Risk factors for lameness and hock injuries in Holstein herds in China

The objective was to investigate the association between herd-level management and facility design and the prevalence of lameness and hock injuries in high-producing dairy cows on commercial freestall farms in China. Housing and management measures, such as stall design, bedding type, and milking routine were collected for the high-producing pen in 34 farms in China. All cows in the pen were gait scored using a 5-point scale, and evaluated for hock injuries using a 3-point scale. Measures associated with the proportion of clinically (score ≥3) or severely (score ≥4) lame cows, and the proportion of cows having at least a minor hock injury (score ≥2) or severe injury (score = 3) at the univariable level were submitted to multivariable general linear models. The prevalence [mean ± SD (range)] of clinical and severe lameness were 31 ± 12 (7–51) and 10 ± 6% (0– 27%), respectively, and the prevalence of cows with at least a minor hock injury and with severe injuries was 40 ± 20 (6 – 95) and 5 ± 9% (0 – 50%), respectively. The prevalence of clinical lameness and severe lameness decreased with herd size (estimate = −0.35 ± 0.09% for a 100-cow increase for clinical lameness; estimate = 0.15 ± 0.06% for a 100-cow increase for severe lameness). Prevalence increased with barn age >9 yr (estimate = 12.73 ± 4.42% for clinical lameness; estimate = 5.79 ± 2.89% for severe lameness). These 2 variables combined explained 49% of the variation in clinical lameness and 30% of the variation in severe lameness. The prevalence of all hock injuries and severe hock injuries decreased with deep bedding (estimate = −20.90 ± 5.66% for all hock injuries; estimate = −3.65 ± 1.41% for severe hock injuries) and increased with barn age >9 yr (estimate = 16.68 ± 7.17% for all hock injuries; estimate = 6.95 ± 1.75% for severe injuries). These 2 variables explained 52 and 58% of the variation, respectively. In conclusion, large variation existed across farms in prevalence of lameness and hock injuries. Changes in housing and management may help control the prevalence of lameness and hock injuries in the emerging dairy industry in China.     

Benchmarking cow comfort on North American freestall dairies: Lameness,leg injuries,lying time,facility design,and management for high-producing Holstein dairy cows

In this paper, we describe a novel approach to corporate involvement in on-farm assessment, driven by the desire to provide a service for dairy producers and to create a vehicle for engagement on issues of dairy cow welfare. This program provides producers with feedback on animal-based (including gait score, leg injuries, and lying time) and facility-based (including freestall design, bedding practices, feed bunk design and management, and stocking density) measures that can be used to better address their management goals. The aim of this paper is to describe variation in the prevalence of lameness and leg injuries, lying behavior, facility design, and management practices for high-producing cows on freestall dairy farms in 3 regions of North America: British Columbia (BC; n = 42); California (CA; n = 39); and the northeastern United States (NE-US; n = 40). Prevalence of clinical lameness averaged (mean ± SD) 27.9 ± 14.1% in BC, 30.8 ± 15.5% in CA, and 54.8 ± 16.7% in NE-US; prevalence of severe lameness averaged 7.1 ± 5.4% in BC, 3.6 ± 4.2% in CA, and 8.2 ± 5.6% in NE-US. Overall prevalence of hock injuries was 42.3 ± 26.2% in BC, 56.2 ± 21.6% in CA, and 81.2 ± 22.5% in NE-US; prevalence of severe injuries was 3.7 ± 5.2% in BC, 1.8 ± 3.1% in CA, 5.4 ± 5.9% in NE-US. Prevalence of swollen knees was minimal in CA (0.3 ± 0.6%) but high (23.1 ± 16.3%) in NE-US (not scored in BC). Lying times were similar across regions (11.0 ± 0.7 h/d in BC, 10.4 ± 0.8 h/d in CA, 10.6 ± 0.9 h/d in NE-US), but individual lying times among cows assessed varied (4.2 to 19.5 h/d, 3.7 to 17.5 h/d, and 2.8 to 20.5 h/d in BC, CA, and NE-US, respectively). These results showed considerable variation in lameness and leg injury prevalence as well as facility design and management among freestall farms in North America. Each of the 3 regions had farms with a very low prevalence of lameness and injuries, suggesting great opportunities for improvement on other farms within the region.     

Housing system, milk production, and zero-grazing effects on lameness and leg injury in dairy cows

The aim of this study was to assess the effect of grazing (G) vs. zero-grazing (ZG), level of milk production, and quality and type of housing system [free stalls (FS) and straw yards (SY)] on the prevalence of lameness and leg injuries in dairy cows. Observations were made on 37 commercial dairy farms across Great Britain. A single visit of 5 d duration was made to each farm. During this visit, lameness scores and the incidence of swellings, rubs, and injuries to hocks and knees were recorded on all the peak- or mid-lactation cows. Aspects of the quality of housing and management that were likely to affect foot and leg health were recorded. There were more lame cows on ZG farms (39 ± 0.02%) than on grazing (G) farms (15 ± 0.01%), and lameness scores were higher on FS farms compared with SY farms (0.25 ± 0.01 vs. 0.05 ± 0.01). Cows on SY farms had fewer hock and knee injuries compared with FS farms. The frequency of knee swellings was higher on ZG farms (0.31 ± 0.02) than on G farms (0.15 ± 0.01). Aspects of the free-stall design affected foot and leg health. The number of hock swellings increased with increasing stall gradient (0.16 ± 0.01 with no slope vs. 0.39 ± 0.02 at a 0 to 1.5% slope). There was an interaction between the length of the free-stall lunging space and the hip width of the cow, indicating that the incidence of lameness is generally highest on farms with small free stalls and heavy cows. High levels of milk production did not affect lameness or leg injury. The results indicate that housing cows throughout the year potentially has a detrimental effect on foot and leg health. However, good free-stall design may reduce lameness and leg lesions.     

Prevalence of and factors associated with hock,knee, and neck injuries on dairy cows in freestall housing in Canada

Injuries are a widespread problem in the dairy industry. The objective of this study was to determine the prevalence of and explore the animal-based and environmental factors associated with hock, knee, and neck injuries on dairy cows in freestall housing in Ontario and Alberta, Canada. Freestall dairy farms in the provinces of Ontario (n = 40) and Alberta (n = 50) were visited for cross-sectional data collection. A purposive sample of 40 lactating Holstein cows was selected for detailed observation on each farm. Cows were scored for hock, knee, and neck injuries on a 3- or 4-point scale, combining the attributes of hair loss, broken skin, and swelling and with a higher score indicating a more severe injury. The highest hock and highest knee score were used in the analysis. Animal-based and environmental measures were taken to explore which factors were associated with injury. Overall, the prevalence of cows with at least one hock, knee, and neck injury was 47, 24, and 9%, respectively. Lame cows had a greater odds of hock injury [odds ratio (OR) = 1.46] than nonlame cows, whereas cows with fewer days in milk (DIM) had reduced odds of hock injury compared with those >120 DIM (OR = 0.47, 0.64, and 0.81 for <50, 50–82, and 83–120 DIM, respectively). The odds of hock injury was lower on sand (OR = 0.07) and concrete (OR = 0.44) stall bases in comparison to mattresses. Conversely, the odds of knee injury was greater on concrete (OR = 3.19) stall bases compared with mattresses. Cows in parity 1 (OR = 0.45 and 0.27 for knee and neck injury, respectively) and 2 (OR = 0.49 and 0.40 for knee and neck injury, respectively) had lower odds of knee and neck injury compared with cows in parity 4+. Low feed rail heights increased the odds of neck injury (OR = 76.71 for rails between 128 and 140 cm and OR = 43.82 for rails ≤128 cm). The odds of knee injury was greater on farms where any cows were observed slipping or falling when moving into the holding area for milking (OR = 2.69) and lower on farms with rubber flooring in the alley along the feed bunk compared with bare concrete floors (OR = 0.19). These results demonstrate that individual animal characteristics, as well as barn design and animal management, are associated with hock, knee, and neck injuries. These data can help to guide investigations into causes and prevention of injuries.     

Prevalence and risk factors for skin lesions on legs of dairy cattle housed in freestalls in Norway

Appropriate indoor housing facilities for dairy cattle promote improved animal welfare. Skin alterations are an indicator of dysfunctional housing. The purpose was to determine the relationship between different housing design and skin lesions, hence providing farmers more insight into how to reduce the occurrence of lesions. A cross-sectional study was conducted on 2,335 animals in 232 Norwegian freestall-housed dairy cattle from September 2006 to June 2007. A model was established to investigate risk factors related to the presence of lesions including hair loss, swelling, and wounds on the legs of dairy cattle. Separate models were developed to investigate risk factors related to the presence of knee and hock lesions. Previously described risk factors were included in the models, together with a questionnaire addressing the attitude of the farmer toward the animals. Mean (± SD) prevalence for hock lesions was 60.5 ± 21.2% with a median value of 64%. The prevalence for knee lesions was 35.3 ± 25.7% with a median of 30%. Cows in herds with a soft freestall base had an odds ratio (OR) for knee and hock lesions of 0.22 (0.06 to 0.73) and 0.62 (0.48 to 0.80), respectively, compared with those in herds with a harder freestall base, such as concrete and compact rubber mats. There was an increased risk of hock lesions when the length in the lying area in a double-row freestall was >250 cm (OR = 2.96; 1.02 to 8.60) compared with ≤250 cm, and when the length of the lying area against a wall was >260 cm (OR = 2.11; 1.53 to 2.90) compared with ≤260 cm. The risk for knee lesions increased if a row against a wall was >270 cm (OR = 1.72; 1.09 to 2.72) compared with ≤270 cm. Hock lesions were associated with lame cows (OR = 5.76; 1.14 to 29.18) versus nonlame cows, and with cows in their second or higher parity (OR = 1.27; 1.06 to 1.52) versus cows in their first parity. Knee lesions were associated with farmers’ negative attitudes toward animals in pain (OR = 3.28; 1.79 to 6.03) versus those with positive attitudes; cows in the beginning of their lactation (OR = 1.84; 1.24 to 2.74) versus those at the end of their lactation; and tall animals (OR = 1.27; 1.00 to 1.61) versus shorter animals. These results show that freestall design is important with respect to skin lesions as are the characteristics of individual animals and the farmer.     

Perceptions and risk factors for lameness on organic and small conventional dairy farms

Lameness is an important multifactorial disease that affects dairy cattle on both organic (ORG) and conventional (CON) farms. The objective of this study was to characterize perception of lameness and identify risk factors for lameness prevalence on ORG and similarly-sized CON farms. Dairy herds (n = 292) were enrolled across 3 states (NY, OR, WI), with CON herds enrolled based on similar herd size and location of ORG herds. During a single herd visit, information was collected about management practices and lameness events occurring in the previous 60 d, and paperwork was left to record lameness events during the 60 d after the visit. During the herd visit, study personnel scored cows for body condition, lameness, and hock condition. For analysis, CON herds were further divided into CON grazing and CON nongrazing. A Poisson regression model was used to assess risk factors for prevalence of cows scored lame. On these relatively small, lower producing farms, the prevalence of lameness in cows scored by study personnel was less than previously reported for larger, higher producing dairy herds located in the United States. Prevalence of lameness was weakly and positively correlated with the rate of lameness calculated using farmer records. Researchers observed lame cows on some farms where farmers perceived that lameness never occurred. An increased prevalence of cows scored lame by study personnel was associated with an increased prevalence of hock lesions, use of CON nongrazing management, and routine use of a footbath. Multiple strategies may be used to manage lameness on farms, including increasing farmer perception of lameness and reduction in exposure of cows to risk factors that contribute to development of lameness.     

The association between reproductive performance and milk yield in Chilean Holstein cattle

The objective of this study was to evaluate the relationship between reproductive performance and milk yield in central-southern Chilean Holstein cattle that calved from 1990 to 2003. The analysis included 150,457 lactations obtained from a certified recording system. Reproductive indexes included in the study were calving interval (CI, d), calving to first service interval (CFSI, d), calving to conception interval (CCI, d), services per conception (SC), and conception rate at first service (CRFS). Survival analysis for the risk of pregnancy was also conducted. Models for reproductive indexes were significant and included, as independent variables, year and season of parturition, parity, length of dry period, milk and fat production standardized to 305 d, herd size, and herd. In 1990 and 2003, respectively, means ± SEM for CI were 399 ± 1.6 and 415 ± 1.1 d; for CFSI were 85 ± 0.6 and 97 ± 0.6 d; for CCI were 124 ± 1.3 d and 137 ± 1 d; and for SC were 1.6 ± 0.02 and 1.7 ± 0.01. For every 100 kg of 305-d standardized milk yield, the CCI increased by 0.6 d and CRFS decreased by 0.9%. Association between milk yield and the risk of pregnancy was almost zero when a Cox proportional regression model was conducted (hazard ratio = 1.005; 95% confidence interval = 1.002 to 1.008). We conclude that CCI has increased over time and is related negatively to the increase in milk yield experienced by central-southern Chilean Holstein cattle during the last 15 yr. Nevertheless, risk of pregnancy was not explained by the individual level of standardized 305-d milk yield of cows studied.     

Ranking experts' preferences regarding measures and methods of assessment of welfare in dairy herds using Adaptive Conjoint Analysis

Welfare in dairy herds can be addressed using different concepts. The difficulty is to extract which measures are the most important to practically address welfare at the herd level and the methods to assess traits considered most important. Therefore, the preferences of 24 acknowledged European welfare experts were ranked regarding 70 measures suitable to assess dairy cattle welfare at herd level using the Adaptive Conjoint Analysis (ACA; Sawtooth Software, Inc., Sequim, WA) technique. The experts were selected on the basis of 3 criteria: at least 5 yr experience in animal welfare research; recent scientific publications in the field of animal welfare; and, at the most, 3 animal species including dairy cattle as their field of expertise. The 70 traits were ranked by using the median ACA questionnaire utility scores and the range between the answers of the 24 experts. A high utility score with a low range between the answers of the experts was considered as suitable to assess welfare at farm level. Measures meeting these criteria were prevalence of lameness cases (107.3 ± 11.7), competition for feed and water (96.4 ± 13.9), and number of freestalls per 10 cows (84.8 ± 13.3). Based on the utility score alone, these former measures were replaced by stereotypic behavior (111.7 ± 17.1), prevalence of lameness cases (107.3 ± 11.7), body condition score (108.0 ± 18.9), and hock lesions (104.7 ± 16.1). Subsequently, to demonstrate that the ACA technique can be used to rank either well-known or inconclusive methods of assessment, the methods for the traits lameness cases and the hygiene of the calving pen were ranked using another 2 ACA questionnaires. The results are based on the opinions of selected, internationally acknowledged dairy cattle welfare experts within the European Union. In the future, other parties like dairy farmers and farmers’ organization should be included to achieve consensus about the most suitable traits applicable in practice. The currently investigated traits do not always apply to all dairy husbandry systems across the world, but are based on a system that includes indoor housing during winter. It is concluded that ACA is a useful technique to rank the different scientific opinions of experts regarding suitable traits and methods of assessment of dairy cattle at the herd level.     

Animal welfare in cross-ventilated, compost-bedded pack, and naturally ventilated dairy barns in the upper Midwest

The objective of this cohort study was to investigate animal welfare in 2 newer dairy housing options in the upper Midwest, cross-ventilated freestall barns (CV) and compost-bedded-pack barns (CB), compared with conventional, naturally ventilated freestall barns (NV). The study was conducted on 18 commercial dairy farms, 6 of each housing type, in Minnesota and eastern South Dakota. The primary breed in all farms was Holstein; 1 CV and 1 NV herd had approximately 30% Jersey-Holstein crossbreds. All freestall herds used sand for bedding. Farms were visited 4 times (once in each season) between January and November 2008, and approximately 93% of all animals in each pen were visually scored on each visit. Outcome-based measurements of welfare (locomotion, hock lesions, body condition score, hygiene, respiration rates, mortality, and mastitis prevalence) were collected on each farm. Lameness prevalence (proportion of cows with locomotion score ≥3 on a 1 to 5 scale, where 1 = normal and 5 = severely lame) in CB barns (4.4%) was lower than that in NV (15.9%) and CV (13.1%) barns. Lameness prevalence was similar between CV and NV barns. Hock lesion prevalence (proportion of cows with a lesion score ≥2 on a 1 to 3 scale, where 1 = normal, 2 = hair loss, and 3 = swelling) was lower in CB barns (3.8%) than in CV (31.2%) and NV barns (23.9%). Hygiene scores (1 to 5 scale, where 1 = clean and 5 = very dirty) were higher for CB (3.18) than CV (2.83) and NV (2.77) barns, with no differences between CV and NV barns. Body condition scores, respiration rates, mastitis prevalence, culling, and mortality rates did not differ among housing systems. The CV and NV barns were evaluated using the cow comfort index (proportion of cows lying down in a stall divided by all animals touching a stall) and the stall usage index (proportion of cows lying divided by all animals in the pen not eating). The CV barns tended to have greater cow comfort index (85.9%) than the NV barns (81.4%) and had greater stall usage index (76.8% and 71.5%, respectively). Dairy cattle housed in CB barns had reduced lameness and hock lesions compared with those housed in freestall barns and had no adverse associations with body condition, respiration rates, mastitis prevalence, culling, or mortality. When comparing the 2 freestall housing options, CV barns had improved cow comfort indices compared with NV barns. Although cows in CB barns had better feet and leg health, as indicated by the reduced lameness and hock lesion prevalence, acquiring bedding and managing the bedded pack could limit their use.     

Management,operational, animal health,and economic characteristics of large dairy herds in 4 states in the Upper Midwest of the United States

Recent trends in dairy farm structure in the United States have included a decreasing number of farms, although farm size has increased, especially the share of milk production from very large herds (>2,500 cows). The objectives of this observational study were to describe common management practices; to characterize labor and operational structure; to measure some aspects of animal health, including lameness, hock lesions, mortality, and mastitis incidence; and to summarize cost of production on farms with more than 2,500 cows in 4 states in the Upper Midwest of the United States. The study included 15 dairy farms in Minnesota, Wisconsin, Iowa, and South Dakota. Farms were visited twice, once each year, and on-farm herd records were collected for those 2 yr. On-farm herd records were used to investigate mortality, culling, pregnancy rate, and clinical mastitis incidence. At least 1 high-producing pen of mature cows and 1 pen of fresh cows were scored for locomotion. Likewise, at least 1 pen of high-producing mature cows was scored for cleanliness and hock lesions. Median herd size was 3,975 cows (range = 2,606–13,266). Milk sold per employee was 1,120,745 kg and the number of cows per employee was 105. Eighty percent of the farms had Holstein cows, 13% had Jersey, and 7% had Jersey-Holstein crosses. All farms used artificial insemination as the sole form of breeding and 100% of the farms used hormonal synchronization or timed artificial insemination programs in their reproductive protocols; 21-d pregnancy rate was 21.7%. Median lameness prevalence was 18.3% and median severe lameness prevalence was 5.1%. Median hock lesion prevalence was 17.4% and median severe hock lesion prevalence was 1.9%; mortality rate was 7.4%. Clinical mastitis incidence was 62.5 cases per 100 cow-years. Feed costs accounted for approximately 53% of the total cost of producing milk, followed by labor at 11%, interest and depreciation expenses at 10%, and replacement costs at 9.5%. Herds in the top 50th percentile for profitability had a net income of $2.40 per hundredweight of milk sold compared with $0.95 per hundredweight for herds in the bottom 50th percentile. Although results of this study were helpful in understanding how large dairy systems operate in the Upper Midwest, more research is yet needed with a larger number of farms and wider variety of management practices to identify factors within these large farms that promote optimal animal health and profitability.     

Prevalence of periparturient diseases and effects on fertility of seasonally calving grazing dairy cows supplemented with concentrates

The objectives were to characterize the prevalence of periparturient diseases and their effects on reproductive performance of dairy cows in seasonal grazing farms. A total of 957 multiparous cows in 2 farms (555 in farm A and 402 in farm B) were evaluated and diseases characterized. At calving, dystocia, twin birth, stillbirth, and retained fetal membranes were recorded and grouped as calving problems. On d 7 ± 3 and 14 ± 3 postpartum, cows were evaluated for metritis and on d 28 ± 3 for clinical endometritis based on scoring of the vaginal discharge. From parturition to 30 d after artificial insemination (AI), prevalence of mastitis, lameness, and digestive and respiratory problems were recorded. For subclinical diseases, diagnosis was based on blood samples collected from 771 cows and analyzed for concentrations of Ca, nonesterified fatty acids (NEFA), and β-hydroxybutyrate. Cows were considered as having elevated NEFA concentration if the concentration was ≥0.70 mM, subclinical ketosis if the β-hydroxybutyrate concentration was ≥0.96 mM, and subclinical hypocalcemia if the Ca concentration was ≤2.14 mM. Ovaries were scanned on d 35 ± 3 and 49 ± 3 postpartum for determination of estrous cyclicity. All cows were enrolled in a timed AI program and inseminated on the first day of the breeding season: on average, 86 d postpartum. Overall, 37.5% (359/957) of the cows presented at least 1 clinical disease and 59.0% (455/771) had at least 1 subclinical health problem. Prevalence of individual diseases was 8.5% for calving problems, 5.3% for metritis, 15.0% for clinical endometritis, 13.4% for subclinical endometritis, 15.3% for mastitis, 2.5% for respiratory problems, 4.0% for digestive problems, 3.2% for lameness, 20.0% for elevated NEFA concentration, 35.4% for subclinical ketosis, and 43.3% for subclinical hypocalcemia. Clinical and subclinical diseases had additive negative effects on reproduction, delaying resumption of estrous cyclicity and reducing pregnancy per AI (P/AI). Occurrence of multiple diseases further reduced reproductive efficiency compared with a single disease. Individually, subclinical hypocalcemia, elevated NEFA concentration, metritis, and respiratory and digestive problems reduced estrous cyclicity by d 49 postpartum. Elevated NEFA concentration, calving problem, metritis, clinical and subclinical endometritis, and digestive problems reduced P/AI on d 65 after AI. Moreover, calving problems and clinical endometritis increased the risk of pregnancy loss between gestation d 30 and 65. Serum concentrations of Ca and NEFA were negatively correlated, and both were associated with prevalence of uterine diseases. In conclusion, periparturient diseases were highly prevalent in seasonally calving grazing dairies and affected cows had delayed resumption of estrous cyclicity, reduced P/AI, and increased risk of pregnancy loss.     

Separate housing for one month after calving improves production and health in primiparous cows but not in multiparous cows

The hypothesis was that dairy cows housed for 1 mo after calving in a separate group with herd mates would produce more milk and would be healthier than cows integrated in a group of all lactating cows immediately after calving. The experiment was conducted with 489 cows in 6 commercial loose-housing dairy herds where cows were randomly selected for treatment (separate housing) or control. Cows selected for treatment were housed for 1 mo after calving in a separate section, and controls were housed in the remaining section of the barn for lactating cows. Data were compared for milk yield, somatic cell count, medical treatments, reproductive performance, culling, mortality, and clinical observation of scores for body condition, leg and udder hygiene, lameness, hock lesions, other cutaneous lesions, vaginal discharge, and condition of the hair coat. The analysis of the effect of separate housing showed that primiparous cows produced more milk [approximately 230 kg of energy-corrected milk from 0 to 305 d in milk (DIM)], whereas multiparous and especially parity 3+ cows produced less milk (approximately 394 kg of energy-corrected milk from 0 to 305 DIM) during the lactation. Separate housing had no effect on mortality or reproductive efficiency. In primiparous cows, the number of medical treatments for ketosis was reduced by separate housing [hazard ratio 0.33, 95% confidence interval (CI): 0.13-0.83]. Clinical evaluations showed that separate housing decreased the scores for hock lesions in cows at 0 to 30 DIM (odds ratio 0.41, CI: 0.19-0.91), whereas the scoring of leg cleanliness showed more dirty legs in separated cows at 0 to 30 DIM (odds ratio 3.61, CI: 2.01-6.47) compared with cows integrated into the herd immediately. The body condition score in separated cows was reduced from 0 to 30 DIM (score reduced by 0.16, CI: 0.07-0.25) and from 31 to 60 DIM (score reduced by 0.13, CI: 0.04-0.23) compared with cows integrated immediately. We concluded that separate housing for 1 mo after calving increased milk yield in primiparous cows but not in multiparous cows, which produced less milk. The hypothesis about fewer health problems could only be confirmed with regard to fewer primiparous cows being treated for ketosis.     

The effect of out-wintering pad design on hoof health and locomotion score of dairy cows

This study compared locomotion, hoof health, and lameness of dairy cows confined in either indoor free stalls (FS) or 1 of 3 out-wintering pad (OWP) designs. Out-wintering pad treatments were 1) uncovered OWP with a concrete feed apron (UP); 2) covered OWP with a concrete feed apron (CO); and 3) uncovered OWP on top of which grass was ensiled so that the cows could self-feed (SP). Cows were assigned to treatment at drying off using a randomized complete block design. They remained on treatment until calving, when they were turned out to pasture. Sole lesions, heel erosion, dermatitis, and claw hardness on both hind feet were scored according to severity at assignment to treatment, at calving, and 9 and 14 wk postpartum. Locomotion score was recorded weekly after calving for 14 wk. Incidence of clinical lameness was recorded during the treatment period and in the subsequent lactation. Treatment had no effect on sole lesion score, but scores increased over time (calving = 5.5 ± 1.3, wk 9 = 10.8 ± 1.3, wk 14 = 14.2 ± 1.3, mean ± SE). Self-fed cows had higher heel erosion scores (6.4 ± 0.4) than FS and CO cows (4.7 ± 0.4 and 4.7 ± 0.4, respectively) at calving. Cows on SP had the highest dermatitis scores [1.14 (0-2) mean (interquartile range)] and FS cows the lowest [0.51 (0-0)]. Hooves were hardest at assignment to treatment (43.9 ± 0.6) with a significant reduction in hardness at calving (40.0 ± 0.6). The hooves of CO cows were harder than those of SP and UP cows (CO = 43.3 ± 0.7, SP = 41.7 ± 0.7, UP = 41.7 ± 0.7, Shore D scale). There was no treatment effect on locomotion scores or lameness incidence. Higher dermatitis scores and heel erosion in SP may be due to exposure to excreta and moisture, because the SP treatment had no manure removal system at the feed face. In FS, the alleys and the feed face were cleaned regularly by automatic scraper, explaining the lower dermatitis scores recorded indoors. Providing shelter for OWP likely reduced exposure to environmental moisture. This ensured that the hooves of CO cows remained as hard as those of FS cows. Low correlations between hardness and pathologies indicate that other factors are involved in the development of hoof pathologies. Confining dry dairy cows on OWP does not increase locomotion scores or lameness incidence.     

Survey of management practices on reproductive performance of dairy cattle on large US commercial farms

A survey regarding general management, sire selection, reproductive management, inseminator training and technique, heat abatement, body condition scoring, facility design and grouping, nutrition, employee training and management, and animal health and bio-security was carried out from March to September of 2004 in 153 herds in the Alta Genetics (Watertown, WI) Advantage Progeny Testing Program. A total of 103 herds (67.3%) completed the survey. Herd size was 613 ± 46 cows, with herds located in Wisconsin (26), California (12), New York (11), Minnesota (10), Michigan (7), Washington (6), Pennsylvania (6), Iowa (5), Idaho (5), Texas (4), Ohio (4), and other states (7). These farms sold 34.5 ± 0.3 kg of milk/d per cow, with an annual culling rate of 34 ± 1% and a calving interval of 13.8 ± 0.1 mo. Cows were observed for estrus 2.8 ± 0.3 times/d, for a duration of 27 ± 4 min, but 78% of the respondents admitted that detection of estrus was not the employee's sole responsibility at that time. Managers tried to achieve pregnancy until 8.8 ± 0.9 failed inseminations, 300 ± 26 d postpartum, or milk yield <17.7 ± 0.5 kg/d. Nonpregnant cows were culled at 326 ± 36 d postpartum or milk yield <16.4 ± 0.3 kg/d. Mean durations of the voluntary waiting period were 52 ± 1.3 and 53 ± 1.4 d for primiparous and multiparous cows, respectively. Hormonal synchronization or timed artificial insemination programs were used in 87% of the herds, with 86% synchronizing first services, 77% resynchronizing repeat services, and 59% treating cystic, anestrous, or anovular cows. Finding good employees was identified as the greatest labor challenge, followed by training and supervising employees. Mastitis and hairy heel warts were noted as the greatest animal health concerns, followed by lameness, abortions, and death losses, whereas the greatest reproductive challenges were artificial insemination service rate, conception rate, twinning, and retained placenta or metritis. Results of this study can provide a useful benchmark or reference with regard to commonly used management practices on large commercial US dairy farms at the present time.     

Technical note: A comparison of 2 methods of assessing lameness prevalence in tiestall herds

We compared 2 methods for identifying lame cows and estimating the prevalence of lameness in tiestalls. Cows (n = 320) in 9 tiestall herds were scored as lame both by the presence of limping while walking and by stall lameness scores (SLS). The SLS was based on the number of the following behaviors that the cow showed while standing in the tiestall: weight shifting, standing on the edge of the stall, uneven weight bearing while standing, and uneven weight bearing while moving from side to side. Two observers watched video-recordings of the cows. Intraobserver agreements for the 4 SLS behaviors ranged from 92 to 100%, and interobserver agreement ranged from 81 to 100%. The overall prevalence of lameness based on an SLS of ≥2 was similar to that of limping (39 vs. 40%). The sensitivity of the classification based on the SLS was 0.63 and the specificity was 0.77 in identifying cows with a limp; accuracy varied across farms from 62.2 to 80.4%, with a mean of 71.7%. A cow with an SLS of ≥2 had 4.88 times the odds of limping than a cow with an SLS of <2. The prevalence of lameness on farms based on SLS was highly correlated with the prevalence of limping (Pearson correlation = 0.88; n = 9), and prevalence estimates from the 2 methods diverged most when the mean herd prevalence was lower. The SLS method provides an estimate of the prevalence of lameness in tiestall herds comparable with traditional gait scoring, but does not require that the cows be untied. The SLS method could be used to improve lameness detection on tiestall farms and obtain estimates of lameness prevalence without the need to walk the cows.     

Cow-level and herd-level risk factors for subclinical endometritis in lactating Holstein cows

The objectives of this study were to obtain prevalence estimates for subclinical endometritis (SCE), determine cow- and herd-level risk factors, and evaluate the reproductive consequences of SCE. A cross-sectional study was used to determine prevalence and risk factors with cows followed in a prospective study to determine reproductive outcomes. Lactating Holstein cows were sampled between 40 and 60 d in milk using low-volume uterine lavage, and cytology was evaluated to determine SCE status. In total, 779 cows from 38 herds were used in the analysis. The cow-level prevalence of SCE was 25.9%. Within-herd level prevalence ranged from 4.8 to 52.6% (median 26.3%, interquartile range 15.6 to 33.3%). Cow-level risk factors identified were ketosis [odds ratio (OR) 3.83; 95% confidence interval (CI) 1.82-8.07], acute metritis (OR 1.86; 95% CI 1.05-3.30], and the interaction between milk production and parity. Primiparous cows that produced more milk had increased odds of having SCE, whereas multiparous cows that produced more milk had decreased odds of having SCE. Herd-level risk factors identified were housing early postpartum cows on bedded packs (herd-level SCE = 36.1%), which increased herd prevalence of SCE by 16.7% (SE 5.58) compared with early postpartum cows housed in freestalls (herd-level SCE = 19.4%), and straw bedding in the calving pen, which decreased herd prevalence of SCE by 10.7% (SE 3.59) compared with herds that used other bedding material. In this study, primiparous cows with and without SCE had similar reproductive performance; however, multiparous cows with SCE had median days open 44 d longer (159 d; 95% CI 126-186 d) compared with unaffected multiparous cows (115 d; 95% CI 106-132 d).     

A meta-analysis of the impact of monensin in lactating dairy cattle. Part 3. Health and reproduction

A meta-analysis of the impact of monensin on health and reproductive outcomes in dairy cattle was conducted. A total of 16 papers were identified with sufficient data and quality to evaluate health and reproductive outcomes for monensin. The available trials provided approximately 9,500 cows with sufficient data for analysis. This provided good statistical power to examine the effects of monensin on health and reproduction. Over all the trials analyzed, monensin decreased the risk of ketosis [relative risk (RR) = 0.75], displaced abomasums (RR = 0.75), and mastitis (RR = 0.91). No significant effects of monensin were found for milk fever, lameness, dystocia, retained placenta, or metritis. Monensin had no effect on first-service conception risk (RR = 0.97) or days to pregnancy (hazard ratio = 0.93). However, the impact of monensin on dystocia, retained placenta, and metritis was heterogeneous for all 3 outcome measures and random effect models were utilized. Causes of the heterogeneity were explored with meta-regression. Days of treatment with monensin before calving increased the risk of dystocia. Delivery method of monensin influenced the incidence of retained placenta and metritis, with risk being lower with controlled release capsule treatment compared with delivery in either topdress or in a total mixed ration. Days of treatment before calving also influenced retained placenta with an increase in risk with more days treated before calving. Improvements in ketosis, displaced abomasums, and mastitis with monensin were achieved. Exposure to prolonged treatment in the dry period with monensin may increase the risk of dystocia and retained placenta.     

Effect of prepartum administration of recombinant bovine somatotropin on health and performance of lactating dairy cows

A double-blind, randomized clinical trial was conducted in 5 commercial dairy herds in southern Ontario with 1,362 cows enrolled to evaluate the effect of prepartum administration of recombinant bovine somatotropin (rbST) on health and performance. Cows were randomly assigned to receive either 325 mg of sometribove zinc suspension (n = 680) or a placebo injection (n = 682; control) subcutaneously every 14 d until calving. Treatments started 28 to 22 d before expected calving, with a maximum of 3 treatments per cow. Serum samples taken at the time of enrollment, 1 wk before calving, and weekly for 3 wk after calving were analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, aspartate aminotransferase, calcium, and haptoglobin. Diseases were recorded by farm staff. Incidences of clinical ketosis, clinical mastitis, displaced abomasum, metritis, retained placenta, milk fever, and lameness were similar between groups. Body condition score was lower for treated than for control cows at 3 wk after calving (3.13 and 3.17, respectively). Serum NEFA tended to be higher for treated than for control cows by 0.01 mmol/L. Overall BHBA was not different between groups, but BHBA for treated cows was higher in wk 1 after calving (750 and 698 μmol/L, respectively) and tended to be higher in wk 2 after calving (779 and 735 μmol/L, respectively). Incidence of hyperketonemia was similar between groups. Treated cows had higher serum glucose compared with control cows (2.8 and 2.7 mmol/L, respectively). We detected no differences in serum aspartate aminotransferase, calcium, or haptoglobin between groups. Milk yield was recorded daily for each cow for 63 d, and did not differ between groups (37.1 ± 0.5 kg and 36.7 ± 0.5 kg, respectively) but we detected a tendency for treated cows to produce 0.8 kg/d more milk than control cows in wk 1 after calving. We observed no difference between groups in the time from calving to first insemination or the probability of pregnancy at the first insemination. Groups did not differ in the proportion of anovular cows at 53 ± 3 d in milk based on serum progesterone measured from a subset of cows (38.0 and 34.3%, respectively, for treated and control groups). We found no difference between groups in dry matter intake from 21 d before calving to 63 d after calving in a subset of cows (17.4 ± 0.4 and 17.5 ± 0.4 kg/d, respectively). Based on results of the current study, biweekly (every 14 d) administration of rbST before calving to prevent disease and enhance performance is not recommended.     

Prepartum stocking density: Effects on metabolic,health, reproductive,and productive responses

The objectives of the current experiment were to determine the effects of 2 prepartum stocking densities on milk yield, concentration of metabolites during the peripartum period, and health and reproductive parameters of dairy cows. Jersey cows enrolled in the experiment at 254 ± 3 d of gestation were balanced for parity (nulliparous vs. parous) and previous lactation projected 305-d mature equivalent milk yield (parous) and assigned to 1 of 2 treatments: 80% headlock stocking density (80SD; 38 animals/48 headlocks) and 100% headlock stocking density (100SD; 48 animals/48 headlocks). The number of experimental units was 8 (4 replicates and 2 pens/treatment per replicate). In total, 154 nulliparous and 184 parous animals were enrolled in the 80SD treatment and 186 nulliparous and 232 parous animals were enrolled in the 100SD treatment. At the start of each replicate, treatments were switched within pen. Cows were milked thrice daily and monthly milk yield, fat and protein content, and somatic cell count data were recorded up to 155 d postpartum. Plasma nonesterified fatty acid concentration was measured weekly, from −18 ± 3 to 17 ± 3 d relative to calving, and plasma β-hydroxybutyrate was measured weekly, from 1 ± 2 to 17 ± 3 d relative to calving. Cows were examined 1, 4 ± 1, 7 ± 1, 10 ± 1, and 13 ± 1 d relative to calving for diagnosis of uterine diseases. Blood was sampled for determination of progesterone concentration and resumption of ovarian cycles 35 ± 3 and 45 ± 3 d relative to calving. Average headlock (74.1 ± 0.4 vs. 94.5 ± 0.3%) and stall (80.8 ± 0.4 vs. 103.1 ± 0.4%) stocking density was lower for the 80SD treatment compared with the 100SD treatment. Treatment did not affect incidence of retained fetal membranes (80SD = 5.1, 100SD = 7.8%), metritis (80SD = 21.2, 100SD = 16.7%), acute metritis (80SD = 9.9, 100SD = 9.4%), and vaginal purulent discharge (80SD = 5.8, 100SD = 7.9%). Concentrations of nonesterified fatty acids (80SD = 251.5 ± 6.1, 100SD = 245.9 ± 5.6 μmol/L) and β-hydroxybutyrate (80SD = 508.2 ± 14.3, 100SD = 490.9 ± 13.6 μmol/L) were not different between treatments. Treatment had no effect on percentage of cows removed from the herd on the first 60 d postpartum (80SD = 6.1, 100SD = 5.1%) and on rate of removal from the herd up to 305 d postpartum 80SD = referent, 100SD [adjusted hazard ratio (95% confidence interval)] = 1.02 (0.75, 1.38). Percentages of cows pregnant to first (80SD = 41.9, 100SD = 48.4%) and second (80SD = 49.3, 100SD = 42.0%) postpartum AI were not different between treatments. Finally, treatment did not affect energy-corrected milk yield up to 155 d postpartum (80SD = 33.8 ± 0.5, 100SD = 33.4 ± 0.5 kg/d). In herds with weekly or twice weekly movement of new cows to the prepartum pen and separate housing of nulliparous and parous animals, a target stocking density of 100% of headlocks on the day of movement is not expected to affect health, metabolic, reproductive, and productive parameters.     

Associations between herd-level factors and lying behavior of freestall-housed dairy cows

Our objective was to investigate the associations between herd-level factors and lying behavior of high-producing dairy cows housed in freestall barns. Lying behavior of approximately 40 focal cows in one high-producing pen was monitored on each of 40 farms in the northeastern United States (NE) and 39 farms in California (CA). All cows within the pen were gait scored using a 1-to-5 scale to calculate the prevalence of clinical lameness (score ≥3) and severe lameness (score ≥4). Facility and management measures, including stall design, bedding, and flooring type within the pen, were collected. Herd-level factors associated with daily lying time, standard deviation (SD) of daily lying time, frequency of lying bouts, and lying bout duration at the univariate level were submitted to multivariable general linear models. In the NE, daily lying time increased with the use of deep bedding (estimate = 0.80 ± 0.31 h/d) and as average days in milk (DIM) of the focal cows increased (estimate = 0.08 ± 0.04 h/d for a 10-d increase in DIM). The SD of daily lying time decreased as stall stocking density increased (estimate = −0.08 ± 0.03 h/d for a 10% increase), and increased with the presence of rubber flooring in the pen (estimate = 0.16 ± 0.08 h/d) and percentage of stalls with fecal contamination (estimate = 0.04 ± 0.01 h/d for a 10% increase). Frequency of lying bouts decreased (estimate = −1.90 ± 0.63 bouts/d) and average bout duration increased (estimate = 15.44 ± 3.02 min) with the use of deep bedding. In CA, where all farms used deep bedding, daily lying time increased as average DIM of the focal cows increased (estimate = 0.08 ± 0.03 h/d for a 10-d increase). The SD of daily lying time decreased when feed was delivered more than once per day (estimate = −0.24 ± 0.08 h/d). The percentage of lame cows was correlated with the percentage of stalls with fecal contamination (r = 0.45), which in turn was associated with fewer (estimate = −0.25 ± 0.06 bouts/d) and longer lying bouts (estimate = 1.85 ± 0.39 min/d). These findings suggest that lying time be interpreted in conjunction with variability in lying time and bout structure and in context with lameness prevalence, production parameters, and facility characteristics.