Effectiveness of Cooperative Extension Manure Management Programs

Equine farms are increasing in number in many areas of the United States. Unlike traditional farming operations, equine farm managers may be less likely to use and are less connected to extension services. A manure management survey was mailed to 2000 New Jersey equine farms during the winter of 2006 to 2007; 472 surveys were returned (24% return rate). Respondents were asked from where they get manure management information; 27% received information from Rutgers Cooperative Extension, whereas 21% get information from a feed dealer, 6% from another retailer, 19% from the internet, 39% from magazines, 47% from other horse owners, and 25% from other sources. Veterinarians were not a variable in this survey; although they are a source of equine information, it is unclear how reliable a source they might be about manure management. They can play a role in manure management programs, particularly referral to other sources of information. Data were modeled to compare extension against all other sources and develop a prediction of where respondents receive information. This model had a predictive accuracy of 70.03% and R² of 0.08 (P > .10). This model showed that those receiving information from extension were likely to have 21 to 40 acres of pasture, were likely to spread manure on 6 to 10 acres, and likely to soil test regularly. Results indicate that cooperative extension was not the first or second information source for horse producers, although larger farms and those that soil tested on a regular basis were more likely to use extension services (P < .05).     

Risk factors for Johne's disease in Scotland--the results of a survey of farmers

The reported incidence of Johne's disease has been increasing in the east of Scotland since 1993. A postal questionnaire survey was sent to 127 farms to identify potential risk factors for Johne's disease in relation to wildlife and farm management practices, and 86 returns were obtained. Of 22 farms which had been assumed to be free of the disease, on the basis of information held by local veterinary centres, seven (32 per cent) reported cases of Johne's disease in the 1990s, indicating that the disease is under-reported. Logistic regression analyses showed that eight of 63 potentially explanatory variables were significant at the 5 per cent level in affecting the likelihood of farms reporting Johne's disease. Of these, large numbers of livestock and rabbits, and access of wildlife to feed stores were the clearest and most consistent risk factors associated with the disease. The application of manure to grazing pasture, the type of water supply for the cattle and the numbers of crows were also related to the presence of Johne's disease but the nature of these relationships was less clear. Only 38 per cent of the farms reported taking any control measures to combat Johne's disease, but three of the control measures were relevant to risk factors identified as significant by the survey, namely maintaining a clean water supply, controlling rabbits and not spreading manure on to grazing pasture.     

Mycobacterium avium subsp. paratuberculosis from free-ranging deer and rabbits surrounding Minnesota dairy herds

The objectives of this study were to estimate the prevalence of Mycobacterium avium subsp. paratuberculosis (MAP) among deer and rabbits surrounding infected and noninfected Minnesota dairy farms using fecal culture, and to describe the frequency that farm management practices were used that could potentially lead to transmission of infection between these species. Fecal samples from cows and the cow environment were collected from 108 Minnesota dairy herds, and fecal pellets from free-ranging white-tailed deer and eastern cottontail rabbits were collected from locations surrounding 114 farms; all samples were tested using bacterial culture. In addition, a questionnaire was administered to 114 herd owners. Sixty-two percent of the dairy herds had at least 1 positive fecal pool or environmental sample. A total of 218 rabbit samples were collected from 90% of the herds, and 309 deer samples were collected from 47% of the herds. On 2 (4%) of the farms sampled, 1 deer fecal sample was MAP positive. Both farms had samples from the cow fecal pool and cow environment that were positive by culture. On 2 (2%) other farms, 1 rabbit fecal sample was positive by culture to MAP, with one of these farms having positive cow fecal pools and cow environmental samples. Pasture was used on 79% of the study farms as a grazing area for cattle, mainly for dry cows (75%) and bred or prebred heifers (87%). Of the 114 farms, 88 (77%) provided access to drylot for their cattle, mainly for milking cows (77/88; 88%) and bred heifers (87%). Of all study farms, 90 (79%) used some solid manure broadcasting on their crop fields. Of all 114 farms, the estimated probability of daily physical contact between cattle manure and deer or rabbits was 20% and 25%, respectively. Possible contact between cattle manure and deer or rabbits was estimated to occur primarily from March through December. The frequency of pasture or drylot use and manure spreading on crop fields may be important risk factors for transmission of MAP among dairy cattle, deer, and rabbits. Although the MAP prevalence among rabbits and deer is low, their role as MAP reservoirs should be considered.     

黑河流域草地资源保护与建设

黑河流域除绿洲地区外有160万hm2的草地,进行草地分户、围栏封育、人工改良草地;牧户按地定畜、优化牧场、推广良种、改良畜群;按草定牧、实行休牧和轮牧;革新观念、子羔出栏、加速出栏周期、保障牧民增收等措施可保护草地资源,加速草地建设,繁荣牧区经济.     

The effects of farm management practices on liver fluke prevalence and the current internal parasite control measures employed on Irish dairy farms

Fasciolosis caused by Fasciola hepatica is responsible for major production losses in cattle farms. The objectives of this study were to assess the effect of farm management practices on liver fluke prevalence on Irish dairy farms and to document the current control measures against parasitic diseases. In total, 369 dairy farms throughout Ireland were sampled from October to December 2013, each providing a single bulk tank milk (BTM) sample for liver fluke antibody-detection ELISA testing and completing a questionnaire on their farm management. The analysis of samples showed that cows on 78% (n = 288) of dairy farms had been exposed to liver fluke. There was a difference (P < 0.05) between farms where cows were positive or negative for liver fluke antibodies in (a) the total number of adult dairy cows in herds, (b) the number of adult dairy cows contributing to BTM samples, and (c) the size of the total area of grassland, with positive farms having larger numbers in each case. There was no difference (P > 0.05) between positive and negative farms in (a) the grazing of dry cows together with replacement cows, (b) whether or not grazed grassland was mowed for conservation, (c) the type of drinking water provision system, (d) spreading of cattle manure on grassland or (e) for grazing season length (GSL; mean = 262.5 days). Also, there were differences (P < 0.001) between drainage statuses for GSL with farms on good drainage having longer GSL than moderately drained farms. The GSL for dairy cows on farms with good drainage was 11 days longer than for those with moderate drainage (P < 0.001). The percentage of farmers that used an active ingredient during the non-lactating period against liver fluke, gastrointestinal nematodes, lungworm, and rumen fluke was 96%, 85%, 77% and 90%, respectively. Albendazole was the most frequently used active ingredient for treatment against gastrointestinal nematodes (57%), liver fluke (40%) and lungworm (47%), respectively. There was a difference (P < 0.05) in the use of triclabendazole and albendazole between positive and negative farms, with triclabendazole use being more common in positive farms. This study highlighted differences in dairy management practices between Irish farms with dairy herds exposed or not exposed to liver fluke and stressed the need of fine-scale mapping of the disease patterns even at farm level to increase the accuracy of risk models. Also, comprehensive advice and professional support services to farmers on appropriate farm management practices are very important for an effective anthelmintic control strategy.     

Bison and Cattle Grazing Impacts on Grassland Stream Morphology in the Flint Hills of Kansas

Despite a shift from yr-round bison grazing throughout the Great Plains before European settlement to extensive seasonal cattle grazing, little is known about ungulate grazing impacts on grassland streams. In this study we 1) determine whether grazing management is a significant driver of grassland stream morphology within the Flint Hills Ecoregion (Kansas, United States); 2) determine if yr-round bison grazing (the precolonial condition) and seasonal cattle grazing (the currently dominant grazing practice in the region) result in distinct stream morphology; and 3) determine if the introduction of cattle into ungrazed watersheds produces significant changes to channel morphology. We use a replicated watershed-scale study design and survey 17 streams across four grazing treatments (ungrazed, long-term bison grazed [yr-round], long-term cattle grazed [seasonal], and newly cattle grazed [seasonal]). Baseline geomorphic surveys were completed in 2010 following consistent grazing management since 1992, and resurveys were completed in 2011 and 2013 to determine short-term grazing impacts. Under the conditions of the experiment, we did not detect significant differences (P > 0.10) in channel morphology or stream bed substrate size among grazing treatments following nearly 2 decades of consistent grazing management. Cattle introduction into ungrazed watersheds resulted in modest (P < 0.05) stream widening (0.19 m, 3.9%) following two grazing seasons. Bison grazed watersheds also experienced modest (P < 0.05) stream widening (0.20 m, 5.1%) during the resurvey period. Stream widening from 2010 to 2013 within newly cattle-grazed and long-term bison-grazed treatments indicates that cattle and bison are capable of producing moderate alterations to grassland stream morphology over short time periods. However, longer time periods containing more diverse hydrologic conditions may be necessary to generate larger geomorphic changes between surveys. Although we detected modest changes to stream morphology in response to grazing over short time periods, overall, stream morphology does not vary among grazing treatments in the study area.     

草地家畜放牧系统草畜平衡调控技术研究

划区轮牧是提高草地家畜系统产出和实现草地畜牧业可持续发展的最佳放牧制度。放牧管理的方针是把草层高度(草地牧草生物量)保持在最利于草地生长、草地质量和家畜采食的范围内。饲料计划依据不同的时期和管理层次分为饲料概算、饲料预算和放牧计划三个水平。饲料供给由草地牧草生长速度、草地生物量和补饲确定,而饲料需求由牧场家畜数量及其生产指标水平决定。实行季节畜牧业的经营管理策略,使草地供给和家畜需求达到季节和全年的动态平衡。系统管理和效益的三个关键是划区围栏、畜群结构和载畜量。     

The effect of grazing management on livestock exposure to parasites via the faecal–oral route

In grazing systems, heterogeneous distributions of forage resources and faeces result in localised accumulations of nutrients and parasites (both macroparasites and microparasites), creating trade-offs between the costs of exposure to infestation or infection and the benefits of nutrient intake. Each contact between livestock and faeces in the environment is a potential parasite/pathogen transmission event. Thus, herbivores must make foraging decisions in complex environments which will affect their intake of both nutrients and parasites. However, the pattern of forage and faecal resources in agricultural environments will also be affected by the grazing management system in place. The aim of this study was to investigate the effect of grazing management on the risk of infection/infestation to livestock. We used a spatially explicit individual based stochastic foraging model to simulate livestock contact (both grazing and investigative) with faeces in the environment. The model was parameterised to simulate cattle grazing under three types of grazing management: set stock (i.e. where sward growth and cattle intake are in equilibrium in a single field); a two pasture rotation grazing system with increasing number of rotations; and a rotational grazing system with two rotations and increasing subdivisions of the pasture. Overall the amount of cattle contact with faecal-contaminated patches was similar in both set stocking and rotational grazing scenarios, suggesting no difference in the risk of infection or infestation between the different systems. However, the timing and absolute amounts of peak contact varied greatly indicating that different grazing management systems expose livestock to risks of different types of parasites at different times of the grazing season. Intensive rotational systems with small pasture blocks (especially the first grazing period) maximised livestock contact with fresh faeces, and thus exposure to microparasites (e.g. bacterial pathogens). Livestock re-entering pasture blocks in rotational systems and set stocked livestock had the highest contact with old faeces and thus have a greater risk of macroparasite transmission (gastrointestinal nematodes). This study highlights how livestock management affects the highly dynamic interaction between livestock and distributions of parasites in the environment and thus the levels of livestock exposure to parasites and pathogens via the faecal–oral route.     

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.     

The seroprevalence of Toxoplasma gondii in Ontario sheep flocks

In a random sample of 103 sheep farms in Ontario, 99% of the farms had some sheep serologically positive for Toxoplasma gondii, based on an enzymelinked immunosorbent assay (ELISA). The percent of sheep affected within farms ranged from 3.8% to 97.8%, with an average flock prevalence of 57.6%. When farm management variables were considered in a multivariate analysis, significantly lower rates of serologically positive sheep were associated with neutering of female cats and clipping of ewes' perineums before lambing; significantly higher prevalence rates were found on farms where sheep were purchased from other flocks, pigs were raised on the same farm, sheep shared pasture with other animals, flowing water was available at pasture, and pastured replacements had access to housing. As well, in univariate analyses, higher prevalence was positively associated with an increasing number of cat litters born over the previous two years and offering creep feed or forage to lambs, and inversely with the amount of labor expended on sheep rearing.     

Associations between dairy herd management factors and bulk tank milk antibody levels against Ostertagia ostertagi

A cross-sectional questionnaire survey was performed on dairy herds in Flanders (Belgium) to detect management factors that are associated with an increased gastrointestinal parasite infection level of adult dairy cows. At the end of the grazing season, information concerning general herd factors, pasture management and anthelmintic treatment strategy was obtained from 956 herds. A bulk tank milk sample was obtained from 779 out of the 956 herds and the antibody levels (ODR) against Ostertagia ostertagi were determined. The associations between ODR and herd management factors were studied by two linear regression models. The first model evaluated the effect of general herd factors and the level of the cows' exposure to pasture. Large sized herds had significantly lower ODRs as compared to medium (P=0.001) or small sized herds (P=0.03). Herds with only dairy cows had lower ODRs than herds with both dairy and beef cows (P=0.02). An increased exposure to pasture of the cows was associated with higher ODRs (P<0.001). The second model was built to evaluate the effect of pasture management factors and anthelmintic treatment strategy. Later turn-out on pasture (P<0.001) and mowing (P=0.002) were both significantly associated with lower ODRs. Cows that had a restricted grazing time per day tended to have lower ODR than cows that grazed 24 h per day (P=0.07). An increased exposure to pasture of the heifers was significantly associated with higher ODRs (P=0.001). No associations were found between ODR and calf related management factors, anthelmintic treatment strategy, time of turn-in, rotational grazing type or stocking rate. Later turn-out on pasture, mowing and restricting the grazing time per day are factors that can be applied immediately on dairy farms to reduce economical losses due to gastrointestinal nematodes.     

Use of Best Management Practices and Pasture and Soil Quality on Maryland Horse Farms

Agricultural operations, including horse farms, can contribute nonpoint source (NPS) pollution to surface water. The use of best management practices (BMPs) is the most effective way to prevent the movement of pollutants to surface water from nonpoint source pollution. Previous mailed survey studies have assessed the use of BMPs at the county and state level, but a visual assessment of horse farms is necessary to validate survey results. An observational field study was conducted to assess BMP use and soil and pasture quality and to create a model to predict soil erosion on Maryland horse farms. Fifty-one farms were selected based on stocking density (acres per horse [ac horse^-1]), farm use, and presence of water on property. All farms were visited from September through November 2009. In each pasture with grazing horses, the correct use of BMPs was assessed, grass height and vegetative cover were measured, and composite soil samples were collected. Less than half of the 18 assessed BMPs were being used by participants. Although most participants maintained the recommended vegetative cover and grass height, soil erosion was a major problem in pastures. Most farms had optimum soil nutrient concentrations (Ca, K, and P), excessive Mg values, and basic soil pH. Vegetative cover and grass height measurements were positively correlated with stocking density (r = 0.345, P < .0001; and r = 0.291, P < .0001, respectively). Farm use was the only variable that predicted soil erosion on farms (P = .006). Farms used for pleasure were least likely to have soil erosion, whereas farms used for breeding were more likely to have soil erosion (P = .0058). Despite the low-to-moderate adoption of BMPs, the maintenance of recommended vegetative cover and grass height as well as optimum values of soil nutrients indicated participating Maryland horse farms have a low potential for nutrient movement and NPS pollution.     

Dairy technology adoption in smallholder farms in “Dejen” district, Ethiopia

Factors influencing dairy technology adoption and impact on milk yield were studied in 240 smallholder farms in Dejen district, Ethiopia. The majority of the smallholders had more than 20 years of farming experience and were living at more than 10 km distance from market or trading centers (67% and 54% in that order). The dairy technologies studied included the use of crossbred animals, improved feed technologies and improved management practices. Application of acaricides, deworming, vaccination, heat-detection and haymaking had wide application (more than 80% adoption levels) while urea straw treatment, silage making, rotational grazing and fodder beet development were the least practiced ones. Only 20 percent of the cows were crossbred animals. It has been found that higher level of technology adoption is associated with better milk yield regardless of the breed of cattle (local or crossbred) owned by the farmers. Milk yields in local breeds increased by 0.07 times when the number of technologies increased by one unit. In crossbred cows, this rate of increase was five fold higher (0.38 times for one unit increase). Correlation coefficients between and within farm household characteristics and technologies adoption were, generally, significant. Male-headed households adopted significantly higher number of technologies than female-headed households (P?<?0.001). Technology adoption rates increased significantly with increased education level and family size and decreasing distance from market or trade centers (P?<?0.01). The level of technology adoption by smallholder farmers is still unsatisfactory and is highly dependent on gender, family size and level of education of smallholder farmers and location of farms.     

奶牛场温室气体排放与减排措施

奶牛养殖在产能提升的同时也排放了大量温室气体。本文梳理了奶牛养殖场温室气体排放的重点环节,主要分为奶牛养殖活动温室气体排放以及牛场日常运行耗能两个方面;结合奶牛养殖肠道发酵和粪污管理的温室气体核算方法,归类整理了主要的减排措施,包括进行提高饲料质量和转化效率、粪污高效管理、清洁能源替代等方式,助力奶牛养殖实现低碳乃至零碳排放。     

Subacute ruminal acidosis (SARA) in grazing Irish dairy cows

Subacute ruminal acidosis (SARA) is a significant production disease of dairy cattle. Previous concerns have been raised over the occurrence of SARA in pasture-fed dairy cattle and the potential consequences of laminitis and lameness. Highly digestible perennial rye grass contains high concentrations of rapidly fermentable carbohydrate and low concentrations of physical effective fibre that may result in SARA. This study conducted a point prevalence survey of rumen health status in grazing Irish dairy cattle fed predominantly perennial rye grass-based pasture. The survey assessed rumen fluid, animal health status, milk production data and pasture composition. A total of 144 cows between 80 and 150 days in milk were sampled on 12 farms. Eleven percent of cows were classified as affected with SARA (pH < or = 5.5), 42% were marginal (pH 5.6-5.8) and 47% were normal (pH>5.8). The study showed that low rumen pH is prevalent in grazing Irish dairy cattle consuming perennial rye grass-based pasture and raises concerns regarding effective pasture utilisation and possible consequences for animal health.     

Dairy farming financial structures in Hokkaido, Japan and New Zealand

The productivity and financial performance of dairy farms in New Zealand and Japan (Hokkaido) were analyzed. By recomposing the official statistics on the dairy industry relative to Japan, New Zealand has low milk yield productivity per cow, but higher per hectare performance because of their seasonal breeding and pasture grazing systems. In the revenue and expenses analysis, New Zealand had a high cash surplus ratio compared with Hokkaido. In the cost analysis, for expenses on a “per kg of raw milk” basis, New Zealand milk production costs are 29% of those in Hokkaido. More than 60% of the production costs were attributable to feed, interest charges and wages in New Zealand. In Hokkaido, the feed cost alone accounted for 73% of the total cost. There is also a remarkably high interest expenditure in New Zealand caused by non‐subsidized fund procurement from finance organizations. In the financial analysis, New Zealand dairy farms have only approximately 50% of the total assets per cow compared with farms in Hokkaido. But total liabilities per cow in Hokkaido are twofold to threefold greater than in New Zealand. The difference between total assets and total liabilities shows that Hokkaido dairy farmers have an equity that is 50–200% greater than New Zealand dairy farmers. In the management analysis, New Zealand has a low turnover ratio of gross assets caused by the seasonal breeding system. In conclusion, New Zealand has higher per hectare production performance than Hokkaido, but has a low utilization of gross assets caused by a seasonal breeding system based on pasture grazing.     

A survey of manure management on pig farms in Northern Vietnam

Animal manure can provide nutrients for crop and fish production and input for biogas production but, if managed inappropriately, can also have a negative impact on the environment. The objective of this survey was to provide information about pig production and manure management practices in the Northern part of Vietnam in order to identify and prioritize research needs for future improvements in pig manure management. A survey was conducted by in-depth interviews on 54 pig farms in two Northern Vietnamese provinces, Thai Binh and Bac Giang. In addition to the survey, also key informant responses were obtained in the two provinces to help identify problems with existing manure management. The survey showed that large-scale pig producers (> 100 fatteners or 20 sows) had more pigs per hectare than medium-scale (19–99 fatteners, 5–19 sows) or small-scale (< 19 fatteners, < 5 sows) producers. Biogas was produced from 43% of the total manure produced on all surveyed farms, and was used for cooking. The proportion of total manure applied to crops was only 5% in Thai Binh and 35% in Bac Giang. Large-scale producers tended to operate smaller fishponds, and medium-scale farms operated larger ones. The farmers were of the opinion that fish in ponds fertilized with pig manure grew significantly faster than did fish in ponds supplied with other feed or types of fertilizer. Twenty percent of pig producers reported that they raised pigs just to provide manure to feed their pond fish. A large proportion (19%) of the total manure produced was discharged into public sewage systems, rivers and lakes. Of the 54 householders interviewed, 46 believed that animal manure caused serious damage to the environment. Farmers interviewed had little or no expertise in handling liquid manure, composting solid manure, or reducing contamination by means of microbial reduction of pollutants during manure management. In general, specialized pig production is seen as a commercial operation, while manure management remains non-commercial. The survey implied that more information to farmers, as well as stronger regulation of manure management, is needed in Vietnam.     

A cross-sectional survey of Thoroughbred stud farm management in the North Island of New Zealand

AIM: To obtain initial baseline data on the management of Thoroughbred stud farms in the North Island of New Zealand.

METHODS: Data on the management of Thoroughbred stud farms were collected from a sample of 22 stud farms located in the south Auckland/Waikato region (n=15) and lower North Island (n=7) of New Zealand, using a face-to-face survey. The studmaster provided information on the size, scope and management of the farms during the 2004/2005 breeding season. Analysis was based on the location of the farm and size of the breeding operation (number of resident mares).

RESULTS: Effective farm size ranged from 20 to 526 ha and averaged 167 (standard error (SE) 36) and 88 (SE 49) ha in the south Auckland/Waikato and lower North Island areas, respectively. Some farms in the Auckland/Waikato region stood shuttle stallions. The median number of stallions per farm was three (range 0.9), and the median mare-to-stallion ratio was 43 (range 10.250). The farms had a mean of 50 (range 7.180) wet mares and 21 (range 0.100) dry mares. The number of mares per breeding stallion increased with increasing size of breeding operation (p=0.04), being 28 (95% confidence interval (CI) = 10.56) vs 40 (95% CI=16.74) vs 74 (95% CI=44.113) for moderate (≤70 mares), medium (90–199 mares) and large (≥200 mares in total) operations, respectively. Seventy-one percent of farms aimed to breed dry mares early in the breeding season, and used a combination of lights, hormone therapy, and rising plane of nutrition to achieve this.

Foaling took place in foaling paddocks monitored using a night foaling attendant (17/22) or with foaling alarms (5/22). At birth, 17/22 studmasters routinely administered antibiotics, 14/22 administered tetanus antitoxin, 9/22 administered an enema to foals, and 2/22 did not routinely administer prophylactic treatments. Weaning occurred at 5 (range 3.7–7) months of age, and foals were confined to a box for 1–2 weeks on 16/22 farms. Weaned foals were drenched with anthelmintics every 7 (range 4–9) weeks, and were fed 2.9 (range 1–6) kg of concentrate feed while at pasture until intensive management associated with preparation of the horses for auction began 13 (range 6–20) weeks before the yearling sales. Eight farms weighed the weanlings, at least monthly, to monitor growth.

CONCLUSIONS AND CLINICAL RELEVANCE: The management of Thoroughbred horses was relatively consistent throughout the regions surveyed. Utilisation of breeding stallions tended to be more efficient on the larger stud farms in the south Auckland/Waikato region. Even though foals are grown at pasture they are often provided with large quantities of concentrate feed.     

Anthelmintic resistance and management of nematode parasites on beef cattle-rearing farms in the North Island of New Zealand

AIM: To provide information on current farmers’ opinions and farming practices thought to be related to anthelmintic resistance, and to test for associations between the presence of anthelmintic resistance and management practices on beef cattle- rearing farms in the North Island of New Zealand.

METHODS: A study using an interview-based questionnaire about management of internal parasites was conducted on 62 beef cattle-rearing farms in the North Island of New Zealand, using case-control analyses to test for associations between management practices and the presence or absence of resistance to ivermectin or albendazole. Resistance was inferred from faecal nematode egg count (FEC) reduction (FECR) tests (FECRTs) when there was <90% reduction in FEC 7-10 days after treatment of calves <12 months of age.

RESULTS: Of the 59 farmers who completed the questionnaire, most (n=40) ranked parasites highly, and at about the same level as quality and quantity of feed, as important production-limiting factors for their enterprises. In contrast, anthelmintic resistance was not perceived to be a problem on 13 farms, and its importance was rated low on 24, moderate on 15, and high on only six farms. Despite all farms having planned parasite control programmes, there was heavy reliance on clinical signs of parasitism to determine frequency of treatments. About one in three farmers with beef breeder cows routinely treated their calves at marking, one in five treated mixed-age cows, and almost half treated rising 2-year-old cows before calving. One in four farmers used anthelmintics on calves on 8–12 occasions in their first year of life. Co-grazing with other species was rare, but follow-on grazing within 3 months after older cattle or sheep was common. On most farms, grazing cattle was restricted to part of the farm, a finding with implications for parasite control and persistence of larvae in refugia. Macrocyclic lactone (ML) anthelmintics or their combinations with other action families were currently, and for the past 5 years, used more frequently than benzimidazoles and levamisole, and benzimidazole-levami- sole combinations. The prevalence of resistance to ivermectin was high (82%) and no plausible model of associations could be constructed from the data. The prevalence of resistance to albendazole was 60%, and the risk of resistance increased as the number of rising 1-year-old cattle present mid-winter increased, and decreased as the number of breeding cows >2 years old present mid-winter increased.

CONCLUSION: It is clear that in practice anthelmintic resistance is a secondary consideration to obtaining productivity advantages from the use of anthelmintics in beef cattle. Farmers’ opinions were divided on many issues and the overall impres- sion was of confused and diverse thinking regarding the principles of the use of anthelmintics. The overall outlook regarding anthelmintic resistance in cattle is bleak unless the need for integrated and long-term research activities is acted upon soon.     

Does Stocking Rate Manipulation Promote Pasture Sustainability in the Humid Tropics?

Stocking rate manipulation was examined as a means of improving plant diversity (as a measure of pasture sustainability and forage value) in a native grass pasture used for dairy production in the humid tropics of Veracruz, Mexico. Given that environmental impact reduces biotic diversity, plant phylogenetic and functional diversity should decline with increased stocking rate. Stocking rates of 2, 3, and 4 cows · ha^?1 and a rotational grazing plan of 3 d of occupation and 27 d of rest per pasture were applied continuously over 5 yr. Across 200 quadrats in each of two replicate paddocks per treatment, observed species richness, phylogenetic diversity (average taxonomic distinctness based on species presence/absence), and functional diversity (life-cycle duration and growth habit) were assessed. Most species were forb/herbs and forb/herb-subshrubs. Perennial species declined with increased stocking rate (F = 16.36, 0.05 > P > 0.02) while annual-perennial species increased (F = 76.88, 0.01 > P > 0.005); the proportion of annual species was least prominent and did not differ significantly. Observed species richness and phylogenetic diversity did not differ significantly with stocking rate. The correlation between functional diversity for life-cycle duration and phylogenetic diversity was significant and positive, suggesting that plant communities were predominantly assembled randomly from the surrounding species pool rather than through interspecies interactions acting to naturally filter immigrant species, thus leading to more opportunistic and undesired species. Although grazing pressure was not sufficient to alter indices or production measures, they did reveal shifts that may precede further pasture decline, indicating pasture sustainability was not being achieved. These rapid assessment methods permit monitoring for early warnings of reductions in pasture sustainability and forage quality for cattle.