D.M. Veira

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.

Transmission and control of Escherichia coli O157:H7 — A review

Escherichia coli 157:H7 has evolved as an important foodborne pathogen since its initial description in 1982. Outbreaks of illness associated with E. coli O157:H7 have been reported throughout the northern hemisphere, most frequently in Canada, the United States, Japan, and the United Kingdom. In Canada, infections due to E. coli O157: H7 appear to be more common in the western provinces than in the east, in rural vs. urban environments, and during summer as opposed to winter months. Undercooked ground beef has been implicated as the primary vehicle in E. coli O157:H7 infection, but contaminated fruits, vegetables and water have also been linked to E. coli O157:H7 outbreaks. Epidemiological investigations demonstrate that dairy and beef cattle are primary reservoirs of this organism, carrying it asymptomatically and shedding it intermittently and seasonally in their feces. Surveys in Canada and the United States indicate widespread distribution of E. coli O157:H7 in cattle operations. The prevalence of E....

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.

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.

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 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.

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.

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.

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.

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.