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The objectives of this study were to assess sow flooring preference and behavior during sound, induced lame and lameness recovery states. Thirty-four multiparous, non-pregnant sows were compared prior to and following lameness induction (day 0). Behavior was recorded on six days (days −1, +1, +2, +3, +4 and +10). Three flooring locations (Alley, Concrete and Mat) and four behaviors (lying lateral, lying sternal, sitting and standing) were recorded. Sows increased Mat frequency and decreased Alley frequency on day +1 (most lame) relative to day −1. Lying lateral frequency increased, whereas lying sternal and standing frequencies decreased between day −1 and day +1. Sows appear to prefer the Mat within 24 h following lameness induction. Lying lateral is likely a more comfortable position than standing or lying sternal in these lame sows. In conclusion, these behaviors may be reliable indicators to further ascertain if a sow is lame. [ABSTRACT FROM PUBLISHER]

The objective of this study was to investigate the effects of carprofen administered immediately before cautery dehorning on nociception and stress. Forty Holstein calves aged approximately 6 to 8 wk old were either placebo treated and sham dehorned (n = 10) or cautery dehorned following administration of carprofen (1.4 mg/kg) subcutaneously (n = 10) or orally (n = 10) or a subcutaneous and oral placebo (n = 10) in a randomized, controlled trial. All animals were given a cornual nerve block using lidocaine before dehorning. Response variables including mechanical nociception threshold, ocular temperature, heart rate, and respiratory rate were measured before and following cautery dehorning for 96 h. Blood samples were also collected over 96 h following dehorning and analyzed for plasma cortisol and substance P concentrations by RIA. Plasma carprofen concentration and ex vivo PGE2 concentrations were also determined for this time period. Average daily gain was calculated for 7 d after dehorning. Data were analyzed using a linear mixed effects model with repeated measures, controlling for baseline values by their inclusion as a covariate in addition to planned contrasts. Dehorning was associated with decreased nociception thresholds throughout the study and a stress response immediately after dehorning, following the loss of local anesthesia, and 48 h after dehorning compared with sham-dehorned calves. Carprofen was well absorbed after administration and reached concentrations that inhibited ex vivo PGE2 concentrations for 72 h (subcutaneous) and 96 h (oral) compared with placebo-treated calves (P < 0.05). Carprofen-treated calves tended to be less sensitive (P = 0.097) to nociceptive threshold tests. Overall, at the dosing regimen studied, the effect of carprofen on sensitivity and stress following cautery dehorning was minimal. Consideration of route of administration and dose determination studies may be warranted. [ABSTRACT FROM AUTHOR]

Perioperative analgesic effects of oral firocoxib following cautery disbudding were investigated in preweaned calves. Twenty Holstein calves approximately 4 to 6 wk old received a single oral dose of firocoxib, a nonsteroidal antiinflammatory, at 0.5 mg/kg (n = 10) or placebo (n = 10) in a randomized controlled clinical trial. Responses, including ocular temperature determined by infrared thermography, pressure algometry measuring mechanical nociception threshold, and heart rate, were evaluated at 2, 4, 7, 8, and 24 h after cornual nerve block and cautery disbudding. Blood samples were collected over 96 h and analyzed for plasma cortisol and substance P concentrations by RIA. Additionally, ex vivo prostaglandin E2 concentrations were determined over a 72-h study period using an enzyme immunoassay. Data were analyzed using a linear mixed effects model with repeated measures. An inhibition of ex vivo prostaglandin E2 synthesis was observed from 12 to 48 h following disbudding in calves treated with firocoxib. Cautery disbudding was associated with an increased nociception for the duration of sampling (24 h). During the initial 24-h period following disbudding, no difference in response between treatment groups was noted. Following 24 h, mean cortisol concentrations diverged between the 2 study groups with placebo-treated calves having increased cortisol concentrations at approximately 48 h after disbudding. Furthermore, the overall integrated cortisol response as calculated as area under the effect curve tended to be reduced in firocoxib-treated calves. The prolonged effects of cautery dehorning require further investigation. Moreover, the effect of firocoxib on cortisol reduction observed in this study requires additional exploration. [ABSTRACT FROM AUTHOR]

Pain associated with lameness on farm is a negative affective state and has a detrimental impact on individual farm animal welfare. Animal pain can be managed utilizing husbandry tools and through pharmacological approaches. Nonsteroidal anti-inflammatory drugs including meloxicam and flunixin meglumine are compounds used in many species for pain management because they are easy to administer, long lasting, and cost-effective. Assessing an animal's biomechanical parameters using such tools as the embedded microcomputer-based force plate system and GAITFour pressure mat gait analysis walkway system provides an objective, sensitive, and precise means to detect animals in lame states. The objectives of this study were to determine the efficacy of meloxicam and flunixin meglumine for pain mitigation in lame sows using the embedded microcomputer-based force plate system and GAITFour pressure mat gait analysis walkway system. Lameness was induced in 24 mature mixed-parity sows using a chemical synovitis model and compared 3 treatments: meloxicam (1.0 mg/kg per os), flunixin meglumine (2.2 mg/kg intramuscular) and sterile saline (intramuscular). Weight distribution (kg) for each foot was collected twice per second for a total of 5 min for each time point using the embedded microcomputerbased force plate system. Stride time, stride length, maximum pressure, activated sensors, and stance time were collected using 3 quality walks (readings) for each time point using the GAITFour pressure mat gait analysis walkway system. Sows administered flunixin meglumine or meloxicam tolerated more weight on their lame leg compared with saline sows (P < 0.005). Sows administered flunixin meglumine or meloxicam had smaller differences in stance time, maximum pressure, and activated sensors between the sound and lame legs compared with saline-treated sows between 37 and 60 h after lameness induction (P < 0.03). In conclusion, flunixin meglumine and meloxicam administration mitigated pain sensitivity in sows after lameness induction when pain sensitivity was evaluated with the embedded microcomputer-based force plate system and GAITFour pressure mat gait analysis walkway system. Analgesic drugs may be a key tool to manage negative pain affective states associated with lameness. [ABSTRACT FROM AUTHOR]

Increasing feed efficiency is an important goal for improving sustainable pork production and profitability for producers. To study feed efficiency, genetic selection based on residual feed intake (RFI) was used to create 2 divergent lines. Low-RFI pigs consume less feed for equal weight gain compared to their less efficient, high-RFI counterparts. Therefore, our objective was to assess how a pig's behavioral reactivity toward fear-eliciting stimuli related to RFI selection and improvement of feed efficiency. In this study, behavioral reactivity of pigs divergently selected for RFI was evaluated using human approach (HAT) and novel object (NOT) tests. Forty low-RFI and 40 high-RFI barrows and gilts (n = 20 for each genetic line; 101 ± 9 d old) from ninth-generation Yorkshire RFI selection lines were randomly selected and evaluated once using HAT and once using NOT over a 2-wk period utilizing a crossover experimental design. Each pig was individually tested within a 4.9 × 2.4 m test arena for 10 min; behavior was evaluated using live and video observations. The test arena floor was divided into 4 zones; zone 1 being oral, nasal, and/or facial contact with the human (HAT) or orange traffic cone (NOT) and zone 4 being furthest from the human or cone and included the point where the pig entered the arena. During both HAT and NOT, low- RFI pigs entered zone 1 less frequently compared to high-RFI pigs (P ≤ 0.03). During NOT, low-RFI pigs changed head orientation more frequently (P = 0.001) but attempted to escape less frequently (low-RFI = 0.97 ± 0.21 vs. high-RFI = 2.08 ± 0.38; P = 0.0002) and spent 2% less time attempting to escape compared to high-RFI pigs (P = 0.04). Different barrow and gilt responses were observed during HAT and NOT. During HAT, barrows spent 2% more time within zone 1 (P = 0.03), crossed fewer zone lines (P < 0.0001), changed head orientation less frequently (P = 0.002), and froze less frequently compared to gilts (P = 0.02). However, during NOT, barrows froze more frequently (P = 0.0007) and spent 2% longer freezing (P = 0.05). When the behavior and RFI relationship was examined using odds ratios, decreasing RFI by 1 kg/d decreased the odds of freezing by 4 times but increased the odds of attempting to escape by 5.26 times during NOT (P ≤ 0.04). These results suggest that divergent selection for RFI resulted in subtle behavioral reactivity differences and did not impact swine welfare with respect to responses to fear-eliciting stimuli. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt, Zephyr-E, for euthanasia of suckling and weaned pigs from 3 to 9 kg (5-49 d of age) using signs of insensibility and death as well as postmortem assessment of traumatic brain injury (TBI). The Zephyr-E was used by 15 stock people to euthanize 150 compromised pigs from 4 farrowing and nursery units from commercial farms and 2 research stations. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac arrest following Zephyr-E application. Skull fracture displacement (FD) was quantified from computed tomography (CT) scans (n = 24), macroscopic scoring was used to assess brain hemorrhage and skull fracture severity (n = 150), and microscopic scoring was used to assess subdural hemorrhage (SDH) and parenchymal hemorrhage within specific brain regions that are responsible for consciousness and vital function (n = 32). The Zephyr-E caused immediate, sustained insensibility until death in 98.6% of pigs. On average, clonic convulsions (CC) ceased in 82.2 s (±3.4 SE), brain death was achieved in 144.9 s (±5.4 SE), and cardiac arrest occurred in 226.5 s (±8.7 SE). Time of brain death and cardiac arrest differed significantly among stock people (P = 0.0225 and P = 0.0369). Age was positively related to the duration of CC (P = 0.0092), time of brain death (P = 0.0025), and cardiac arrest (P = 0.0068) with shorter durations seen in younger pigs. Average FD was 8.3 mm (±1.0 SE). Macroscopic scores were significantly differnt among weight classes for subcutaneous (P = 0.0402) and subdural-ventral (P = 0.0037) hemorrhage with the lowest severity hemorrhage found in the 9-kg weight category. Microscopic scores differed among brain sections (P = 0.0070) for SDH with lower scores found in the brainstem compared to the cerebral cortex and midbrain. Parenchymal hemorrhage differed among brain sections (P = 0.0052) and weight categories (P = 0.0128) with the lowest scores in the midbrain and brainstem and the 7- and 9-kg weight categories. The Zephyr-E was highly effective for the euthanasia of pigs up to 9 kg (49 d) based on immediate insensibility sustained until death. Postmortem results confirmed that severe skull fracture and widespread brain hemorrhage were caused by the Zephyr-E nonpenetrating captive bolt. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal nociception threshold (TNT) tests when sows were in painful and nonpainful transient lameness phases. A total of 24 mixed parity crossbred sows (220.15 ± 21.23 kg) were utilized for the MNT test, and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the TNT test. On induction day (DO), all sows were anesthetized and injected with Amphotericin B (10mg/mL) in the distal interphalangeal joint space in both claws of one randomly selected hind limb to induce transient lameness. Three days were compared: (1) D-1 (sound phase, defined as 1 d before induction), (2) D+1 (most lame phase, defined as 1 d after induction), and (3) D+6 (resolution phase, defined as 6 d after induction). After completion of the first round, sows were given a 7-d rest period and then the procedures were repeated with lameness induced in the contralateral hind limb. During the MNT test, pressure was applied perpendicularly to 3 landmarks in a randomized sequence for each sow: 1) middle of cannon on the hind limb (cannon), 2) 1 cm above the coronary band on the medial hind claw (medial claw), and 3) 1 cm above the coronary band on the lateral hind claw (lateral claw). During the TNT test, a radiant heat stimulus was directed 1 cm above the coronary band. The data were analyzed using the MIXED procedure in SAS with sow as the experimental unit. Differences were analyzed between sound and lame limbs on each day. For the MNT test, pressure tolerated by the lame limb decreased for every landmark (P< 0.05) when comparing D-1 and D+1. The sound limb tolerated more pressure on D+1 and D+6 than on baseline D-1 (P < 0.05). Thermal stimulation tolerated by the sound limb did not change over the 3d (P> 0.05). However, the sows tolerated less heat stimulation on their lame limb on D+1 compared to D-1 levels (P < 0.05). Both MNT and TNT tests indicated greater pain sensitivity thresholds when sows were acutely lame. [ABSTRACT FROM AUTHOR]

Piglets reared in swine production in the USA undergo painful procedures that include castration, tail docking, teeth clipping, and identification with ear notching or tagging. These procedures are usually performed without pain mitigation. The objective of this project was to develop recommendations for pain mitigation in 1- to 28-day-old piglets undergoing these procedures. The National Pork Board funded project to develop recommendations for pain mitigation in piglets. Recommendation development followed a defined multi-step process that included an evidence summary and estimates of the efficacies of interventions. The results of a systematic review of the interventions were reported in a companion paper. This manuscript describes the recommendation development process and the final recommendations. Recommendations were developed for three interventions (CO2/O2 general anesthesia, non-steroidal anti-inflammatory drugs (NSAIDs), and lidocaine) for use during castration. The ability to make strong recommendations was limited by low-quality evidence and strong certainty about variation in stakeholder values and preferences. The panel strongly recommended against the use of a CO2/O2 general anesthesia mixture, weakly recommended for the use of NSAIDs and weakly recommended against the use of lidocaine for pain mitigation during castration of 1- to 28-day-old piglets. [ABSTRACT FROM AUTHOR]

Infectious bovine keratoconjunctivitis (IBK) is a common ocular disease in cattle, associated with a 6.8 to 13.6 kg decrease in weaning weight. Antibiotic therapy is available but it is unclear if pain mitigation as an adjunct therapy would reduce the weight loss associated with IBK. Before assessing the impact of pain mitigation therapies, it is first necessary to validate approaches to qualifying ocular pain. The objective of this study was to evaluate approaches to qualifying ocular pain in bovine calves (Bos taurus) with IBK. Our a priori assumption was that scarification or corneal ulcerations consistent with IBK are painful compared to normal eyes. To quantify this difference in pain, we assessed 4 tools: pressure algometry-mechanical nociceptive threshold (PA-MNT), corneal touch thresholds (CTT) obtained with the use of a Cochet-Bonnet aesthesiometer, and assessment for the presence of blepharospasm and photophobia as metrics for pain. Using a 1-eye randomized controlled challenge trial, 31 calves with healthy eyes were randomly allocated to treatment groups, and then a left or right eye was randomly assigned for corneal scarification and inoculation with Moraxella bovoculi or Moraxella bovis. A repeated measures analysis of variance was used for PA-MNT, with significance set at P < 0.05. A log (base 10) transformation was used to stabilize the variance, and Tukey's t tests were used to test differences between assessment days for each landmark. Calves had statistically significantly lower PA-MNT scores (which indicates more pain) the day after scarification relative to baseline measurements (4 d before scarification). For example, at 1 landmark the median PA-MNT (kg/force) prescarification was 4.82 (95% confidence interval [CI]: 3.92-5.93) and 3.43 (95% CI: 2.79-4.22) postscarification. These data suggest PA-MNT may be a tool for quantifying ocular pain in calves. No differences (P < 0.1) in PA-MNT scores between scarified and not-scarified eyes were detected for any landmark on any day. This result suggests that the pain response occurs over the entire face, not just the affected eye. Corneal ulcerations consistent with IBK were not associated with statistically significant differences in PA-MNT or CTT at eye or calf levels. Not surprisingly, scarified eyes were more likely to exhibit blepharospasm and photophobia compared to healthy eyes. Due to blepharospasm, the use of the Cochet-Bonnet to evaluate corneal sensitivity by CTT was of limited value. [ABSTRACT FROM AUTHOR]

The objectives of this study were to assess efficacy and welfare implications of gas euthanasia when applied to weaned and neonate pigs. Parameters associ-ated with welfare, which were measured before loss of consciousness, included open-mouth breathing, ataxia, righting response, and escape attempts. Two age groups (weaned and neonate) were assessed in 9 gas treatments arranged in a 2 x 4 factorial design, with 2 gas types (C02 = 100% C02 and 50:50 = 50:50 C02:argon) and 4 flow rates (box volume exchange/min: slow = 20%; medium = 35%; fast = 50%; prefill = prefilled followed by 20%) and a control treatment in which ambient air was passed through the box. Pig pairs (10/treatment) were placed in a modified Euthanex AgPro system (Euthanex Corp, Palmer, PA). Behavioral and physio-logical responses were observed directly and from video recordings for latency, duration, prevalence (percent of pigs affected), and frequency (number of occurrences/ pig). Data were analyzed as linear mixed models or with a Cox proportional hazard model as appropriate. Piglet pair was the experimental unit. For the weaned pig, wel-fare was superior with C02 relative to 50:50 within 1 or more flow rates on the basis of reduced duration of open-mouth breathing, duration of ataxia, frequency of escape attempts, and duration and frequency of righting response (P < 0.05). No measured parameters indicated superior welfare with the use of 50:50, whereas latencies to loss of posture and last movement favored C02 (P < 0.05). Faster flow rates were associated with reduced (P < 0.05) duration or frequency of open-mouth breath-ing, ataxia, and righting response, as well as superior (JP < 0.05) indicators of efficacy, including latencies to loss of posture, gasping, and last movement, relative to slower flow rates. Weaned pigs were more likely to def-ecate (P < 0.01), display nasal discharge (P < 0.05), and display longer (P < 0.001 ) latencies to loss of posture and last movement than neonates. Duration of ataxia was the only parameter for which neonates were superior (P < 0.01) to weaned pigs during euthanasia. As such, a 50:50 C02: argon gas mixture and slower flow rates should be avoided when euthanizing weaned or neonate pigs with gas methods. Neonate pigs succumb to the effects of gas euthanasia quicker than weaned pigs and display fewer signs of distress. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt (NPCB), the Zephyr-Euthanasia (Zephyr-E), for euthanasia of neonatal piglets < 72 h of age using signs of insensibility and death, as well as postmortem assessment of traumatic brain injuiy (TBI). The Zephyr-E was used by 10 stock people to euthanize 100 low viability neonatal piglets from 3 commercial farrowing units and 1 research farm. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac an-est after Zephyr-E application. Hemorrhage severity and skull fracture displacement (FD) were quantified from computed tomography scans (n = 10), macroscopic scoring was used to assess brain hemorrhage and skull fracture (SK) severity (n = 100), and microscopic scoring was used to assess subdural (SDH) and parenchymal (PH) hemorrhage within specific brain regions that are responsible for consciousness and vital function (n = 10). All 100 piglets were rendered immediately insensible withoutreturn to sensibility. On average, clonic convulsions (CC) ceased in 101 s (±7.4 SE), brain death was achieved in 229 s (±9.18 SE), and cardiac arrest occurred in 420 s (±13.57 SE). Time of cardiac arrest differed significantly among stock people when either body weight (BW: P = 0.0053) or body mass index (BMI: P = 0.0059) was used as a covariate. The BMI was inversely related to the duration of CC (P = 0.0227). Moderate to severe hemorrhage severity was reported in 9 of 10 piglets. There was no relationship between FD and BW (P = 0.8408) or BMI (P = 0.6439). Macroscopic analyses indicated moderate to severe hemorrhage and SK in all piglets. No differences were found among brain sections for SDH (P = 0.2302); PH was greater in the cerebral cortex than in the midbrain and brainstem (P = 0.0328). The Zephyr-E NPCB reliably caused immediate, sustained insensibility followed by death in neonatal piglets. Postmortem assessment confirmed that application of the Zephyr-E caused widespread, irreversible brain damage. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effects of dentition on feed-oriented behavior and feed consumption before weaning at 28 d, and whether premolar eruption or occlusion at the time of weaning influenced postweaning growth or behavior. Over 3 trials, 24 litters of Yorkshire piglets (n = 233) were provided with creep feed marked with 1% chrornic oxide on d 5. Dental exams were performed on d 2, 6, 9, 13, 16, 20, 23, and 27. Fecal samples were visually assessed for feed consumption (via fecal color) on the same day as dental exams, beginning on d 6. The duration of time spent at, and frequency of visits to, the creep feeder were determined from continuous video recordings on d 7, 10, 14, 17, 21, and 24 for 6 h/d (0700 to 1000 h, 1300 to 1600 h). After weaning, behavior was recorded every 5 mm for three 2-h time periods (0600 to 0800 h, 1100 to 1300 h, and 1600 to 1800 h) on d 2, 4, 6, 8, 10, and 12. Piglets younger than 17 d with their premolars erupted and occluded spent less time at the creep feeder and visited it less often than piglets without their premolars erupted and occluded [duration: p3 (premolar position 3 on maxilla), d 7 (P = 0.005); p4 (premolar position 4 on mandible), d 7 (P < 0.0001), d 10 (P = 0.003); p4 (premolar position 4 on maxilla), d 17 (P = 0.012); occlusion, d 7 (P < 0.0001), d 10 (P = 0.0004); visits: p3, d 7 (P < 0.0001); p4, d 7 (P < 0.0001), d 10 (P 0.001); p3 (premolar position 3 on mandible), d 14 (P = 0.037); p , d 17 (P = 0.024); occlusion, d 7 (P < 0.0001), d 10 (P = 0.003)]. By d 21 of age, this trend reversed such that piglets with premolars erupted and occluded spent more time at the feeder and visited it more frequently [duration: p3, d 24 (P = 0.025); p4, d 24 (P = 0.0005); occlusion, d 21 (P = 0.001), d 24 (P = 0.0001); visits: p3, d 21 (P = 0.0002), d 24 (P < 0.0001); p3, d 24 (P = 0.0002); occlusion, d 21 (P < 0.0001), d 24 (P < 0.0001)]. The percentages of piglets with positive fecal scores were 0, 1.4, 4.6, 8.0, 29.0, 44.9, and 60.6% on d 7, 10, 14, 17, 21, 24, and 27, respectively (P < 0.0001 between each day). No associations were found between the eruption or occlusion of premolars and feed consumption before weaning (P> 0.05), and no dental measures influenced growth rates (P > 0.10) or behavior (P > 0.10) after weaning. A more precise method may be necessary for detecting associations between dental eruption and feed consumption. However, the behavioral results indicate that, before weaning at 28 d, younger piglets are inhibited from feeding when their premolars first erupt, whereas older piglets with a more advanced dentition are more attracted to feed. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the efficacy of meloxicarn (MEL) as supportive therapy for calves with neonatal calf diarrhea complex. For this double–blind controlled trial, 62 Holstein male calves were purchased at birth and transported to a research facility. At the naturally occurring onset of diarrhea, defined as the first occurrence of a fecal score greater than 2 on a 4–point scale, calves were enrolled in the study. Each calf with diarrhea was randomly assigned to receive a single subcutaneous injection of MEL at a rate of 0.5 mg/kg of BW or an equal volume of placebo (PLA) solution. Milk, starter ration, and water intakes were determined daily for each calf from arrival until 56 d of age. The calves were weighed on arrival and each week thereafter. Time to weaning and weaning weight were recorded for each calf. Crude associations between treatment and each outcome variable were examined using t–tests and Pearson chi–squared tests. Subsequently, multivariable regression models were constructed to examine the impact of MEL therapy on meaningful outcome variables. The primary experimental unit in all analyses was the individual calf. In total, 56 calves presented with clinical signs of diarrhea and were enrolled in the study. Two PLA–treated calves died after being enrolled in the study, and there was no calf mortality among the MEL–treated calves. For calves that developed diarrhea after 10 d of age, MEL–treated calves were more likely to consume their entire daily milk allowance (P < 0.05) as compared with PLA–treated calves. Meloxicam–treated calves began consuming starter ration earlier (P < 0.01) and at a greater rate (P < 0.001), and consumed more water (P < 0.001) compared with PLA–treateci animals. Over the study period, calves treated with MEL gained BW at a faster rate (P < 0.01) than calves treated with PLA. There was no difference in weaning weight (P > 0.05), but MEl–calves tended to wean earlier (P = 0.11) than PLA–treated calves. These results demonstrate that calves receiving a single injection of MEL at the onset of diarrhea had improved appetite and performance compared with PLA–treated calves. Thus, MEL is an effective supportive therapy for neonatal calf diarrhea complex. [ABSTRACT FROM AUTHOR]

A companion paper in the last issue reviewed the literature on effects of frequency of intercourse on fecundability. At moderately high coital frequencies, predicted effects of further increases on fecundability based on previous work vary widely. New modelling reported here, designed to take into account the ageing of gametes, attempts to identify a set of limits within which the true relationship of coital frequency and fecundability at moderate to high frequencies may confidently be expected to lie. [ABSTRACT FROM AUTHOR]

Weaned pig responses to CO2 were examined using approach-avoidance and conditioned place avoidance paradigms. Apref-erence-testing device was designed with 2 identical chambers separated by a sliding door and an exhaust sink. Twelve crossbred pigs were individually trained for 5 consecutive days to enter the treatment chamber (TC) when the sliding door was opened to obtain a food reward and had 6 min to move freely between the chambers before the test concluded. The same methods were used during the testing phase, with CO2 concentrations in the TC maintained at 1 of 3 levels: 10, 20, and 30%. Tests concluded when loss of posture occurred or after 6 min. Pigs experienced each of the CO2 treatments on gas day (G), preceded by ambient conditions on 1 baseline day (B) and on 1 wash out day (W) during 3 rounds. We hypothesized that pigs would display avoidance at higher CO2 levels and that when aversion occurred, conditioned place avoidance would be observed on the W for that round. Behavior was collected using live observations and video recordings. Latency data were analyzed using PROC GLIMMIX in SAS 9.4 (SAS Inst. Inc., Cary, NC) and are presented as least squares means ± SEM. During testing, 2 pigs failed to enter the TC on any of the days and were removed from the analysis. Of the 10 remaining, all pigs entered the TC on all B, G, and W Loss of posture was displayed by 0, 5, and 4 pigs at 10, 20, and 30% CO2, respectively (192 ± 23 s for 20% CO2 and 78 ± 6 s for 30% CO2). Latency to enter the TC was greater on G than on B and W (3.3 ± 1.38 s for B, 20.8 ± 8.9 s for G, and 10.9 ± 4.5 s for W; P = 0.0009). Similarly, latency to leave the TC was less on G than on B and W (213.4 ± 37.1 s for B, 48.9 ± 9.1 s for G, and 273.1 ± 55.5 s for W; P < 0.0001). Latency to reenter the TC was greater on G than on B and W (37 ± 10.5 s for B, 106.5 ± 27.9 s for G, and 12.2 ± 3.8 s for W; P < 0.0001). No consistent differences were observed for CO2 levels, suggesting that all the concentrations tested were aversive to pigs to some degree. However, aversion was not sufficient to provoke avoidance behavior by naive pigs or pigs that lost posture during previous exposure. [ABSTRACT FROM AUTHOR]

Improving feed efficiency is essential for increasing sustainable production and producer profitability. It is also necessary to ensure that feed efficiency modifications do not negatively impact animal welfare, as concerns have been raised on how genetic selection for feed efficiency impacts livestock ability to cope with stress. Therefore, our objective was to determine if divergent selection for residual feed intake (RFI) altered pig behavioral reactivity toward novel stimuli. In Exp. 1, 40 low-RFI (more feed efficient) and 40 high-RFI (less feed efficient) eighth generation Yorkshire RFI selection line barrows (107 ± 9 d old) were evaluated. Experiment 2 evaluated 40 low-RFI and 40 high-RFI ninth generation barrows and gilts (101 ± 9 d old). All pigs were individually tested using both a human approach test (HAT) and a novel object test (NOT). Pigs were tested for 10 min within a 4.9 by 2.4 m test arena, consisting of 4 zones. Behavior was evaluated using live and video observations, with the hypothesis that behaviorally reactive pigs would display more frequent oral, nasal, and/or facial contact with the human or object (traffic cone); zone entrances; head movements; urination; defecation; escape attempt (rearing on hind legs); and freezing ( ≥ 3 s of no body movement) behaviors. Data were analyzed using the Glimmix procedure of SAS (SAS Inst. Inc., Cary, NC). In Exp. 1, low-RFI barrows entered fewer zones (P < 0.0001), had fewer head movements (P ≤ 0.02), defecated less frequently (P ≤ 0.03), displayed a shorter duration of freezing (P = 0.05), and froze less frequently (P < 0.0001) compared with high-RFI barrows during HAT and NOT. During HAT, low-RFI barrows also attempted to escape less frequently (P = 0.001) compared with high-RFI barrows. In contrast, low-RFI barrows took longer to first contact the novel stimuli in HAT and NOT compared with the high-RFI barrows (P ≤ 0.04). In Exp. 2, low-RFI pigs contacted the novel stimuli in HAT and NOT less frequently compared with high-RFI pigs (P ≤ 0.03). During NOT, low-RFI pigs attempted to escape less frequently (P = 0.0002) and spent less time attempting to escape (P = 0.04) but changed head orientation more frequently compared with high-RFI pigs (P = 0.001). During NOT, barrows froze more frequently (P = 0.0007) and spent a longer time freezing (P = 0.05). During HAT, barrows entered fewer zones (P < 0.0001), changed head orientation less frequently (P = 0.002), froze less frequently (P = 0.02), and spent more time contacting the human compared with gilts (P = 0.03). These results suggest that selection for low-RFI pigs resulted in lower behavioral reactivity. [ABSTRACT FROM AUTHOR]

Culled breeding animals represent 3% of swine slaughtered in the United States. Pigs are culled for multiple reasons including body condition, injury, and poor performance. There are concerns that culled pigs face higher risks of becoming fatigued or nonambulatory during marketing and transport. The objectives of this study were to 1) explore the welfare of culled swine marketed through buying stations, 2) characterize the prevalence of different types of compromised swine, and 3) identify potential risk factors associated with fatigued and nonambulatory pigs. A survey was conducted at integrated and independent buying stations in 2014. Fifteen individual buying stations were enrolled, representing 4 marketing companies with locations in the United States. Detailed animal assessments were conducted at the time of unloading on all incoming trailer loads with every pig on each load assessed. Pigs were scored for condition on arrival (nonambulatory, fatigued, or dead) as well as body condition, injuries, hernias, skin lesions, vulva lesions, tail bites, lameness, abscesses, and prolapses. Pigs that were segregated from their cohorts by buying station employees due to health and welfare concerns were further evaluated based on their final outcome (rested and recovered, euthanized, or died). The number of trailers per day ranged from 1 to 12 incoming loads. Animals per load ranged from 9 to 177, including culled sows, breeding gilts, boars, and market pigs. A total of 7105 pigs and 122 trailer loads were evaluated. Three pigs were dead on arrival (0.04% of total population). Sows and boars made up 86% of the fatigued animals (total population fatigued = 16%), 73% of the lame pigs (total population lame = 5%), and 82% of the animals with a BCS of 1 (total population with BCS of 1 = 4%). Market pigs made up 9% of those with abscesses (total population abscesses = 6%) and 79% of those with hernias (total population with hernias = 3%). Follow-up assessments were conducted on 119 pigs segregated from their cohort, of which 79 were euthanized (66%). Prevalence ratios of fatigue, severe skin lesions, severe abscesses, and poor BCS were greater in sows and gilts than in market pigs (2.18 [confidence interval {CI} 1.84-2.58], 8.48 [CI 3.99-18.05], 3.22 [CI 1.78-5.85], and 2.36 [CI 1.61-3.46], respectively; P < 0.01 for all). The opportunity to identify at-risk pigs that fail to cope with transport and handling stressors can assist decision making about fitness for transport, with implications for humane endpoints and mitigating production losses. [ABSTRACT FROM AUTHOR]

The impact of calving difficulty on the behavior of periparturient dairy cattle has not been reported. The objective of this study was to measure variables associated with difficulty of calving, and to identify the associations of parameters with periparturient behavior. Previously recorded videotapes of 23 cows on day -1, 0 and +1 relative to calving were analyzed. Data included frequency and duration of standing and lying behavior, calving difficulty score, duration of calving and calf body measurements. Calving difficulty was scored as: 0-unassisted, 1-easy pull, 2-hard pull. Video information was analyzed, interpreted and entered. Data was analyzed using logistic and linear regression with Statistix. Heifers were more likely to require assistance during calving (P < 0.01). Male calves weighed significantly more than female calves (P < 0.05). Cow standing and lying behavior differed on the day of calving. Pre-calving, heifers lie for 18 fewer minutes per lying bout compared to cows (37.1 ± 3.8 versus 55.1 ± 6.4 minutes per bout, P<0.02). Mean pre-calving lying time was also influenced by calving difficulty, as cows requiring assistance spent 15 minutes less lying down per bout (P < 0.05). Post-calving, heifers lie for 13 minutes less per bout than cows (40.4 ± 3.1 versus 53.7 ± 8.8, P = 0.09). Cows taking longer to calve lie for fewer minutes each bout (P < 0.02). Finally, dams that had hard pulls lie for 12.5 fewer minutes each bout (P = 0.11). When mean lying bouts post-calving was analyzed, controlling for pre-calving mean lying time, only calving duration remained significant. Calving duration also positively influenced the number of post-calving lying bouts (P = 0.05). Lying behaviour, both pre and post-calving, was the most significant measurement related to calving. Cows with longer calvings spent less time lying down after calving. Differences between lying time for cows and heifers merits further investigation. It is possible that this difference is related to the presence of pain, and that there are opportunities for pain management at calving. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate the effects of free-access acidified milk replacer feeding on the pre- and postweaning health of dairy and veal calves. Individually housed calves were systematically assigned at birth to 1 of 2 feeding programs: free-access feeding (ad libitum) of acidified milk replacer (ACD, n = 249) or traditional restricted feeding (3 L fed twice daily) of milk replacer (RES, n = 249). Calves were fed milk replacer containing 24% crude protein and 18% fat. Acidified milk replacer was prepared to a target pH between 4.0 and 4.5 using formic acid. Calves were weaned off milk replacer at approximately 6 wk of age. Weaning occurred over 5 d, and during this weaning period, ACD calves had access to milk replacer for 12 h/d and RES calves were offered only one feeding of milk replacer (3 L) daily. Calves were monitored daily for signs of disease. Fecal consistency scores were assigned each week from birth until weaning. A subset of calves was systematically selected for fecal sampling at 3 time points between 7 and 27 d of age. Fecal samples were analyzed for enterotoxigenic Escherichia coli F5, Cryptosporidium parvum, rotavirus, and coronavirus. Hip width, hip height, body length, heart girth, and body weight were measured at birth and weaning. Postweaning body weight measurements were collected from the heifers at approximately 8 mo of age. Postweaning body weight and carcass grading information was collected from the veal calves at slaughter once a live weight between 300 and 350 kg had been achieved. The odds of ACD calves being treated for a preweaning disease event tended to be lower than that of the RES calves (1.2 vs. 5.2%, respectively). Preweaning mortality, postweaning disease treatment, and postweaning mortality did not differ between feeding treatments. The ACD feeding treatment supported greater preweaning average daily gain (0.59 vs. 0.43 kg/d) and structural growth than RES feeding. Postweaning average daily gain and carcass characteristics were similar for ACD and RES calves. These results indicate that free-access acidified milk replacer feeding tended to support improved health, and greater body weight gain and structural growth during the preweaning period; these effects did not persist in the postweaning period. The growth advantage observed before weaning in the ACD calves likely disappeared due to the weaning methods used. [ABSTRACT FROM AUTHOR]

Research on the assessment and management of pain in cows following difficult or assisted calving is still limited, especially on the effects of analgesics intended to mitigate this pain. The purpose of this study was to assess the effects of flunixin meglumine on the health and production of Holstein cows after calving. In total, 34 flunixin-treated and 38 placebo-treated animals were enrolled in a precalving treatment trial. A total of 633 animals given flunixin and 632 animals administered a placebo were enrolled in a postcalving treatment trial. In both cases, animals were randomly assigned to treatment, and researchers were blind to treatment condition until after analysis. A total of 1,265 animal records were analyzed for milk production for the first 14 d in milk and health outcomes for the first 30 d in milk. Animals treated with flunixin meglumine before calving had a significantly increased risk of stillbirth. Animals treated immediately after calving had increased odds of having a retained placenta and, in turn, increased risk of a high temperature, decreased milk production, and an increased risk of developing metritis. The administration of flunixin meglumine within 24 h of parturition is not recommended in dairy cattle. [ABSTRACT FROM AUTHOR]

Digital dermatitis is an infectious disease that causes lameness in dairy cattle, a primary welfare concern of the dairy industry. One of the common treatments for this painful hoof disease is through the application of an antibiotic bandage that must be removed following treatment. The objectives of this randomized clinical trial were to determine if topical application of tetracycline hydrochloride in a paste would be as therapeutically effective for the treatment of digital dermatitis as a powdered form of tetracycline hydrochloride held in place by a bandage, and to quantify pain associated with digital dermatitis lesions. Two hundred and fourteen Holstein cow hooves with digital dermatitis lesions were randomly assigned to 1 of 3 treatments: a tetracycline hydrochloride paste, tetracycline hydrochloride powder held in place with a bandage for 2 d, or a negative (untreated) control. Lesions were examined at 2 time periods: 3 to 7 d posttreatment and 8 to 12 d posttreatment to determine healing rates. Nociceptive thresholds were measured using a pressure algometer to quantify the pain at the lesion site. The tetracycline hydrochloride paste was as effective as the powdered bandage treatment in terms of healing rates, with 47.4 and 57.1% hooves healed at 8 to 12 d posttreatment, respectively. Both treatments were more effective than the control, in which no lesions healed 8 to 12 d following initial examination. Mean (±SE) nociceptive thresholds for active, healing, and healed lesions differed, with limb-withdrawal response occurring at 7.45 (±0.67) kg, 12.84 (±1.85) kg, and censored to 25 kg (maximum value of algometer) of force applied, respectively. However, active lesions were not consistently associated with pain, as maximum force was tolerated when applied to 19% of active lesions, perhaps due to variability in stoicism between individual cattle or due to changes in pain during the progression of infection. In conclusion, tetracycline hydrochloride paste was as effective as tetracycline hydrochloride bandage, eliminating the need for bandage removal following treatment application. Digital lesions can be painful during both active and healing stages, suggesting the need for treatment and husbandry interventions for pain mitigation. [ABSTRACT FROM AUTHOR]

Effects of a single injection of meloxicam on calf behavior, pain sensitivity, and feed and water intakes were examined following dehorning. Sixty Holstein heifer calves were blocked by age and randomly assigned to receive an i.m. injection of meloxicam (0.5 mg/kg) or a placebo. All calves were given a lidocaine cornual nerve block (5 mL per horn). Treatments and nerve blocks were administered 10 min before cautery dehorning. Continuous sampling of behavior was performed during five 1-h intervals using video recordings, and total daily activity was monitored using an accelerometer. A pain sensitivity test was administered with a pressure algometer, and feed and water intakes were recorded daily. Calves were sham-dehorned 24 h before actual dehorning to establish baseline values, and all variables were assessed at the same times following dehorning and sham dehorning for up to 48 h post-dehorning. Meloxicam-treated calves displayed less ear flicking during the 44 h following dehorning (increases of 4.29 ± 1.10 and 1.31 ± 0.66 ear flicks/h in the first 24 h, and increases of 3.27 ± 0.89 and 0.55 ± 0.50 ear flicks/h during the second 24 h, for control and meloxicam calves, respectively) and less head shaking during the first 9 h following dehorning (increase of 2.53 ± 0.54 and 0.85 ± 0.46 headshakes/h over baseline for control and meloxicam, respectively). Meloxicamtreated calves were less active than controls during the first 5 h following dehorning (activity 34.1 ± 3.2 and 30.6 ± 2.6 for control and meloxicam, respectively) and displayed less sensitivity to pressure algometry 4 h after dehorning (pressure tolerance of 1.62 ± 0.13 kg of force and 2.13 ± 0.15 kg of force for control and meloxicam calves, respectively). Changes in behavior suggest that meloxicam was effective for reducing post-surgical pain and distress associated with calf dehorning. [ABSTRACT FROM AUTHOR]

Bovine respiratory disease (BRD) is a major concern when raising replacement heifers because of the high incidence and long-term effects of this disease, such as decreased growth and increased time to first calving. The objective of this study was to determine the effect of tulathromycin (TUL) treatment at postweaning movement on the incidence of BRD in dairy replacement heifers. A total of 1,395 heifers were enrolled between November 2006 and June 2007 at a commercial heifer-raising facility. Calves were randomly assigned either to treatment with TUL or to a positive control group treated with oxytetracycline (TET). Calves treated with TUL were 0.5 times (95% CI: 0.4 to 0.7) less likely to be treated for BRD in the 60 d following enrollment than calves treated with TET. For calves that had no history of BRD in the pre-enrollment period, TET calves weighed 4.9 ± 0.5 kg less than TUL calves after 6 wk in group housing. If calves were treated for BRD in the pre-enrollment period, there was no treatment effect on growth. Calves with clinical BRD in the 60 d following movement weighed 7.9 ± 0.6 kg less than calves without BRD after 6 wk in group housing. Treatment with TUL at the time of movement to group housing had a beneficial effect on the health and performance through the prevention of BRD in dairy calves with no prior history of the disease. Moreover, BRD after movement to group housing after weaning had a significant effect on the growth of dairy calves. [ABSTRACT FROM AUTHOR]

The objectives were to determine the duration of the stress response associated with cautery dehorning and to assess the effectiveness of the nonsteroidal anti-inflammatory drug meloxicam (Metacam, 20 mg/mL solution for injection) for reducing that response. Sixty Holstein heifer calves were blocked by age and randomly assigned to receive an i.m. injection of meloxicam or a placebo (0.5 mg/kg). All calves were given a lidocaine cornual nerve block delivered 5 mL per side 10 rain before dehorning. To establish baseline values, calves were sham dehorned 24 h before actual dehorning. Blood samples were taken via indwelling jugular catheters at 0, 0.5, 1, 1.5, 2, 4, 6, and 24 h after the procedure. Heart and respiratory rates were also taken at these times. Data were analyzed using PROC MIXED in SAS. Analysis of covariance was employed to assess the difference between sham and dehorning at each time period. Dehorning was associated with elevated serum cortisol (d - 1: 33.9 ± 1.26; d 0: 46.2 ± 2.33 nmol/L) and heart rate (d -1: 108 ± 1.8; d 0: 109.4 ± 2.4 beats per minute) in both groups for 24 h, and elevated respiratory rate (sham: 42.2 ± 1.95 vs. dehorning: 45.1 ± 2.19 respirations per minute) in both groups for 6 h. A treatment x time interaction was found for cortisol, with meloxicam calves having lower serum cortisol than controls until 6 h after dehorning (meloxicam: 49.7 ± 4.37 vs. control: 63.0 ± 6.94 nmol/L). There was no difference between the treatment groups at 24 h (meloxicam: 35.2 ± 2.74 and control: 34.8 ± 3.64 nmol/L of cortisol). Overall, the changes in heart rates (increase meloxicam: 3.74 ± 0.96 vs. control: 4.70 ± 1.87) and respiratory rates (increase meloxicam: 2 ± 0.1 vs. control: 4 ± 0.2) were greater in the control group compared with the meloxicam group. These results indicate that meloxicam reduced the physiological stress response to dehorning. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify relationships between tie-stall design and selected cow-based injury, lameness, and cleanliness measurements. All lactating dairy cows (n = 17,893) from 317 Ontario tie-stall dairy farms were evaluated once between March and September 2003. Stall dimensions were recorded and cows were scored for neck and hock lesions, broken tails, back arch, hind claw rotation, and udder and hind limb cleanliness. Neck lesions were significantly associated with tie-rail height. Hock lesions were positively associated with presence of an electric trainer and hind limb and udder cleanliness and negatively associated with tie-chain length. A negative association was found between broken tails and tie-rail height and a positive association between broken tails and udder and hind limb cleanliness. As mean stall length increased, fewer cows had hind-claw rotation. Having more dirty cows was associated negatively with stall length and chain length, and positively associated with the presence of an electric trainer. Proportion of cows with clean udders increased with the percentage of cows with clean hind limbs and with tie-rail height. As the prevalence of clean udders increased the prevalence of broken tails decreased. This study provides insight into how tie-stall dimensions may influence aspects of dairy cow welfare. Application of these principles could improve tie-stall design. [ABSTRACT FROM AUTHOR]