Behavior of cattle during hot-iron and freeze branding and the effects on subsequent handling ease.
(73/77)
Three hundred feedlot steers (320 +/- 2 kg) were assigned to freeze brand, hot-iron brand, and sham branding treatments according to a randomized branding arrangement. Behaviors believed to be indicative of pain (i.e., tail-flicking, kicking, falling, and vocalizing) were recorded during branding. Escape behavior, measured as the amount and duration of force exerted on the headgate and squeeze chute by the animals during treatment, was obtained using load cells and strain gauges. Subsequent handling ease following branding was tested every 2nd d for 10 d by recording the time and effort required to move animals into the chute. Hot-iron-branded steers had greater tail-flick, kick, fall and vocalization frequencies than freeze-branded or sham-branded animals (P < .005). However, freeze-branded animals differed from shams only in regard to tail-flick frequencies (P < .005). The average and maximum exertion forces and the duration of force were greater in hot-iron-than in freeze- and sham-branded steers (P < .001); freeze branded steers had greater values than shams (P < .001). No treatment differences in handling ease were observed. However, all steers required more handling effort for up to 6 d, indicating that handling, per se, was aversive. Results indicate that hot-iron-branded steers experienced more discomfort at the time of branding than freeze-branded and sham steers, and freeze-branded steers experienced more discomfort than shams. (+info)
Influence of sire misidentification on sire x year interaction variance and direct-maternal genetic covariance for weaning weight in beef cattle.
(74/77)
Biased estimates of the genetic correlation between direct and maternal effects may occur when sire x year interaction (SY) effects are ignored in analytical models used to estimate (co)variance components for weaning weight in beef cattle. Using simulation, sire misidentification was explored as a source contributing to estimates of SY variance. Identifications were falsified for 20% of sires of nonparents only or for 20% of sires of all animals. Sire misidentification influenced estimates of genetic and environmental parameters. In populations in which misidentification occurred only in nonparents, heritability estimates for direct growth were reduced, and heritability estimates of maternal effects were inflated. Also, spurious SY variance and direct-maternal covariance were produced. Direct-maternal covariance was biased in a positive direction, and SY variance was on the order of 1 to 3% of the phenotypic variance. (+info)
Effects of prenatal stress on suckling calves.
(75/77)
Pregnant Brahman cows (n = 42), bred to either Brahman or Tuli bulls, were randomly assigned to one of three treatments: 1) transported in a stock trailer for 24.2 km, unloaded at a second farm and penned for 1 h, and then returned to the original farm (TRANS); 2) i.v. injection of ACTH, 1 IU/kg BW (ACTH); or 3) walked through the handling facilities (SHAM). Treatments were initiated on d 60 and repeated at 80, 100, 120, and 140 d of gestation. The calves from these cows were subjected to tests to measure their capacity to react to stress. In Test 1, Tuli-sired calves were restrained at 10 and 150 d of age for 3.5 h. In Test 2, Brahman-sired calves were restrained for 3.5 h and given an injection of ACTH (.125 IU ACTH/kg of BW). In Test 3, Test-2 calves were restrained at 180 d of age and hot-iron branded. In Test 4, Test-1 calves were restrained at 180 d of age and given an injection of cortisol (6.7 ng/kg BW) to estimate cortisol clearance rate. During all tests, calves were restrained for 3.5 h, and heart rates were recorded and blood samples were taken at -15, 0, 15, 30, 45, 60, 90, 120, and 180 min. The 10- and 150-d-old TRANS calves maintained greater plasma cortisol in Test 1 (restraint) than the ACTH and SHAM calves (P < .01). The ACTH challenge (Test 2) increased plasma cortisol and ACTH, but cow treatment did not alter the response (P > .4). In response to branding (Test 3), the TRANS, ACTH, and SHAM calves' overall mean plasma cortisol was not affected by treatment (52, 51, and 43 +/- 3 ng/mL, respectively; P > .1), nor was the calves' overall heart rate (91, 94, and 86 +/- 3 beats/min, respectively; P > . 1). In Test 4, TRANS calves cleared plasma of cortisol at a slower rate than did the SHAM calves (P < .01), but not the ACTH calves (261, 374, and 473 +/- 50 mL/min, respectively; P > .1). The TRANS calves had an overall greater heart rate than did the ACTH or the SHAM calves (91, 79, and 77 +/- 2 beats/min, respectively; P < .001). Exposing cows to repeated transportation stress during gestation altered their calf's physiological response to stress, and these alterations could have a profound influence on the calfs ability to adapt to stress, thereby influencing its welfare. Further research should examine the growth, immune function, and reproductive function of prenatally stressed calves to determine whether these changes in plasma cortisol are beneficial or deleterious. (+info)
National Beef Quality Audit-1995: survey of producer-related defects and carcass quality and quantity attributes.
(76/77)
The National Beef Quality Audit-1995 was conducted to evaluate the progress of the beef industry since the time of the National Beef Quality Audit-1991 in improving quality and consistency of beef. Nine plants were assigned for auditing to Colorado State University, Oklahoma State University, and Texas A&M University. Personnel from each institution visited three of their nine plants twice, once in the spring/summer and once in the fall/winter. Data were collected on 50% of each lot on the slaughter floor and 10% in the cooler during a single day's production (one or two shifts, as appropriate). Of the cattle audited on the slaughter floor, 47.7% had no brands, 3.0% had a shoulder brand, 16.8% had a side brand, 38.7% had a butt brand, and 6.2% had brands in multiple locations. Data revealed that 51.6% of the carcasses had no bruises, 30.9% had one bruise, 12.8% had two bruises, 3.7% had three bruises, .9% had four bruises, and .1% had more than four bruises. In addition, 7.2% of the bruises evaluated were located on the round, 41.1% were on the loin, 20.8% on the rib, and 30.8% on the chuck. Livers, lungs, tripe, heads, tongues, and whole carcasses were condemned at rates of 22.2, 5.0, 11.0, .9, 3.8, and .1%, respectively. Mean USDA yield grade and quality grade traits were as follows: USDA yield grade, 2.8; carcass weight, 338.4 kg; adjusted fat thickness, 1.2 cm; longissimus muscle area, 81.9 cm2; kidney, pelvic, and heart fat, 2.1%; USDA quality grade, High Select; overall maturity, A60; and marbling score, Small-minus. (+info)
Comparison of image analysis, exertion force, and behavior measurements for use in the assessment of beef cattle responses to hot-iron and freeze branding.
(77/77)
Thirty-three steers (328 +/- 2 kg) from a total of 300 animals were randomly selected for a comparison of techniques designed to quantify the behavioral response to painful procedures. The steers were randomly assigned to freeze-branding, (F), hot-iron branding (H), and sham branding (S) treatments. The responses of all steers were videotaped to quantify the amount and intensity of head movements during branding. In addition, the force that steers exerted on the headgate and squeeze chute during branding was recorded using strain gauges and load cells. Behaviors believed to be indicative of pain (tail-flicking, kicking, falling, and vocalizing) were also recorded during branding. These techniques were compared for their effectiveness in measuring behavioral responses of steers during branding. Hot-iron-branded steers had greater maximum and average head movement distances and velocities than F or S steers (P < .05), and F steers only had greater maximum values than S animals (P < .05). The maximum exertion forces obtained from headgate load cells were also greater in H than in F or S steers (P < .05); however, no differences were observed between H and F treatments for squeeze load cell or headgate strain gauge data. Hot-iron-branded steers had the greatest incidence of tail-flicks, kicks, falls in the chute, and vocalizations, and S steers had the least. Results indicate that H steers experienced more discomfort at the time of branding than F and S steers, whereas F steers experienced more discomfort than shams. Image analysis was a superior technique for detecting treatment differences compared with exertion force measurements and frequency counts of tail-flicks, kicks, falls, and vocalization during branding. (+info)