the doses being repeated at 12 hour intervals. Twenty four hours after sulphadimidine administration 90 and 73 per cent of the dose was excreted in urine during summer and winter, respectively. The drug was excreted mainly as free amine.     

Risk factors associated with the prevalence of interdigital dermatitis in sheep from 1999 to 2000

As part of an investigation into improving the treatment and control of lameness in sheep flocks in England and Wales, a postal survey was conducted in November 2000. Farmers were asked to estimate the prevalence of footrot and interdigital dermatitis in their flocks. In the ewes the prevalence of interdigital dermatitis remained relatively stable throughout the year, but there was a large increase in lambs during late spring and early summer. Logistic regression models were used to assess statistically significant risk factors associated with prevalences of the condition of 5 per cent or more in ewes and 10 per cent or more in lambs. Factors that increased the risk in ewes were 'sometimes/never' catching lame sheep compared with 'always' farm land 100 m or less above sea level and renting-in winter grazing; factors that increased the risk in lambs were a prevalence of 5 per cent or more of footrot in ewes, 'sometimes/never' catching lame ewes compared with 'always', 'sometimes/never' treating ewes with footrot with parenteral antibiotics compared with 'always', showing sheep at agricultural events, farm land 100 m or less above sea level, and a prevalence of 5 per cent or more of interdigital dermatitis in ewes. Turning sheep on to a field which had been free from livestock for at least two weeks after footbathing decreased the risk of interdigital dermatitis in lambs. Footbathing without the use of a clean field compared with not footbathing did not significantly affect the prevalence of the interdigital dermatitis.     

THE INCIDENCE OF DYSTOCIA IN FINE-WOOL MERINO EWES

The mean incidence of dystocia in 1,510 fine-wool Merino ewes over a ten-year period was 4.1% of ewes lambing. In the 10 year period, 10% of all neonatal mortality was attributed to dystocia and in only 23% of dystocias was lamb presentation abnormal. The incidence of dystocia was not related to age of ewe. Significantly more ewes experienced dystocia at spring than winter (P less than 0.05) or summer (P less than 0.01) lambings. The mean birth weights of dystocic single and twin born lambs were 4.19 and 3.38 kg respectively. The corresponding birth weights of lambs that did not experience dystocia were 3.69 and 3.00 kg. More ewes experienced dystocia when stocked at 12 or 16 per ha than at 8 per ha (P less than 0.05). Fifty per cent of recorded dystocias occurred in ewes stocked at 16 per ha, 40 per cent at 12 per ha and 10 per cent at 8 per ha. Ewe body weight pre-lambing was not related to the incidence of dystocia but it would appear that weaker ewes are more likely to have a difficult birth than ewes that are stronger and in better condition.     

Follicular progesterone levels decrease during the period of seasonal infertility in sows

Impaired reproductive performance exhibited by the domestic sow during the late summer and early autumn months is referred to as seasonal infertility. This study was carried out to determine whether there are changes in ovarian morphology and follicular steroidogenesis associated with season, which may be associated with seasonal infertility. Ovaries were collected in pairs from sows sourced from two farms and slaughtered 4 days after weaning during winter and summer. The mean progesterone concentration in follicular fluid (FF) collected from small follicles was lower in summer (701.3 ± 115.54 nm) compared with winter (1235.55 ± 164.47 nm; p<0.001). The mean progesterone concentration in the FF of large follicles was also lower in summer (1469.2 ± 156.51 nm) compared with winter (2470.9 ± 169.13 nm; p<0.001). The number of large surface antral follicles (5-8 mm in diameter) on the ovaries recovered from Farm A sows was higher during summer (17.76 ± 0.56) than in winter (15.38 ± 0.54; p<0.05). Similarly, the number of small follicles (3-4 mm in diameter) on Farm A sow ovaries was higher in summer (8.46 ± 0.66) than in winter (4.63 ± 0.53; p<0.001). In contrast, the number of small follicles on the surface of ovaries recovered from Farm B sows was higher during winter (10.17 ± 1.50) than in summer (6.45 ± 1.00; p<0.01). The number of pre-ovulatory follicles (>8 mm in diameter) was also higher in winter (1.23 ± 1.68) when compared to summer (0.51 ± 0.3; p<0.001) on the ovaries of sows from Farm B. The results suggest that there are seasonal differences in follicular steroidogenesis and ovarian dynamics. These findings add support to the theory that altered follicular steroidogenesis and ovarian morphology may possibly be the mechanism behind reduced reproductive performance during the period of seasonal infertility in sows.     

Observations on the population dynamics of five cyathostome nematode species of horses in northern USA

Monthly variations in the magnitude of adult and larval cyathostome burdens were observed in 55 horses necropsied over a 15-month period in the northern USA. Peak numbers of adult cyathostomes occurred in late winter (March) and late summer (September). Larval cyathostomes demonstrated peak numbers from February to April and again in October, beginning one month earlier than the spring adult peak and one month after the autumn adult peak, respectively. The reproductive status of individual female Cyathostomum catinatum, Cyath coronatum, Cylicocyclus nassatus, Cylicostephanus goldi and Cylicostephanus longibursatus was classified as immature, gravid or spent. Seasonal changes in these classifications were monitored as a marker for the age structure of these populations. Each reproductive category of female small strongyle was dominant during only one period per year and these periods were similarly distributed for all five species examined. Immature cyathostomes were most common from late winter to spring (March to May); gravid worms were predominant beginning in spring (April/May) and continuing into autumn (October to December). Spent females prevailed from autumn through winter (October to March/April).     

Prevalence and epidemiology of the major gastrointestinal parasites of horses in Perth, Western Australia

A survey was conducted on the prevalence of the major gastrointestinal parasites in 140 horses necropsied in Perth, Western Australia, during 1979 to 1982. Adult Strongylus vulgaris were found in 22.5 per cent of horses and verminous arteritis in 62.9 per cent. The peak worm prevalence was in November to January (summer). S edentatus had a similar prevalence and seasonality but S equinus was not found in this survey. Draschia megastoma and Habronema muscae were found in 66.2 per cent and 35.3 per cent of horses respectively. Infection is probably acquired in summer when 8 per cent of the Musca domestica in the vicinity of the stables carried third stage spiruroid larvae. Gasterophilus intestinalis and G nasalis occurred in 36.4 per cent and 22.1 per cent of the horses respectively and 52.1 per cent of horses were infected with one or both species. The peak prevalence of G intestinalis larvae occurred in December with a trough in February-April; the peak prevalence of G nasalis was in May with a trough in November-December. Parascaris equorum was found in 9.9 per cent of the horses and in 21.3 per cent of those less than three years old. Anoplocephala perfoliata was found in 4.9 per cent of the horses and most of these were in older horses.     

Male tortoiseshell cats in the United Kingdom

A questionnaire concerning the coat colour and sex of cats being vaccinated or neutered was sent to 2585 veterinary practices; 393 (15.2 per cent) were returned and information was obtained about 9816 cats. Of 4598 males, 20 were recorded as tortoiseshell (0.43 per cent). The frequency of the orange gene was 19.7 per cent assuming that male tortoiseshell cats had two X chromosomes. The chromosome complement and/or gonadal histology of 14 male tortoiseshell cats is described. Cytogenetic analysis of 11 animals revealed six with a 38,XX/38,XY complement, two with 39,XXY, two with 38,XX, and one with a 38,XY complement.     

Variation in the level of grain defect light flecks and spots on cattle hides.

The occurrence of hide damage light flecks and spots was determined on tanned hides from 28 herds during a period of 8 to 12 months. Light flecks and spots are described as small areas of grain loss up to 3 mm in diameter that are seen on dyed crust cattle leather. Damage was found on 75.8% of all hides. The neck and shoulders were the anatomical region with the highest prevalence of damage. Sixty-eight per cent of all hides had light flecks and spots in this region. The forelimbs and dewlap were the anatomical region with the second highest occurrence with a prevalence of 39.1%. This distribution corresponded to the known distribution of lice in cattle. No significant differences were observed in age, sex, prevalence of lice in the herd assessed in March or infestations with different lice species. The frequency of light flecks and spots varied significantly during the year. The frequency was highest in the late winter and early spring, decreased significantly during the summer and was lowest in the autumn. This variation supported the importance of lice in the development of light flecks and spots and suggested a relatively long healing period for the damages induced by lice.     

The cost of summer mastitis.

The incidence of summer mastitis on 95 dairy farms in southern England was monitored in the summer of 1987. Data on the type of animal infected, the fate of the animals immediately and over the succeeding lactation, and the procedures used in treating the infections were collected for 144 cases. Twenty-five per cent of cases were attended by veterinary surgeons. Most of the animals received parenteral antibiotics and on average each received five tubes of intramammary antibiotic. The incidence of infection was highest in pregnant and calving heifers, more than 2 per cent of the animals at risk, and lowest (0.04 per cent) in calves, although more than twice as many dry cows were infected. Over half of the farms reported summer mastitis, with 36 per cent suffering more than one case. The greatest economic loss, 49 per cent of the total, was from lost milk production; and 37 per cent was from lost animal value, cull and calf losses. The average loss was 192 pounds per case. Using national incidence data from England and Wales, the cost to the UK dairy industry in 1987 was 6.22 million pounds.     

Epidemiological characteristics of rabies in South Korea from 1993 to 2001

In the nine years from 1993 to 2001, 210 cases of rabies were recorded in domestic animals in South Korea; 115 cattle, 94 dogs and one farmed deer were affected. The annual incidence of rabies cases increased to a peak of 64 in 1998, and then decreased to about 30 cases per year. The cases were confined to the northern part of Kyounggi and Kangwon provinces. One hundred and forty-six cases (69.5 per cent) occurred in Kyounggi and 64 cases (30.5 per cent) in Kangwon province, and about 82 per cent of them were confined to two counties in Kyounggi province (29 per cent in Paju and 28.1 per cent in Younchun) and to Chulwon county in Kangwon province (25.2 per cent). However, over several years the outbreaks gradually moved south and east in both Kyounggi and Kangwon provinces. There were more rabies cases in cattle than in dogs, suggesting that the disease is transmitted by the sylvatic cycle. To investigate the relationship between rabies in domestic animals and wild animals, 107 wild animals, including Korean raccoon dogs, badgers, weasels and feral cats, were tested for rabies; 21 of the 67 Korean raccoon dogs tested (31 per cent) were infected. The cases in domestic animals were most common in winter, from December to February, and least common in summer, from June to September.     

Nodular onchocercosis of red deer in central Spain

The presence of nodular onchocercosis was investigated post-mortem in 142 red deer (11 calves, 35 yearlings and 96 adults) shot from February 1998 to January 1999, and July-November 1999 in "Quintos de Mora" (Toledo, central Spain), a game property belonging to the National Wildlife Reserves. Between 6 and 13 animals were analysed monthly by inspection for subcutaneous nodules of Onchocerca spp. Subcutaneous nodules of Onchocerca sp. were detected in 24% of the animals. Anatomical locations for nodules were the back and flanks. Infection ranged from 1 to 29 nodules per animal. Adult worms collected from nodules were identified as O. flexuosa. No apparent seasonal trend was observed either in prevalence or in mean intensity of infection, which fluctuated between 48% (5+/-8 nodules) in winter 1998 and 5% (1+/-0 nodules) in summer 1999. Prevalence of infection was significantly higher in adult (30%) than in young animals (9% in calves, 11% in yearlings), although no age effect on intensity was observed. The size of the nodules was measured to evaluate the age of infection. Small (recent) nodules (5-6mm of diameter) were collected in late spring, summer and fall; medium-sized nodules (12-15 mm) were in second half of summer, fall and winter, and large (mature) nodules (20-25 mm) in fall, winter and part of spring. Significant differences were found among host age groups.     

Anthelmintic control of lungworm in donkeys

A field study was designed to investigate the re-establishment of patent lungworm infections in donkeys following an anthelmintic treatment regime which was effective against Dictyocaulus arnfieldi. In April 1979 faecal samples from 259 donkeys were examined and each animal classified as a negative, low positive or high positive excretor of lungworm larvae. During the summer the control group of 126 donkeys showed an increase in the number of excretors from 80 per cent in April to 91 per cent in October. At the same time there was a rise in the faecal larval output of individual animals so that by October 59 per cent were classified as high positive compared with only 20 per cent in April. The treated group of 133 donkeys received 3.5 g mebendazole daily for 5 days during April and as a result the number of excretors fell from 66 per cent pretreatment to 23 per cent one month after treatment. Despite exposure to infected pastures throughout the summer this figure was maintained at a comparatively low level and by October patent infections had been re-established in only 15 per cent of the donkeys that were negative after treatment.     

Prevalence of wet litter and the associated risk factors in broiler flocks in the United Kingdom

A postal questionnaire was sent to the managers of 857 broiler farms in the UK to determine the prevalence and risk factors for wet litter. The response rate was 75 per cent. Wet litter was reported by 75 per cent (95 per cent confidence interval [CI] 71.3 to 78.3) of the respondents in at least one flock during the year 2001 and 56.1 per cent (95 per cent CI 52.0 to 60.0) of them reported that they had an outbreak of wet litter in their most recently reared flock. Wet litter occurred more often during the winter months and farms using side ventilation systems were at an increased risk (odds ratio 1.74; 95 per cent CI 1.09 to 2.76). A multivariable analysis was carried out using two different definitions of wet litter as outcome variables - all cases of wet litter, and cases of wet litter associated with disease. Consistent risk factors for both outcomes were coccidiosis, feed equipment failures and the availability of separate farm clothing for each house. Cases of wet litter associated with disease were reported by 33.7 per cent (95 per cent CI 28.8 to 39.1) of the managers in their last flock and were associated with the use of hand sanitisers and broiler houses with walls made of concrete.     

An epidemiological study of summer eczema in Icelandic horses in Norway

A survey of summer eczema was conducted on 391 Icelandic horses in Norway. The study showed a prevalence of summer eczema of 17.6 per cent in the horses investigated. Icelandic horses born in Norway where shown to be less affected with summer eczema than imported horses, 8.2 per cent and 26.9 per cent respectively (P less than 0.001). There was no difference in the prevalence of summer eczema relative to gender or colour of the horse. The number of horses affected with summer eczema rose with increasing age and the number of years which had elapsed since importation. On average, Icelandic horses born in Norway developed summer eczema at the age of 5.3 years. The onset of disease for imported horses was, on average, 4.1 years after importation. The study also revealed that a significantly greater number of horses imported from Iceland to Norway during the period October to April, which has a minimal or low activity of insects (32.3 per cent), had developed summer eczema, compared with horses imported during the period May to September, when insects are more active (16.7 per cent), (P = 0.044). Horses with summer eczema were shown to be significantly more affected by respiratory disease than non-affected horses (P = 0.0086). The most common sites and clinical signs of summer eczema are also described.