Phenotypic and genetic associations between feeding behavior and carcass merit in crossbred growing cattle

In growing cattle, the phenotypic and genetic relationships between feeding behavior and both live animal ultrasound measures and subsequent carcass merit are generally poorly characterized. The objective of the current study was to quantify the phenotypic and genetic associations between a plethora of feeding behavior traits with both pre-slaughter ultrasound traits and post-slaughter carcass credentials in crossbred Bos taurus cattle. Carcass data were available on 3,146 young bulls, steers, and heifers, of which 2,795 and 2,445 also had records for pre-slaughter ultrasound muscle depth and intramuscular fat percentage, respectively; a total of 1,548 steers and heifers had information on all of the feeding behavior, ultrasound, and carcass traits. Young bulls were fed concentrates, while steers and heifers were fed a total mixed ration. Feeding behavior traits were defined based on individual feed events or meal events (i.e., individual feed events grouped into meals). Animal linear mixed models were used to estimate (co)variance components. Phenotypic correlations between feeding behavior and both ultrasound and carcass traits were generally weak and not different from zero, although there were phenotypic correlations of 0.40, 0.26, and 0.37 between carcass weight and feeding rate, energy intake per feed event, and energy intake per meal, respectively. Genetically, cattle that had heavier carcass weights, better carcass conformation, or a higher dressing percentage fed for a shorter time per day (genetic correlations [±SE] of −0.46 ± 0.12, −0.39 ± 0.11, and −0.50 ± 0.10, respectively). Genetic correlations of 0.43 ± 0.12 and 0.68 ± 0.13 were estimated between dressing difference (i.e., differential between live weight pre-slaughter and carcass weight) and energy intake per feed event and energy intake per meal, respectively. Neither intramuscular fat percentage measured on live animals nor carcass fat score (i.e., a measure of subcutaneous fat cover of the carcass) was genetically associated with any of the feeding behavior traits. The genetic associations between some feeding behavior traits and both ultrasound and carcass traits herein suggested that indirect responses in the feeding behavior of growing cattle from selection for improved carcass merit would be expected. Such changes in feeding behavior patterns in cattle may be reduced by measuring and including feeding behavior in a multiple-trait selection index alongside carcass traits.

Surnames Derived from Pastoral Terminology

Growing cattle and especially sheep was one of the main traditional Romanian occupations. Some of the terms used in this field became nicknames and later surnames. The Romanian anthroponymic database includes such surnames (listed in the Annex) and specifies the distribution of the bearers by county and region.

PSVI-20 Extent of genetic variation in feeding behavior and genetic associations with performance and feed efficiency in crossbred growing cattle

To the best of our knowledge, the genetic variability in feeding behavior, as well as relationships with performance and feed efficiency, has not been investigated in a cattle population of greater than 1,500 animals. Our objective was to quantify the genetic parameters of several feeding behavior traits, and their genetic associations with both performance and feed efficiency traits, in crossbred growing cattle. Feed intake and live-weight data were available on 6,088 bulls, steers and heifers; of these, 4,672 cattle had backfat and muscle ultrasound data, and 1,548 steers and heifers had feeding behavior data. Genetic (co)variance parameters were estimated using animal linear mixed models; fixed effects included test group, heterosis, recombination loss, dam parity, age in months at the end of test, and the two-way interaction between age in months at the end of test and sex. Heritability was estimated to be 0.51 (0.097), 0.61 (0.100), 0.44 (0.093), 0.48 (0.094), and 0.47 (0.095) for feed events per day, feeding time per day, feeding rate, feed event duration, and energy intake per feed event, respectively. Coefficients of genetic variation ranged from 0.11 (feeding time per day) to 0.22 (feed event duration). Genetically heavier cattle with a higher energy intake per day, and faster growth rate, had a faster feeding rate and a greater energy intake per feed event. Genetic correlations between feeding behavior and feed efficiency were generally not different from zero, however, there was a genetic correlation of 0.36 (0.11) between feeding time per day and residual energy intake. Significant heritable and exploitable genetic variation exists in several feeding behavior traits in crossbred growing cattle which are also correlated with several performance traits. As some feeding behavior traits may be relatively less resource intensive to measure, they could be useful as predictor traits in beef cattle genetic evaluations.

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

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.

Effects of replacing wet distillers grains with supplemental SoyPass in forage based growing cattle diets

One hundred twenty individually fed steers (initial BW 283 kg ± 32) were utilized in an 84-d growing trial to evaluate effects of increased metabolizable lysine from non-enzymatically browned soybean meal (SoyPass) in grass hay-based diets containing wet distillers grains plus solubles (WDGS). The treatments were arranged as a 2 × 3 factorial with two levels of protein supplement as 20% (low; DL20) or 35% (high; DL35) of dietary DM using WDGS as the basal protein source, and three increments of SoyPass (SP) replacing 0%, 30%, or 60% of the WDGS DM in the protein supplement yielding six dietary treatments. Average daily gain (ADG), dry matter intake (DMI), gain:feed (G:F), and plasma urea N (PUN) data were analyzed using the MIXED procedure of SAS as a 2 × 3 factorial. Animal was the experimental unit and fixed effects included body weight block, dietary inclusion of distillers grains (DL20, DL35), dietary inclusion of SoyPass (SP) (3 levels), and DL × SP inclusion interactions. Linear and quadratic interactions between DL and SP inclusion were analyzed using covariate regression . No interactions were detected for ADG between SP and DL (P = 0.76). Additionally, SP had no effect on ADG (P = 0.49). However, ADG was increased for steers consuming the DL35 diet compared to DL20 (1.13 vs. 0.86 kg/d, respectively; P < 0.01). A DL × SP interaction was detected for dry-matter intake (DMI; P = 0.01). As SP replaced WDGS in the DL35 diet, DMI increased linearly from 8.10 to 8.93 kg/d (P = 0.02). In the DL20 diet, DMI was not different as SP replaced WDGS (P ≥ 0.11). Therefore, G:F tended to decrease linearly (P = 0.06) as SP replaced WDGS in the DL35 diet, while no difference (P ≥ 0.11) was detected in the DL20 diet, suggesting SP contained less energy than WDGS but did improve dietary lysine balance. Furthermore, plasma urea nitrogen (PUN) increased linearly as SP replaced WDGS in the DL20 diet (P < 0.01) but was not affected by SP substitution in the DL35 diet (P ≥ 0.19). When WDGS is fed at a low (20% DM) or high (35% DM) inclusion rate in a forage based diet, replacing the distillers with a source of protected amino acids supplied through heat-treated soybean meal, did not improve performance. A more concentrated or energy dense form of amino acids may be beneficial in forage-based growing cattle diets containing 20% distillers grains, but is not needed in diets with 35% distillers grains.

Determination of Sex in Ungulate Herbivores via near Infrared Spectroscopy of Hair: Growing Cattle as a Surrogate Model

Near infrared spectroscopy (NIRS) has been used in a variety of medical and veterinary science applications. In particular, NIRS calibrations have been developed in livestock for steroid content in cattle hair, and wound age or stage of healing in hot iron cattle brands. These NIRS applications also have potential utility in forensic science. Portable NIRS instruments facilitate measurements on live animals and or animal samples in the field. The objective of this study was to evaluate the efficacy of determining sex in growing cattle via NIRS of hair utilizing a portable spectrometer. In two consecutive years, log 1/R spectra (350–2500 nm) were collected using an ASD Field Spec fitted with a contact probe. Experimental subjects were Bos taurus cross calves (n = 12, yr 1; n = 14, yr 2) born to cows grazing central Arizona rangeland. Calf age was approximately 60, 90 and 210 d at branding, estrus synchronization, and weaning, respectively. As cattle were gathered for these routine working events, a total of 7 M and 19 F calves were scanned 3 times each over the left ribcage. A linear discriminant function was applied to spectral data in order to determine sample membership in M or F groups at each collection date. Chi-square procedures were used to determine differences (P < 0.05) in proportion of correct identifications per group and collection date. Overall, 86% of F and 72% of M were correctly (P < 0.05) identified. Corresponding values were 82% for F and 71% for M at branding, 100% for F and 89% for M at estrus synchronization, and 86% for F and 64% for M at weaning. Calf sex was successfully determined using portable NIRS in this proof of concept study. Efficacy of this method should be evaluated for different ungulate herbivores and under additional collection scenarios.

77 Evaluation of Models Used to Predict Dry Matter Intake in Forage-Based Diets

Data from experiments conducted at the University of Nebraska-Lincoln were pooled to compare predicted and observed dry matter intake (DMI) of growing cattle consuming foraged-based diets (corn silage, grass, alfalfa, or sorghum-hay) to determine the accuracy of current modeling systems. Experiments (n = 22) were a minimum of 84 days and included individually fed calves using the Calan gate system with 8 to 12 calves per treatment mean or pen-fed calves with 8 to 12 head per pen. Average body weight (BW) of calves ranged from 235 to 397 kg with average daily gain (ADG) between 0.16 and 1.65 kg. Cattle were fed ad libitum and mid-point BW and ADG were entered into the Beef Cattle Nutrient Requirements Model (2016) to determine predicted DMI. Simple regression was used to compare predicted and observed DMI to determine the accuracy of the prediction model. Ninety-three treatment means were evaluated and were separated into three categories: hay-based diets (n = 24), hay-based diets with distillers grains (n = 31), and corn silage-based diets (n =38). The model for observed versus predicted DMI was significant (P < 0.05; R2 = 0.09) when comparing all means but had a poor R2. The model was the best at predicting DMI for forage-based diets (P < 0.08; R2 = 0.22). Observed and predicted DMI were regressed along TDN values, calculated using book values and digestion studies. As TDN increased, observed DMI increased linearly (P < 0.01) and predicted DMI had a quadratic response (P < 0.01), increasing up to 63% and then decreasing with increasing TDN. The model over predicted DMI intake for TDN < 63% and under predicted DMI in forage-based diets greater than 63% TDN. Further development of the current modeling system through addition of intake data from forage fed growing cattle is needed