Evaluation of partial body weight for predicting body weight and average daily gain in growing beef cattle

Abstract

Information on body weight and average daily gain (ADG) of growing animals is key not only to monitoring performance, but also for use in genetic evaluations in the pursuit of achieving sustainable genetic gain. Accurate calculation of ADG, however, requires serial measures of body weight over at least 70 days. This can be resource intensive and thus alternative approaches to predicting individual animal ADG warrant investigation. One such approach is the use of continuously collected individual animal partial body weights. The objective of the present study was to determine the utility of partial body weights in predicting both body weight and ADG; a secondary objective was to deduce the appropriate length of test to determine ADG from partial body weight records. The dataset used consisted of partial body weights, predicted body weights and recorded body weights recorded for 8,972 growing cattle from a range of different breed types in 35 contemporary groups. The relationships among partial body weight, predicted body weight and recorded body weight at the beginning and end of the performance test were determined and calculated ADG per animal from each body weight measure were also compared. On average, partial body weight explained 90.7 ± 2.0% of the variation in recorded body weight at the beginning of the postweaning gain test and 87.9 ± 2.9% of the variation in recorded body weight at its end. The GrowSafe proprietary algorithm to predict body weight from the partial body weight strengthened these coefficients of determination to 95.1 ± 0.9% and 94.9 ± 0.8%, respectively. The ADG calculated from the partial body weight or from the predicted body weight were very strongly correlated (r = 0.95); correlations between these ADG values with those calculated from the recorded body weights were weaker at 0.81 and 0.78, respectively. For some applications, ADG may be measured with sufficient accuracy with a test period of 50 days using partial body weights. The intended inference space is to individual trials which have been represented in this study by contemporary groups of growing cattle from different genotypes.

Identification of Key Pathways Associated With Residual Feed Intake of Beef Cattle Based on Whole Blood Transcriptome Data Analyzed Using Gene Set Enrichment Analysis

“…A total of 56 crossbred growing beef steers with average BW of 261.3 ± 18.5 kg were fed a high-forage total mixed ration (TMR; primarily consisting of triticale silage; rye grass silage; and a ration balancing Supplementary Table 1 ) in five confinement dry lot pens (15 by 47 m 2 ), each served by three GrowSafe 8000 (GrowSafe Systems Ltd., Airdrie, Alberta, Canada) feeding nodes to measure individual feed intake and two In-Pen Weighing Positions (IPW Positions, Vytelle LLC) to measure daily BW for a total of 49 d after 15-d adjustment period to the feeding facilities. The use of IPW Positions has enabled the measurement of individual animal BW multiple times in a day ( 5 ). The IPW Positions measure the partial BW by weighing the front end of an animal ( 6 ).…”

“…The partial BW of the animals was measured every second the animals stayed on the scale while drinking. More details on the accuracy, use and applicability of IPW positions have been described in previous studies ( 5 , 6 ). In this study, approximately 617 ± 92 daily BW data points (after filtering outliers) per animal were generated and were regressed on time to calculate beginning BW, mid-test BW, and average daily gain (ADG) of each animal.…”

Characterization of rumen microbiome and immune genes expression of crossbred beef steers with divergent residual feed intake phenotypes

“…A total of 108 crossbred growing beef steers with average BW of 282 ± 30.4 kg were fed a high-forage total mixed ration (TMR; primarily consisting of corn silage; ground hay; and a ration balancing supplement; CP = 13.2%, NDF = 45.9% NDF, and NEg = 0.93 Mcal/kg) in a con nement dry lot equipped with GrowSafe intake nodes (GrowSafe Systems Ltd., Airdrie, Alberta, Canada) for a total of 70 d. Steers had ad libitum access to the experimental diet and water. Individual feed intake and daily BW were measured with GrowSafe automated feed intake, and two In-Pen Weighing Positions (IPW Positions, Vytelle LLC) as described by (MacNeil et al, 2021;Wells et al, 2021) respectively. Daily BW for each animal was regressed on time to calculate beginning BW and average daily gain (ADG).…”

Residual Feed Intake in Beef Cattle Is Associated With Differences in Hepatic mRNA Expression of Fatty Acid, Amino Acid, and Mitochondrial Energy Metabolism Genes

“…The beef steers were kept in five dry lot pens (10 -12 steers per pen) each equipped with three GrowSafe 8000 intake nodes (GrowSafe Systems Ltd., Airdrie, Alberta, Canada) to measure individual feed intake and In-Pen Weighing Positions (IPW, Vytelle LLC), positioned at a water trough in each pen to measure BW of individual animals several times daily (Wells et al, 2021). The use of IPW to measure BW has enabled the measurement of feed efficiency with sufficient accuracy with a test period of 49 d (MacNeil et al, 2021;Wells et al, 2021). Steers were identified with a passive, half-duplex, transponder ear tag (Allflex USA Inc., Dallas-Fort Worth, TX) before entry into the test facility.…”

“…The IPW Positions measured the partial BW by weighing the front end of an animal every second the animals stayed on the scale while drinking. Details on the use and accuracy of IPW positions have been published in previous studies (MacNeil et al, 2021;Wells et al, 2021). Approximately 617 ± 92 daily BW data points (after filtering outliers) per animal were generated in this study and were regressed on time using simple linear regression to calculate beginning BW, mid-test BW, and average daily gain (ADG).…”