Management practices and use of anthelmintics on dairy cattle farms in The Netherlands: results of a questionnaire survey

In December 1996, a questionnaire about farm management and parasite control measures in calves was sent to 956 randomly chosen dairy cattle farmers in The Netherlands. Another 150 farmers in the vicinity of Deventer who had vaccinated their calves in 1995 against lungworm were approached with the same questions. Our objective was to investigate the consequences on worm control of the withdrawal of the lungworm vaccine from the market for reasons of possible BSE contamination of the vaccine. Of the returned questionnaires, 411 (43%) of the `at random' group and 89 (59.3%) of the `Deventer' group were valid. The most important data with regard to the farms of the `at random' group (411) were: mean area 31.6 ha, mean number of calves 23, heifers 23 and milking cows 53. Sheep (mean 37) were present on 18.3% of the farms. With regard to management: 74.5% of the farmers turned the calves in their first year onto pasture, 25.5% kept them indoors. The average time on pasture was ca. 5 months. Rotational grazing was practised on 81.4% of the farms, on 18.6% calves were set stocked. The first pasture of the calves was mown before turn-out on 72.9% of the farms. On 48.2% of these farms, calves were always moved to mown pastures. With regard to treatments: 33.8% of the farmers vaccinated their calves against lungworm in the years 1993, 1994 and 1995. Despite the withdrawal of the vaccine from the market in 1996, 7.2% of the farmers vaccinated their calves as recommended, with two doses, and 13.1% with a single dose. At turn-out, 41.5% of the farmers gave the calves a preventive anthelmintic treatment. Of these treatments, 66.9% were sustained of pulse release long acting devices. During the grazing season, 36.6% of the farmers treated their calves. After housing, 50.3% of the farmers gave a treatment. Signs of lungworm infection were noticed on 18.6% of the farms. Of the `Deventer' group (89 farmers), 96.6% turned the calves out. Of these farmers, 86.0% had used the lungworm vaccine in 1995. In 1996, 52.7% of the farmers had vaccinated the calves: 36.5% with a single dose and 16.2% with the double dose. Of the 35 farmers who did not vaccinate in 1996, 62.9% gave a preventive treatment at turn-out. Clinical signs of lungworm infection were not observed on the 12 farms which vaccinated the calves twice. On 11% of the farms which vaccinated once and on 14% of the farms which did not vaccinate, signs of lungworm infection were observed. It is concluded that more than 80% of Dutch dairy cattle farmers take appropriate measures to control gastrointestinal nematode and lungworm infections in calves in their first grazing season by grazing on aftermath, rotational grazing on mown pastures combined or not with preventive anthelmintic treatments. However, combinations of aftermath grazing and preventive treatment occurred on 30% of the farms. This may be overprotective and may prevent sufficient build up of immunity, causing worm problems at a later age. The withdrawal of the lungworm vaccine from the market did not cause a rise in lungworm problems. Some farmers did vaccinate, despite the withdrawal. The majority used other preventive treatment measures, mainly the application of long acting boli.     

A survey on the occurrence of resistance to anthelmintics of gastrointestinal nematodes of goats in Mozambique

A survey to study the extent of anthelmintic resistance was conducted in Maputo and Gaza, two of the ten provinces of Mozambique, during February and March, 1999. A total of 12 flocks, six in Maputo and six in Gaza, was surveyed. The faecal egg count reduction test was used to assess the efficacy of three anthelmintics most often used in Mozambique, namely albendazole, fenbendazole and levamisole. The degree of resistance was calculated using two different methods, and varied according to the method used. Using the formula of Coles, Bauer, Borgsteede, Geerts, Klei, Taylor & Waller (1992), resistance to the benzimidazoles was detected in one flock in Maputo and one in Gaza, and to levamisole in three flocks in Maputo and one in Gaza. When the formula of Dash, Hall & Barger (1988) was used, however, resistance to the benzimidazoles was detected in only one flock in Maputo, and no resistance to levamisole was detected. The 12 farms surveyed were too few for conclusions to be made on the prevalence of anthelmintic resistance in goats in Mozambique as a whole. Therefore, an extensive survey at national level is needed. This study gives evidence, however, that anthelmintic resistance in nematode parasites of goats is an emerging problem, to which special attention should be paid.     

A survey to identify economic opportunities for smallholder dairy farms in Bangladesh

Identified economic opportunities for planning interventions greatly increase farmers’ compliance with an extension programme. We investigated opportunities for interventions to increase dairy farmers’ income in four areas of Bangladesh, including the districts of Mymensingh, Khulna-Satkhira, Sirajgonj-Pabna and Chittagong. The data were collected from 1440 dairy farms at a one-day visit and were summarized as the difference between management targets and each herd’s calculated management indices. The average number of lactating cows, feed cost as a percentage of income from milk, milk sold as percentage of milk produced, lactating cows as a percentage of mature cows, and lactating cows as a percentage of total cattle varied from 1.5 to 3.4, from 52.5% to 92.1%, from 78.7% to 92.6%, from 81.9% to 86.7% and from 34.3% to 37.7%, respectively. The average age at first calving, calf production interval, lactation length, and milk production were 35.0–44.3 months, 14.0–17.6 months, 249–286 days and 3.5–7.2 litres, respectively, depending on the locality. The average cost for producing 100 litres of milk was 18.9–35.1 US dollars. The production cost increased when daily milk production per cow decreased (r² = 0.43–0.55). Management improvements directed towards increasing average milk production per cow per day, increasing lactation length, decreasing age to first calving, and decreasing calf production interval could expect to yield an average income increase up to a range of 676.3–1730.6 US dollars depending on the milk-producing area.     

Distribution and repeatability of nematode faecal egg counts in dairy goats: a farm survey and implications for worm control

The aims of this study were to characterise trichostrongyle egg excretion in dairy goat flocks under various epidemiological conditions, and to assess the relative importance of animals in their first lactation and goats with high levels of milk production on the total egg output of the flock. The repeatability of egg excretion was estimated on 4 different dates in 14 dairy goat farms in France. Egg outputs were positively skewed on most farms suggesting an aggregated distribution of parasites. Within-year repeatability coefficients ranged from 0.29 to 0.82 suggesting that, on most farms, animals with high egg excretion on one occasion are likely to show high rates of excretion on other occasions. Comparisons of egg outputs from the selected subgroups showed that the high producing goats contributed prominently to egg excretion, particularly at times of peak parasitism. Results from goats in their first lactation were more equivocal. These results provide a rationale for anthelmintic strategies in dairy goats based on phenotypic characters.     

An economic opportunity survey of small dairy farms in Paraguay

Participatory rural appraisal (PRA) in 15 small farms and an economic opportunity survey (EOS) in 13 were carried out in the Cordillera basin of Paraguay to identify production constraints and the best ways to achieve economic gain. PRA showed farmers’ perception was that nutrition was the main constraint. The EOS showed that over 70% of the milk produced was sold in the neighbourhood. The average number of adult cows (lactating and dry cows) per farm ranged from 15 to 120, of which 62.2% to 80% were lactating cows. Milk production per cow on one day ranged from 8.5 to 18.2 litres and average lactation length was more than 300 days. Average age at first calving varied from 31 to 39 months. The highest economic opportunity was observed for increased milk production. Age at first calving and calf production interval were also found to be important constraints. Ultrasonography survey of the ovaries 20 maiden heifers over six months showed inadequate activity. Partially budgeted interventions were instituted to improve nutrition and management of maiden heifers, in-calf cows and those in early lactation. More forages were grown. PRA and EOS were shown to be useful tools in identifying production constraints.     

Use of anthelmintics for nematode control in sheep in West Germany: results of a survey]

A survey by questionnaires was performed on 543 (0.9% of all) sheep flocks in western Germany in 1988/89 to obtain informations about deworming practices against gastrointestinal nematodes. The major informations are: Anthelmintic treatments were associated with the reproductive status of ewes and the breeding of lambs in most of the flocks. They were performed at an epidemiologically appropriate time in many cases but were not accompanied by essential management practices. (Pro)benzimidazole compounds were the anthelmintics most frequently used by more than 95% of the farmers; 22% and 13% of the farmers additionally or exclusively administered levamisole/pyrantel and ivermectin, respectively. On average, treatment of ewes and lambs against nematodes was performed 2.5 times and 2.8 times a year, respectively. The mean frequency of deworming differed regionally and was generally greater in pedigree breeding flocks than in commercial breeding flocks; it was significantly affected by the husbandry system, the number of ewes per flock, the size of available pasture and the class of anthelmintics employed. The results of this survey revealed that many German sheep farmers obviously lack an awareness of the rationale of preventive and economic control practices against gastrointestinal nematodes.     

Prevalence of microorganisms associated with udder infections in dairy goats on small-scale farms in Kenya

Six hundred and thirty clinically-normal milk samples from dairy goat flocks comprising a mixed population of German Alpine, Toggenburg, Saanen and Galla crosses were examined over a 3-month period to determine the prevalence of bacterial organisms. Bacteria were isolated in 28.7% of the milk samples (181/630) either singly (92.8%) or in combination (7.2%). The most prevalent bacterial organisms were Staphylococcus spp. (60.3%), followed by Micrococcus spp. (17.7%), Acinetobacter spp. (5%), Actinomyces spp. (5%) and Streptococcus spp. (1.1%). The Staphylococcus spp. were mainly coagulase negative (64.3%). Coagulase-negative staphylococci and coagulase-positive staphylococci accounted for 37.5% and 22.7% respectively of the total bacteria isolated. The isolation of bacteria, some of which are important in clinical and subclinical mastitis, in apparently normal caprine milk, indicates that particular attention should be given to the management of these dairy goat flocks in order to avoid the development of cases of clinical mastitis.     

Working towards a reduction in cattle lameness: 1. Understanding barriers to lameness control on dairy farms

On 222 dairy farms, the farmer’s perception of the scale of the herd lameness problem was compared with the prevalence detected by observation of the milking herd, and a questionnaire explored the barriers to lameness reduction. Ninety percent of farmers did not perceive lameness to be a major problem on their farm, although the average prevalence of lameness was 36%. For 62% of the sample, lameness was not the top priority for efforts made to improve herd health. Time and labour were important limiting factors for lameness control activities and financial constraints prevented farmers taking action on advice in 30% of cases. Farmers’ understanding the implications of lameness for the farm business was limited. Lameness reduction is restricted by farmers’ perception of lameness, but also by time, labour and finance; these issues need to be addressed at the industry level to support animal welfare improvement.     

Radioimmunoassay of milk progesterone as a tool for fertility control in smallholder dairy farms

This study focused on the use of radioimmunoassay of progesterone in milk for the diagnosis of post-partum ovarian cyclicity and accurate detection of oestrus and non-pregnancy in cows in the artificial insemination (AI) programme in Bangladesh. In Investigation 1, milk samples were collected on day 0 (day of AI), day 9–13 and day 21–24 from 444 milking cows of various breeds presented for the first post-partum insemination by 413 farmers living at 182 villages/regions in Mymensingh District from 6 AI centres and sub-centres. Each cow was then examined three times after each AI until it stopped returning to oestrus. Sixty to 90 days after the last AI, the cows were examined per rectum to confirm the pregnancy. Milk progesterone data on day 21–24 contributed to a clear diagnosis with respect to non-pregnancy in 100% cows, indicating a possible use of this progesterone assay for identifying non-pregnant cows in AI programmes. In Investigation 2, milk progesterone was monitored two times in a month with a 10-day interval in 88 cows. The samples were taken between 10 days after calving and the first detected oestrus, followed by two more samples 10 days apart. The proportion of cows accurately detected in oestrus was 30%. Another 30% were stated to be in oestrus when they were not (false positive) and 40% were not detected when they were in oestrus (false negative). The mean intervals between calving and oestrus and between calving luteal activity were 40 to 362 days (median = 120, n = 82) and 34 to 398 (median = 111, n = 64) days, respectively. The body condition scores at calving and at the initiation of luteal activity influenced the interval between calving and luteal activity (p < 0.05). Cows suckled twice daily initiated luteal activity earlier than their counterparts suckled several times daily (p < 0.05). Determination of progesterone in milk on day 21–24 is a good means for detecting non-pregnant cows.     

Prevalence of Toxoplasma gondii antibodies in dairy goats from 1982 to 1984

Serum samples from 1,000 dairy goats from northwest United States (1982 to 1984) were examined for Toxoplasma gondii antibodies by a modified agglutination test. Toxoplasma gondii antibody titers were less than 1.40 for 779 goats, 1.40 for 153 goats, and greater than or equal to 1:400 for 68 goats. Seroprevalence increased with age of goats; 3.7% of 54 six-month-old goats were seropositive (greater than or equal to 1:40) vs 17.8% of 218 one-year-old goats.     

VAMPP: a veterinary automated management and production control programme for dairy farms (the application of MUMPS for data processing)

The application of MUMPS in a computerised recording system for herd health and production control on dairy farms is reviewed. MUMPS is an interactive multi-user database management system, which is both an operating system and a high level computer language. In this system, coding of veterinary and management events prior to data entry is not needed. Programmes and data structure can easily be adapted and extended due to the features of MUMPS. The system for dairy farms allows epidemiological analyses, due to the flexibility of the programme. The programme is used by farmers and veterinary surgeons by means of terminals linked to a central computer. The system provides action lists for farmers and veterinary surgeons; the information on these lists is presented in a multidisciplinary way. Several herd reports and analyses, including frequency distributions and graphs, are given. These reports enable the investigation of cross-relations between farm aspects, and aid in the detection of problem areas.     

Paratuberculosis on small ruminant dairy farms in Ontario,Canada: A survey of management practices

A cross-sectional study was undertaken (October 2010 to August 2011) to determine the risk factors for dairy goat herds and dairy sheep flocks testing positive for paratuberculosis (PTB) in Ontario, Canada. A questionnaire was administered to 50 producers during a farm visit in which concurrently, 20 randomly selected, lactating animals over the age of 2 years underwent sampling for paratuberculosis testing. Only 1 of 50 farms (2.0%) was closed to animal movement, whereas 96.6% of dairy goat farms and 94.1% of sheep farms purchased livestock from other producers. Only 10.3% of dairy goat, and no dairy sheep farms used artificial insemination. Manure was spread on grazing pastures by 65.5% and 70.6% of dairy goat and dairy sheep farms, respectively. Because of the high true-prevalence of paratuberculosis infection detected, no risk factor analysis could be performed. This study demonstrates that biosecurity practices conducive to transmission of PTB are highly prevalent in Ontario small ruminant dairy farms.     

Culling decisions of dairy farmers during a 3-year Salmonella control study

Salmonella enterica subsp. enterica-serotypes lead to periodically increased morbidity and mortality in cattle herds. The bacteria can also lead to serious infections in humans. Consequently, Denmark has started a surveillance and control programme in 2002. The programme focuses on Salmonella Dublin which is the most prevalent and most persistent serotype in the Danish cattle population. A field study in 10 dairy herds with persistent Salmonella infections was carried out over three years to gain experience with control procedures including risk assessment, targeted control actions and test-and-cull procedures. From autumn 2003 until end of 2006 quarterly milk quality control samples from all lactating cows and biannual blood samples from all young stock above the age of three months were tested using an indirect antibody ELISA. The most recent and previous test results were used to categorise all animals into risk groups. These risk groups and all individual ELISA-results were communicated to the farmers as colour-coded lists four to six times per year. Farmers were advised to manage the risk of Salmonella transmission from cattle with repeatedly high ELISA results (flagged as "red") or cows with at least one recent moderately high ELISA result (flagged as "yellow") on the lists. Risk management included, e.g. culling or separation of the cows at calving. We analysed culling decisions using two models. For heifers a hierarchical multivariable logistic model with herd as random effect evaluated if animals with red and yellow flags had higher probability of being slaughtered or sold before first calving than animals without any risk flags. For adult cows a semi-parametric proportional hazard survival model was used to test the effect of number of red and yellow flags on hazards of culling at different time points and interactions with prevalence in the herd while accounting for parity, stage of lactation, milk yield, somatic cell count and the hierarchical structure of the data with animals clustered at herd level. This study illustrates how investigation of culling decisions made by herd managers when they have access to test-status of individual animals and overall apparent prevalence during control of an infection can lead to useful new knowledge. Overall herd managers were more likely to cull cattle with increasing number of yellow and red flags than animals with no flags. However, cattle were more likely to be culled with yellow and red flags during times with low or medium high within-herd seroprevalence than at times with high seroprevalence. These results are valuable knowledge for modelling and planning of control strategies and for making recommendations to farmers about control options.     

Veterinary assistance to dairy farms in the Netherlands: an assessment of the situation by dairy farmers

A questionnaire-based study was conducted among 466 dairy farmers in the Netherlands. The study investigated the experiences and opinions of dairy farmers about veterinary herd health and production management programmes. The dairy farmers were selected at random, and thus some took part in such programmes whereas others did not. The questionnaire comprised general questions about the farm operation and specific questions about the herd health programme and the practice conducting it, as well as perceived advantages and disadvantages of the veterinary programme. Farmers who did not participate in such programmes were questioned about their reasons for not participating. Both groups were questioned about future perspectives and opportunities. The costs of the programme appeared to be a drawback for participation but not as much as perceived by the practices. According to farmers, programmes focus too much on curative aspects and too little on analysis or prevention, where the needs are. Farm areas not included in the programme are so far not yet covered by other institutions, contrary to the expectations of the veterinarians. In the future, the farmers would be willing to take part in similar or expanded programmes, provided that certain conditions, such as product definition, structure, planning, costs, are properly met.     

Management practices to control gastrointestinal parasites in dairy and beef goats in Minas Gerais; Brazil

Parasitic infection is recognized worldwide as a limiting factor in the production of goats, and various control methods are used to reduce economic losses, often without considering the epidemiology of the parasites. This has led to the development of highly tolerant parasite populations and the presence of chemical residues in the beef and milk. The objective of this study was to determine the level of knowledge of goat farmers about parasitic diseases and to correlate this with the epidemiology of endoparasites and parasite control practices in goat farms in the state of Minas Gerais, Brazil. The analysis was based on a questionnaire applied by trained veterinarians. The sample was homogeneous throughout the state, covering 18.4% (157/853) of municipalities. Eighty-four dairy goat farms in 81 municipalities and 200 properties with beef goats in 76 municipalities were evaluated. The herd size per goat farm ranged from 4 to 57 (average 24) for beef herds and from 2 to 308 (average 63) for dairy farms. The majority of the beef herd production was extensive and semi-extensive (98.5%), while the dairy herds were maintained under intensive farming (98.8%). The mixed production of goats and sheep was reported by 36.5% of beef goat farmers and by 20.2% of dairy goat farmers. Among the beef goats farms on which the technological level was determined, 2.0% were categorized as having high technological level, 34.5% as medium, and 63.5% as low. Of the 84 dairy farms, 30% operated at a high, 47% at a medium, and 23% at a low technological level. The adoption of practices to reduce parasitism, such as the quarantine of animals, treatment of newly arrived animals, regular cleaning of the floor, and technical assistance, was significantly higher on dairy farms than on beef farms. Although 85.7% of dairy farmers and 83% of beef farmers medicate their animals, the treatments were performed without technical criteria, and deworming intervals ranged from 30 to 120 days or more. The average interval between treatments was significantly longer in dairy goat herds (4.8 months) than in the beef herds (3.6 months). The most commonly used drugs were macrocyclic lactones (37.7% in dairy and 39.5% in beef herds) and benzimidazoles (48.9% in dairy and 31.5% in beef herds). Goat production in Minas Gerais is still in its infancy, and even though using a control program associated with other health practices, producers still rely heavily on chemicals to get satisfactory results.     

Financial incentive to control paratuberculosis (Johne's disease) on dairy farms in the United Kingdom

This paper estimates the financial incentive to control paratuberculosis on dairy farms by establishing the level of expenditure that would minimise the total cost of the disease (output losses plus control expenditure). Given the late onset of the clinical signs and the lack of treatments, control was focused on minimising the financial impact of paratuberculosis by adjusting the dairy cow replacement policy. The optimum replacement policies for disease-free herds and infected herds were compared by using dynamic programming. At the standard settings, the disease justified adjusting the culling policy; under constant bioeconomic assumptions, it reduced the expected annuity from milk production under the optimal replacement policy by about 10 per cent (27 pounds sterling per cow annually), a considerably lower figure than for other major endemic diseases that affect dairy cows in the uk. The effect was even less at lower milk prices, suggesting that there is at present little incentive for dairy farmers to put more resources into controlling the disease. However, the incentive could be increased if more information were available about how best to manage the disease under specific farm circumstances. Any effect that paratuberculosis may have on the future demand for milk and hence on milk prices would also be an important consideration.     

宁夏羊胃肠道线虫对现行驱虫药的抗药性调查

采用粪便虫卵减少试验对宁夏地区所属灵武、贺兰、盐池、吴忠、中宁、中卫、永宁和银川市郊8个县（市）的12个绵羊场、6个山羊场进行了丙硫苯咪唑和阿维菌素抗药性的随机调查。结果表明：在用丙硫苯咪唑调查的10个绵羊场和6个山羊场中，虫卵减少率在95％以下和95％的置信域下限在90％以下的有山羊场2个、绵羊场2个，证明对丙硫苯咪唑有抗药性；1个绵羊场和1个山羊场的虫卵减少率是96．3％、95．9％，但95％置信域的下限在90％以下，具有抗药性可疑；山羊群中丙硫苯咪唑的抗药性为33．3％，绵羊群为20．0％。用同样的方法调查了1个山羊场和5个绵羊场（其中有4个羊场曾执行了丙硫苯咪唑的试验），查出1个山羊场和1个绵羊场对阿维菌素具有抗药性可疑，其虫卵减少率分别为97．3％和95．5％，置信域下限在90％以下。揭示了宁夏地区羊消化道线虫对现行驱虫药的抗药状态，为今后防治提供了依据。