Weaning Of Beef Calves Research Articles

Environmental enrichment during yard weaning alters the performance of calves in an attention bias and a novel object recognition test

The weaning of beef calves in yards places multiple stressors on the animals, and environmental enrichment may help mitigate some of these stressors and improve animal welfare. This trial assessed the impacts of enrichment provision to beef calves during yard weaning using measures of biological functioning, behaviour, and affective state. Overall, calves utilised the brush more than the other provided enrichments, which were a hanging rope and a ball. Enrichment influenced the behaviours of calves during both an attention bias test, with enriched calves exhibiting behaviours associated with greater anxiety, and a novel object recognition test, with enriched calves spending less time interacting with objects. In their home pens, enriched calves performed more drinking and grooming behaviours. However, no significant differences were seen between treatments for body weight, faecal cortisol metabolites, and internal body temperature. Enrichment also did not influence any longer-term measurements of body weight, flight speed, or crush score. The study design was impacted by mud, requiring the regrouping of the animals. Thus, some results should be interpreted with caution. Overall, this study demonstrates that further work is required into the assessment of affective states for these animals as it could not be confirmed whether the results seen indicate that calf welfare was improved or impaired through enrichment provision.

Effects of bacterial DFM and tannins on measures of immunity and growth performance of newly weaned beef calves

Weaning of beef calves has been previously shown to be a stressful event. A number of feed additives have been developed to attenuate the periods of stress in calves, such as direct-fed microbials (DFM) and tannins (TN). A two-year study was conducted to determine the effect of DFM plus tannins (DFM+TN) on newly weaned calf performance and indicators of innate and humoral immune response. Angus calves (n = 142 in year 1; 143 in year 2) were weaned at approximately 6 mo of age, immediately transferred to a feedlot, and fed one of two diets for 42 days: a receiving ration without added DFM+TN (CON), or the same ration with (DFM+TN; 2×108 CFU/hd/d Propionibacterium acidipropionici; 5×107 CFU/hd/d Lactobacillus animalis; 5×107 CFU/hd/d Bifidobacterium animalis and 15 g/hd/d tannins). Body weights were taken on two consecutive days and averaged at the beginning and ending of the study, while single day weights were taken on d 28. In year 2, blood samples from coccygeal vascular complex were collected on d 0, 14, and 28 to measure post-vaccination Bovine viral Diarrhea (BVDV) titers. Upon completion of the 42-d study (year 2 only), calves (n = 72) were transported to Laramie, WY (242 km for 3 h) and additional blood samples were taken on d 0, 2, 4, 7, and 9, relative to transportation, to measure plasma haptoglobin concentrations. There were no differences detected for year (P > 0.18), initial (P = 0.42) and final BW (P = 0.43) or DMI (P = 0.31) due to dietary treatment. However, DFM+TN calves had lower (P = 0.001) overall feed:gain (F:G) and a tendency for greater overall ADG (P = 0.06) compared to CON calves. DFM+TN calves tended to have greater (P = 0.11) total gain overall than CON calves. There were no differences (P ≥ 0.22) in growth performance of calves after transportation. The DFM+TN calves had lower (P < 0.001) haptoglobin concentrations at d 0 and d 4 compared to CON calves (treatment × day effect P = 0.09). Weaned calves fed DFM+TN tended to have greater growth performance, including an improved feed efficiency during the first 42 d post weaning and had a reduction in plasma haptoglobin (d 0 and d 4 post-transport) concentrations relative to CON calves.

Influence of calf vigour and suckling assistance from birth to weaning in Guzerá beef cattle

Context Maternal ability, cow nutrition, and calf sex are factors that affect beef cattle production in extensive systems. The Guzerá cattle is an important breed in Brazil, where satisfactory growth rates are reported; however, studies on post-parturition calf and cow behaviour are scarce. Aims This study aimed to identify the influence of vigour at birth (ability to stand and suckle without assistance) and human assistance in colostrum intake (HA) on the haematological profile, cortisol concentration, and growth until weaning of Guzerá beef calf. Methods The following traits were observed in 73 male and 83 female calves: cow age at calving, sex, birthweight, vigour, HA, haematological profile, cortisol concentration, bodyweight at 120 days (W120), weaning weight, average daily gain and mortality. Variance analysis was performed using the general linear model procedure of the SAS software. Key results Haematocrit (P = 0.04) and red blood cells (P = 0.004) were higher in calves requiring HA. Cortisol was also higher (P = 0.03) in calves that required HA (81.34 ng/mL × 59.40 ng/mL). The weaning weight and average daily gain were higher (P &lt; 0.05) in calves that did not require HA and showed good vigour (200.38 kg and 0.83 kg/day respectively) than in calves that required HA and showed good vigour (163.7 kg and 0.68 kg/day respectively). The mortality rate was higher in calves that showed poor vigour at birth (25%). Conclusions Both vigour and the need for HA are important traits that should be evaluated during the development of newborn calves. These assessments in the herd can contribute to minimise the mortality rate and maximise the health and weight gain until weaning of beef calves. Implications Few studies have reported the role of vigour and colostrum intake in the development of calves. Despite the difficulty of human interference in extensive cattle farming, the calf vigour combined with human assistance at birth can minimise the losses and increase the performance of beef cattle.

Comparison of effects of four weaning methods on health and performance of beef calves

Weaning of beef calves is a stressful event that negatively impacts health and performance. A variety of interventions have been proposed to reduce stress and improve gains following weaning. This study used 288 7- to 8-month-old calves from two separate locations, to examine four different weaning strategies, as well as the impact of shipment. Calves were blocked by weight and sex, and then randomly assigned to one of four treatments: abrupt weaning (AW), where calves were separated from the dam on day 0 (D0) and allowed no further contact with the dam; fence line (FL), where calves were weaned on D0 but had fence line contact with dams for 7 days; nose flap (NF), where on day -6 calves received a nose flap that interferes with suckling, then had the flap removed and were weaned from the dam on D0; and intermittent separation (SEP), where calves were removed from dams for 24-h intervals on day -13 and day -6, then weaned on D0, but allowed fence line contact with the dam for 7 days. Each treatment group was further divided into two subgroups, one of which was shipped early (D0 for AW, day 7 for others) or shipped later (day 28). Body weight and sickness were recorded for all groups. Results showed a negative impact on gain for early shipping compared to later shipping, and poorer gain in AW calves than most other treatments. Results of the analyses of morbidity were inconclusive. This study found that delayed shipment following FL weaning improves performance under common management conditions for the US cow–calf industry.

Effects of cow parity on voluntary hay intake and performance responses to early weaning of beef calves

The objective of this study was to investigate the effect of early calf weaning from both primiparous and multiparous beef cows on hay intake and measures of performance. Over two consecutive years, 96 Brahman×British cows (48 cows/year) and their calves were stratified by parity and calving date and randomly assigned to one of two weaning treatments (n=24 cows/weaning treatment; 12 primiparous and 12 multiparous). Weaning treatments consisted of normal-weaned (calf remaining with cow throughout the study) or early weaned (calves removed from cow at 86±5 days of age). An estrus synchronization and fixed-timed artificial insemination protocol (CO-Synch+CIDR) was applied to all cows at 21 days after early weaning. Following fixed-timed artificial insemination, cows were put onto bahiagrass (Paspalum notatum) pastures (3 pastures/treatment; 4 cows/pasture) for a 60-day period to evaluate voluntary hay intake. During this time, cows were provided free-choice access to grass hay (‘Florona’ stargrass; Cynodon nlemfuensis) and 2.3 kg per head daily of a urea-fortified molasses supplement. Hay intake was determined by subtracting the dried weight of residual hay from the amount offered over the 60-day evaluation period. Cow body weight and body condition score were measured on day 0 and 60. Immediately following the hay intake determinationperiod,allcowsweregroupedbyweaningtreatmentandexposedtomatureAngusbullsfor21days.Pregnancydetermination toartificialinseminationandnaturalservicewasdeterminedbytransrectalutrasonographyontwooccasionsconducted60daysafterartificial insemination and again 40 days after bull removal. Multiparous cows had greater hay dry matter intake (Pb0.001), body weight (Pb0.001), and body condition score (Pb0.001) than primiparous cows throughout the study. Overall, early weaning resulted in greater than a 16% decrease(Pb0.01)inhaydrymatterintake,irrespectiveofparity.Early-weanedcowshadgreater(Pb0.01) bodyweight andbodycondition score than normal-weaned cows on day 60, but not day 0. Pregnancy rate to artificial insemination was greater (Pb0.01) for multiparous compared to primiparous cows. There was a weaning treatment×parity interaction for overall pregnancy rate, whereas early-weaned primiparous, but not multiparous, cows had a greater (Pb0.05) overall pregnancy rate compared to their normal-weaned contemporaries. These data imply that early calf weaning (90 days of age) will increase body weight and body condition in both multiparous and primiparous cows; however, early-weaning provides a greater advantage to overall pregnancy ratewhen applied to primiparous versus multiparous cows.

Correcting bias from the standard linear adjustment of weaning weight to an age-constant basis for beef calves1

Standard linear adjustment of weaning weight to a constant age has been shown to introduce bias in the adjusted weight due to nonlinear growth from birth to weaning of beef calves. Ten years of field records from the five strains of Beefbooster Cattle Alberta Ltd. seed stock herds were used to investigate the use of correction factors to adjust standard 180-d weight (WT180) for this bias. Statistical analyses were performed within strain and followed three steps: 1) the full data set was split into an estimation set (ES) and a validation set (VS), 2) WT180 from the ES was used to develop estimates of correction factors using a model including herd (H), year (YR), age of dam (DA), sex of calf (S), all two and three-way interactions, and any significant linear and quadratic covariates of calf age at weaning deviated from 180 d (DEVCA) and interactions between DEVCA and DA, S or DA x S, and 3) significant DEVCA coefficients were used to correct WT180 from the VS, then WT180 and the corrected weight (WTCOR) from the VS were analyzed with the same model as in Step 2 and significance of DEVCA terms were compared. Two types of data splitting were used. Adjusted R2 was calculated to describe the proportion of total variation of DEVCA terms explained for WT180 from the ES. The DEVCA terms explained .08 to 1.54% of the total variation for the five strains. Linear and quadratic correction factors were both positive and negative. Bias in WT180 from the ES within 180 +/- 35 d of age ranged from 2.8 to 21.7 kg.(ABSTRACT TRUNCATED AT 250 WORDS)