Diagnosis of uterine and vaginal disorders by different methodologies is affected by concentration of estradiol in plasma from lactating Holstein cows.

The relationship between plasma estradiol concentration at time of examination and prevalence of uterine disorders, agreement among methods, and associations of diagnosis with pregnancy hazard and milk yield was studied in 268 Holstein cows examined at 30±3 (exam 1) and 44±3 d in milk (DIM; exam 2). Purulent vaginal discharge was sampled using 2 methods: gloved hand and Metricheck (Simcro, Hamilton, New Zealand; PVD; score ≥3). Percentage of polymorphonuclear leukocytes was determined by endometrial cytology (CYTO; exam 1: ≥18%, exam 2: ≥10%); diameter of uterine horns (UTH; >20 mm), diameter of the inner layer of the cervix (CVX; >20.5 mm), presence of fluid in the uterine lumen (FL), and ovarian structures were evaluated by ultrasonography. A blood sample was collected at each exam for estradiol analysis. Prevalence at exams 1 and 2 was, respectively, 14.2 and 18.5% (PVD), 21.4 and 10.1% (FL), and 40.6 and 50.2% (CYTO). Prevalence of PVD at exam 1 was greater among cows with estradiol ≥2 pg/mL (19.4 vs. 8.2%). Agreement of all methods with CYTO was poor, the greatest being between CYTO and FL (exam 1; kappa=0.19). Agreement between CYTO and PVD, and between CYTO and FL (exam 1; kappa=0.15 and 0.35, respectively) was higher among cows with estradiol ≥2 pg/mL. Likelihood of PVD at exam 1 was greater if cows were positive for CVX [odds ratio (OR)=3.0], FL (OR=2.6) or had estradiol ≥2 pg/mL (OR=2.7). Likelihood of CYTO increased with dystocia (OR=2.3) and FL (OR=2.5). Estradiol did not influence diagnosis at exam 2. Positive FL or CYTO at exam 1 was associated with reductions in milk yield of 59 to 180 kg by 45 DIM. Pregnancy hazard until 250 DIM was reduced by CYTO at exam 1 (hazard ratio=0.74) and by PVD (hazard ratio=0.68) at exam 2. However, FL and CYTO reduced pregnancy hazard only when estradiol was ≥2 pg/mL (exam 1), whereas PVD reduced pregnancy hazard when diagnosed at exam 2 with estradiol <2 pg/mL. Overall, agreement was poor and effects of positive diagnosis differed according to method and DIM at exam. Estradiol concentration influenced prevalence, agreement, likelihood of positive diagnosis, and its effects on days to pregnancy.

Factors affecting expression of estrus measured by activity monitors and conception risk of lactating dairy cows.

The objective of this study was to determine risk-factors affecting increase in physical activity during estrus and pregnancy per artificial insemination (P/AI) in lactating dairy cows. Cows were monitored continuously by 2 automated activity monitors [a collar-mounted accelerometer (HT; Heatime, SCR Engineers, Netanya, Israel) and a leg-mounted pedometer (BO; Boumatic Heat-seeker-TX, Boumatic Dairy Equipment, Madison, WI)]. When an increase in activity was detected, body condition score (BCS) and blood samples were collected, ovaries were scanned by ultrasonography, and, if the cow was eligible for breeding, artificial insemination was performed. Milk production and health-related data were recorded throughout the experimental period. Pregnancy diagnosis was performed at 42 ± 7 d of gestation. Data were analyzed using Pearson correlation, ANOVA, and logistic regression. A total of 1,099 true events of estrus from 318 lactating Holstein cows were recorded, averaging 3.46 ± 1.1 events per cow. Positive predictive value for estrus episodes detected by the HT and BO systems were 89.6 and 85.5%, respectively. Mean peak activity at estrus (PA) recorded by the HT system was 71.6 ± 20.7 index-value, and 334.3 ± 155.7% relative increase by the BO system. Compared with primiparous, multiparous cows expressed estrus with lower PA (69.3 ± 0.8 vs. 75.9 ± 1.1 index for HT; 323.9 ± 6.0 vs. 354.8 ± 8.48% for BO) and shorter duration (DU; 10.7 ± 0.2 vs. 12.0 ± 0.3 h); DU was measured by HT only. Lower BCS was associated with decreased PA measured by both systems, estrus DU, and P/AI. Peak activity was weakly correlated with milk production on the day of artificial insemination (r = -0.20); however, when categorized into quartiles, the highest-yield cows had lower PA and DU. Follicle diameter was not correlated with PA or DU, but cows with greater concentrations of estradiol had higher PA. Cows with greater PA in both systems had greater P/AI than those with lower PA (36.5 vs. 24.6% for HT, 33.5 vs. 21.4% for BO). In conclusion, measurements of estrus events captured by automated activity monitors are correlated with BCS, parity, and secondary behavior signs related to estrus. Surprisingly, estrus intensity and duration were only weakly correlated with milk production, preovulatory follicle diameter, and concentrations of estradiol at estrus. Cows that had measurements of high-intensity estrus were significantly more fertile than low-intensity estrus.

Feeding a higher forage diet prepartum decreases incidences of subclinical ketosis in transition dairy cows.

A common feeding practice during the dry period is to switch dairy cows to an energy-dense diet 3 wk prepartum, but this practice may lead to the overconsumption of energy and increase the risk of metabolic disease postpartum. The aim of this trial was to compare the metabolic status of transition Holstein dairy cows fed a 77% forage diet (77F; NEl = 1.46 Mcal/kg; NDF = 41%) vs. those fed an 87% forage diet (87F; NEl = 1.41 Mcal/kg; 48% NDF). Approximately 60 d before calving, cows were dried off, housed in a free stall barn, and fed the 87F diet. Three weeks before expected calving, cows were randomly assigned to either the 77F treatment and switched to this diet (n = 45) or assigned to the 87F treatment and stayed on the dry cow ration until parturition (n = 42). After parturition, all cows were fed a common lactation diet (NEl = 1.59 Mcal/kg; 36% NDF). Dry matter intake was measured daily from 2 wk before to 2 wk after calving. Blood was sampled daily for 10 d postpartum. Subclinical ketosis was diagnosed using a threshold of ß-hydroxybutyrate (BHBA) ≥ 1.0 mmol/L after calving. The percentage of cows pregnant and odds of being pregnant for each treatment group were determined at 60, 90, and 120 d in milk through ultrasound by the herd veterinarian. Cows on the 87F diet consumed less DM prepartum than those on the 77F diet (12.7 ± 0.3 kg/d vs. 15.4 ± 0.3 kg/d, P < 0.001), but no difference in DMI was detected after calving (19.7 ± 5.5 kg/d; P = 0.87). Although the calculated prepartum required energy intake was the same for the 2 treatments (15.3 ± 1.2 Mcal/d; P = 0.16), cows on the 77F diet consumed 4.5 Mcal/d more than those on the 87F diet (22.5 ± 0.5 Mcal/d vs. 18.0 ± 0.5 Mcal/d; P < 0.001). Postpartum concentration of BHBA was less for cows fed the 87F diet prepartum (0.49 ± 0.02 mmol/L vs. 0.59 ± 0.02 mmol/L; P = 0.02), and fewer animals on this diet were diagnosed subclinical ketosis (SCK; 49% vs. 17%; P = 0.001). Milk production tended to be less for cows fed the 87F diet prepartum (47.3 ± 0.4 kg/d vs. 48.8 ± 0.4 kg/d; P = 0.10) for the first 22 wk of lactation, which was significant for d 7 to 28 of lactation (44.6 ± 1.1 kg/d vs. 47.6 ± 1.0 kg/d; P = 0.05). Although sample size was small to draw strong conclusions on reproductive performance, at 120 d in milk, cows on the 87F diet were 0.3 times more likely to be pregnant (P = 0.03). These results indicate that feeding an 87F diet before calving can reduce rates of SCK in transition dairy cows.

Postweaning performance of heifers fed starter with and without hay during the milk-feeding period.

This study assessed the carryover effects of providing forage during the milk-feeding period on postweaning feed intake and growth of heifers. At 11 wk of age, heifers previously (3 to 77 d of age) reared on starter (n=8) or starter plus grass hay (n=8) were switched to a single diet consisting of restricted amounts of concentrate [60% of the starter required to support daily body weight (BW) gain of 800 g] with ad libitum access to coarsely chopped orchardgrass hay. Feed intake and growth were measured from 11 to 18 wk of age. Starter dry matter (DM) intake averaged 2.14 ± 0.15 kg/d for both treatments. Forage consumption and total (starter plus hay) DM, neutral detergent fiber, crude protein, and metabolizable energy intakes were greater in heifers previously fed forage compared with those provided no forage. Initial and final BW were similar for the 2 treatments (108.2 ± 9.1 and 149.6 ± 9.3 kg, respectively). Overall average daily gain in heifers previously fed starter alone (0.92 ± 0.05,kg/d) tended to be greater than those previously fed starter plus hay (0.79 ± 0.06,kg/d). Total DM intake (starter plus hay) was lower in heifers previously fed starter alone than those fed starter plus hay (3.55 ± 0.13 vs. 4.08 ± 0.15 kg/d, respectively). Feed efficiency (BW gain/DM intake) after switching to a common diet was greater in calves previously fed starter alone than in those previously fed starter plus hay (0.26 ± 0.01 vs. 0.19 ± 0.01, respectively). However, heifers provided access to hay had a smaller body barrel (an indicator of gut fill) at 15 wk (127.7 ± 1.7 vs. 134.3 ± 2.7 cm) and 17 wk (132.4 ± 1.9 vs. 141.0 ± 2.2 cm) of age and had greater blood ß-hydroxybutyrate (0.22 ± 0.04 vs. 0.32 ± 0.04 mmol/L) compared with heifers that did not have access to hay earlier in life. These results indicate that provision of hay early in life promotes forage intake when heifers are switched to a high forage diet. However, greater feed consumption did not translate into live BW gain. Higher feed efficiency after switching to a common diet in heifers previously fed starter alone compared with those fed starter plus hay must be viewed with caution because intestinal content likely varied between treatment groups.

Evaluation of a system for monitoring rumination in heifers and calves.

The Hi-Tag electronic rumination-monitoring system (SCR Engineers Ltd., Netanya, Israel), based on capturing audio recordings, provides a reasonable measure of rumination time in dairy cows, but has not been validated for milk-fed or weaned heifers. The objective of this study was to validate the Hi-Tag rumination-monitoring system in heifers and calves and to assess whether suckling from a teat interfered with recording from this system. Assessments of 2 independent observers were highly correlated (r=0.99, n=20), indicating that direct visual observations provide a useful standard. Measures from the Hi-Tag system were validated by comparing values with those from a single human observer, using observations from three 2-h intervals from 35 Holstein calves and heifers aged 4, 6, and 9 wk and 3, 6, and 9 mo, respectively. In 9-mo-old heifers, rumination times obtained from the electronic system were highly correlated with visual observations (r=0.88, R2=0.77, n=15), and the mean difference was minor (-4±8 min/2-h interval). The accuracy of data from the automated system decreased when used on heifers less than 9 mo old. Suckling did not interfere with the electronic system (r=-0.1, n=18). These results indicate that the Hi-Tag system is an accurate tool for monitoring rumination behavior in Holstein Friesian heifers from the age of 9 mo.

Technical note: Comparison of rectal and vaginal temperatures in lactating dairy cows.

A method commonly used to identify illness in dairy cows is measuring body temperatures with a rectal thermometer, but vaginal measures are becoming common in research. The primary objective of this study was to validate vaginal measures of body temperature by comparing them with rectal temperatures. Data loggers used to collect vaginal temperatures can be programmed to collect many readings per day, providing an opportunity to interpret effects of health in relation to diurnal differences in temperatures. Thus, a secondary objective was to compare the diurnal pattern in body temperatures for cows with and without retained placenta (RP). Body temperature was monitored for 8 d in 29 cows that had recently calved (enrolled 2 d after calving; 7 of these cows were diagnosed with RP) and in 13 cows in peak lactation (98±8 d in milk). Rectal temperatures were taken at 0630, 0930, 1230, 1530, 1830, and 2130h (±30 min) with a digital thermometer for 8 d consecutively. During the same period, vaginal temperatures were measured every 10 min with a microprocessor-controlled data logger attached to a modified vaginal controlled internal drug release insert. Values from the vaginal loggers were averaged over 1h and paired with the corresponding rectal temperature. There was a relationship between rectal and vaginal temperatures for fresh cows (n=1,393; r=0.81) and for peak-lactation cows (n=556; r=0.46). Cows with RP had higher body temperatures (39.2±0.01) compared with healthy cows (39.1±0.01). Body temperature was higher at night, and lower between 0800 to 1000 h for healthy cows (39.0±0.02) and between 1100 to 1300 h for RP cows (39.1±0.02). In summary, vaginal temperatures were associated with rectal measures, and provided the advantage of capturing dirurnal changes in body temperature.

Technical note: Evaluation of a scoring system for rumen fill in dairy cows.

Changes in feed intake are useful in early detection of disease in dairy cows. Cost and complexity limit our ability to monitor dry matter intake (DMI) of individual cows kept in loose-housing systems. A 5-point subjective scoring system has been developed to visually describe rumen fill, but no work to date has evaluated these scores as an indicator of feed intake. The objective of this study was to evaluate the performance of within-cow changes in visual rumen fill scores as estimates of changes of DMI and feed intake in dairy cows. Our results illustrate that rumen fill scored on a scale from 1 to 5 has substantial intra- (Cohen's kappa coefficient=0.69) and interobserver (Cohen's kappa coefficient=0.68) repeatability. Within-cow changes in visual rumen fill score are correlated with changes in DMI (Spearman's rank correlation=0.68). The depth of the paralumbar fossa (mean +/- SD; 5.6+/-0.9 cm) changes considerably (up to 4.8 cm) within 70+/-5 min. This more objective measure was also correlated with visual rumen fill scores (Spearman's rank correlation=-0.62). Our results indicate that subjective rumen fill scores are statistically associated with both an objective measure of paralumbar fossa indentation and feed intake. However, much of the variation in visual rumen fill scores is not associated with either measure, suggesting that caution is required in clinical usage of these scores.

Effects of sawdust bedding dry matter on lying behavior of dairy cows: a dose-dependent response.

The objective was to determine the effect of sawdust bedding dry matter on the lying behavior of Holstein cows. Dry matter (DM) was varied systematically over 5 treatment levels to test how cows respond to damp bedding. This experiment was repeated during summer and winter to test if the effects of damp bedding varied with season. The 5 bedding treatments averaged (+/-SD) 89.8+/-3.7, 74.2+/-6.4, 62.2+/-6.3, 43.9+/-4.0, and 34.7+/-3.8% DM. Over the course of the trial, minimum and maximum temperatures in the barn were 2.6+/-2.0 and 6.8+/-2.2 degrees C in the winter and 13.3+/-2.5 and 22.6+/-4.1 degrees C in the summer. In both seasons, 5 groups of 3 nonlactating cows were housed in free stalls bedded with sawdust. Following a 5-d acclimation period on dry bedding, groups were exposed to the 5 bedding treatments in a 5 x 5 Latin square. Each treatment lasted 4 d, followed by 1 d when the cows were provided with dry bedding. Stall usage was assessed by 24-h video scanned at 5-min intervals. Responses were analyzed within group (n=5) as the observational unit. Bedding DM affected lying time, averaging 10.4+/-0.4 h/d on the wettest treatment and increasing to 11.5+/-0.4 h/d on the driest bedding. Lying time varied with season, averaging 12.1+/-0.4 h/d across treatments during the winter and 9.9+/-0.6 h/d during the summer, but season and bedding DM did not interact. These results indicate that access to dry bedding is important for dairy cows.

Short communication: repeatability of measures of rectal temperature in dairy cows.

Although taking body temperature by rectal thermometer is the method most commonly used to identify sick cows in the postpartum period, no data on the repeatability of this measure are available. The overall objective of this study was to evaluate variability of rectal temperatures in dairy cows considering different factors (intra- and interinvestigator repeatability, different thermometers, penetration depth into the rectum, and defecation). High coefficients of correlation (r=0.98) and small differences between values of rectal temperatures (observer A=39.3+/-1.0 degrees C and observer B=39.4+/-1.0 degrees C) provide evidence that rectal temperature was a repeatable measure in dairy cows. Testing was carried out using 4 different digital thermometers: GLA M750 (GLA Agricultural Electronics, San Luis Obispo, CA), MTI8101 (SES Scala Electronics, Stahnsdorf, Germany), MT1831 (Microlife AG, Widnau, Switzerland) and Domotherm TH1 (Uebe Medical GmbH, Wertheim, Germany). Thermometers were inserted into the rectum to a certain depth (GLA M750 and MTI8101=11.5cm; MT1831=8.4cm; Domotherm TH1=7.7cm) and a measure was finished when a visual or acoustic signal was emitted by the thermometer. The measures could be influenced by the procedure itself (up to 0.5 degrees C), type of thermometer (up to 0.3 degrees C), and the penetration depth (11.5cm or 6.0cm in one of the experiments) into the rectum (up to 0.4 degrees C difference between a penetration depth of 11.5cm and 6.0cm in one of the experiments). Differences in rectal temperature before and after defecation were minor (<0.1 degrees C). These results indicate that some care is required in generalizing rectal measures of body temperature.

Inducing active and passive immunity in sheep to paralysis caused by Dermacentor andersoni.

Arcott sheep were evaluated as a model for studying active and passive immunity to tick paralysis caused by Dermacentor andersoni (Stiles). The incidence of tick paralysis in sheep increased from 0 at doses < or = 0.33 ticks per kg to 100% at > or = 0.8 ticks per kg. The dose required for 50% paralysis was 0.42 ticks per kg. Expressing dose as a ratio of initial ticks per unit body weight removed differences in response due to sheep weight. The interval from infestation to paralysis decreased from >12 d at 0.4 ticks per kg to <8 d at 1.3 ticks per kg. After exposure to a paralyzing doses of ticks, the incidence of paralysis varied among sheep that were naive (six of six, 100% paralysis), previously paralyzed (zero of six, 0% paralysis), and passively immunized with an intravenous treatment of 300 ml of serum from immune cattle (two of six, 33% paralysis). Sheep that were actively immunized by previous exposure had antibodies to a greater number of tick salivary antigens compared with those that were not immune. Antibodies to a 43.3-kDa antigen had 72% agreement with immunity to paralysis, and a sensitivity and specificity of 0.60 and 0.88, respectively. In conclusion, previously paralyzed sheep had developed antibodies against D. andersoni and were not susceptible to subsequent paralysis, whereas passive immunization conferred protection against paralysis in only some sheep.

Technical note: Validation of a system for monitoring rumination in dairy cows.

Increased rumination in dairy cattle has been associated with increased saliva production and improved rumen health. Most estimates of rumination are based on direct visual observations. Recently, an electronic system was developed that allows for automated monitoring of rumination in cattle. The objective was to validate the data generated by this electronic (Hi-Tag, SCR Engineers Ltd., Netanya, Israel) rumination monitoring system. Assessments of 2 independent observers were highly correlated (r = 0.99, n = 23), indicating that direct human observations were suitable as the reference method. Measures from the Hi-Tag electronic system were validated by comparing values with those from a human observer for fifty-one 2-h observation periods from 27 Holstein cows. Rumination times (35.1 +/- 3.2 min) from the electronic system were highly correlated with those from direct observation (r = 0.93, R(2) = 0.87, n = 51), indicating that the electronic system was an accurate tool for monitoring this behavior in dairy cows.

Prepartum feeding behavior is an early indicator of subclinical ketosis.

Cows diagnosed with subclinical ketosis (SCK) after calving are at increased risk of developing other diseases and compromised reproductive performance. The objective of this study was to determine whether changes in feeding and social behaviors during the transition period were associated with SCK during the week after calving. Feeding behaviors of 101 Holstein dairy cows were monitored from 3 wk before to 3 wk after calving. Ten otherwise healthy animals were identified as having SCK by serum beta-hydroxybutyrate levels >or=1,000 micromol/L taken during wk +1. These animals were matched by parity with 10 healthy animals. During the week before calving and the 2 wk after calving, animals with SCK had lower dry matter intake, had fewer visits to the feeder, and spent less time at the feeder than healthy animals. For every 10-min decrease in average daily time spent at the feeder during the week before calving, the risk of SCK increased by 1.9 times. During the same week, a 1-kg decrease in average daily dry matter intake increased the risk of SCK by 2.2 times. The largest increase in risk of SCK was associated with a 1-kg increase in the change in average daily intake from wk -2 to -1. During the week before calving, animals with SCK initiated fewer displacements at the feed bunk compared with animals that remained healthy after calving. The results of this study provide evidence that time spent feeding, dry matter intake, and social behavior play an important role in transition cow health. These results indicate that special consideration should be given to management and social factors that can negatively affect dry matter intake and feed bunk attendance during the transition period.

The stall-design paradox: neck rails increase lameness but improve udder and stall hygiene.

Housing conditions for dairy cows are thought to affect lameness, but almost no experimental work has addressed this link. The aim was to assess the effect of one feature of free-stall design, the position of the neck rail, testing the prediction that cows will be more likely to become lame if using pens with the neck rail positioned such that it prevents standing fully inside the stall. Cows (n = 32) were housed in 8 pens. Treatments were tested using a crossover design; treatments were allocated alternately to pens at the beginning of the experiment and switched halfway through the 10-wk experiment. Cows spent 27 +/- 3 min/d standing with all 4 feet in stalls with less restrictive neck rails. In contrast, cows averaged just 1 +/- 3 min/d when the neck rail was positioned restrictively. Cows spent less time standing with only the front 2 feet in the stall with less restrictive neck rails (33 vs. 49 +/- 6 min/d). Gait scores improved when cows were kept in the less restrictive stalls and worsened when cows were kept in pens with the restrictive neck rail (median score 2.5 vs. 3.5 after 5 wk on treatment). Of 13 new cases of lameness, 11 occurred in pens with the restrictive neck-rail position. Similarly, of the 16 new cases of sole lesions, 15 occurred during the period when cows were housed in pens with a restrictive neck rail. Stalls with the neck rail positioned less restrictively had higher contamination scores than stalls with the restrictive neck rails (3.7 vs. 0.4 +/- 0.2), and cows using those stalls had dirtier udders and longer teat-cleaning times (8.3 vs. 7.0 +/- 0.2 min for 12 cows). This study provides the first experimental evidence that aspects of stall design can reduce the risk of lameness and hoof disease. The results illustrated that changes in design that resulted in improvements in cow comfort and hoof health came at the expense of cow and stall cleanliness.

Competition at the feed bunk changes the feeding, standing, and social behavior of transition dairy cows.

Transition dairy cows are vulnerable to the negative consequences of depressed feed intake around calving. Competition can decrease feeding activity in midlactation cows, but the effects of competition on the transition cow are not well understood. The objective was to test the effect of competition on the behavior and feed intake of transition cows. Standing behavior, feeding behavior, and dry matter intake were monitored from 1 wk before to 2 wk after calving for 36 Holstein dairy cows. Displacements at the feed bins were recorded the week before calving. Cows were assigned to either competitive (2:1 cows:feed bin) or noncompetitive (1:1 cow:feed bin) treatments. Treatment groups were balanced for parity and baseline feeding measures, resulting in 8 primiparous and 10 multiparous cows per treatment. Competition increased the number of displacements at the feed bins for both primiparous and multiparous cows. Primiparous cows had no change in feed intake or standing time when fed in a competitive environment, but did increase the time spent for each meal during the week before calving (28 +/- 1.5 vs. 24 +/- 1.5 min/meal). In the week before and after calving, competitively fed multiparous cows had a lower feeding time per visit than noncompetitively fed cows (4.2 +/- 0.5 vs. 5.8 +/- 0.5 kg/visit and 5.3 +/- 0.7 vs. 7.0 +/- 0.7 kg/visit, respectively). Multiparous cows ate at a faster rate 2 wk after calving (142 +/- 11 vs. 105 +/- 11 g/min). Multiparous cows in the competitive treatment increased the time they spent standing (without eating) during the week after calving compared with cows in the noncompetitive treatment (820 +/- 44 vs. 649 +/- 44 min/d). Feeding rate was correlated with a displacement index in multiparous cows, whereby cows with lower displacement indices ate more rapidly. Results indicate that restricting access to feed increases displacements regardless of parity, and alters the feeding and standing behavior of primiparous and multiparous cows differently.

Neck-rail position in the free stall affects standing behavior and udder and stall cleanliness.

This study tested the effect of neck-rail position on stall usage and udder and stall cleanliness. Thirty Holstein lactating cows were tested in groups of 6. Each group was tested with each of 5 neck-rail positions (130, 145, 160, 175, and 190 cm from the rear curb, at a constant height of 125 cm above the bedded surface) for 1 wk, with the order of testing allocated in a 5 x 5 Latin square. When the neck rail was positioned further from the rear curb, cows spent less time standing with their front 2 hooves in the stall (2.2 +/- 0.26 h/d at 130 cm vs. 1.7 +/- 0.27 h/d at 190 cm, mean +/- SE) and more time standing with all 4 hooves in the stall (0.0 +/- 0.02 h/d at 130 cm vs. 0.6 +/- 0.07 h/d at 190 cm). These effects of neck-rail position tended to be more marked for smaller cows, perhaps because the standing behavior of larger cows was restricted even in the 190-cm treatment. Cows were more likely to defecate and urinate in the stalls when the neck rail was positioned further from the rear curb. Cows using these stalls tended to have dirtier udders and these stalls required more cleaning time (0.4 +/- 0.16 min/d at the 130-cm position vs. 1.6 +/- 0.35 min/d at the 190-cm position). In summary, positioning the neck rail further from the curb increased the time that cows spent standing fully in the stall. This change in standing behavior is likely beneficial for hoof health, but reduced udder and stall cleanliness.

Cattle can develop immunity to paralysis caused by Dermacentor andersoni.

Cattle exposed to a paralyzing strain of Dermacentor andersoni (Stiles) were all paralyzed during an initial exposure, but the incidence of paralysis decreased to 17 and 0% after two subsequent exposures to virulent flat ticks. Cattle with a single exposure to paralyzing ticks became paralyzed when challenged with ticks that had been prefed on cattle. Western blots indicated that cattle developed antibody responses to 13 antigens in paralyzing tick saliva. The likelihood of paralysis was inversely related to the number of saliva proteins that cattle developed antibody responses to. Cattle challenged with prefed ticks developed antibody response to fewer saliva antigens than cattle challenged with flat ticks. Variation in tick dose did not influence the expression of paralysis. Daily survival of ticks was similar on all groups of cattle, and tick weight was not reduced on previously challenged cattle, indicating immunity developed to the paralysis toxin rather than tick feeding. Four saliva antigens (molecular weights ranging from 36.9 to 42.2 kDa) were associated with the development of immunity to paralysis.

Short communication: Haptoglobin as an early indicator of metritis.

The purpose of this study was to determine whether haptoglobin (Hp) could be used as a predictive measure for metritis. Cattle were grouped into 3 health categories based on the condition of vaginal discharge and body temperature after calving: severe metritis (n = 12), mild metritis (n = 32), and healthy (n = 23). Blood was collected and analyzed for Hp concentration on d -20 +/- 5, -6 +/- 2, -2 +/- 1, and d 0 relative to calving, and then every 3 d after calving until d +21. Cows with mild and severe metritis had greater Hp concentrations than healthy cows between d 0 and d +12. Mean (+/-SE) Hp concentrations peaked on d +3 in the cows with mild metritis (1.06 +/- 0.15 g/L) and on d +6 in cows with severe metritis (1.62 +/- 0.47 g/L). Mean concentrations for the healthy group were 0.58 +/- 0.12 g/L and 0.31 +/- 0.08 g/L on d +3 and d +6, respectively. Clinical signs of pathological discharge for the mildly and severely metritic cows did not occur until, on average, 8.6 +/- 3.9 d and 5.3 +/- 1.9 d after calving, respectively. Cows with Hp concentrations >or=1 g/L on d +3 were 6.7 times more likely to develop severe or mild metritis; this predictive threshold has a sensitivity of 50% and specificity of 87%. These results indicate that an acute phase inflammatory response precedes clinical metritis and that Hp screening may assist in the early detection of metritis, providing increased opportunities for early treatment and prevention.

Short communication: dominance in free-stall-housed dairy cattle is dependent upon resource.

The main objective was to assess the consistency in competitive success across 3 common resources available to dairy cows housed in free-stall barns. Specifically, we determined if those cows that displaced other cows most often at the feed bunk (high-ranking) had priority of access to free-stalls or a mechanical brush. Our secondary objective was to determine if the displacements at each resource were a function of usage of that resource. These objectives were tested using 6 groups of 12 lactating dairy cows housed in pens with 0.6 m of bunk space per cow, 1 free-stall per cow, and 1 mechanical brush per pen. Time-lapse video was used to quantify the time spent feeding, in the stalls, and using the mechanical brush. The incidence of displacements at the feed alley and lying area was measured for 3 d consecutively. Usage was lower for the brush, so displacements were monitored for 14 d consecutively. The individual measures of competitive success were not highly correlated between resources indicating a cow that frequently displaced other cows for access to one particular resource did not always do so when accessing the other resources. Competition at the feeder was responsible for 87.6 +/- 1.4% of displacements observed throughout the experiment, indicating that gaining access to feed was a high priority for cows. These results suggest that competitive success by dairy cows may vary according to each cow's motivation to access the resource.

The effects of feed bunk competition on the feed sorting behavior of close-up dry cows.

The objectives of this research were to describe the feed sorting, feeding behavior, and feed intake of cows consuming a close-up ration and to determine if these behaviors are affected by competition for access to the feed bunk. Thirty-six dry Holstein cows, consuming a close-up total mixed ration diet, were assigned to 1 of 2 treatments: 1) noncompetitive (1 cow/feed bin) or 2) competitive (2 cows/feed bin). Dry matter intake, feeding behavior, and sorting behavior were monitored for each feed bin on 4 separate days during wk 2 and 3 before the anticipated calving dates of the cows. Fresh feed and orts were sampled daily from each bin and were subjected to particle size analysis. The particle size separator consisted of 3 screens (18, 9, and 1.18 mm) and a bottom pan resulting in 4 fractions (long, medium, short, and fine). Sorting was calculated as the actual intake of each particle size fraction expressed as a percentage of the predicted intake of that fraction. Regardless of treatment, the cows sorted against long particles and for short and fine particles. Competition at the feed bunk had no effect on the sorting behavior, dry matter intake, or feeding time of the cows, but did dramatically increase the feeding rate of the cows. The competitively fed cows also had fewer meals per day, and tended to have larger and longer meals. Our results suggest that increased competition at the feed bunk promotes feeding behavior patterns that will likely increase the between-cow variation in composition of total mixed ration consumed.

Effects of bedding quality on lying behavior of dairy cows.

Cows prefer to spend more time lying down in free stalls with more bedding, but no research to date has addressed the effects of bedding quality. Bedding in stalls often becomes wet either from exposure to the elements or from feces and urine. The aim of this study was to test the effect of wet bedding on stall preference and use. Four groups of 6 nonlactating Holstein cows were housed in free stalls bedded daily with approximately 0.1 m of fresh sawdust. Following a 5-d adaptation period, each group of cows was tested sequentially with access to stalls with either dry or wet sawdust bedding (86.4 +/- 2.1 vs. 26.5 +/- 2.1% dry matter), each for 2 d. These no-choice phases were followed by a 2-d free-choice phase during which cows had simultaneous access to stalls containing either wet or dry bedding. Stall usage was assessed by using 24-h video recordings scanned at 10-min intervals, and responses were analyzed by using a mixed model, with group (n = 4) as the observational unit. The minimum and maximum environmental temperatures during the experiment were 3.4 +/- 2.2 and 6.8 +/- 2.5 degrees C, respectively. When cows had access only to stalls with wet bedding, they spent 8.8 +/- 0.8 h/d lying down, which increased to 13.8 +/- 0.8 h/d when stalls with dry bedding were provided. Cows spent more time standing with their front 2 hooves in the stall when provided with wet vs. dry bedding (92 +/- 10 vs. 32 +/- 10 min/d). During the free-choice phase, all cows spent more time lying down in the dry stalls, spending 12.5 +/- 0.3 h/d in the dry stalls vs. 0.9 +/- 0.3 h/ d in stalls with wet bedding. In conclusion, dairy cows show a clear preference for a dry lying surface, and they spend much more time standing outside the stall when only wet bedding is available.