N.B. Cook

Time budgets of lactating dairy cattle in commercial freestall herds

The aim of this study was to examine the time budgets of 205 lactating dairy cows housed in 16 freestall barns in Wisconsin and to determine the relationships between components of the time budget and herd- and cow-level fixed effects using mixed models. Using continuous video surveillance, time lying in the stall, time standing in the stall, time standing in the alleys (including drinking), time feeding, and time milking (time out of the pen for milking and transit) during a 24-h period were measured for each cow. In addition, the number of lying bouts and the mean duration of each lying bout per 24-h period were determined. Time milking varied between cows from 0.5 to 6.0 h/d, with a mean ± standard deviation of 2.7 ± 1.1h/d. Time milking was influenced significantly by pen stocking density, and time milking negatively affected time feeding, time lying, and time in the alley, but not time standing in the stall. Locomotion score, either directly or through an interaction with stall base type (a rubber crumb-filled mattress, MAT, or sand bedding, SAND), influenced pen activity. Lame cows spent less time feeding, less time in the alleys, and more time standing in the stalls in MAT herds, but not in SAND herds. The effect of lameness on lying time is complex and dependent on the time available for rest and differences in resting behavior observed between cows in MAT and SAND herds. In MAT herds, rest was characterized by a larger number of lying bouts of shorter duration than in SAND herds (mean = 14.4; confidence interval, CI: 12.4 to 16.5 vs. mean = 10.2; CI: 8.2 to 12.2 bouts per d, and mean = 1.0; CI: 0.9 to 1.1 vs. mean = 1.3, CI: 1.2 to 1.4h bout duration for MAT and SAND herds, respectively). Lameness was associated with an increase in time standing in the stall and a reduction in the mean (CI) number of lying bouts per day from 13.2 (CI: 12.3 to 14.1) bouts/d for nonlame cows to 10.9 (CI: 9.30 to 12.8) bouts/d for moderately lame cows, and an overall reduction in lying time in MAT herds compared with SAND herds (11.5; CI: 10.0 to 13.0 vs. 12.7; CI: 11.0 to 14.3h/d, respectively). These results show that time out of the pen milking, stall base type, and lameness significantly affect time budgets of cows housed in freestall facilities.

An experimental infection model to induce digital dermatitis infection in cattle

Bovine digital dermatitis (DD), also known as papillomatous digital dermatitis (foot warts), has been recognized as a major cause of lameness in cattle, with important economic and welfare consequences. The evaluation of therapeutic and preventive interventions aiming to control DD infections in dairy cattle is often challenged by the complex multifactorial etiology of the disease. An experimental infection model to induce acute DD lesions in a controlled environment is proposed. The goal was to provide a standard way of reproducing DD infections independent of external factors that could confound the natural course of the disease, such as management practices or infection pressure, resulting in transmission of DD between animals. A group of 4 yearling Holstein heifers free of any clinical evidence of hoof disease was recruited from a commercial dairy farm and housed in an experimental facility in 1 pen with slatted flooring. The hind feet were wrapped to mimic conditions of prolonged moisture (maceration) and reduced access to air (closure) and inoculated at the heel and dewclaw areas with a homogenate of a naturally occurring DD lesion skin biopsy or a culture broth of Treponema spp. After a period of 12 to 25 d, 4 of 6 and 1 of 4 dewclaw areas inoculated with biopsied DD lesion or a Treponema spp. culture, respectively, had gross lesions compatible with DD. Histopathology confirmed the gross diagnosis in the sites inoculated with tissue homogenate. In the site inoculated with Treponema spp. culture broth, histopathology revealed an incipient DD lesion. Treponema spp. were detected by PCR in both naturally occurring DD homogenate and Treponema spp. culture broth inoculation sites. An experimental infection model to induce acute DD in cattle was developed, which may be used to evaluate interventions to control DD and study the pathogenesis of this infectious hoof disease in a controlled manner.

The effect of lameness on the resting behavior and metabolic status of dairy cattle during the transition period in a freestall-housed dairy herd

The objective of this observational study was to examine the effect of lameness on the resting behavior of dairy cattle through the transition period in a mattress-bedded commercial freestall facility, and explore the relationships between lameness, behavior, and metabolic indicators of disease. A convenience sample was used, comprised of 40 multiparous and 17 primiparous Holstein cows that were recruited as they entered the close-up pen and tracked through the maternity, hospital, and fresh pens. At recruitment, 87.5% of multiparous cows and 23.5% of primiparous cows showed evidence of abnormal gait. Lying time decreased from 16 d before calving from a least squares means ± standard error of 13.5 ± 0.6 h/d to a nadir of 10.6 ± 0.38 h/d on the day of calving. After a period of increased rest after calving, lying time stabilized by d 6 to between 9.8 and 10.8h/d. This change was accompanied by an increase in the number of lying bouts per day from least squares means (95% confidence limits) of 11.2 (10.0 to 12.4) bouts per day to a peak of 17.7 (16.5 to 18.8) bouts per day on the day before calving, and a decrease in the duration of each lying bout. Resting behavior was influenced by calving month, temperature humidity index, body condition, parity, and lameness. Moderate and severely lame cows had significantly longer lying times throughout the transition period before and after calving, but most notable was a dramatic increase in the number of lying bouts observed 3 d before and after calving. In the straw-bedded, loose-housed maternity pen, moderate and severely lame cows had 20.3 (19.1 to 21.5) bouts per day, compared with 15.6 (14.3 to 16.8) bouts per day for nonlame cows. We hypothesized that this alteration in behavior may be associated with hypersensitivity to pain due to lameness. A total of 26.3% of cows tested above a threshold of 1,400 μM β-hydroxybutyrate. Moderate and severely lame cows had a least squares means (95% confidence limits) β-hydroxybutyrate concentration of 1,165 (1,037 to 1,291) μM that was significantly greater than 697 (560 to 834) μM for slightly lame cows and 687 (551 to 824) μM for nonlame cows. In summary, lameness significantly altered the resting behavior of cows during the transition period and was associated with elevated risk for ketosis in the study herd.

Management practices associated with conception rate and service rate of lactating Holstein cows in large, commercial dairy herds.

Data from lactating Holstein cows in herds that participate in a commercial progeny testing program were analyzed to explain management factors associated with herd-average conception and service rates on large commercial dairies. On-farm herd management software was used as the source of data related to production, reproduction, culling, and milk quality for 108 herds. Also, a survey regarding management, facilities, nutrition, and labor was completed on 86 farms. A total of 41 explanatory variables related to management factors and conditions that could affect conception and service rate were considered in this study. Models explaining conception and service rates were developed using a machine learning algorithm for constructing model trees. The most important explanatory variables associated with conception rate were the percentage of repeated inseminations between 4 and 17 d post-artificial insemination, stocking density in the breeding pen, length of the voluntary waiting period, days at pregnancy examination, and somatic cell score. The most important explanatory variables associated with service rate were the number of lactating cows per breeding technician, use of a resynchronization program, utilization of soakers in the holding area during the summer, and bunk space per cow in the breeding pen. The aforementioned models explained 35% and 40% of the observed variation in conception rate and service rate, respectively, and underline the association of herd-level management factors not strictly related to reproduction with herd reproductive performance.

First-lactation performance in cows affected by digital dermatitis during the rearing period

The long-term effects of prepartum digital dermatitis (DD) on first-lactation performance were evaluated in a cohort of 719 pregnant heifers. All heifers were followed for a period of 6 mo until calving and classified on the basis of the number of DD events diagnosed during this period as type I, type II, or type III (no DD, one DD event, and multiple DD events, respectively). Health during the initial 60d in milk (DIM), reproductive and hoof health outcomes, and milk production were compared between the 3 heifer type groups. All logistic and linear models were adjusted for age, height, and girth circumference at enrollment, and the type of trace mineral supplementation during the prepartum period. Overall, cows experiencing DD during the rearing period showed worse production and health outcomes compared with healthy heifers during the first lactation. The percentages of assisted calvings, stillbirths, culled before 60 DIM, and diseased cows during the fresh period were numerically higher in type III cows compared with type I cows. However, none of these differences were statistically significant at the 95% confidence level. Significantly lower conception at first service [odds ratio (OR)=0.55, 95% confidence interval (95% CI): 0.33, 0.89] and increased number of days open (mean=24d, 95% CI: 5.2, 43) were observed in type III cows compared with type I cows. In relation to hoof health, a significantly increased risk of DD during the first lactation was found in type II and III cows (OR=5.16, 95% CI: 3.23, 8.29; and OR=12.5, 95% CI: 7.52, 21.1, respectively), as well as earlier occurrence of DD following calving (OR=59d, 95% CI=20, 96, and OR=74d, 95% CI: 37, 109). Compared with type I cows, statistically significant milk production losses during the initial 305 DIM of 199 and 335kg were estimated in type II and III cows, respectively. This difference was due to a greater rate of production decline (less persistence) after peak yield. No differences in monthly fat and protein percentages or somatic cell counts were observed between the heifer types. Given the long-term effects of DD on health, reproduction, and production, one of the priorities during the rearing period of dairy heifers should be efficient DD prevention and control programs. Such intensive intervention programs based on active long-term DD surveillance, mitigation of risk factors, and prompt treatment are expected to increase overall animal well-being and farm profitability by minimizing the effect of DD during the first lactation.

Observations on the design and use of footbaths for the control of infectious hoof disease in dairy cattle

A survey of 65 freestall-housed dairy herds in five different countries, with an average of 1023 milking cows, found that footbaths were used 1-4 times per day for 1-7 days per week, with between 80 and 3000 cows passing through the bath between chemical changes. The most common agents used were copper sulfate (41/65) and formalin (22/65). Twenty-seven herds (42%) used more than one chemical. The median footbath measured 2.03 m long by 0.81m wide, and was filled to a depth of 0.11 m with a volume of 189 L (range 80-1417 L). An observational behavioral study was conducted using a custom-designed footbath to test four different bath dimensions, with two different step-in heights. The number of immersions per rear foot was counted for each footbath design for each cow passing through the bath on two consecutive days. While a higher step-in height significantly increased the number of foot immersions, the effect was small compared to the effect of length. The probability of each rear foot receiving at least two immersions reached 95% at a bath length of 3.0m, and a significant increase in the frequency of three and four immersions per foot was observed between 3.0 and 3.7 m. In order to optimize the number of foot immersions per cow pass, while limiting the footbath volume, this study recommends a bath 3.0-3.7 m long, 0.5-0.6m wide, with a 28 cm step-in height.

Comfort Zone-Design Free Stalls: Do They Influence the Stall Use Behavior of Lame Cows?

The behavior of 59 cows in 4 herds, each with Comfort Zone-design free stalls with dimensions suitable for 700-kg, mature Holstein dairy cows, was filmed for a 48-h period. Comparison was made between nonlame, slightly lame, and moderately lame cows on either rubber-crumb-filled mattress stall surfaces bedded with a small amount of sawdust (2 herds) or a Pack Mat design, which consisted of a rubber-crumb-filled mattress pad installed 5 cm below a raised rear curb, bedded with 5 to 8 cm of sand bedding (2 herds). All other stall design components were similar. Despite adequate resting space and freedom to perform normal rising and lying movements, lame cows on mattresses stood in the stall for >2 h longer than nonlame cows. Although a significant increase in stall standing behavior was observed in lame cows on Pack Mat stalls, the mean (95% confidence interval) standing time in the stall was only 0.7 (0 to 3.0) h/d for nonlame cows and 1.6 (0 to 4.2) h/d for moderately lame cows, which was less than the 2.1 (0 to 4.4), 4.3 (1.6 to 6.9), and 4.9 (2.5 to 7.3) h/d spent standing in the stall for nonlame, slightly lame, and moderately lame cows on mattresses, respectively. This observation supports the hypothesis that it is the nature of the stall surface that dictates changes in stall standing behavior observed in lame cows, rather than other components of stall design. The finding that only 5 to 8 cm of sand over a mattress pad provides most of the benefits of deep sand-bedded stalls, along with other advantages related to stall maintenance and manure handling, gives farmers another useful housing alternative with which to improve cow comfort and well-being.

Management characteristics, lameness, and body injuries of dairy cattle housed in high-performance dairy herds in Wisconsin.

The objective of this study was to benchmark the prevalence of lameness, hock and knee injuries, and neck and back injuries among high-performance, freestall-housed dairy herds in Wisconsin. A random selection of 66 herds with 200 or more cows was derived from herds that clustered with high performance in year 2011 Dairy Herd Improvement records for milk production, udder health, reproduction, and other health parameters. Herds were surveyed to collect information about management, facilities, and well-being. Well-being measures were obtained through direct observation of the high-producing mature cow group, surveying 9,690 cows in total. Total herd size averaged (mean ± standard deviation) 851±717 cows, ranging 203 to 2,966 cows, with an energy-corrected milk production of 40.1±4.4kg/cow per day. Prevalence of clinical lameness (5-point scale, locomotion score ≥3) and severe lameness (locomotion score ≥4) averaged 13.2±7.3 and 2.5±2.7%, respectively. The prevalence of all hock and knee injuries, including hair loss, swelling, and ulceration, was similar at 50.3±28.3 and 53.0±24.0%, respectively. Severe (swelling and ulceration) hock and knee injury prevalence were 12.2±15.3 and 6.2±5.5%, respectively. The prevalence of all neck injuries (including hair loss, swelling and ulceration) was 8.6±16.3%; whereas the prevalence of swollen or abraded necks was low, averaging 2.0±4.1%. Back injuries (proportion of cows with missing or abraded spinous processes, hooks, or pins) followed a similar trend with a low mean prevalence of 3.6±3.4%. Overall, physical well-being characteristics of this selection of high-producing, freestall-housed dairy herds provide evidence that lameness and injury are not inevitable consequences of the confinement housing of large numbers of dairy cattle. In particular, lameness prevalence rivals that of lower-production grazing systems. However, hock and other injury risk remains a concern that can be addressed through a choice in stall surface type. Use of deep, loose bedding yielded significant advantages over a mat or mattress type surface in terms of lameness, hock and knee injury, and proportion of cows with dirty udders (distinct demarcated to confluent plaques of manure). The performance benchmarks achieved by these herds may be used to set standards by which similarly managed herds may be judged using welfare audit tools.

Risk factors for postpartum problems in dairy cows: Explanatory and predictive modeling

The postpartum period is associated with a high incidence of most dairy cattle diseases and a high risk of removal from the herd. Postpartum diseases often share risk factors, and these factors may trigger a cascade of other diseases. The objective of this cohort study was to derive explanatory and predictive models for treatment or removal from the herd within the first 30 d in milk (TXR30). The TXR30 outcome was specifically defined as ≥1 treatment for ≥1 occurrence of milk fever, retained placenta, metritis, ketosis, displaced abomasum, lameness, or pneumonia; removal from the herd (sold or died); or both treatment and later herd removal. The study population consisted of 765 multiparous and 544 primiparous cows (predominantly Holstein) from 4 large commercial freestall-housed dairy herds. Treatment or removal from the herd was recorded as a binary outcome for each cow. Potential explanatory and predictive variables were limited to routine cow data that could be collected either before or within 24 h of calving. Models for multiparous and primiparous cows were developed separately because previous lactation variables are available only for multiparous cows. Adjusted odds ratios for TXR30 in the explanatory model for the multiparous cohort were 2.1 for lactation 3 compared with lactation 2, and 2.3 for lactation 4 or greater compared with lactation 2; 2.3 for locomotion score 3 or 4 compared with score 1; 3.3 for an abnormality at calving compared with no calving abnormality; 1.8 for each 1-standard deviation increase in previous lactation length; and 0.4 for each 5,000-kg increment in previous lactation milk yield in cows with longer previous lactation length. The final predictive model for TXR30 in multiparous cows included predictors similar but not identical to those included in the explanatory model. The area under the curve for the receiver operating characteristic curve from the final predictive model for the multiparous cohort was 0.70, with 60% sensitivity. For the primiparous cohort, calving abnormality increased the odds of TXR30 and was the only variable included in both the explanatory and predictive models. The area under the curve for the receiver operating characteristic curve from the final predictive model for the primiparous cohort was 0.66, with 35% sensitivity. This study identified key risk factors for TXR30 and developed equations for the prediction of TXR30. This information can help dairy producers better understand causes of postpartum problems.

Immune response against Treponema spp. and ELISA detection of digital dermatitis

The objective of this longitudinal study was to evaluate the immune response against Treponema spp. infection in dairy heifers affected with digital dermatitis (DD). In addition, the accuracy of an indirect ELISA detecting anti-Treponema IgG antibodies in identifying clinical DD status has been assessed. A cohort of 688 pregnant Holstein heifers was evaluated at least 3 times before calving during a period of 6 mo. Complete clinical assessment of DD presence on the back feet of each heifer and blood extraction were performed in a stand-up chute. Digital dermatitis cases were characterized by the M-stage classification system and size and level of skin proliferation. An ELISA was performed on blood serum samples obtained from a subcohort of 130 heifers. For description purposes, the animals were classified by the number of clinical cases experienced during the study period as type I (no clinical cases were observed), type II (only 1 acute clinical case diagnosed), and type III (at least 2 acute clinical cases diagnosed). Multivariable repeated-measures models were used to evaluate the immune response against Treponema spp. infection. A binormal Bayesian model for the ELISA data without cut-point values was used to assess the accuracy of the ELISA as a diagnostic tool. Animals that never experienced a DD event throughout the study kept a constant low level of antibody titer. A 56% increase in mean ELISA titer was observed in heifers upon a first clinical DD case diagnosis. After topical treatment of an acute DD case with oxytetracycline, the antibody titer decreased progressively in type II heifers, achieving mean levels of those observed in healthy cows after a mean of 223 d. Surprisingly, antibody titer was not increased in the presence of M1 (DD lesion <20mm in diameter surrounded by healthy skin) and M4.1 (DD lesion <20mm in diameter embedded in a circumscribed dyskeratotic or proliferative skin alteration) DD stages. Type III cows showed a slight increase in antibody levels. The presence of skin proliferation at first DD diagnosis was found to be associated with an odds ratio of 2.04 of becoming a type III heifer in relation to heifers presenting first lesions without skin proliferation. The ELISA validity was estimated by an area under the curve of 0.88. Predicted probabilities of infection are provided for a range of ELISA values and prevalence of infection. Early detection and treatment is essential to control DD and the ELISA can be used in understanding the immunopathology of DD and shows great promise for prescreening purposes during DD management programs in combination with traditional clinical inspection.