Effect of handling intensity at the time of transport for slaughter on physiological response and carcass characteristics in beef cattle fed ractopamine hydrochloride.

The effects of handling intensity on the physiological response and carcass characteristics of feedlot cattle fed ractopamine hydrochloride were evaluated at the time of transport to slaughter. Eighty steers (BW = 668 ± 36 kg) representing 10 lots of similar breed, frame size, and degree of finish were blocked by lot, stratified by weight, and randomly assigned to 1 of 2 handling intensities (HI) over a 1,600 m dirt alley course: 1) low-stress handling (LSH) or 2) high-stress handling (HSH). For the LSH treatment, 4 penmates were kept at a walk with the use of a lead rider. For the HSH treatment, 4 penmates were kept at a minimum of a trot and received 2 applications of an electric prod (approximately 1 s per impulse) at 2 separate instances: first in the alley before post-handling sampling, and again during loading for transportation to the abattoir. Behavioral observations and physical indicators of stress were recorded a minimum of 1 h before handling (baseline), immediately after handling (POSTHAND), and while in lairage after a 200 km transport to the abattoir. Vital parameters were recorded at baseline and POSTHAND. Venous blood samples were collected via jugular venipuncture at baseline and POSTHAND, and mixed arterial and venous blood samples were collected during exsanguination at slaughter. Muscle tremors tended to be more prevalent in HSH cattle at POSTHAND ( = 0.10). The HSH cattle tended to have greater POSTHAND heart rate ( = 0.08); however, there was no effect of HI on POSTHAND respiration rate or rectal temperature ( 0.34). The HSH cattle had greater lactate, epinephrine, norepinephrine, cortisol, and glucose concentrations at POSTHAND ( ≤ 0.02). Additionally, HSH cattle had lower POSTHAND blood pH, bicarbonate, base excess, and partial pressure carbon dioxide ( < 0.0001). Bicarbonate concentrations were greater in HSH cattle at slaughter ( = 0.05); however, there were no differences between HI treatments for the remaining blood variables ( 0.11). Concentrations of stress hormones and CK were significantly greater at slaughter relative to baseline and POSTHAND for both LSH and HSH cattle ( < 0.001). These findings suggest cattle trotted without a lead rider develop metabolic acidosis, and illustrate the importance of low-stress handling at the time of transport for slaughter. Further research is warranted to develop strategies to mitigate stress at the time of transport and ensure the welfare of beef cattle presented to abattoirs.

Effects of ractopamine hydrochloride on growth performance, carcass characteristics, and physiological response to different handling techniques.

Feedlot cattle ( = 128; BW = 549 ± 60 kg) were used to evaluate the effects of ractopamine hydrochloride (RAC) on growth performance, physiological response to handling, and mobility during shipment for slaughter in a study utilizing a split-plot design with a 2 × 2 factorial arrangement of treatments: 1) diet (CON [no ß-adrenergic agonist] vs. RAC [400 mg·animal·d ractopamine hydrochloride for 28 d]) and 2) handling intensity (HI; low-stress handling [LSH; cattle moved at a walking pace with no electric prod use] vs. high-stress handling [HSH; cattle moved at a minimum of a trot and an electric prod applied while in the alley for posthandling restraint and during loading for shipment to the abattoir]). Cattle fed RAC tended to have greater ADG and G:F ( = 0.06), and had greater HCW and LM area ( = 0.04). The HI treatments were applied on the day after the 28-d growth performance period. Blood samples were collected before HI treatment (baseline), after HI treatments (POSTHAND), after transport to the abattoir (POSTTRANS), and during exsanguination at slaughter. A diet × HI interaction ( = 0.01) was observed in the change in cortisol from baseline to POSTTRANS, and there tended ( ≤ 0.07) to be diet × HI interactions for the change in epinephrine from baseline to POSTHAND and for the change in creatine kinase (CK) from baseline to POSTTRANS. Feeding RAC and HSH both increased the change from baseline to POSTHAND in norepinephrine and pH ( ≤ 0.05). The HSH cattle also had greater changes from baseline to POSTHAND in blood HCO, base excess, partial pressure of CO, lactate, cortisol, and glucose ( ≤ 0.01). Ractopamine and HSH both produced greater increases in CK concentrations from baseline to slaughter ( < 0.01). Mobility was not affected by RAC at the feedlot or following an average 6-h lairage ( ≥ 0.43). This study confirms RAC improves growth performance and suggests metabolic acidosis, a precursor to fatigued cattle syndrome, develops in cattle allowed to trot without the use of a lead rider regardless of RAC administration. Cattle fed RAC displayed altered hormonal responses to handling and transport stress, and the overall proportion of cattle with compromised mobility appears to increase later in the marketing channel. These findings warrant additional research aimed at better understanding the physiological response to stress and protect the welfare of cattle during shipment for slaughter.

Emotional crying, depressed mood, and secretory immunoglobulin A.

The relationship between emotional crying and secretory immunoglobulin A (S-IgA) in whole saliva was examined. Previous research had indicated that lower S-IgA was associated with crying. Similar results were found in the present study. Depressed mood was not associated with S-IgA.

Effects of tilmicosin on acute undifferentiated respiratory tract disease in newly arrived feedlot cattle.

OBJECTIVES: To evaluate effects of tilmicosin when used in fever-based and metaphylactic treatment programs to attenuate acute undifferentiated bovine respiratory disease (BRD) in cattle that recently arrived at feedlots, and to evaluate the effects of tilmicosin for the treatment of BRD. DESIGN: Randomized-block controlled study. ANIMALS: 1,639 calves from livestock auctions. PROCEDURES: Cattle were assigned to 3 groups. Cattle in the nonmedicated (control) group were not given antibiotics during processing. Cattle in the fever-based treatment group were given tilmicosin (10 mg/kg [4.5 mg/lb] of body weight, s.c.) during processing when their rectal temperature was > or = 40 C (104 F). All cattle in the metaphylactic treatment group were given tilmicosin (10 mg/kg, s.c.) during processing. Calves with BRD were treated with tilmicosin (10 mg/kg, s.c.). RESULTS: Morbidity rates in the metaphylactic (30.4%) and fever-based (44.7%) treatment groups were less than that for the nonmedicated group (54.8%). Mortality rate for the metaphylactic group during the first 28 days (1.1%) and during the entire study (1.7%) was less than that for the nonmedicated group (3.3 and 4.6%, respectively). Differences were not observed in therapeutic response rates among calves with BRD that were treated. CLINICAL IMPLICATIONS: Fever-based and metaphylactic treatment programs that used tilmicosin decreased the prevalence of BRD and improved growth of calves. Metaphylactic treatment decreased the number of fatalities caused by BRD in high-risk calves. Fever-based treatment was less effective than metaphylactic treatment for decreasing the prevalence of BRD in newly arrived cattle.

Development of the Children's Eating Behaviour Questionnaire.

Individual differences in several aspects of eating style have been implicated in the development of weight problems in children and adults, but there are presently no reliable and valid scales that assess a range of dimensions of eating style. This paper describes the development and preliminary validation of a parent-rated instrument to assess eight dimensions of eating style in children; the Children's Eating Behaviour Questionnaire (CEBQ). Constructs for inclusion were derived both from the existing literature on eating behaviour in children and adults, and from interviews with parents. They included responsiveness to food, enjoyment of food, satiety responsiveness, slowness in eating. fussiness, emotional overeating, emotional undereating. and desire for drinks. A large pool of items covering each of these constructs was developed. The number of items was then successively culled through analysis of responses from three samples of families of young children (N = 131; N = 187; N = 218), to produce a 35-item instrument with eight scales which were internally valid and had good test-retest reliability. Investigation of variations by gender and age revealed only minimal gender differences in any aspect of eating style. Satiety responsiveness and slowness in eating diminished from age 3 to 8. Enjoyment of food and food responsiveness increased over this age range. The CEBQ should provide a useful measure of eating style for research into the early precursors of obesity or eating disorders. This is especially important in relation to the growing evidence for the heritability of obesity, where good measurement of the associated behavioural phenotype will be crucial in investigating the contribution of inherited variations in eating behaviour to the process of weight gain.

Young children's food preferences: a comparison of three modalities of food stimuli.

Food preferences are widely agreed to be important determinants of eating behaviour in young children. Existing studies of methods of assessing preferences have suggested tasting and ranking foods can generate reliable responses with young children, but there have been few attempts to assess other methods which might provide a more convenient alternative in situations where the use of real foods could be difficult (e.g. outside the laboratory), or tasting could be undesirable (e.g. if there are large numbers of foods, or foods which children would be unwilling to taste). The present study is a comparison of the reliability of preferences measured using: (i) real foods; (ii) food photographs; and (iii) food models, in 3 to 5-year-old children. The results showed that the tasting method produced good results, replicating existing data from U.S. samples. Food photographs came a close second in reliability but food models produced unreliable rankings, especially in the youngest group. Five-year-olds produced significantly more consistent results than the younger children. These results indicate that using real foods as the stimuli produces the most reliable taste preferences with children in this young age range, but photographs may provide a convenient alternative with adequate reliability.

Rattling the plate--reasons and rationales for early weaning.

To identify a range of attitudes and beliefs which influence the timing of introduction to solid food, five focus group discussions were undertaken within a maternity hospital setting. These sessions explored early feeding behaviour, stimuli to changing feeding habits and subsequent responses in 22 primiparous and seven multiparous mothers (mean age 27.0+/-4.8 years) with babies aged 8-18 weeks (mean age 13.0+/-4.2 weeks). One-third of the participants had introduced solid food to their infants (mean age of introduction 11.6 weeks, range 2-16 weeks). Mothers believed that the introduction of solids was baby led and initiated by some physical characteristic or behavioural action of the infant. All mothers were aware of current recommendations to avoid the introduction of solid food until 4 months. Few knew why this should be and concepts of long-term ill health were difficult to conceptualize. The conflict between rigid feeding guidelines and flexible advice from supportive health professionals created confusion over the importance of good weaning practices. The current findings highlight issues relevant to the introduction of solid food, and provide a foundation for further research which can identify the relative importance of these factors and provide a rationale for the design of contemporary intervention strategies.