Comparison of environment quality measurements between 3 types of calf housing in the United Kingdom.

Preweaning calves are kept in a range of housing types that offer variable protection against the weather and provide differing internal environments. This cross-sectional observational study assessed the effect of housing type (shed, polytunnel, or hutches) on internal environmental parameters, using 2 blocks of 8-wk measurements from 10 commercial dairy farms in the south of England, covering both summer and winter periods. Continuous measurements for internal and external temperature and humidity were recorded by data logger placed within the calf housing and used to calculate the temperature-humidity index (THI). Weekly point readings were also taken for temperature, humidity, light, air speed, ammonia level, and airborne particulate matter. Airborne bacterial levels were determined at wk 2, 5, and 8 by incubating air samples at 35°C for 24 h in aerobic conditions. Data were analyzed using linear mixed models. Housing type influenced THI significantly in both seasons. In summer, calves were exposed to heat stress conditions (THI ≥72) for 39, 31, and 14 of 46 d in polytunnel housing, hutches, and sheds, respectively. The maximum summer temperature (37.0°C) was recorded in both hutch and polytunnel housing, with sheds remaining consistently cooler (maximum 31.0°C). In winter, the lowest minimum internal temperature recorded was in hutches at -4.5°C, with both the sheds and polytunnel, but not hutches, providing a significant increase in temperature compared with the external environment. Hutches remained ≤ 10°C for 86% of the winter study period. Light levels were reduced in all housing types compared with the external environment. The particulate matter in air that is capable of reaching the lungs (particulate matter <10 µm) was highest in sheds, intermediate in hutches, and lowest in polytunnel housing (0.97 ± 3.75, 0.37 ± 0.44, and 0.20 ± 0.24 mg/m3, respectively). This was mirrored by airborne bacterial numbers, which were also highest in sheds (8,017 ± 2,141 cfu/m3), intermediate in hutches (6,870 ± 2,084 cfu/m3), and lowest in the polytunnel (3,357 ± 2,572 cfu/m3). Round, white, catalase-positive, and oxidase-negative colonies were most prevalent, likely indicating Staphylococcus species. This study demonstrated that UK calves are routinely exposed to either heat or cold stress, especially when housed in hutches or polytunnels. Sheds had the highest levels of particulate matter and airborne bacteria, both known contributory factors for respiratory disease. These findings demonstrate that all calf housing systems result in environmental compromises that could have long-term impacts on calf health and growth; therefore, further studies should identify husbandry and housing modifications to mitigate these factors.

Comparison of bulk milk antibody and youngstock serology screens for determining herd status for Bovine Viral Diarrhoea Virus.

BACKGROUND: This paper examines the use of Bulk Milk antibody (BM Ab), Youngstock (YS) serology (Check Tests) and Bulk Milk PCR (BM PCR) for determining the presence or absence of animals persistently infected (PI) with Bovine Viral Diarrhoea Virus (BVDV) within a herd. Data is presented from 26 herds where average herd sizes were 343 and 98 animals for dairy and beef units respectively. Seventeen herds had sufficient data to analyse using Receiver Operating Characteristic (ROC) and probability curves enabling calculation of the sensitivity and specificity of BM Ab and YS Check tests for determining the presence of PI animals within herds in this dataset. RESULTS: Using BM Ab to screen a herd for the presence of PI animals, achieved a herd level sensitivity and specificity of 80.00 % (44.39-97.48 %) and 85.71 % (42.13-99.64 %) respectively (95 % confidence intervals quoted). Sensitivity and specificity of YS Check Tests at a cut off of 3/10 Ab positive YS were 81.82 % (48.22-97.72 %) and 66.67 % (22.28-95.67 %) respectively (95 % confidence interval). These results were achieved by comparing the screening tests to whole herd PI searches that took place 1-19 months after the initial screen with a mean interval of 8 months. Removal of this delay by taking BM samples on the day of a whole herd test and simulating a YS Check Test from the herd test data produced improvements in the reliability of the Check Tests. BM Ab sensitivity and specificity remained unchanged. However, the Check Test sensitivity and specificity improved to 90.9 % (58.72-99.77 %) and 100 % (54.07-100 %) respectively (95 % confidence interval) at a cut of off 2.5/10 Ab positive animals. Our limited BM PCR results identified 5/23 dairy farms with a positive BM PCR result; two contained milking PIs, two had non-milking PIs and another had no PIs identified. CONCLUSIONS: Delaying a PI search following an initial herd screen decreased the diagnostic accuracy and relevance of our results. With careful interpretation, longitudinal surveillance using a combination of the techniques discussed can successfully determine farm status and therefore allow changes in BVDV status to be detected early, thus enabling prompt action in the event of a BVDV incursion.

A phylogenetic analysis of Bovine Viral Diarrhoea Virus (BVDV) isolates from six different regions of the UK and links to animal movement data.

Bovine Viral Diarrhoea Virus (BVDV) is a pestivirus which infects cattle populations worldwide and is recognised as a significant source of economic loss through its impact on health and productivity. Studies investigating the molecular epidemiology of BVDV can give invaluable information about the diversity of viral strains present in a population and this, in turn, can inform control programs, drive vaccine development and determine likely infection sources. The current study investigated 104 viral isolates from forty farms across the UK. Through phylogenetic and nucleotide sequence analysis of the 5'UTR and Npro regions of the isolates investigated, it was determined that BVDV 1a was the predominant sub-genotype. However, BVDV 1b, 1e and 1i were also identified and, for the first time in the UK, BVDV 1d. Through analysis of animal movement data alongside the phylogenetic analysis of these BVD isolates, it was possible to link animal movements to the viral isolates present on several premises and, for the first time, begin to elucidate the routes of viral transmission. With further work, this type of analysis would enable accurate determination and quantification of the true biosecurity risk factors associated with BVDV transmission.

Effects of the Individual and Pair Housing of Calves on Long-Term Heifer Production on a UK Commercial Dairy Farm.

Pair housing of pre-weaning dairy calves has previously demonstrated positive impacts on their growth, health and behaviour, but longer-term effects on production are still relatively unknown. This study followed a cohort of 431 Holstein heifers, recruited from a single UK commercial dairy farm, from weaning until either culling or the end of their first lactation. All animals were allocated to either individual or pair housing as a pre-weaning calf. Following weaning, all heifers were similarly managed through group housing, feeding with total mixed rations, the use of automatic heat detection for artificial insemination and weighing every two months until conception. Farm staff identified disease occurrences, which were treated following standard operating procedures. First-lactation monthly milk recording was used to measure milk yields and somatic cell counts. Overall mortality (voluntary and involuntary) was 26.6%, with a decreased hazard of exiting the herd if the heifer was pair housed as a calf (HR 0.70; p = 0.067). The voluntary cull rate was highest in the post-insemination period (13.0%) due to poor fertility. Heifers that were pair housed as calves had significantly increased odds of developing udder health issues as a primiparous cow (OR = 1.93, p = 0.022). Despite this, the 305-day milk yields were not associated with the housing group. However, the total milk produced per calf recruited into the original study was greater for pair-housed compared with individually housed calves (8088 kg vs. 7115 kg; p = 0.071), which is likely due to the significantly higher hazard of individually housed calves exiting the herd prematurely.

Effects of Individual and Pair Housing of Calves on Short-Term Health and Behaviour on a UK Commercial Dairy Farm.

Social pair housing of calves has previously demonstrated positive impacts for calves, so this study aimed to compare the health and behaviour of calves kept in individual compared to pair housing on a single commercial UK dairy farm. A total of 457 Holstein and Jersey heifer calves were recruited and systematically allocated to individual and pair housing. Weekly visits were conducted up to 8 weeks of age, with weight and presence of clinical disease measured using both a standardized scoring system and thoracic ultrasonography. A subset of calves (n = 90) had accelerometers attached to monitor activity, with CCTV placed above a further 16 pens to allow behavioural assessments to be made via continuous focal sampling at 1 and 5 weeks of age. During the study, there was a mortality rate of 2.8%, and an average daily liveweight gain (ADLG) of 0.72 kg/day, with no significant effect of housing group (p = 0.76). However, individually housed calves had increased odds of developing disease (OR = 1.88, p = 0.014). Accelerometer data showed that housing group had no effect on lying times, with a mean of 18 h 11 min per day (SD 39 min) spent lying down. The motion index was significantly higher in pair-housed calves (F1,83 = 440.3, p < 0.01), potentially due to more social play behaviour. The total time engaged in non-nutritive oral behaviours (NNOBs) was not impacted by housing group (p = 0.72). Pair-housed calves split their time conducting NNOBs equally between inanimate objects and on their pen mates' body. Individually housed calves spent significantly more time with their head out of the front of the pen (p = 0.006), and also engaged in more self-grooming than pair-housed calves (p = 0.017), possibly due to a lack of socialization. The overall findings of this study indicate that within a UK commercial dairy management system, pair-housed calves were healthier and more active than individually housed calves, while housing group did not influence ADLG or the occurrence of NNOBs.

A Retrospective Case Study into the Effect of Hoof Lesions on the Lying Behaviour of Holstein-Friesian in a Loose-Housed System.

The association between hoof lesions and lying behaviour was assessed on a Holstein-Friesian dairy farm in England. Twenty-nine cows were included in the study. Cows with claw horn disruption lesions (CHDL, n = 8), soft tissue lesions (STL, n = 6), and no lesions (NL, n = 15) were assessed. Data were collected on parity, days in milk (DIM), and mobility scores. Cows were trimmed and treated, and lesions were recorded by a professional foot trimmer. Lying behaviour was assessed before and after claw trimming. The milking herd (n = 96) prevalence of lameness was 32.3%. Mobility was scored using the Agriculture and Horticulture Development Board (AHDB) Mobility Scoring system. Mobility scores were significantly different across lesions groups (p = 0.022). CHDL cows had a mean mobility score of 2.0 ± 0.9 (mean ± SD), STL were scored 1.2 ± 1.3, and NL cows were 0.9 ± 0.7. CHDL were associated with longer lying times (15.00 ± 1.04 h/d; p = 0.0006) and shorter standing times (9.68 ± 2.38 h/d; p = 0.0351) compared with NL lying times (11.77 ± 1.67 h/d) and standing times (12.21 ± 1.67 h/d). STL cows spent significantly less time lying (11.30 ± 2.44; p = 0.0013) than CHDL but not NL cows. No significant differences were found with any of the other lying behaviours. After trimming, CHDL cows spent significantly less time lying down than before trimming (13.66 ± 0.98; p = 0.0125). Cows with NL spent significantly more time lying down (12.57 ± 1.90; p = 0.0398) and had a shorter minimum lying bout duration (0.17 ± 0.09; p = 0.0236) after trimming. In conclusion, lying behaviour in dairy cattle was impacted by type of hoof lesions and hoof trimming.

The Health and Behavioural Effects of Individual versus Pair Housing of Calves at Different Ages on a UK Commercial Dairy Farm.

Housing management of dairy calves is one of the factors that contributes to a successful rearing outcome. Individual housing of pre-weaned calves is thought to provide enhanced biosecurity and easier monitoring of the individual, and so remains prevalent in the UK. Behavioural studies have, however, found that pair housing is important for social learning, with positive impacts on health and welfare. This study utilised a single UK commercial dairy farm to establish if individual housing, pair housing from birth, or pair housing from three weeks of age affected health and behavioural parameters. Calves were housed in these allocated groups from birth to eight weeks of age, when they were moved into group pens of five calves for weaning at 10 weeks of age. All management routines other than the housing group were the same for enrolled calves. One hundred Holstein calves were recruited over a six-month period, and systematically allocated to a housing group. Weekly visits were conducted up to 10 weeks of age (weaning) for each calf, with weight, solid feed intake, and presence of clinical disease measured. In addition, a novel object approach test was carried out at six weeks, and a thoracic ultrasound was performed at seven weeks. Housing group had no effect on the average daily liveweight gain (ADLG) (p = 0.74), with an average of 0.66 kg/day over the pre-weaning period. However, on group housing at 8-10 weeks of age, there was a numerical increase in ADLG in the pair housed calves compared to the individually housed calves over the weaning period. Housing group had no significant effect on disease prevalence (p = 0.98) or the time taken to approach the novel object (p = 0.29). However, pair housed calves had increased mean total solid feed intakes from weeks 2-8 (p = 0.011), with 6.2 ± 0.67 kg (standard error of the mean-SEM), 12.7 ± 0.73 kg and 13.6 ± 0.70 kg ingested by individually housed, pair housed from birth and pair housed from three weeks of age, respectively. The overall findings of this study indicate that within a UK commercial dairy management system, there is no detrimental effect of housing calves within pairs (either from birth or three weeks of age) compared to individual housing.