RESUMO
This study examined the effects of a nonsteroidal antiinflammatory agent (NSAID) on physiological responses of calves immediately after hot-iron dehorning (DH) and during the time that local anesthetic (LA) wears off (2 to 3 h) after this procedure. Forty-six calves (33 +/- 0.3 d of age) were randomly assigned to 6 treatments: hot-iron DH versus sham DH with either no pain mitigation, LA alone, or LA with NSAID (i.v. Meloxicam). Eye temperature (measured using infrared thermography) was recorded every 5 min for 3 h after treatments. Heart rate (HR) and heart rate variability (HRV) were recorded continuously; for analysis of HRV, short segments of 512 interbeat intervals were examined. After DH without LA or NSAID, HR increased by 35 +/- 3.0 beats/min in the first 5 min and remained elevated above baseline for 3 h. The HRV around the time of DH did not differ between treatments; however, the root mean square of successive differences decreased from 68 to 41 +/- 12.6 ms immediately following DH without pain relief, suggesting a decrease in vagal tone at this time. Between 2 and 3 h following DH with LA, there was a decrease in eye temperature (-0.6 +/- 0.1 degrees C), an increase in HR (8 +/- 3.0 beats per min) and changes in HRV. Changes in HRV at this time included a decreased high-frequency power and an increase in the low-frequency power and low-frequency/high-frequency ratio, indicating a change in sympatho-vagal balance. The changes in eye temperature, HR, and HRV between 2 and 3 h following DH with LA indicated the onset of pain coinciding with the time that the LA effects wear off. In addition, this study demonstrated that the combination of LA and NSAID mitigated the onset of pain responses when the LA wanes.
Assuntos
Anestésicos Locais/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Indústria de Laticínios/métodos , Cornos/cirurgia , Temperatura Alta , Dor/veterinária , Animais , Temperatura Corporal , Bovinos , Feminino , Frequência Cardíaca , Lidocaína/uso terapêutico , Masculino , Meloxicam , Fenômenos Fisiológicos Oculares , Dor/tratamento farmacológico , Dor/prevenção & controle , Distribuição Aleatória , Tiazinas/uso terapêutico , Tiazóis/uso terapêutico , Fatores de TempoRESUMO
Three trials involving 396 pigs were conducted to determine the effects of regrouping finishing swine (83.8 +/- .69 kg) on weight gain and behavior during the subsequent 2-wk period. The methodology between Trials 1, 2, and 3 differed primarily in the total number of pigs tested (72, 144, and 180, respectively) and the number of pigs per pen (3, 3 or 5, and 5, respectively). In all trials, like-sexed pigs were moved into a new pen location and allotted to one of three treatments: 1) a group of familiar pen mates (Control), 2) a group composed of unfamiliar pigs (Mixed), and 3) pigs mixed with strangers for 24 h and then reunited with original pen mates for the duration of the trial (Mixed 24 h). In the pooled analysis, control pigs gained faster (P < .01) than Mixed pigs (.87 and .77 kg/d, respectively) over the 2-wk period. Mixed 24-h pigs were intermediate in gain (.80 kg/d), indicating that the most severe aggression normally observed during the first 24 h accounts for only a portion of the setback. Apparently the negative social stress associated with being in the presence of unfamiliar pigs persisted beyond the first 24 h and was sufficient to limit weight gain over the 2-wk period. Time spent fighting was reduced from 1.72 min/h during a 6-h period on d 1 to .39 min/h during a 3-h period by d 2 in the Mixed group. Fighting was still observed in the Mixed pens 8 d after regrouping (.23 min/h), indicative of ongoing social conflicts.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Comportamento Animal/fisiologia , Estresse Fisiológico/veterinária , Suínos/fisiologia , Aumento de Peso/fisiologia , Agressão , Ração Animal/normas , Animais , Feminino , Masculino , Distribuição Aleatória , Caracteres Sexuais , Estresse Fisiológico/fisiopatologia , Estresse Psicológico/fisiopatologia , Suínos/crescimento & desenvolvimento , Suínos/psicologia , Doenças dos Suínos/fisiopatologiaRESUMO
Three trials were conducted involving 393 ewes to determine the feasibility of using cubicles to provide isolation for parturient ewes in lambing pens. The cubicles consisted of an enclosure with 1 m high walls and a small (.6 m wide) opening to allow ewes free access. In trial 1, 42% of the parturitions occurred in the cubicles, which occupied only 19% of the pen area. No preference was noted for large (1.8 x 1.8 m) vs small (1.8 x 1.2 m) cubicles. Use of the cubicles increased from 4% of the time 24 h before parturition to 25% of the time during the 6 h immediately preceding parturition. In trial 2, ewes did not show a preference for open vs covered walls on cubicles or for open vs covered cubicle ceilings. Cubicles were again used to a greater (P less than .01) extent than would be predicted by their relative area (26% use, 18% area). In the final trial, mature ewes used cubicles to a greater (P less than .10) extent than did yearlings (55 vs 38%, respectively). Cubicles and areas of the pen farthest from the working area of the herdsman were most frequently (P less than .001) used during parturition. Cubicles appeared to be effective in preventing separation of newborn lambs from their dam and in reducing interference by other ewes.
Assuntos
Abrigo para Animais , Trabalho de Parto , Comportamento Materno , Ovinos/fisiologia , Animais , Feminino , GravidezRESUMO
Objectives of this study were to estimate the magnitude of the effects of various factors associated with ewes and their ram lamb mates on fertility, prolificacy, lamb survival, lamb weaning weight and ewe productivity and to estimate the heritability and repeatability of each trait. Records from 731 ewe-years, 75 ram lamb sires and 616 lambs born from the University of Illinois Rambouillet flock were used. Ewes mated to single-born ram lambs had higher fertility rates (P less than .01), gave birth to lambs with higher survival rates (P less than .01), weaned lighter (P less than .05) individual lambs but weaned more weight of lamb per ewe exposed (P less than .01) than ewes mated to multiple-born ram lambs. Ram lamb breeding weight, ram lamb scrotal circumference, ewe breeding weight and ewe age had relatively large and positive effects on the composite trait of weight of lamb weaned per ewe exposed and significant effects on a number of the component traits. Heritability and repeatability estimates were, respectively, as follows: fertility, 3%, 3%; prolificacy, 34%, 19%; lamb survival, 15%, 8%; lamb weaning weight, 7%, 36%; and ewe productivity, 27%, 10%.
Assuntos
Cruzamento , Fertilidade , Prenhez/fisiologia , Ovinos/fisiologia , Fatores Etários , Animais , Peso Corporal , Feminino , Masculino , Gravidez , Escroto/anatomia & histologia , Fatores Sexuais , Ovinos/crescimento & desenvolvimentoRESUMO
A 2 X 2 factorial experiment was conducted using growing lambs to compare single-level vs double-decked pens and high (.32 m2/lamb) vs low (.48 m2/lamb) densities. Three replicates of each treatment combination were involved using 30 lambs/pen. In the double-decked pens, an upper deck located over the rear section of the lower level provided one-third of the total floor area. Feed and water were provided on the lower level only and lambs could move freely between levels by means of a slatted ramp. All floors were of expanded metal. Use of the various areas of the pens was determined during a 24-h observation and by a videotape recording of the double-decked pens during the daylight hours. Fleece contamination was determined by visual observation and standard wool testing procedures. Gain was determined over the 8-wk period of each replicate. The high density treatment resulted in 1.5 kg/lamb (10%) less gain (P less than .01) and, in the case of double-decked pens, different patterns of space utilization compared with the low density treatment. Lambs in the low density pens were able to move more successfully from resting areas to the feeding area in the afternoon (P less than .01). The double-decked system did not significantly affect weight gain, but resulted in dirtier fleeces (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Comportamento Animal , Peso Corporal , Abrigo para Animais , Ovinos/fisiologia , Animais , Lã/análiseRESUMO
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.
Assuntos
Sistemas de Identificação Animal/métodos , Comportamento Animal/fisiologia , Bovinos/fisiologia , Manobra Psicológica , Criação de Animais Domésticos/métodos , Bem-Estar do Animal , Animais , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/etiologia , Temperatura Baixa , Temperatura Alta , Incidência , Masculino , Dor/epidemiologia , Dor/etiologia , Dor/veterinária , Esforço Físico/fisiologiaRESUMO
The impetus to find alternative methods to stressful routine management procedures has increased in recent years in the hope of improving animal welfare. The potential of using depigmenting compounds to create a permanent visible mark was evaluated in two beef heifers. Eight compounds (hydroquinone [H], 4-ethoxyphenol [4-EP], 4-methylcatechol [4-MC], 4-tert-butylcatechol [4-t-BC], 4-methoxyphenol [4-MP], monobenzone [M], hydroquinone bis (2-hydroxyethyl) ether (HHEE), and catechol [C]) were injected intradermally at concentrations of 10 and 20%. These compounds were screened in four different carriers (ethanol, glycerol, propylene glycol, and liposome cream) to test their effectiveness in producing depigmented hair. Transdermal patches containing 5, 7, and 10% liposome preparations of 4-MC and 4-MP produced depigmentation, but this depigmentation was not as visible as when the same preparations were injected. Histological examination of biopsies and observations of the injected sites were compared to sites that were only injected with the carrier solution. Compounds H, 4-EP, 4-MC, 4-t-BC, 4-MP, and M produced visible depigmentation lasting up to 3 mo. The duration of the effect seemed dependent on the hair cycle length and stage of cycle at time of application. None of the depigmenting compounds tested produced a permanent depigmenting effect.
Assuntos
Sistemas de Identificação Animal/veterinária , Bem-Estar do Animal , Bovinos , Pigmentação da Pele/efeitos dos fármacos , Pele/efeitos dos fármacos , Administração Cutânea , Sistemas de Identificação Animal/métodos , Animais , Catecóis/administração & dosagem , Catecóis/farmacologia , Portadores de Fármacos , Feminino , Cabelo/efeitos dos fármacos , Hidroquinonas/administração & dosagem , Hidroquinonas/farmacologia , Injeções Intradérmicas/veterinária , Fenóis/administração & dosagem , Fenóis/farmacologia , Pele/patologiaRESUMO
The objectives of this study were to identify nongenetic factors influencing scrotal circumference size and growth and to estimate heritabilities of scrotal circumference size at different ages and scrotal circumference growth between ages. Data on scrotal circumference, live weight, and age were recorded over 6 yr (1982 to 1987) on 541 spring-born Rambouillet ram lambs (109 sires, 307 dams) at the Dixon Springs Agricultural Center. Scrotal circumference and live weight were predicted at four ages (90, 120, 150, and 180 d) for each lamb. The two models used to evaluate factors affecting scrotal circumference size at fixed ages were the same except for the addition of live weight and live weight squared to one of the models. Likewise, the two models used for scrotal circumference growth between ages were the same except for the addition of live weight change and live weight change squared to one of the models. Year and type of birth were significant sources of variation for both traits under both models. Regression coefficients for live weight and live weight squared on scrotal circumference size and for live weight change and live weight change squared on scrotal circumference growth and for day of birth within year for both traits were generally different from zero (P less than .05). Heritability estimates for scrotal circumference size at fixed ages ranged from .19 to .41. Adjustments for live weight led to an average 41.5% increase in heritability estimates. For scrotal circumference growth, heritabilities ranged from .17 to .60 and adjustments for live weight change resulted in an average 13% decrease in estimates.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Cruzamento , Escroto/anatomia & histologia , Ovinos/genética , Testículo/anatomia & histologia , Fatores Etários , Animais , Peso Corporal , Tamanho da Ninhada de Vivíparos , Masculino , Modelos Biológicos , Análise de Regressão , Escroto/crescimento & desenvolvimento , Ovinos/anatomia & histologia , Ovinos/crescimento & desenvolvimento , Testículo/crescimento & desenvolvimentoRESUMO
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.
Assuntos
Sistemas de Identificação Animal/métodos , Comportamento Animal/fisiologia , Bovinos/fisiologia , Movimentos da Cabeça/fisiologia , Medição da Dor/veterinária , Animais , Estudos de Coortes , Congelamento , Temperatura Alta , Processamento de Imagem Assistida por Computador/métodos , Masculino , Medição da Dor/métodos , Esforço Físico/fisiologia , Distribuição Aleatória , Gravação de Videoteipe/estatística & dados numéricosRESUMO
Experiments were conducted to investigate the effects of the presence of a trainer cow on behavior, performance, health, and feeding patterns of newly weaned beef calves. In Exp. 1,252 weaned calves (270+/-18 kg) were allocated to 22 pens (11 to 15 calves per pen). A trainer cow was randomly assigned to each of 11 pens. Calves were weighed prior to feeding on d 0, 3, 7, 14, 21, and 28. Rectal temperatures were taken on each of these days (except d 28) and blood samples were collected on d 0, 3, and 7 and subsequently analyzed for serum haptoglobin and leukotoxin antibody titers. Instantaneous scan observations of calf behavior were made at 10-min intervals between 0730 and 1730 on d 1, 2, 4, 5, and 6. A similar protocol was used in Exp. 2, in which 297 calves (258+/-17 kg) were allocated to 24 pens. Blood analyses included haptoglobin, white blood cell counts (WBC), and neutrophil:lymphocyte (NL) ratios. In Exp. 3, the above protocol was followed and patterns of feed bunk attendance of individual calves were also monitored using radio frequency identification by passive transponder ear tags. Trainer cows did not influence (P > .10) calf rectal temperatures, requirements for antibiotic therapy, WBC, NL ratios, or leukotoxin antibody titers. Pooled across treatments, NL ratios were lower (P < .01) on d 0 (.31) than on d 3 (.36) or d 7 (.39). Although differences in weight gain were detected in some periods within the three experiments, there were no differences (P > .10) overall (d 0 to 28). Trainer cows did not affect (P > .05) frequency or duration of bunk visits by the calves. Averaged across treatments, frequency and duration of bunk visits increased (P < .001) from 9.6 visits/d and 56.7 min/d between d 0 and 3 to 12.3 visits/d and 108.9 min/d between d 15 and 21. The number of calves observed eating during scan sampling observations also increased from 16.4% on d 1 to 25% on d 4 (P < .10) and 29% on d 5 and 6 (P < .05). More (P < .05) calves were observed lying on d 1 (41.7%) and d 2 (45.3%) than on d 4 (37.5%), d 5 (34.8%), or d 6 (36.2%). With a trainer cow present, fewer (36.7% vs 41.5%; P < .001) calves were observed lying and more (11.7% vs 10.2%; P = .08) were observed walking than when no cow was present. Trainer cows did not improve calf health, time spent at the feed bunk, or performance of newly weaned calves.
Assuntos
Criação de Animais Domésticos/métodos , Bovinos/crescimento & desenvolvimento , Comportamento Social , Animais , Anticorpos/análise , Temperatura Corporal , Ingestão de Energia , Exotoxinas/imunologia , Haptoglobinas/análise , Masculino , Desmame , Aumento de PesoRESUMO
Maternal and neonatal behavior differs among food-producing mammals, and our management must reflect these differences. Sows will show more elaborate preparturient behavior than the other species as they attempt to build a nest that will last for several days. Because the nest is the focal point of maternal behavior for several days, the sow does not need to recognize her piglets until they are about 1 week of age. Although this facilitates the fostering of piglets between litters, the teat order developed by piglets during the first day or two makes it difficult for alien piglets to suckle when first fostered. Piglets are weaned at a relatively early age, and this results in conflict as neonatal behavior persists in an environment that requires better developed feeding patterns. Restrictions placed on ewes and cows by confinement at the time of parturition may result in their being unable to select an appropriate birth site. Our management must accommodate these needs by providing sites that are protected from the harsh environment and also allow separation from the rest of the flock. This is particularly important for ewes bearing multiple young, for lambs frequently become separated from the ewe while she is caring for another lamb. Both cows and ewes must be allowed to bond to their offspring soon after birth if they are to provide adequate maternal care. Fostering in these species involves manipulation of identifying stimuli to overcome the dam's ability to recognize her own young shortly after birth. Suckling problems, due to pendulous udders on cows and multiple lambs in sheep, may require attention by the stockman shortly after birth. Weaning does not result in major behavioral problems in sheep or beef cattle that are weaned after the young are consuming solid feed on a regular basis. Dairy calves, which are initially weaned onto milk replacer at a very early age, may develop inappropriate sucking behaviors that persist beyond weaning onto a solid diet. Despite our growing knowledge of maternal and neonatal behavior, mortality among piglets, lambs, and calves is still high. However, many of the most recent findings have yet to be incorporated into management procedures or standard practice. As this occurs, we should be able to reduce losses of young animals.
Assuntos
Animais Domésticos , Animais Recém-Nascidos , Comportamento Animal , Comportamento Materno , Prenhez , Animais , Animais Domésticos/fisiologia , Animais Recém-Nascidos/fisiologia , Animais Lactentes/fisiologia , Feminino , Trabalho de Parto/fisiologia , Gravidez , DesmameRESUMO
In order to assess the value of vocal response as an indicator of welfare in cattle, it is necessary to investigate factors which influence vocal behaviour of individuals, that are independent of the specific environmental conditions to which they are exposed. The effect of parental differences, sex, age and weight on vocal responses of calves to visual isolation were examined. The relationship between vocal response and the amount of body movement during isolation were also evaluated.Seventeen full-sibling families of beef calves (N=130) were created by breeding five sires with 13 superovulated dams. Embryos were transferred into unrelated cows, which reared the calves to weaning age. Vocal response of calves and body movement were measured on four occasions, while they were visually isolated for 1min on a single animal scale platform. The first two observations were made on the day of weaning (mean age 166 days) and the following day. At the third and fourth observations their average ages were 278 and 350 days, respectively. On the four occasions 33.3, 34.8, 27.8 and 38.6% of calves, respectively, vocalized. Both sire and family had a significant influence on the number of vocalizations and acoustic properties of the sounds. Electronically-measured movement while on the scale was also influenced by sire and family, but there was no relationship between vocal responses and body movement. There was a tendency (P=0.08) for older and therefore heavier calves to produce longer vocalizations. In the final observing session, age and weight were positively correlated with fundamental frequency and the sound pressure level at the frequency of greatest intensity, and negatively correlated with the loudest harmonic. At the last two observations, significantly more heifer calves than bull calves vocalized. There was little difference between the acoustic properties of heifers' and bulls' vocalizations.The considerable individual variability in vocal response within a group of identically-treated calves is partly due to parental genetic influences that are independent of rearing and early experience. Other endogenous characteristics such as sex, age and weight also influence vocal response. But there is no clear relationship between individual temperament (as assessed by the amount of body movement during isolation) and characteristics of vocal response.
RESUMO
Eighty-nine steer and bull calves (210 +/- 20 d of age) were randomly assigned to a 2 x 2 factorial arrangement of treatments to study the effect of sham or band castration (CAST) with or without pain medication (MED) on performance, behavior, cortisol, and Escherichia coli shedding. Steers (serving as controls; C) were previously castrated at 34 +/- 10 d of age, whereas bulls (B) remained intact until band application on d 20 of the experiment. One-half of the calves in each group received pain medication (M; xylazine epidural and intravenous flunixin meglumine) or saline (NM) solutions at 0.5 h before castration. Feed intake, ADG, and feeding behavior were measured over a 3-wk period before (used as covariates) and a 6-wk period after castration. Fecal and saliva samples were collected from 32 calves for E. coli enumeration at -7 (covariate), 2, 5, and 7 d, and for cortisol concentration at -0.5 (covariate), 0, 0.5, 1, 2, 4, 24, 48, 168, and 336 h relative to castration, respectively. Lying behavior was measured in the home pen and step length at exit from the chute. There were no significant CAST x MED interactions on growth rate or feed intake. Overall ADG was less in B compared with C (P < 0.001), but feed intake was less during wk 4 only (P = 0.01). On average, M had less intake (P = 0.02) and eating rate (P = 0.04) than NM calves. The BM had less fecal E. coli counts than CM (P = 0.05) and castrated and nonmedicated calves (P = 0.08). Salivary cortisol was less in BM compared with the rest of treatments at 1 and 2 h after banding (P Assuntos
Analgésicos/uso terapêutico
, Bovinos/cirurgia
, Hidrocortisona/análise
, Orquiectomia/veterinária
, Saliva/química
, Animais
, Comportamento Animal
, Bovinos/crescimento & desenvolvimento
, Ingestão de Alimentos
, Escherichia coli/patogenicidade
, Masculino
, Dor/prevenção & controle
, Dor/veterinária
, Aumento de Peso
RESUMO
Four trials were conducted to explore possible advantages of weaning beef calves in two stages compared with the traditional method of weaning by abrupt separation. In the two-stage treatment, calves were prevented from nursing their dam for a period (Stage 1) before their separation (Stage 2). Control calves nursed from their dams until they were separated. Calf weights and behavior were recorded before and after the separation of cows and calves. Following separation, calves weaned in two stages vocalized 96.6% less (P = 0.001) and spent 78.9% less time walking (P = 0.001), 23.0% more time eating (P = 0.001), and 24.1% more time resting (P = 0.001) than control calves. Compared with controls, two-stage calves had lower (P < 0.001) ADG when nursing was deprived (Stage 1), but greater (P < 0.001) ADG during the 7 d following separation. In Trial 3, calves weaned by the two-stage method had greater (P = 0.05) growth rates than control calves for 7 wk after separation, but no treatment effects on ADG were detected (P > 0.38) in Trials 1 and 2. Over the entire study period (before and after separation), ADG did not differ (P > 0.10) for both treatments. In Trial 4, calves weaned in two stages walked 1.3 km/d more (P < 0.05) during the 4-d period when nursing was prevented (Stage 1) and 5.8 km/d less (P < 0.05) during the 4-d period after separation than controls. Differences between treatments were the greatest in the 2 d after separation. On the first day after separation, two-stage calves walked 5.2 +/- 0.5 km/ d, whereas control calves walked 16.7 +/- 3.1 km/d. Calves weaned in two stages were less distressed than calves weaned by the traditional method of abrupt separation based on behavioral data, but overall calf ADG did not differ for either method in this study. Nutritional management of two-stage weaned calves during the nursing-deprived period should be evaluated in future research because poor pasture conditions may have decreased gains by calves weaned by the two-stage method in this study.
Assuntos
Criação de Animais Domésticos/métodos , Comportamento Animal/fisiologia , Bovinos/crescimento & desenvolvimento , Bovinos/psicologia , Desmame , Criação de Animais Domésticos/instrumentação , Animais , Feminino , Masculino , Atividade Motora/fisiologia , Distribuição Aleatória , Fatores de Tempo , Aumento de Peso/fisiologiaRESUMO
Two behavioral traits, temperament and habituation, were measured in 130 calves from 17 full-sib families which comprise the Canadian Beef Cattle Reference Herd. Using variance components, heritability was calculated as 0.36 for temperament and 0.46 for habituation. Genotyping of 162 microsatellites at approximately 20 cM intervals allowed the detection of six quantitative trait loci (QTL) for behavior traits on cattle chromosomes 1, 5, 9, 11, 14, 15.