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The aim of this study was to assess the effects of conditioning, rest, and post-rest transport duration on welfare indicators of 6-7 mo old beef calves. A total of 328 weaned calves (237 ± 29.7 kg BW) were randomly assigned to a 2 × 2 × 2 factorial design: conditioning, conditioned (C) or non-conditioned (N); rest, 0 (R0) or 8 (R8) h, and post-rest transport, 4 (T4) or 15 (T15) h. Calves were sampled prior to and after 20h of transport, prior to and after the additional 4 or 15-h transport, and at 1, 2, 3, 5, 14, and 28 d after transport ended. Data were analyzed using the GLIMMIX procedure of SAS. Fixed effects were conditioning, transport and time nested within rest period, while random effects were animal and pen. For R0-T4 calves, the mean L-lactate concentrations were greater than R8-T4 calves on d 1 and 2 (p-values = 0.02) while, for R0 calves, mean ADG was greater than R8 calves 14 to 28 d after transport (p-values < 0.01). For R8-T4 calves 1 week after transport, mean ADG was greater and mean WBC counts were less than R8-T15 calves on d 5 (p-values < 0.01). For N calves, overall mean haptoglobin, creatine kinase, serum amyloid-A, and non-esterified fatty acids were greater than C calves (p-values = 0.05). Overall, few and inconsistent differences were observed for rest, where rest improved L-lactate but affected ADG. Few differences were observed for transport, where shorter transport durations after the rest improved ADG and WBC counts. In general, N calves had greater physiological indicators of reduced welfare than C calves. Based on these findings, the best way to improve calf welfare during and after transport is to condition them prior to transport. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effects of conditioning, rest, and post-rest transport duration on welfare indicators of 6-7 mo old beef calves. Three hundred and twenty-eight weaned calves (237 ± 29.7 kg BW) were randomly assigned to a 2 × 2 × 2 nested factorial design: conditioning, conditioned (C) or non-conditioned (N); rest, 0 (R0) or 8 (R8) h, and post-rest transport, 4 (T4) or 15 (T15) h. Calves were sampled prior to the first loading (L1), after 20h of transport, prior to and after the additional 4 or 15-h transport, and at 1, 2, 3, 5, 14, and 28 d after transport ended. Data were analyzed using the GLIMMIX procedure of SAS. Fixed effects included conditioning, transport and time nested within rest period, while random effects included animal and pen. Greater shrink (P < 0.01) was observed in C than N calves after the initial 20-h transport. The N calves had greater (P < 0.01) ADG than C calves between L1 and d 5, while C had greater (P < 0.01) ADG than N calves between 14 and 28 d. L-lactate concentrations and flight speed were greater (P = 0.05) in C than N calves between L1 and d 5. The R8-T4 calves had greater (P < 0.01) ADG than R8-T15 calves between L1 and d 5. The R0-T4 calves had greater (P = 0.02) L-lactate concentrations than R0-T15 and R8-T4 calves on d 1. The R0 calves had greater (P < 0.01) ADG than R8 calves between 14 and 28 d. Preliminary results show physiological, behavioral, and performance differences across treatments, however, additional indicators are required to accurately assess the effect of conditioning, rest, and post-rest transport durations on calf welfare. [ABSTRACT FROM AUTHOR]

Simple Summary: Lactate is a metabolite used in animal research as an indicator of muscle fatigue; therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ hand-held analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected from 96 steers prior to loading and after 36 h of transportation, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ hand-held analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Correlations were calculated to assess the strength of the relationship between the L-lactate concentrations measured between methods. The strength of the correlation and the level of statistical significance varied over the observed time points, while the correlation for the pooled data was weak. Based on the low strength of the correlation, the Lactate Scout+ analyzer is not a suitable alternative to a colorimetric assay for measuring L-lactate in transported cattle. Lactate is a product of anaerobic glycolysis, used in animal research as an indicator of muscle fatigue. Therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected by venipuncture from 96 steers (Black or Red Angus × Hereford/Simmental and Black or Red Angus × Charolais; 247 ± 38.2 kg BW) prior to loading (LO1) and after 36 h of transport, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Pearson correlations were calculated to assess the strength of the relationship between the experimental methods for the quantification of L-lactate concentrations. The magnitude and direction of the correlation, and the level of statistical significance varied over the observed time points, ranging from r = −0.03 (p = 0.75; LO1) to r = 0.75 (p < 0.0001; d 3). The correlation for the pooled data was weak but statistically significant (r = 0.33, p < 0.0001). Based on the low magnitude of the correlation due to variability across sampling time points in this study, the Lactate Scout+ analyzer is not a suitable alternative to a lab-based assay (considered the gold standard) for measuring L-lactate in transported cattle. [ABSTRACT FROM AUTHOR]