A field investigation of causes of abortion in dairy cattle

Cases of abortion on dairy farms on the Lancashire/Cumbria border were investigated by means of a systematic diagnostic procedure, using the facilities of a veterinary practice's laboratory, and the Ministry of Agriculture, Fisheries and Food veterinary investigation centre. Among approximately 3600 animals, 149 abortions were investigated on 54 farms in two years, an annual abortion rate of 2 per cent. A diagnosis was made in 34 per cent of the cases, based on a pathological examination of aborted material and bacteriological and serological findings. The most common pathogens associated with abortion were bovine viral diarrhoea virus (39 cases), bacterial or fungal infections (20 cases), infectious bovine rhinotracheitis virus (19 cases), and Leptospira hardjo (18 cases), either as single or multiple infections.     

A systematic compilation and classification of the literature on lameness in cattle

This paper presents the first systematic review of the literature on lameness in cattle. It identifies, tabulates and classifies relevant published work and was conducted using electronic reference databases (BIDS ISI, BIOSIS, MEDLINE and the CAB Abstracts CD-ROM). A total of 1373 unique references were obtained from 1981 to 2000, of which 914 were written in the English language. A written search protocol was designed to ensure transparency and repeatability. Pilot studies were undertaken to create search terms that minimised bias and ensured relevance. Electronic files of the search terms allow the database to be updated in future. A further 93 references were included from the most recent international conference on lameness giving a total of 1007 English language references. The systematic review process is described, including a method of classifying papers according to their study design and statistical analysis, and it is hoped that other veterinary researchers will conduct similar reviews in their fields. The compiled and classified references are available as a searchable database through the web-sitehttp://cattle-lameness.dhs.org/. The review may be used in several ways; to identify practical interventions to reduce lameness in dairy cows and to use the resultant web-site as the basis of a decision support system for farmers, veterinarians and advisors.     

A field study on estrus detection in lactating beef cattle

Estrus detection efficacy and heat detection protocol were studied by means of a field study carried out on 878 lactating beef cows in 60 French herds. Average herd size was 48, and 75% of the farmers partly or exclusively used artificial insemination. The cows were calved between October 1992 and March 1993. Estrus was recorded daily by the farmers. Cycling status was determined by progesterone radioimmuno-assay 2 months after calving. The relationship between the estrus detection protocol and the delay period from calving to first observed estrus was analysed using survival curves and the Cox proportional hazard model, adjusting for confounders. Seventy-one percent of the cows were seen in estrus by the farmers; the interval between calving and the first observed estrus ranged from 9 days to more than 5 months and the median was 56 days. Two months after calving, 44% of the cycling cows had not been seen in heat by the farmers and 11% of the non-cycling cows had been reported to have been in estrus. The heat detection protocol varied widely between farmers, depending on the considered estrus signs, schedule and time spent looking for signs. Two factors were significantly related to a shorter interval from calving to first observed heat: the use of artificial insemination (which relates to the farmer's interest in heat detection) and an overall daily time spent for heat detection greater than 1 h. Cows in tie stalls had a delayed interval to the first observed estrus. These results show that many farmers did not adapt their reproduction practice sufficiently to an earlier calving period. There is room for improvement since in many cases the heat detection protocol does not match the required standards for optimal heat detection.     

Treatment of proximal hind-limb lameness in cattle

Lameness of the hind limb (tarsus and proximal) in cattle is considered from the viewpoint of diagnosis and prognosis. Indications and techniques for radiography are discussed, as well as when indicated.     

Prevention and control of lameness in dairy cattle

The prevention and control of lameness are essential if a dairy herd is to return a profit. Breeding, feeding, housing, and management practices are all involved, and errors or omissions in any of these areas can result in catastrophic lameness. An accurate diagnosis and proper treatment are necessary to minimize losses when lameness occurs.     

Interval between detection of lameness by locomotion scoring and treatment for lameness: A survival analysis

Estimates of point prevalence suggest that locomotion scoring identifies three times as many lame cows than when estimated by farmers. The aim of this study was to ascertain the impact of this under-recognition on the interval between identification of lameness (using locomotion score) and treatment. The study was undertaken on a 463-cow, spring-calving, pasture-fed herd in the lower North Island of New Zealand. All cows were locomotion scored (using a 1-5 scale) weekly during one milking season (July 2008 to May 2009). Survival analyses were then used to quantify the number of days between identification of a specific locomotion score and presentation, by farm staff, of a cow for lameness treatment. All cows which had a locomotion score of >3 were presented for lameness treatment subsequently, although >40% were treated more than 3weeks after being identified. Only 75% of events where cows had a locomotion score of 3 were followed by treatment with >65% of those treatments occurring >3weeks after the first score of 3. Improving the recognition of lameness by farm staff is thus likely to appreciably reduce the interval between reduced mobility and lameness treatment.     

Diagnostic techniques in the investigation of shoulder lameness

Methods of investigating horses with suspected shoulder lameness are described and discussed. The gait of shoulder lameness is characterised and compared with that of lower forelimb lameness. If lameness is slight, differentiation may be difficult, but if moderate, upper forelimb lameness usually results in shortening of the cranial phase of the stride and a low limb flight. Clinically, it may not be possible to differentiate between shoulder and elbow lameness without intra-articular anaesthesia. Practical aspects of intra-articular anaesthesia of the shoulder joint are reviewed. Synovial fluid must be retrieved to ensure that the needle is intra-articular. Up to 60 mins may elapse after injection of local anaesthetic before significant improvement occurs. Lameness is often improved rather than eliminated. A technique for standing radiography of the shoulder is described and the limitations of assessing a joint only by lateral projections are highlighted. There may be difficulties in positioning weanling foals and yearlings, resulting in superimposition of the shoulder joint, cervical and thoracic vertebra and ribs. It is concluded that a combination of a thorough clinical examination, faradism, local anaesthesia, synovial fluid analysis and radiography usually enables an accurate diagnosis to be reached.     

Evaluation of the DG29 test for early detection of pregnancy in cattle

The objective of this study was to evaluate a commercial blood test (DG29) for pregnancy in cattle. Compared with ultrasound, the sensitivity of the assay for detecting pregnancy around day 30 post-insemination was 99.4% [95% confidence interval (CI): 96.1–100]. The specificity was 100% (95% CI: 84.7–100) in noninseminated cattle, and 66.7%; (95% CI: 49.7–80.4) in inseminated nonpregnant cattle. Positive and negative predictive values were 92.6% and 96.3%, respectively, in a sample of inseminated cattle in which 80% were pregnant.     

Environmental factors associated with lameness in dairy cattle

An epidemiological survey of the incidence of different foot diseases causing lameness was undertaken on 80 French dairy farms between 1979 and 1980. A total of 29.5 cases of lesions per 100 cows was recorded in that period, which represents a higher incidence that of clinical mastitis (20.37).

Data concerning the incidence of foot lesions, farm structures, herd management system, feeding and soil characteristics were analysed using the ξ² test of independence and one-way analysis of variance. Results showed that a high incidence of infectious and metabolic foot disorders was associated with loose housing, feeding based on maize silage, absence of a footbath, foot trimming and mineral supplementation.

A relationship was also observed between articular lesions and grass-silage feeding. Tied-housed cows fed hay were less affected. Regular hoof trimming at pasture and a long time spent checking the animals were found to have a positive effect on foot health. A low incidence of foot disorders was also associated with a larger variety in dietary components. A high incidence of lameness was reported in large herds kept on rough floors.     

Development of an approach to lameness examination in cattle

In the preceding pages, the various components of an examination have been described. Each clinician will formulate his own method of utilizing these components. The following are suggested steps in a practical approach to the diagnosis of lameness. Evaluate the conditions under which restraint of the animal is possible (corral, free stall, stanchion barn). Assess the temperament, physical strength, and general amenability of the animal to be examined. If the animal is at liberty, its movements can be studied. If it is standing quietly observe it. If the animal is tied up and it seems feasible to examine the animal while it is walking, observe the animal and take its history while it is still tied up. Aggressive and wild animals should be observed, but little beneficial information will be gained from a regional approach to evaluating movement at this stage. Even if the seat of lameness seems to be in the proximal limb, it is mandatory in every case to examine the hooves and interdigital space at some stage during the evaluation. However, if the probability of proximal lameness is high, the clinician may proceed to make a complete evaluation, which would include studying the quality of movement before checking that the distal extremity is normal in every way. If the clinician decides to proceed with an examination of the digital region and is unable to locate a causative lesion in the extremity, he would then evaluate movement and manipulate and palpate the proximal limb. If no cause of the lameness becomes apparent, the nerve supply to the extremity would then be blocked.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and subclinical lameness in young fattenin cattle

Time dependent changes of subclinical and clinical lameness were analysed in 493 fattening bulls in three different herds with a total number of 30,621 animals. In the majority of cases subclinical lameness were observed which were caused by metabolic acidosis or deficiencies in mineral intake (P and probably Ca). The activity of alkaline phosphatase in plasma exhibited an increase and the dry matter in bone (tubera coxae) a decrease before the appearance of clinical symptoms. Changes in bone composition were accompanied by alterations of plasma Ca and P concentrations, which finally led to clinical lameness. Hence the diagnosis was verified by simple laboratory methods as the precondition for successful treatment and prophylaxis of lameness caused by metabolic disorders.     

Changes in limb loading with lameness for a number of Friesian cattle

Lameness in cattle is an expensive problem. Gait studies may assist in understanding the factors involved. The gait changes of four lame cows were related to the gaits of non-lame cows. The vertical forces and horizontal fore-and-aft forces during the stance phase of steps were investigated using a force plate. The maximum vertical force (MVF) was often reduced on lame limbs. The horizontal forces showed an initial decelerative force followed by an accelerative force. For sound cows the maximum accelerative force (MAF) and the maximum decelerative force (MDF) were of the same order of magnitude, while those for lame animals were generally modified. Forces applied to the non-lame limbs of lame cows were also changed, probably to reduce further the loads exerted upon the lame foot.     

Effect of wet weather on lameness in dairy cattle

The incidence of lameness in cows recorded by five veterinary practices over one year and one practice over four years was plotted with rainfall and potential soil moisture deficit. Correlation coefficients calculated between lameness, rainfall and potential soil moisture deficit over two-week periods showed the incidence of lameness in summer to be significantly related to the potential soil moisture deficit in the same two-week period and rainfall in the previous two-week period. Differences in patterns of lameness incidence among practices and years were also partly explained by differences in rainfall and potential soil moisture deficit; however, these effects were small compared with those of other factors that affect lameness incidence such as herd size, age and stage of lactation.     

Bone scintigraphy in the investigation of occult lameness in the dog

99mTechnetium methylene diphosphonate (99mTc-MDP) scintigraphy was performed in 14 dogs of different breeds after clinical lameness examination, radiography and synovial fluid analysis failed to localise lameness to a specific area of pain. The scintigraphic protocol included an intravenous injection of 17 MBq 99mTc-MDP/kg bodyweight and vascular, soft tissue and bone phase scans in standardised positions with a low-energy all-purpose collimator. Confirmation of diagnosis was achieved in nine dogs by arthroscopy, repeated lesion-orientated radiography, computed tomography and response to treatment. In seven cases, bone phase scans showed single elbow uptakes, in two cases unilateral limb uptake, and in one case each a single shoulder and tibia uptake; in three cases there was no increased uptake. Vascular and soft tissue phase images did not reveal additional information. Diagnosis of humeral condyle fissures, a fragmented medial coronoid process, panosteitis and arthropathy was possible in nine cases. Skeletal pathology was ruled out in three normal scintigrams. In two dogs with unilateral uptake of multiple joints, no diagnostic benefit was gained from scintigraphy. The highly sensitive and relatively specific uptake allowed localisation and characterisation or exclusion of skeletal lesions in most dogs.     

A sandwich enzyme immunoassay for bovine interferon-γ and its use for the detection of tuberculosis in cattle

An in vitro cellular assay for bovine tuberculosis has recently been developed. This assay detects gamma-interferon released in response to specific antigen in a whole blood culture system. The bio-assay previously described for the detection of bovine gamma-interferon (IFN-gamma) has now been replaced with a sandwich enzyme immunoassay (EIA) which utilises two monoclonal antibodies to bovine IFN-gamma. The EIA detects less than 25pg/ml of recombinant bovine IFN-gamma and is specific for biologically active bovine IFN-gamma; and does not detect bovine alpha or beta interferon. IFN-gamma from sheep, goat and buffalo, but not from pig, deer or man, are also recognised by the EIA. The bovine IFN-gamma EIA when used in conjunction with the whole blood culture system has resulted in a simple, rapid and sensitive in vitro assay for specific cell mediated immune responsiveness to M. bovis infection in cattle.     

Nutritional factors of lameness and metabolic bone disease in cattle

Lameness in cattle has numerous causes, and many factors interact to interfere with normal locomotion. The nutrients that have been implicated are protein, energy, calcium, phosphorus, copper, manganese, selenium, zinc, and vitamins A, D, and E. The fact that several nutrients may be involved with the problem should not be overlooked. There may also be factors in the diet that interact with the nutrient (particularly with trace minerals) that must be considered. When congenital skeletal deformities are being investigated, the veterinarian should not overlook the nutrition of the dam during pregnancy. When recommending dietary changes, a veterinarian should be careful that new imbalances have not been created and that the producer is not adding nutrients to the diet other than those suggested.