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Dive into the research topics where Cassandra B. Tucker is active.

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Featured researches published by Cassandra B. Tucker.


Journal of Dairy Science | 2010

Evaluation of data loggers, sampling intervals, and editing techniques for measuring the lying behavior of dairy cattle

D.N. Ledgerwood; Christoph Winckler; Cassandra B. Tucker

Lying behavior in dairy cattle can provide insight into how cows interact with their environment. Although lying behavior is a useful indicator of cow comfort, it can be time consuming to measure. In response to these time constraints, using data loggers to automate behavioral recording has become increasingly common. We tested the accuracy of the Onset Pendant G data logger (Onset Computer Corporation, Bourne, MA) for measuring lying behavior in dairy cattle (n=24 cows; 12 in each of 2 experiments). Cows wore the logger on the lateral (experiment 1) or medial (experiment 2) side of the hind leg above the metatarsophalangeal joint. Loggers recorded behavior at 4 sampling intervals (6, 30, 60, and 300 s) for at least 1.5 d. Data were smoothed using 3 editing methods to examine the effects of short, potentially erroneous readings. For this purpose, Microsoft Excel macros (Microsoft Corp., Redmond, WA) converted readings (i.e., lying events bordered by standing or vice versa) occurring singly or in consecutive runs of ≤2 or ≤6. Behavior was simultaneously recorded with digital video equipment. The logger accurately measured lying and standing. For example, predictability, sensitivity, and specificity were >99% using 30-s sampling and the single-event filter compared with continuously scored video recordings. The 6- and 30-s sampling intervals were comparable for all aspects of lying behavior when short events were filtered from the data set. Estimates of lying time generated from the 300-s interval unfiltered regimen were positively related (R(2) ≥ 0.99) to estimates of lying time from video, but this sampling regimen overestimated the number of lying bouts. This is likely because short standing and lying bouts were missed (12 and 34% of lying and standing bouts were <300 s in experiment 1 and 2, respectively). In summary, the data logger accurately measured all aspects of lying behavior when the sampling interval was ≤30 s and when short readings of lying and standing were filtered from the data set.


Journal of Dairy Science | 2010

The amount of shade influences the behavior and physiology of dairy cattle

Karin E. Schütz; Andrea R. Rogers; Y.A. Poulouin; Neil R. Cox; Cassandra B. Tucker

The objective was to understand how the amount of shade (shade cloth blocking 99% of solar radiation) influenced the behavior and physiology of Holstein-Friesian dairy cattle managed on pasture. We compared behavior, body temperature, and respiration rate of cattle provided with 1 of 3 treatments for 5 d: access to 2.4m(2) or 9.6m(2) shade/cow, or no shade (n=4 groups/treatment, 10 animals/group). Behavioral observations were carried out between 1000 and 1550h. Cows spent more than twice as much time in the larger shade (24 vs. 50% of observations for 2.4m(2) and 9.6m(2) shade/cow, respectively, SED: 1.7%) and engaged in fewer aggressive interactions when more shade was provided (10.7 vs. 3.2 aggressive interactions/m(2) during 5.8h of observation for 2.4m(2) and 9.6m(2) shade/cow, respectively, SED: 3.16 interactions/m(2)). Time around the water trough increased when little or no shade was provided (11, 5, and 2% of observations within 4.5m of water trough for no shade, 2.4m(2), and 9.6m(2) shade/cow, SED: 2.4%). Respiration rate was higher when cows had less shade available (62, 57, and 51 breaths/min for no shade, 2.4m(2), and 9.6m(2) shade/cow, respectively, SED: 2.1 breaths/min). All cows used the shade more when 9.6m(2) shade/cow was provided; simultaneous use was observed in 15 versus 0% of observations in the 9.6m(2) and 2.4m(2) treatments on the warmest day, respectively. Weather conditions influenced both the behavioral and physiological responses, and these changes were more pronounced when less or no shade was available. Cows spent more time in shade and less time lying with increasing heat load. In addition, aggressive interactions in the shade, time around the water trough, mean body temperature, and respiration rate increased with environmental heat load. Our findings highlight the importance of determining and providing an effective amount of shade to cattle.


Journal of Dairy Science | 2010

Associations between cow hygiene, hock injuries, and free stall usage on US dairy farms

Jason E. Lombard; Cassandra B. Tucker; M.A.G. von Keyserlingk; C.A. Kopral; D.M. Weary

This cross-sectional study evaluated cow comfort measures in free stall dairies across the United States as part of the National Animal Health Monitoring Systems Dairy 2007 study. The study was conducted in 17 states and evaluations were completed between March 5 and September 5, 2007. Assessors recorded hygiene and hock scores, number of cows housed in the pen, the number of cows standing with only the front feet in a stall, standing fully in a stall, and lying in a stall. Facility design measures included bedding type, bedding quantity, stall length and width, presence of a neck rail or brisket locator, and relevant distances from the rear and bed of the stall. Of the 491 operations that completed the cow comfort assessment, 297 had Holstein cows housed in free stalls and were included in this analysis. Negative binomial models were constructed to evaluate the following outcomes: the number of cows that were very dirty, had severe hock injuries, stood with front feet in the stall, stood with all feet in the stall, and were lying in the stall. Hygiene was better on farms that did not tail dock cows compared with those that did (5.7 vs. 8.8% were dirty) and on farms located in the studys west region compared with those located in the east region (5.2 vs. 9.7% were dirty). Severe hock injuries were less common on farms in the west than those in the east (0.5 vs. 4.1%). In addition, severe hock injuries were less common on farms that used dirt as a stall base or sand as bedding compared with farms that did not. A higher percentage of cows was standing with front feet in the stall at higher ambient temperatures (incidence rate ratio=1.016) and as time since feeding increased (incidence rate ratio=1.030). A lower percentage of cows were standing with front feet in the stall when the stalls were shorter and when there were fewer cows per stall. Standing fully in a stall was performed by a higher percentage of cows during the summer than during the spring (13.6 vs. 8.1%), when cows were provided free stalls with rubber mats or mattresses, and as the distance from the rear curb to neck rail increased. A higher percentage of cows were lying in a stall when sand bedding was used, when bedding was added more frequently, and during the spring months. Results of this national survey indicate that tail docking provides no benefit to cow hygiene and that stall base and bedding are key factors influencing hock injuries and stall usage on US free stall dairy farms.


Journal of Dairy Science | 2011

Dairy cattle prefer shade over sprinklers: Effects on behavior and physiology

Karin E. Schütz; Andrea R. Rogers; Neil R. Cox; J.R. Webster; Cassandra B. Tucker

Cattle will readily use shade in warm weather, but less is known about voluntary use of sprinklers. We examined preferences of 96 Holstein-Friesian dairy cows (milk yield: 12.7±3.48 kg per day; mean±SD) for sprinklers, shade, or ambient conditions after walking 2.0 km or 0.3 km before afternoon milking (n=48 cows/distance). Each cow was individually tested on 3 consecutive days with a different paired choice each day: 1) shade or sprinklers, 2) shade or ambient conditions, 3) sprinklers or ambient conditions. Average air temperature during testing was 22.3°C. Cows preferred shade over sprinklers (62 vs. 38% ± 5.0%; mean ± SE) and shade over ambient conditions (65 vs. 35% ± 5.1%; mean±SE). Cows showed no preference between sprinklers and ambient conditions (44% of the cows chose sprinklers, SE=5.3%). The preference for shade over sprinklers and ambient conditions increased with air temperature, solar radiation, and wind speed. Walking distance did not influence the preference for any treatment. Respiration rate was decreased most by sprinklers (38% decrease) but also decreased in shade and ambient conditions (17 and 13% decrease, respectively; standard error of the difference=4.7%). Similarly, surface temperature was decreased most by sprinklers (11.4% decrease), compared with that by shade (1.0% decrease), or that by ambient conditions (1.4% increase; standard error of the difference=1.82%). Furthermore, sprinklers reduced insect avoidance behaviors, including number of tail flicks and hoof stamps. In conclusion, dairy cattle preferred to use shade in summer despite sprinklers being more efficient in decreasing heat load and insect avoidance behavior.


Journal of Dairy Science | 2009

Cow comfort in tie-stalls: Increased depth of shavings or straw bedding increases lying time

Cassandra B. Tucker; D.M. Weary; M.A.G. von Keyserlingk; K. A. Beauchemin

Over half of US dairy operations use tie-stalls, but these farming systems have received relatively little research attention in terms of stall design and management. The current study tested the effects of the amount of 2 bedding materials, straw and shavings, on dairy cattle lying behavior. The effects of 4 levels of shavings, 3, 9, 15, and 24 kg/stall (experiment 1, n = 12), and high and low levels of straw in 2 separate experiments: 1, 3, 5, and 7 kg/stall (experiment 2, n = 12) and 0.5, 1, 2, and 3 kg/stall (experiment 3, n = 12) were assessed. Treatments were compared using a crossover design with lactating cows housed in tie-stalls fitted with mattresses. Treatments were applied for 1 wk. Total lying time, number of lying bouts, and the length of each lying bout was recorded with data loggers. In experiment 1, cows spent 3 min more lying down for each additional kilogram of shavings (11.0, 11.7, 11.6, and 12.1 +/- 0.24 h/d for 3, 9, 15, and 24 kg/stall shavings, respectively). In experiment 2, cows increased lying time by 12 min for every additional kilogram of straw (11.2, 12.0, 11.8, and 12.4 +/- 0.24 h/d for 1, 3, 5, and 7 kg/stall of straw, respectively). There were no differences in lying behavior among the lower levels of straw tested in experiment 3 (11.7 +/- 0.32 h/d). These results indicated that additional bedding above a scant amount improves cow comfort, as measured by lying time, likely because a well-bedded surface is more compressible.


Journal of Dairy Science | 2009

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

J.A. Fregonesi; M.A.G. von Keyserlingk; Cassandra B. Tucker; D.M. Veira; D.M. Weary

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.


Journal of Dairy Science | 2009

Effect of milking frequency and feeding level before and after dry off on dairy cattle behavior and udder characteristics.

Cassandra B. Tucker; S.J. Lacy-Hulbert; J.R. Webster

The effects of 2 common dry-off management procedures, feed restriction [8 vs. 16 kg of dry matter (DM)/d] and reduced milking frequency (once, 1x vs. twice, 2x/d), on the behavior and udder characteristics of dairy cattle were assessed in late lactation and the early dry period. Milking cows 1x instead of 2x in the week before dry off reduced milk yield (7.0 vs. 8.9 +/- 0.95 kg/d for 1x and 2x, respectively), but had little effect on behavior before or after cessation of milking. In comparison, feed restriction reduced milk yield (6.9 vs. 9.1 +/- 0.95 kg/d for 8 and 16 kg of DM/d, respectively), udder firmness after dry off (7.3 vs. 8.0 +/- 0.24 g force for 8 and 16 kg of DM/d, respectively), milk leakage (2 d after dry off, 14% of cows offered 8 kg of DM/d were leaking milk compared with 42% cows offered 16 kg of DM/d), and the likelihood of Streptococcus uberis intramammary infection (nonclinical mastitis; 12.5 vs. 62.5% of groups with at least 1 cow with a new intramammary infection for 8 and 16 kg of DM/d, respectively). Despite these benefits, cows offered only 8 kg of DM/d spent less time eating (7.3 vs. 8.3 +/- 0.28 h/d for 8 and 16 kg DM/d, respectively), more time lying (8.8 vs. 7.3 +/- 0.24 h/d), and vocalized more before dry off than cows offered 16 kg of DM/d (0.8 vs. 0.2 +/- 0.15 calls/min for 8 and 16 kg of DM/d, respectively). These behavioral changes indicate that this level of feed restriction may cause hunger. Information is needed about alternative dry-off procedures that maintain the health benefits and comfort associated with lower milk yield before dry off but prevent hunger, such as feeding low quality diets ad libitum.


Journal of Animal Science | 2014

Healing of surgical castration wounds: a description and an evaluation of flunixin.

Erin M. Mintline; Anita Varga; Joseph Banuelos; Kristen A. Walker; Bruce R. Hoar; Daniel J. Drake; D.M. Weary; Johann F. Coetzee; Matthew L. Stock; Cassandra B. Tucker

Previous studies have shown that surgical castration wounds take between 10 and 61 d to heal. The objectives of this work were to describe healing, inflammation, lying behavior, and serum concentration of substance P after surgical castration in beef calves and to evaluate the effect of a possible intervention, a single injection of flunixin meglumine (1.1 mg/kg IV, a NSAID), on the healing process. Calves (mean±SE: 25±2.0 d of age; 54±1.4 kg BW) were surgically castrated with or without an injection of flunixin immediately before the procedure (n=24/treatment). Healing was measured with a 5-point scale (1=fresh wound, 5=no visible incision or inflammation) as well as weight gain, scrotal size, and scrotal surface temperature, on d 1, 2, 3, 7, 14, 21, 28, 35, 49, and 63 after castration. Serum concentration of substance P was recorded on all d, including d 0, but not d 63. Lying behavior was recorded with loggers from 2 d before to 29 d after castration. Inflammation, as measured by scrotal size, peaked on d 2 and 3 after the procedure (e.g., 51±1.0 mm on d 2 versus 28±1.3 mm before castration) and then declined with time (P<0.001). The first wound to score as fully healed (i.e., 5/5) was seen on d 28; by d 63, 98% of wounds were fully healed. The greatest changes in healing score occurred between d 21 and 35; this was also the peak of wound surface temperature and may correspond with revascularization. Serum concentration of substance P was highest before castration (41±1.2 pg/mL), possibly because the sample was collected after the lidocaine ring block was administered, which was likely painful, and because of separation from the dam and restraint. Values began to drop by d 3 (34±1.2 pg/mL) and leveled out by d 21 (30±1.2 pg/mL; P<0.001). Calves given flunixin had more lying bouts than those that received saline (flunixin by time interaction; P=0.052), but this pattern emerged on and after d 8, well after the 3 to 8 h half-life of this NSAID. In conclusion, castration caused inflammation in the days that followed, and the wounds required a minimum of 4 wk to heal. Provision of an NSAID had no effect on these outcomes.


Journal of Dairy Science | 2013

Effects of adjustable and stationary fans with misters on core body temperature and lying behavior of lactating dairy cows in a semiarid climate

S.D. Anderson; Barry J. Bradford; Joseph P. Harner; Cassandra B. Tucker; Christopher Y. Choi; J.D. Allen; L.W. Hall; S. Rungruang; R. J. Collier; J.F. Smith

Cows readily seek shade to reduce solar heat load during periods of high ambient temperature. Typically, auxiliary cooling systems are oriented to maximize cooling for shaded cows. However, when a shade structure is oriented north-south, stationary fan and mister cooling systems are unable to track shade as the suns angle shifts throughout the day, and thus can become ineffective. The FlipFan Dairy Cooling System (Schaefer Ventilation Equipment, Sauk Rapids, MN) employs fans and misters that follow shade and compensate for wind speed by rotating on a horizontal axis. Multiparous, lactating Holstein cows (n=144) on a commercial dairy in Arizona were cooled by a fixed system comprised of stationary fans and misters acting as control or the adjustable FlipFan operated for 16.5 h/d (0830 to 0100 h). Core body temperatures (CBT) of 64 cows (4 pens/treatment; 8 cows/pen; 6d) and lying behavior of 144 cows (4 pens/treatment; 18 cows/pen; 5d) were collected by intravaginal and leg data loggers, respectively. Cows were balanced by milk production, blocked by days in milk, and randomly assigned to pen within block. Pen was the experimental unit. In a second experiment, isothermal maps were developed using a fixed system of thermal data loggers arranged in the shaded areas of the pens at different times of day and were analyzed for differences in the temperature-humidity index (THI) achieved by each cooling treatment. Ambient conditions consisted of a mean temperature of 33.0°C, mean relative humidity of 40.3%, and mean THI of 80.2. Mean 24-h CBT for FlipFan was lower than control (38.9 vs. 39.1±0.04°C). A treatment × time interaction was observed in which CBT of FlipFan was 0.4°C lower than control from 0600 to 0800h and 1500 to 1600h. Cows cooled by FlipFan spent more time lying down compared with those cooled by control (9.5 vs. 8.6 h/d). Cows under FlipFan had more frequent lying bouts than did those under control (12.8 vs. 10.7 bouts/d). Lower CBT and decreased standing time are consistent with the findings of other studies when ambient heat load was reduced. In the second experiment, the FlipFan system achieved a lower THI in the morning and evening (5.9 and 1.7%, respectively), and the THI also tended to be 0.8% lower in the afternoon compared with that of control. Results indicate that FlipFan is more effective than a stationary fan and mister system at decreasing CBT, increasing lying time and bouts, and providing a more desirable microenvironment for cows throughout the day in a semiarid environment.


Journal of Animal Science | 2013

Physiological, behavioral, and serological responses of horses to shaded or unshaded pens in a hot, sunny environment

K. E. Holcomb; Cassandra B. Tucker; Carolyn L. Stull

Housing recommendations for horses invariably include providing access to shade on hot, sunny days, but the potential benefits have not been scientifically studied. This experiment measured physiological, behavioral, and serological responses of horses confined individually to completely shaded (SH) or completely unshaded (SUN) drylot pens during the summer in Davis, CA. Twelve healthy adult horses in a crossover design experienced both treatments for 5 d each. Rectal temperature, respiration rate, skin temperature, and sweat scores were recorded hourly from 1230 to 1730 h daily. Observations were recorded from 1200 to 1800 h for proximity to water, foraging, locomotion, and insect avoidance behaviors. Daily blood samples were obtained to measure cortisol, hematocrit, and neutrophil-to-lymphocyte ratio. Automated and handheld sensors were used to record environmental conditions. The mean ambient temperature from 1200 to 1800 h during the study was 30.6 °C. Rectal temperature was greater for horses in SUN than for SH (mean 37.8 °C and 37.5 °C, respectively, SE = 0.06, P = 0.002) as was respiration rate (25.5 and 20.5 breaths/min, SE = 1.3, P = 0.008), and skin temperature (35.6 °C and 34.6 °C, SE = 0.1, P < 0.001). Horses in SUN showed sweat in 51.4% of observations vs. 1.1% for horses in SH. Horses in SUN spent more time than SH horses standing near their water source (34.0% of observations vs. 20.2%, SE = 0.3, P = 0.004). No differences were observed for foraging, locomotion, or insect avoidance behavior (P > 0.05). Cortisol concentrations were greater in SUN than SH (3.4 and 2.6 μg/dL, respectively, P < 0.001) but remained within the normal range for resting horses. No treatment differences were observed for hematocrit or neutrophil-to-lymphocyte ratio (P > 0.05). Horses exhibited treatment differences in the physiological measures first, most notably in rectal temperature at 1230 h, corresponding to peak solar radiation. Behavioral responses followed these physiological changes, with treatment differences in time standing near water becoming apparent at 1400 h as ambient and black globe temperature increased. Our results indicate that both the SH and SUN treatment groups exhibited thermoregulatory responses to these summer conditions and horses benefited from shade, as it mitigated these physiological and behavioral changes. These results are applicable in developing best management practices for the care of domestic horses.

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D.M. Weary

University of British Columbia

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