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Ruminal tympany (bloat) has long been an issue for large and small livestock operations. Though improvements in feedlot management practices have reduced its occurrence, it is still highly prevalent and is known to detrimentally affect animal performance, welfare, and in many instances, lead to animal death. Current decision support systems and diet formulation software omit the inclusion of bloat prediction based on animal performance. Here, we aim to predict bloat incidence in implanted and non-implanted feedlot steers from performance data comparing linear (LDB) and non-linear decision boundaries. Eighteen crossbred Angus × Hereford steers: BW (491.13 ± 25.78 kg) and age (12 ± 1 mo) were randomly distributed into implanted and non-implanted treatments. All animals were randomly assigned to one of two pens fit with automated monitoring systems for BW, freshwater intake, and water intake behavior: water intake event visit, no water intake event visit (NWIE), and time spent drinking. DM intake (DMI) was individually recorded from all animals through the Calan Gate system for 135 d (30 d adaptation, 105 d experimental diet). Incidences of bloat were recorded as bloat instances regardless of severity to ensure that early onset detection of bloat was recorded and properly identified in predictive models. Logistic regression with a binomial distribution and a logit link function was utilized to predict the incidences of bloat through LDB. Feature selection and penalization of coefficients were explored through L1 (sum of absolute values) and L2 (sum of squares) penalization to avoid overfitting of models. Additional NLDB and a non-parametric LDB are examined for prediction. Accuracy, specificity, and sensitivity were high for the models reported. No significant differences were observed between LDB and NLDB, with the highest specificity (predicting bloat) value of 0.820 for stepwise feature selection algorithms, and a value of 0.832 for the artificial neural network. Highest accuracy was 0.829 for ridge regression, and 0.847 for the random forest with hyperparameter tuning. DM intake, BW, and NWIE were the three most important variables for the prediction of feedlot bloat showing clear drops in DMI and BW and increases in NWIE when animals bloated. The lack of difference in predictive performance between LDB and NLDB highlights the often-overlooked concept that machine learning algorithms are not always the only/best modeling technique. Additionally, the models reported herein carry acceptable predictive performance for inclusion into management decisions that reduce bloat incidences in feedlot cattle.

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Exploring alternative supplementation sources capable of maximizing feed and water efficiency in nursing Holstein calves is often ignored. The goals herein involve investigating the effects of two isoenergetic supplements on a nonmedicated milk replacer diet on total water intake, milk water intake, fresh water intake, feed intake parameters, and performance of Holstein nursing bull calves. Twenty-three animals (body weight [BW] = 94.67 ± 12.07 kg, age = 67 days old) were randomly assigned to one of three treatments for 68 days: control (CON; ad libitum milk replacer, n = 7), carbohydrate supplement (CHO; corn starch on top of ad libitum milk replacer-based diet, n = 8), or lipid supplement (FAT; menhaden fish oil on top of ad libitum milk replacer-based diet, n = 8). The isoenergetic supplementation consisted of 3% menhaden fish oil addition on DM basis for FAT. This was matched energetically with corn starch for the CHO group resulting in a 7% composition in DM basis. All animals were provided free access to mineral mix and 120 g daily dried microbrewer's spent grains (BG). Data were analyzed with the GLMMIX procedure of SAS in a completely randomized design with the diets as a fixed effect. Dry matter intake (DMI) adjusted by average daily gain (ADG; DMI/ADG) resulted in significantly lower values for supplemented groups with CON = 2.48, CHO = 2.38, and FAT = 2.27 kg/kg (ADG) (P = 0.033). Energy intake values were lower for CON when analyzing metabolizable energy intake (P < 0.0001), net energy intake for maintenance (P < 0.0001), and net energy intake for gain (P < 0.0001), followed by CHO, and then FAT. Total water intake (P < 0.0001), milk water intake (P < 0.0001), and fresh water intake (P < 0.0001) all resulted in CHO consuming 0.5 L or less water than the other two treatments. Energy requirements as digestible energy (P < 0.0001), metabolizable energy (P < 0.0001), net energy for maintenance (P < 0.0001), and net energy for gain (P < 0.0001) were lower for CHO, followed by CON, and then FAT having the highest requirements. Similar results were observed for residual feed (RFI; P = 0.006) and residual water intakes (RTWI; P = 0.902). Ultimately, no performance differences were detected with regards to BW (CON = 146.71, CHO = 146.25, and FAT = 150.48 kg; P > 0.1). These results indicate that lipid-based and starch-based supplementation can potentially increase feed efficiency and decrease voluntary water intake without adversely affecting performance.

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This study investigated individual and combined effects of organic acids, bacteriophages, and ultraviolet light interventions on Salmonella populations in ground beef. Beef trim was inoculated with four Salmonella strains to result in a contamination level of 3.5 log CFU/g after grinding. Lactic (LA) and peroxyacetic (PAA) acids, bacteriophages (S16 and FO1a) (BA), and ultraviolet light (UV) were applied on fresh trim prior to grinding. Applications of individual or combined organic acids did not significantly decrease Salmonella populations in ground beef. Individual applications of BA and UV light decreased approximately 1 log CFU/g (P<0.05). Combined applications of BA and UV provided an optimal decrease of 2 log CFU/g (P<0.05). Organic acid applications do not reduce Salmonella populations in ground beef when applied on trim prior to grinding. Combined applications of UV and BA may be used in industry settings to improve Salmonella control in ground beef.

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The appropriate supply of nutrients in pregnant cows has been associated with the optimal development of foetal tissues, performance of their progeny and their meat quality. The aim of this study was to evaluate supplementation effects of grazing cows in different stages of gestation on skeletal muscle development and performance of the progeny. Thereby, 27 Nellore cows were divided into three groups (n=9 for each group) and their progeny as follows: UNS, unsupplemented during gestation; MID, supplemented from 30 to 180 days of gestation; LATE, supplemented from 181 to 281 days of gestation. The percentage composition of the supplement provided for the matrices was the following: ground corn (26.25%), wheat bran (26.25%) and soya bean meal (47.5%). The supplement was formulated to contain 30% CP. Supplemented matrices received 150 kg of supplement (1 and 1.5 kg/day for cows in the MID and LATE groups, respectively). After birth, a biopsy was performed to obtain samples of skeletal muscle tissue from calves to determine number and size of muscle fibres and for messenger RNA (mRNA) expression analysis. The percentage composition of the supplement provided for the progeny was the following: ground corn grain (30%), wheat bran (30%), soya bean meal (35%) and molasses (5%). The supplement was formulated to contain 25% CP and offered in an amount of 6 g/kg BW. Performance of the progeny was monitored throughout the suckling period. Means were submitted to ANOVA and regression, and UNS, MID and LATE periods of supplementation were compared. Differences were considered at P0.10). Similarly, no differences were observed between calves for nutrient intake (P>0.10). However, greater subcutaneous fat thickness (P=0.006) was observed in the calves of LATE group. The ribeye area (P=0.077) was greater in calves born from supplemented compared with UNS cows. The supplementation of pregnant cows did not affect the muscle fibre size of their progeny (P=0.208). On the other hand, calves born from dams supplemented at mid-gestation had greater muscle fibre number (P=0.093) compared with calves from UNS group. Greater mRNA expression of peroxysome proliferator-activated receptor α (P=0.073) and fibroblast growth factor 2 (P=0.003) was observed in the calves born from MID cows. Although strategic supplementation did not affect the BW of offspring, it did cause changes in carcass traits, number of myofibres, and mRNA expression of a muscle hypertrophy and lipid oxidation markers in skeletal muscle of the offspring.

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A grazing trial was carried out to evaluate the inclusion of three feed additives in supplements (crude protein, CP 230 g/kg dry matter, DM) on the performance, voluntary intake, and digestibility of beef heifers grazing Brachiaria decumbens (CP 81 and neutral detergent fiber, NDF 615 g/kg DM). Thirty-five Nellore heifers (21 months of age and 383 ± 6.29 kg of body weight, BW) were used in a completely randomized design. The treatments were as follows: no supplement (control); supplement fed at 1 kg/animal/day without additives (S); supplement with monensin (S + M); supplement with yeast culture (S + YC); and supplement with enzyme complex (S + EC). All of the supplemented heifers had greater (P < 0.1) average daily gain (∼0.186 kg/day) compared to the control treatment (0.014 kg/day). Average daily gain and final BW were similar (P > 0.1) among supplemented heifers. Monensin inclusion in the supplement decreased (P < 0.1) forage DM (expressed as g/kg BW) and NDF intake (expressed as kg/day and as g/kg BW). All of the feed additive inclusions decreased (P < 0.1) NDF digestibility. In conclusion, the heifers' performance was improved by concentrate supplementation. However, the inclusion of additives did not enhance this effect.

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