Use of a staphylococcal vaccine to reduce prevalence of mastitis and lower somatic cell counts in a registered Saanen dairy goat herd

This investigation evaluated the efficacy of a bacterin in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a dairy goat herd. Does were vaccinated or left as controls, and the levels of mastitis and SCC monitored over 18 months. Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI). The infection rate was 1.64 IMI/doe among vaccinates, which tended to be lower (P < 0.12) than controls (2.67 IMI/doe). The spontaneous cure rate of IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than controls (0.6 cures/doe; P < 0.043). Average SCC of milk samples from vaccinates tended to be lower than that of controls (1274 × 10³/ml vs. 1529 × 10³/ml, respectively) (P < 0.10). Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.     

Copper toxicity in a New Zealand dairy herd

Chronic copper toxicity was diagnosed in a Jersey herd in the Waikato region of New Zealand following an investigation into the deaths of six cattle from a herd of 250 dry cows. Clinical signs and post-mortem examination results were consistent with a hepatopathy, and high concentrations of copper in liver and blood samples of clinically affected animals confirmed copper toxicity. Liver copper concentrations and serum gamma-glutamyl transferase activities were both raised in a group of healthy animals sampled at random from the affected herd, indicating an ongoing risk to the remaining cattle; these animals all had serum copper concentrations within normal limits. Serum samples and liver biopsies were also collected and assayed for copper from animals within two other dairy herds on the same farm; combined results from all three herds showed poor correlation between serum and liver copper concentrations.To reduce liver copper concentrations the affected herd was drenched with 0.5 g ammonium molybdate and 1 g sodium sulphate per cow for five days, and the herd was given no supplementary feed or mineral supplements. Liver biopsies were repeated 44 days after the initial biopsies (approximately 1 month after the end of the drenching program); these showed a significant 37.3% decrease in liver copper concentrations (P <0.02). Also there were no further deaths after the start of the drenching program. Since there was no control group it is impossible to quantify the effect of the drenching program in this case, and dietary changes were also made that would have depleted liver copper stores.Historical analysis of the diet was difficult due to poor record keeping, but multiple sources of copper contributed to a long term copper over supplementation of the herd; the biggest source of copper was a mineral supplement. The farmer perceived this herd to have problems with copper deficiency prior to the diagnosis of copper toxicity, so this case demonstrates the importance of monitoring herd copper status regularly. Also the poor correlation between liver and serum copper concentrations in the three herds sampled demonstrates the importance of using liver copper concentration to assess herd copper status.     

Effect of photoperiod on milk yield and quality, and reproduction in dairy goats

The objective of this study was to examine the effect of long day photoperiod (LDPP) on milk production and reproduction in milk goats. A total of 79 goats were randomly assigned to three treatment groups blocked by day of kidding. Group 1 (Gr1, n = 26) was subjected to natural photoperiod from January 6 to December 5. Group 2 (Gr2, n = 24) was subjected to LDPP (20 h light, 4 h dark) from June 22 to December 5. Group 3 (Gr3, n = 29) was subjected to LDPP from January 6 to December 6. Weekly milk weights and samples were collected for fat, protein and somatic cell count (SCC) determinations. Blood serum was harvested for progesterone (P4) determination. Results indicated a significant effect (p < 0.001) between treatments for body weight changes, feed intake and milk yield. Both light treated groups had a significantly higher (p < 0.001) average daily milk output for the entire lactation period than the control group (G1, 2.193 kg/day; G2, 2.517 kg/day; G3, 2.305 kg/day). Milk fat for the overall lactation was significantly higher in Gr3 (+ 0.19 g/100 ml) than for Gr2 (+ 0.06 g/100 ml) when compared to the control group (x g/100 ml) under natural photoperiod. Somatic cell counts throughout lactation were significantly (p < 0.001) lower for Gr2 (1.70 million/ml) and higher for Gr3 (2.03 million/ml), with the control group (Gr1) having an intermediate level (1.96 million/ml). Progesterone levels between June 9 and August 30 indicated that 27%, 48% and 63% of the animals had P4 levels in excess of 1.0 ng/ml serum for Gr1, Gr2 and Gr3, respectively. Pregnancy diagnosis by ultrasound in December revealed that a high number of does in the light treated groups (10 of 37) were pseudo-pregnant when compared with the control group (1 of 21). Although light appeared to be effective in increasing milk production, further investigations are needed to evaluate the effect of LDPP on pseudo-pregnancy in dairy goats.     

A survey of Salmonella spp and Campylobacter spp in dairy goat faeces and bulk tank milk in the Murcia region of Spain

This study was designed to investigate the occurrence of Salmonella spp and Campylobacter spp in faeces samples from 222 healthy Murciano-Granadina dairy goats reared on 12 farms in Spain and in samples of bulk tank milk from 11 of those herds. Neither Salmonella spp nor Campylobacter spp were isolated from any of the samples. Our results suggest that, under the management practices applied to this breed in Spain, Murciano-Granadina goats are not likely to be a significant reservoir for these food-borne pathogens.     

Risk factors for intramammary infections and relationship with somatic-cell counts in Italian dairy goats

Routine examination of milk was performed on five herds of lactating goats in northern Italy as part of a milk quality-monitoring program in the year 2000. As part of the study, aseptic samples of foremilk were collected monthly from both half udders during the entire lactation for 305 goats, resulting in a total of 4571 samples. The samples were tested with cytological and bacteriological analyses to evaluate the relationship between mammary infections and somatic-cell count (SCC; Fossomatic (TM) method). Prevalence of intramammary infection (IMI) was 40.2% (n = 1837) of all udder-half samples examined. The most-prevalent mastitis agents were coagulase-negative Staphylococci (CNS), 80% (n = 1474 udder-half samples); within this group, Staphylococcus epidermidis was the most-prevalent species (38%). Other prevalence were Staphylococcus aureus 6% (n = 112 udder-half samples) and environmental pathogens 14% of infected udder-half samples (n = 251) with a diverse mixture of species, none of which had a frequency of >4%. Enterococcus faecalis was the most-frequently isolated among this group. Neither Salmonella spp. nor Listeria monocytogenes were detected. The risk (sample level) of infection differed across herds, parities, and stage of lactation according to results from logistic multiple regression. Infection was more common among goats in third and fourth parities and during the later stages of lactation. Of the 2734 samples from uninfected udder halves, the mean log₂ SCC was 3.9 cell/ml; of the 1837 bacteriological positive samples, the mean log₂ SCC was 5.6 cell/ml. According to results from a linear mixed model, concentrations of somatic cells tended to increase with increasing age and days in milk and with the presence of bacteria. Infection with S. aureus was associated with the highest SCS.     

Analysis of production objectives and breeding practices of dairy goats in Kenya

Production objectives and breeding practices of smallholder households participating in dairy goat breeding projects were analysed in relation to their ability to bring about sustainable genetic improvement in the dairy goat flocks in Kenya. A stratified survey involving 311 goat keepers in 4 project sites was used. This employed both qualitative and quantitative research methods to get a holistic view of dairy goats, and take into account the full array of contributions of dairy goats to the smallholder households. Milk production and sales of breeding stock were high priority functions for the objective to create a financial buffer. The breeding objective traits that farmers perceived as being of primary importance were milk yield, growth rate, body size, fertility and disease tolerance. There were logical trade-offs in the choice of these traits by farmers. Female dairy goats were mainly culled due to old age, poor fertility, small body size and poor health. Farmers did not place a large significance on unsatisfactory milk performance when culling female goats, mainly due to the very small production size and the high demand existing for breeding animals. Factors affecting milk yield and flock size presented satisfied a P < 0.1 significance level. The performance levels of dairy goats were mainly influenced by breeding strategies and the resource availability at the farm level. The optimisation of genotype x environment interactions remains the biggest challenge given the objectives set by the farmer.     

Anthelmintic resistance to two drench families in a dairy goat herd: Suggestions for future control options

Extract

Madam:— In early March 1988 a dairy goat farm in the Wellington area was visited, at the request of the owner, to investigate the possible involvement of nematode parasitism in causing persistent diarrhoea in several of the does.     

Effect of terbufos poisoning on the blood cholinesterase and hematological values in a dairy herd

This report describes the effects of a sublethal dose of terbufos (counter 15G formulation) in a dairy herd. Ingestion of terbufos depressed whole blood cholinesterase activity. No recovery of this enzyme was evident until 30 days after ingestion after which a constant rate (0.65%/day) increase was observed.

There was a good correlation between blood cholinesterase levels and clinical signs. Normal cholinesterase levels were reached at approximately 150 days after exposure. Cholinesterase levels in animals, ill prior to exposure, were slow to recover, while levels of healthy cattle surpassed those of control animals. Anemia was observed in some cows at approximately 30 days after exposure. The degree of anemia paralleled the severity of poisoning. The increase in packed cell volume paralleled the return of blood cholinesterase activity.

     

Temporal associations between low body condition,lameness and milk yield in a UK dairy herd

Previous work has hypothesised that cows in low body condition become lame. We tested this in a prospective longitudinal study. Body condition score (BCS), causes of lameness and milk yield were collected from a 600-cow herd over 44-months. Mixed effect binomial models and a continuous outcome model were used to investigate the associations between lameness, BCS and milk yield. In total, 14,320 risk periods were obtained from 1137 cows. There were 1510 lameness treatments: the most common causes of lameness were sole ulcer (SU) (39%), sole haemorrhage (SH) (13%), digital dermatitis (DD) (10%) and white line disease (WLD) (8%). These varied by year and year quarter. Body condition was scored at 60-day intervals. BCS ranged from 1 to 5 with a mean of 2.5, scores were higher in very early lactation but varied widely throughout lactation; approximately 45% of scores were <2.5. The key finding was that BCS < 2.5 was associated with an increased risk of treatment for lameness in the following 0–2 months and >2–4 months for all causes of lameness and also specifically for SU/WLD lameness. BCS < 2.5 was associated with an increased risk of treatment for SH in the following 0–2 months but not >2–4 months. There was no such association with DD. All lameness, SU/WLD, SH and DD were significantly more likely to occur in cows that had been lame previously, but the effect of BCS was present even when all repeat cases of lameness were excluded from the analysis. Milk yield was significantly higher and fell in the month before treatment in cows lame with SU/WLD but it was not significantly higher for cows that were treated for DD compared with non-lame cows. These findings support the hypothesis that low BCS contributes to the development of horn related claw lameness but not infectious claw diseases in dairy cows. One link between low BCS and lameness is a thin digital cushion which has been proposed as a trigger for claw horn disease. Cows with BCS 2 produced more milk than cows with BCS 2.5, however, this was only approximately 100 kg difference in yield over a 305-day lactation. Given the increased risk of lameness in cows with BCS 2, the direct costs of lameness and the small variability in milk yield by BCS, preventing cows from falling to BCS < 2.5 would improve cow welfare and be economically beneficial.     

Monitoring cow comfort and rumen health indices in a cubicle-housed herd with an automatic milking system: a repeated measures approach

Background

Cow rumination and lying behaviour are potentially useful and interrelated indicators of cow health and welfare but there is conflicting evidence about how reliable these measures are. The objective of this study was to quantify the variation of indices of cow comfort and rumen health in a herd with an automatic milking system for which husbandry was relatively constant, in order to propose an alternative approach to optimising the use of these indices when continuous monitoring is not available. During a period of 28 days, standing index, cud chewing index and rumination index were observed.

Results

The daily mean standing index ranged between 9.0 and 18.0 per cent, cud chewing index between 43.5 and 74.0 per cent, and rumination index between 49.0 and 81.0 per cent. The point of lowest variation in the indices was determined as that with the lowest coefficient of variation. The coefficient of variation was lowest for data collected between 240 and 270 minutes after refreshing of the bedding material on the cubicles for both the standing index and rumination index, and for data collected between 120 and 150 minutes after refreshing of the bedding material on the cubicles for the cud chewing index.

Conclusions

In spite of relative constant husbandry practices in a herd with an automatic milking system, the variation in the standing index, cud chewing index and rumination index was still considerable. This suggests these measures should be repeated on several consecutive days, according to population size and wanted margin of error, to be representative and useful.     

Description of a Coxiella burnetii abortion outbreak in a dairy goat herd, and associated serology, PCR and genotyping results

Using PCR on aborted foetal material, Coxiella burnetii infection was confirmed as the cause of abortions in a dairy goat herd with over 1000 adults. Ninety-five (22%) abortions and 355 normal births were recorded from 440 goats over 2months. The herd was sampled three times in 6months to look at the within-herd seroprevalence, with the 1st visit done 24days after the last recorded abortion. The true seroprevalence in the herd was 79.2%, 66.5% and 45.7% on each of these visits, but introduction of a group of young goats prior to the 3d visit influenced these results. Using PCR, widespread environmental contamination was demonstrated in surface dust, bedding, muck heaps, milk, bird droppings and drinking water in the goat shed. MST and MLVA analysis showed the C. burnetii from this outbreak to be of a genotype previously observed in the UK and different from those recorded in the Netherlands outbreak of 2007-2011.     

Peripheral white blood cell counts throughout pregnancy in non-aborting Neospora caninum-seronegative and seropositive high-producing dairy cows in a Holstein Friesian herd

Pregnancy is characterized by transient changes in the maternal immune system, also evident at peripheral level. The present study analyzes the kinetics and possible factors affecting peripheral white blood cell populations throughout pregnancy in a herd of high-producing dairy cows chronically infected or not with Neospora caninum. We examined 54 pregnant parous cows: 29 Neospora-seronegative and 25 Neospora-seropositive cows. Blood samples were collected on Days 90, 120, 150, 180 and 210 of gestation. General Linear Model (GLM) repeated measures analysis of variance showed that the interaction Neospora-seropositivity × parity significantly affected total leukocyte, neutrophil and monocyte counts with lower levels of total leukocytes, lower neutrophil and higher monocyte counts recorded in primiparous Neospora-seropositive cows. In addition, N. caninum-seropositive cows had significantly increased monocyte counts on Day 180 of gestation compared to seronegative ones. Other factors significantly associated with changes in total and/or differential leukocyte profiles were period of pregnancy, season, twin pregnancy and milk production. In conclusion, a parity-associated effect of chronic N. caninum infection was observed on peripheral blood cell profiles in dairy cattle during gestation.     

Investigating the value dairy farmers place on a reduction of lameness in their herds using a willingness to pay approach

A survey was conducted to elicit dairy farmers’ willingness to pay (WTP) to reduce the prevalence of lameness in their herds. A choice experiment questionnaire was administered using face-to-face interviews of 163 farmers in England and Wales. Whole herd lameness assessments by trained researchers recorded a mean lameness prevalence of nearly 24% which was substantially higher than that estimated by farmers. Farmers’ responses to a series of attitudinal questions showed that they strongly agreed that cows can suffer a lot of pain from lameness and believed that they could reduce lameness in their herds.Farmers’ mean WTP to avoid lameness amounted to UK£411 per lame cow but with considerable variation across the sample. Median WTP of UK£249 per lame cow was considered a better measure of central tendency for the sample. In addition, the survey found that farmers had a substantial WTP to avoid the inconvenience associated with lameness control (a median value of UK£97 per lame cow) but that they were generally prepared to incur greater inconvenience if it reduced lameness. The study findings suggest that farmers need a better understanding of the scale and costs of lameness in their herds and the benefits of control. To encourage action, farmers need to be convinced that lameness control measures perceived as inconvenient will be cost effective.     

Abnormally terminated pregnancies in a Tanzanian dairy herd: consequences and clinical management

Of 314 calvings, there were 67 (21.4%) abnormally terminated pregnancies (ATP), 37 of which were abortions, 19 stillbirths and 11 premature calvings. Forty-nine cows with ATP were matched to normally calving herd mates and their milk production data and fertility indices were compared. The ATP were associated with complete failure of lactation in 21 (42%) cases and with short lactation lengths of less than 200 days in nine (18.3%) cases. Lactation in the remaining 19 (38.7%) cows was characterized by a low lactation yield of 2318 ± 211 kg and lactation length 296 ± 13 days. Corresponding parameters for the control herd mates were 3250 ± 190 kg and 314 ± 12 days, respectively. The number of days to first service services per conception and calving interval cows with ATP were 139 ± 17 days, 2.29 ± 0.15 and 465 ± 23,days, respectively. Corresponding fertility indices in the control group were 107 ± 9 days, 1.83 |+- 4.18 and 407 ± 12 days, respectively. Also 11 of 49 (22.3%) cows, with ATP were culled because of infertility witcompared with only five (10.2%) in the controls.

Twenty-six other cows with ATP were randomly difided into two groups. In Group 1, 14 cows were treated with 100 ml of 6% colloidal iodine (Merckojod®, Bayer, Leverkusen, Germany), 40–50 days after calving followed by a prostaglandin F₂ analogue (Estrumate®, ICI, Cheshire, UK) 20 days later. In Group 2, 12 cows were left untreated and served as a control. Treatment reduced the interval to First service by 63 days and the calving interval by 79 days and it increased services per conception by 0.38. No culling was recorded from this group. ATP not only denied a calf to the farm but also reduced milk production. Intrauterine administration of colloidal iodine coupled with PGF₂ could bring ATP animals to near normal fertility.     

Relationship between herd size and annual prevalence of and primary antimicrobial treatments for common diseases on dairy operations in the United States

Dairy operations in states representing 86% of the United States’ national dairy herd were surveyed regarding the occurrence of common dairy diseases or disorders (digestive, respiratory, gastrointestinal, lameness, mastitis, navel infection) in specified production groups (weaned heifers, unweaned heifers, adult cows), and the most common antimicrobial preparation used to treat these conditions. Within disease and production group, disease frequency and characteristics of primary antimicrobial (drug class, availability, spectrum of activity, extra-label usage, withdrawal times) were compared among herd sizes (30–99, 100–499, and ≥500 cows) using chi-square or t-tests that accounted for the sampling design. The most common diseases were mastitis and lameness in cows, and gastrointestinal disease in unweaned calves, affecting 16, 11, and 15% of the target populations, respectively. Herd-level disease prevalence tended to increase as herd size increased, whereas within-herd prevalence tended to decrease as herd size increased. Broad-spectrum antimicrobials were selected as primary treatments by a majority of operations for nearly all diseases surveyed. When treating gastrointestinal disease, navel infection, or reproductive disorders, a majority of operations selected primary treatments not specifically labeled for that condition. Selection of over-the-counter preparations tended to decrease as herd size increased, whereas selection of broad-spectrum preparations tended to increase with herd size.     

The detection and measurement of stray electrical leakages on dairy farms: effects on performance

Sources of stray electrical leakage from Power Supply Authority alternating current (AC), fence energiser pulses and randomly generated pulses and spikes on 55 dairy farms in the Waikato area were identified between December 1986 and March 1988.

The electrical measurements were made using a specifically designed voltmeter able to detect voltages between 0.1V and 1500V, from single voltage spikes of two microseconds oi- greater duration from direct current (DC) as well as 50 Hz AC. Ninety-five sources of stray voltage were identified, and 53 per cent of properties had more than one source of >0.5V. The major source was from electric fence energisers. Rotary platform parlours were among the commonest sources of random or transient voltage spikes. Leakage of AC into one or other of the components of the milk transport system such as vat, plate cooler, milk lift pump and milk line was common.

Owners acknowledged the improvements in milk production, reproductive performance and growth rate of calves after reduction of the exposure of dairy cattle to stray electrical leakage. A representative summary of five case records helps define the range of improvement that may possibly be achieved.     

Mycoplasma bovis infections in Swiss dairy cattle: a clinical investigation

Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.     

Comparative potential therapeutic effect of sesame oil and peanut oil against acute monocrotaline (Crotalaria) poisoning in a rat model

Background

Many Crotalaria plant species contain hepatotoxic pyrrolizidine alkaloids (such as monocrotaline) that can cause acute and chronic poisoning in cattle and other animals.

Hypothesis

Peanut oil, atropine sulfate, and antidiarrheal agents are used to treat acute monocrotaline poisoning. The effect of sesame on acute monocrotaline poisoning has never been investigated.

Animals

Fifty male Sprague‐Dawley rats were used for toxicity studies.

Methods

Experiment 1: Group I, control. Groups II–IV were given monocrotaline (205.2 mg/kg) and euthanized 6, 12, and 24 hours later. Experiment 2: Group I, control. Group II monocrotaline alone (205.2 mg/kg). Groups III–VI were given monocrotaline (205.2 mg/kg) and 1 hour later, Groups III and IV were given sesame oil (1 and 2 mL/kg) and Groups V and VI were given peanut oil (1 and 2 mL/kg).

Results

Monocrotaline significantly decreased (P < .05) serum amylase activity, but, over time, increased (P < .05) pancreatic and lung injury. AST and ALT activity and liver injury peaked at 24 hours. Sesame oil and peanut oil (P < .05) inhibited the changes in all tested parameters in acute monocrotaline poisoning. Although peanut oil inhibited acute monocrotaline poisoning, it induced steatosis, but sesame oil did not.

Conclusion and Clinical Importance

We hypothesize that early pancreatic and lung injury and late liver injury contribute to acute monocrotaline poisoning and that sesame oil is more efficacious than peanut oil against acute monocrotaline poisoning in rats. However, additional studies are needed to confirm that these oils have the same effects in cattle and other animals.     

Detection and characterization ofSalmonella typhimurium from a dairy herd in North Dakota

Nasal secretions, faecal samples and buffy coats were obtained from 102 cattle from a North Dakota dairy herd with a history of calf scours. Treated buffy coats, faecal samples and nasal secretions were inoculated into tetrathionate broth (TB), incubated at 37°C overnight, and plated onto brilliant green agar medium with novobiocin (BGAN). The TB was left at room temperature for 5 days and then used to inoculate fresh TB. The fresh TB was incubated at 37°C over night and plated onto BGAN medium. All the plates were incubated at 37°C over night and observed forSalmonella-like growth. Suspect colonies were further tested andSalmonella isolates were serotyped by the National Veterinary Services laboratory. Twenty-two of the 36 calves sampled harbouredS. typhimurium in their faeces, but no samples from cows were positive. NoSalmonella were isolated from the buffy coats, but 4 calves were shown to haveSalmonella in their nasal secretions. Extended enrichment of the faecal cultures in TB resulted in a significant increase inSalmonella isolations, although 2 samples were positive following the initial enrichment period and not after secondary enrichment. The typicalSalmonella isolate detected from this herd contained a transmissible R-plasmid encoding resistance to tetracycline, kanamycin, sulphisoxazole and ampicillin. This study confirmed that delayed secondary enrichment in TB is superior to primary enrichment for detection ofSalmonella from cattle.Abbreviations Ap ampicillin - BGAN brilliant green agar with novobiocin - Cm chloramphenicol - DSE delayed secondary enrichment - Gn gentamicin - Kn kanamycin - NA nalidixic acid - NADC National Animal Disease Center in Ames, Iowa - NVSL National Veterinary Services Laboratory in Ames, Iowa - PB polymyxin B - PE primary enrichment - Sm streptomycin - Su sulphisoxazole - TB tetrathionate broth - Tc tetracycline - TSI triple sugar iron agar     

Association between age and time from calving and reported lameness in a dairy herd in the Waikato region of New Zealand

Abstract

CASE HISTORY: During the 2014/2015 season 823 predominantly Holstein-Friesian cows calved on a pasture-based farm in the Waikato region of New Zealand. A high prevalence and recurrence rate of lameness had been noted for several years but cows feet were not routinely picked up and therapeutically trimmed.

CLINICAL FINDINGS: At a farm visit in December 2015, 23 cows feet were examined and 18/23 (78%) cows had white line disease and 17/23 (74%) sole haemorrhages, as well as severely overgrown and misshapen hooves.

EPIDEMIOLOGICAL INVESTIGATION: Lameness, culling and reproductive data were collected for the farm for the period from 01 July 2014 to 30 November 2015. In the 2014/2015 season, 207/823 (25.2%) cows were recorded lame, and in the first half of the 2015/16 season 120/850 (14%) cows were recorded lame. Of the cows recorded lame, 52/207 (25.1%) in the 2014/15 season had >1 case of lameness, and 39/120 (32.5%) cows recorded lame in the 2015/2016 season had been lame in the previous season. There was an apparent increase in prevalence between 29–37 weeks post-calving. Cows >7-years-old had seven times the odds of being recorded as lame compared to 2–3-year-old cows (p<0.001). Lameness was not associated with culling, empty rate or days to conception (p>0.3).

DIAGNOSIS: No direct cause for the lameness could be determined.

CONCLUSIONS AND CLINICAL RELEVANCE: It was hypothesised that, along with the degenerative changes in the pedal bone as dairy cows increased in age, suboptimal treatment and overgrowth of hooves resulted in permanent changes in the cows feet, resulting in a high prevalence of lameness in older cattle and a high recurrence rate of lameness within and between seasons. This case highlights the importance of prompt identification and treatment of lame cattle.