The objective of this study was to develop a validated, transient, chemically induced lameness model in sows using subjective and objective lameness detection tools. Experiment 1 determined an effective joint injection technique based on volume and placement of dye using feet collected from 9 finisher pigs and 10 multiparity cull sow carcasses. Experiment 2 confirmed the injection technique in live animals and produced a transient clinical lameness in 4 anesthetized sows injected with amphotericin B (15 mg/mL) in the distal interphalangeal joints of the claw. Clinical lameness was assessed by a categorical lameness scoring system, and a postmortem visual confirmation of joint injection technique was obtained. In Exp. 3, 6 sows were injected with 0, 10, or 15 mg/mL amphotericin B in either the left or right hind foot and were monitored until clinical resolution. Treated sows demonstrated elevated clinical lameness scores. These changes resolved by 7 d after lameness induction. Control sows injected with sterile saline developed a clinical lameness score of 0.5, which resolved 72 h post injection. In Exp. 4, 36 sows were injected with 10 mg/mL amphotericin B in 1 of 4 injection sites (left front claws, right front claws, left rear claws, and right rear claws). All injected sows exhibited a decrease in maximum pressure, stance time, and number of sensors activated on the GaitFour (P < 0.05) sensor system. A static force plate also demonstrated a decrease in weight (kg) being placed on the injected foot when all feet were injected (P ≤ 0.05). Injection of amphotericin B induced a predictable acute lameness that resolved spontaneously and is an effective method to model lameness in sows. 130ABSTRACT: The objective of this study was to develop a validated, transient, chemically induced lameness model in sows using subjective and objective lameness detection tools. Experiment 1 determined an effective joint injection technique based on volume and placement of dye using feet collected from 9 fi nisher pigs and 10 multiparity cull sow carcasses. Experiment 2 confi rmed the injection technique in live animals and produced a transient clinical lameness in 4 anesthetized sows injected with amphotericin B (15 mg/mL) in the distal interphalangeal joints of the claw. Clinical lameness was assessed by a categorical lameness scoring system, and a postmortem visual confi rmation of joint injection technique was obtained. In Exp. 3, 6 sows were injected with 0, 10, or 15 mg/mL amphotericin B in either the left or right hind foot and were monitored until clinical resolution. Treated sows demonstrated elevated clinical lameness scores. These changes resolved by 7 d after lameness induction. Control sows injected with sterile saline developed a clinical lameness score of 0.5, which resolved 72 h post injection. In Exp. 4, 36 sows were injected with 10 mg/mL amphotericin B in 1 of 4 injection sites (left front claws, right front claws, left rear claws, and right rear claws). All injected sows exhibited a decrease in maximum p...
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 (D0), 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 3 d (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. ABSTRACTThe objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal (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 mechanical nociception threshold test and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the thermal nociception threshold test. On induction day (D0), 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 l...
Lameness has been ranked as the third most common reason for culling sows, comprising 15% of the culls marketed in the U.S. Producers assess sow lameness using subjective evaluation, which have been shown to be variable in their application. Objective empirical tools to measure sow lameness on farm are required. Therefore, the purpose of this study were to evaluate the embedded force plate and the GAITFour gait analysis walkway system as objective assessment tools to discriminate between sound and lame phases in multiparous sows. Twenty-four mixed parity crossbred sows were anesthetized and injected with Amphotericin B in the distal interphalangeal joint of both claws of one hind hoof to induce transient lameness. Kinematic data was collected on D−1, D+1 and D+6 relative to induction (D0). For the embedded force plate, weight distributions on each hoof were collected. Gait analysis measures collected were stride time (defined as the time (s) between 2 successive footfalls by the same hoof), stride length (defined as the distance (cm) between 2 sequential footfalls from the same hoof),maximum pressure (defined as the greatest amount of weight (kg/cm 2 ) placed on a single hoof) and stance time (defined as the duration of time (s) the sensors were activated by a hoof in a single stride). For the embedded microcomputer-based force plate system weight placed on the induced hoof decreased on D+1 when compared to D−1 (P® pressure mat gait analysis walkway system, stride time increased on D+1 for all hooves, stride length decreased on D+1 compared to D−1 and maximum pressure placed on the induced hoof decreased on D+1 compared to baseline levels (PStance time increased for all sound hooves on D+1 compared to D−1 (P Keywords force plate, gait analysis, lameness, pain, sow Disciplines Agriculture | Animal Sciences | Large or Food Animal and Equine MedicineComments NOTICE: this is the author's version of a work that was accepted for publication in Livestock Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Livestock Science, 165 (2014) time (defined as the duration of time (sec) the sensors were activated by a hoof in a single stride). 33For the embedded microcomputer-based force plate system weight placed on the induced hoof 34 decreased on D+1 when compared to D-1 (P < 0.0001). For the GAITFour ® pressure mat gait 35 analysis walkway system, stride time increased on D+1 for all hooves, stride length decreased on 36 D+1 compared to D-1 and maximum pressure placed on the induced hoof decreased on D+1 37 compared to baseline levels (P < 0.05). Stance time increased for all sound hooves on D+1 38 compared to D-1 (P < 0.05). In conclusion, the embedded force plate and GAITFour walkway 39 system all demonstrated differences for mature sows duri...
Increasing feed efficiency in swine is important for increasing sustainable food production and profitability for producers; therefore, this is often selected for at breeding. Residual feed intake (RFI) can be used for the genetic selection of pigs for feed efficiency. In our selection project, low-RFI pigs consume less feed for equal weight gain compared to their less efficient, high-RFI counterparts. However, little is known about how feed efficiency influences the pig's behavioral reactivity toward fear-eliciting stimuli. In this study, behavioral reactivity of pigs divergently selected for RFI was evaluated using human approach-(HAT) and novel object tests (NOT). Forty low-RFI (more feed efficient) and 40 high-RFI (less feed efficient) castrated male pigs (barrows; 46.5 ± 8.6 kg) from 8th generation Yorkshire RFI selection lines were randomly selected and evaluated once using HAT and once using NOT over a four week 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 four 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 crossed 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 (HAT: low-RFI = 4.9 ± 0.65 vs. high-RFI = 7.5 ± 0.96; NOT: low-RFI = 4.7 ± 0.66 vs. high-RFI = 7.2 ± 0.96; P < 0.0001) compared to high-RFI pigs. During HAT, low-RFI pigs also attempted to escape less frequently (low-RFI = 0.4 ± 0.14 vs. high-RFI = 1.1 ± 0.30; P = 0.001) compared to high-RFI pigs. In contrast, compared to the high-RFI pigs, low-RFI pigs took 48 s longer during HAT and 52 s longer during NOT to approach zone 1 (P ≤ 0.04). These results indicate that low-RFI pigs had decreased behavioral reactivity during HAT and NOT compared to high-RFI pigs. This may suggest that reducing a pig's behavioral reactivity is an important component of improving feed efficiency; however, it may have implications for animal handling and facility design. KeywordsSwine Feed Efficiency, Pig, Feed efficiency, Stress, Fear, Human approach, Novel object Disciplines Agriculture | Animal Sciences | Genetics and Genomics | Large or Food Animal and Equine Medicine CommentsThis is the author's version of a work that was accepted for publication in Applied Animal Behaviour Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. 21 NOTICE: this is the author's version of a work that was accepted for publication in Applied Animal Behaviour S...
BackgroundThe overall breeding objective for a nucleus swine selection program is to improve crossbred commercial performance. Most genetic improvement programs are based on an assumed high degree of positive relationship between purebred performance in a nucleus herd and their relatives’ crossbred performance in a commercial herd. The objective of this study was to examine the relationship between purebred and crossbred sow longevity performance. Sow longevity was defined as a binary trait with a success occurring if a sow remained in the herd for a certain number of parities and including the cumulative number born alive as a measure of reproductive success. Heritabilities, genetic correlations, and phenotypic correlations were estimated using THRGIBBS1F90.ResultsResults indicated little to no genetic correlations between crossbred and purebred reproductive traits. This indicates that selection for longevity or lifetime performance at the nucleus level may not result in improved longevity and lifetime performance at the crossbred level. Early parity performance was highly correlated with lifetime performance indicating that an indicator trait at an early parity could be used to predict lifetime performance. This would allow a sow to have her own record for the selection trait before she has been removed from the herd.ConclusionsResults from this study aid in quantifying the relationship between purebred and crossbred performance and provide information for genetic companies to consider when developing a selection program where the objective is to improve crossbred sow performance. Utilizing crossbred records in a selection program would be the best way to improve crossbred sow productivity.
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