Risk factors for the introduction and within-herd transmission of Mycobacterium avium subspecies paratuberculosis (MAP) infection in 59 Irish dairy herds

Since 1994, Irish cattle have been exposed to greater risks of acquiring Mycobacterium avium subspecies paratuberculosis (MAP) infection as a consequence of the importation of over 70,000 animals from continental Europe. In recent years, there has been an increase in the number of reported clinical cases of paratuberculosis in Ireland. This study examines the prevalence of factors that promote the introduction and within-herd transmission of Mycobacterium avium subspecies paratuberculosis (MAP) on selected Irish dairy farms in the Cork region, and the association between these factors and the results of MAP screening tests on milk sock filter residue (MFR). A total of 59 dairy farms, selected using non-random methods but apparently free of endemic paratuberculosis, were enrolled into the study. A questionnaire was used to collect data about risk factors for MAP introduction and transmission. The MFR was assessed on six occasions over 24 months for the presence of MAP, using culture and immunomagnetic separation prior to polymerase chain reaction (IMS-PCR). Furthermore, blood samples from all entire male and female animals over one year of age in 20 herds were tested by ELISA. Eighteen (31%) farms had operated as closed herds since 1994, 28 (47%) had purchased from multiple sources and 14 (24%) had either direct or indirect (progeny) contact with imported animals. Milk and colostrum were mixed on 51% of farms, while 88% of farms fed pooled milk. Thirty (51%) herds tested negative to MFR culture and IMS-PCR, 12 (20%) were MFR culture positive, 26 (44%) were IMS-PCR positive and seven (12%) were both culture and IMS-PCR positive. The probability of a positive MFR culture was significantly associated with reduced attendance at calving, and with increased use of individual calf pens and increased (but not significantly) if multiple suckling was practised. There was poor agreement between MFR culture and MFR IMS-PCR results, but moderate agreement between MFR culture and ELISA test results. This study highlights a lack of awareness among Irish dairy farmers about the effect of inadequate biosecurity on MAP introduction. Furthermore, within-herd transmission will be facilitated by traditional calf rearing and waste management practices. The findings of viable MAP in the presence of known transmission factors in non-clinically affected herds could be a prelude to long-term problems for the Irish cattle and agri-business generally.

Coxiella burnetii (Q fever) seroprevalence in cattle

Human cases of Q fever appear to be common in Northern Ireland compared to the rest of the British Isles. The purpose of this study was to describe the seroepidemiology of Coxiella burnetii infection in cattle in Northern Ireland in terms of seroprevalence and determinants of infection. A total of 5182 animals (from a stratified systematic random sample of 273 herds) were tested with a commercial C. burnetii phase 2 IgG ELISA. A total of 6.2% of animals and 48.4% of herds tested positively. Results from a multilevel logistic regression model indicated that the odds of cattle being infected with Q fever increased with age, Friesian breed, being from large herds and from dairy herds. Large dairy herd animal prevalence was 12.5% compared to 2.1% for small beef herds. Preliminary seroprevalence in sheep (12.3%), goats (9.3%), pigs (0%) rats (9.7%) and mice (3.2%) using indirect immunofluorescence is reported.

Effects of the stockperson on dairy cow behaviour and milk yield

The relationship between stockperson behaviour, measured as verbal and physical interactions with the dairy cows (no. ¼ 210), during milking and the subsequent milk yield obtained was examined. The numbers of steps and kicks made by the cows during milking was recorded. The behaviour of two stockteams, each consisting of two stockmen, were recorded over 10 weekend sessions. The two teams varied in the types of interactions and when the stockteam that performed more positive interactions worked with the cows (team A), the cows had a significantly higher milk yield (P , 0·05) although this difference was small (17·54 v. 17·44 kg). When team A was milking the cows also stepped and kicked on the platform significantly more ( P , 0·05) compared with team B. The results also indicated that while each stockteam tended to interact with the same cows each session, different stockpersons interacted with different cows. These findings highlight the importance of the role of the stockperson in milk output and dairy cow behaviour in a commercial setting.

Mycobacterium avium ssp. paratuberculosis: its incidence, heat resistance and detection in milk and dairy products

Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism: and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining ifa problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined.

The relationship between the stockperson's personality and attitudes and the productivity of dairy cows

This study investigated the relationships amongst personality traits and attitudes of 311 dairy stockpeople and the milk yield they obtained. A questionnaire pack consisting of a big-five measure of personality (which includes the traits of extraversion, agreeableness, conscientiousness, emotional stability and intellect), a four-factor attitude questionnaire and associated demographic and production questions was posted out to Northern Ireland dairy farmers. Pearson correlations were used to assess the relationship between personality and attitudes and partial correlations were calculated between milk yield and these psychometric measures. The personality traits of agreeableness and conscientiousness were most strongly correlated to positive attitudes towards working with dairy cows. None of the stockpeople's personality traits were significantly correlated with the milk yield they obtained. Three of the attitude scales, however, were significantly correlated with milk yield; milk yield was related to higher levels of empathy and job satisfaction and lower levels of negative beliefs, These findings, along with previous research, suggest stockperson attitudes may be important in relation to dairy cow welfare and production.

Influence of post-calving regrouping strategy on welfare and performance parameters in dairy heifers

Thirty-six Holstein Friesian heifers (dairy herd replacements) were assigned to one of three regrouping treatments during the post-calving period. In Treatment 1, heifers were introduced individually to an established group of cows and heifers within 24 h of calving ('Single-day 1'). In Treatment 2, heifers were housed individually in a straw pen for I week after calving before being added individually to the group ('Single-day 7'). In Treatment 3, two heifers were housed together in a straw pen for 1 week after calving before being added as a pair to the group ('Pair-day T). The size of the resident group remained constant at 16 animals (10 mature cows and 6 first-lactation heifers). The behaviour of the heifers was assessed during their first 8 h and first month in the resident group, and milk yield parameters, body condition loss and live weight loss were assessed during the first month post-calving. Reproductive performance was assessed during the post-calving period, and hoof health parameters were measured I month prior to calving, and at I and 3 months post-calving. Heifers in the 'Pair-day 7' treatment appeared to associate closely during their first month in the group by spending more time than expected in the same pen area and in adjacent cubicles (P

Effects of breed and production system on lameness parameters in dairy cattle

The aim of the present study was to assess the effects of Holstein-Friesian (HF) and Norwegian (N) dairy cattle genotypes on lameness parameters in dairy cattle within different production systems over the first 2 lactations. Following calving, HF (n = 39) and N (n = 45) heifers were allocated to 1 of 3 systems of production (high level of concentrate, low level of concentrate, and grass-based). High-and low-concentrate animals were continuously housed indoors on a rotational system so that they spent similar amounts of time on slatted and solid concrete floors. Animals on the grass treatment grazed from spring to autumn in both years of the study, so that most animals on this treatment grazed from around peak to late lactation. Claw health was recorded in both hind claws of each animal at 4 observation periods during each lactation as follows: 1) -8 to 70 d postcalving, 2) 71 to 150 d postcalving, 3) 151 to 225 d postcalving, and 4) 226 to 364 d postcalving. Sole lesions, heel erosion, axial wall deviation, sole length of the right lateral hind claw (claw length), right heel width, and right lateral hind heel height were recorded as well as the presence of digital dermatitis. The N cows had lower (better) white line and total lesion scores than HF cows. Cows on the high-and low-concentrate treatments had better sole and total lesion scores than cows on the grass treatment. The HF cows had better locomotion scores than N cows. Breed and production system differences were observed with respect to claw conformation, including claw length, heel width, and heel height. Digital dermatitis was associated with worse sole lesion scores and interacted with production system to influence white line lesion scores and maximum heel erosion scores. This study shows that genetic, environmental, and infectious factors are associated with hoof pathologies in dairy cows.