The impact of sire breed on feedlot performance and carcass characteristics of beef × Holstein steers.

Dairy herds are mating a portion of cows to beef cattle semen to create a value-added calf. Objectives of this study were to compare the feedlot performance and carcass characteristics of beef × Holstein steers by breed when sires represented bulls with commercially available semen. Three groups of single-born, male calves (n = 262) born to Holstein dams on 10 Pennsylvania dairies were sourced during 3 yr. Steers were sired by seven beef breeds: Angus, Charolais, Limousin, Hereford, Red Angus, Simmental, and Wagyu. Steers were picked up within a week of age and raised at two preweaned calf facilities until weaning (8 ±â€…1 wk of age) under similar health and management protocols. Steers were then transported to a commercial calf growing facility where they were managed as a single group until 10 ±â€…2 mo of age when they were moved to be finished at the Pennsylvania Department of Agriculture's Livestock Evaluation Center feedlot. Groups of steers were selected for slaughter based on body weight. Carcass characteristics were evaluated by trained personnel and a three-rib section of the longissimus muscle (LM) was collected from each carcass for Warner-Bratzler shear force (WBSF) evaluation and intramuscular fat determination. Steers sired by all sire breeds except for Limousin had greater average daily gain (ADG; 1.62 to 1.76 kg/d) than Wagyu × Holstein steers (1.39 kg/d; P < 0.05). Angus-sired steers had an 8.6% greater ADG than Red Angus-sired steers (P < 0.05). Angus, Charolais (1.73 kg/d), and Simmental-sired steers (1.68 kg/d) also had greater ADG than Limousin-sired steers (1.55 kg/d; P < 0.05). Wagyu × Holstein steers spent 5 to 26 more days on feed (P < 0.05) than Limousin × Holstein, Simmental × Holstein, Angus × Holstein, and Charolais × Holstein steers. Angus and Charolais-sired steers were also on feed for 19 and 21 d fewer, respectively, than Limousin-sired steers (P < 0.05). Red Angus-sired steers had greater marbling scores than Simmental and Limousin-sired steers and Angus and Charolais-sired steers had greater marbling scores than Limousin-sired steers (P < 0.05). Angus, Limousin, and Hereford-sired steers produced the most tender LM as evaluated by WBSF; Angus-sired carcasses (3.82 kg) were more tender than Charolais (4.30 kg) and Simmental-sired carcasses (4.51 kg; P < 0.05). Limousin and Hereford-sired steers (3.70 and 3.83 kg, respectively) also had more tender steaks than Simmental-sired steers.

Alterations of rumen and fecal microbiome in growing beef and dairy steers fed rumen-protected Capsicum oleoresin.

The microbiome has been linked to animal health and productivity, and thus, modulating animal microbiomes is becoming of increasing interest. Antimicrobial growth promoters (AGP) were once a common technology used to modulate the microbiome, but regulation and consumer pressure have decreased AGP use in food animals. One alternative to antimicrobial growth promoters are phytotherapeutics, compounds derived from plants. Capsaicin is a compound from the Capsicum genus, which includes chili peppers. Capsaicin has antimicrobial properties and could be used to manipulate the gastrointestinal microbiome of cattle. Both the rumen and fecal microbiomes are essential to cattle health and production, and modulation of either microbiome can affect both cattle health and productivity. We hypothesized that the addition of rumen-protected capsaicin to the diet of cattle would alter the composition of the fecal microbiome, but not the rumen microbiome. To determine the impact of rumen-protected capsaicin in cattle, four Holstein and four Angus steers were fed rumen-protected Capsicum oleoresin at 0 (Control), 5, 10, or 15 mg kg-1 diet dry matter. Cattle were fed in treatment groups in a 4 × 4 Latin Square design with a 21-d adaptation phase and a 7-d sample collection phase. Rumen samples were collected on day 22 at 0-, 2-, 6-, 12-, and 18-h post-feeding, and fecal swabs were collected on the last day of sample collection, day 28, within 1 h of feeding. Sequencing data of the 16s rRNA gene was analyzed using the dada2 pipeline and taxa were assigned using the SILVA database. No differences were observed in alpha diversity among fecal or rumen samples for either breed (P > 0.08) and no difference between groups was detected for either breed in rumen samples or for Angus steers in fecal samples (P > 0.42). There was a difference in beta diversity between treatments in fecal samples of Holstein steers (P < 0.01), however, a pairwise comparison of the treatment groups suggests no difference between treatments after adjusting for multiple comparisons. Therefore, we were unable to observe substantial overall variation in the rumen or fecal microbiomes of steers due to increasing concentrations of rumen-protected capsaicin. We do, however, see a trend toward increased concentrations of capsaicin influencing the fecal microbiome structure of Holstein steers despite this lack of significance.

The microbiome is the collection of microbes present in an animal's body and has been discovered to be directly connected to animal health and productivity. In production animals, such as feedlot cattle, the microbiome can be modulated by antimicrobials to promote growth, but increasing consumer pressure to reduce antimicrobial use has producers seeking alternatives. Capsaicin is a phytotherapeutic derived from chili peppers that can be used to modulate the microbiome due to its antimicrobial properties. Eight steers were fed rumen-protected Capsicum oleoresin to determine its effect on average daily gain. In addition, rumen and fecal samples were collected for microbiome testing. No differences were detected in the rumen microbiomes between cattle fed capsaicin (treatment) or those that received no capsaicin (control). While no overall effect was observed on the fecal microbiome of cattle fed different doses of capsaicin or control, we did observe changes in fecal beta diversity due to capsaicin treatment in Holstein steers fed greater doses. The fecal microbiome structure of Holsteins fed greater dosages of capsaicin differed from those fed control or low doses, as observed by the presence of two distinct clusters. This observation suggests an impact of greater doses of capsaicin treatment on microbiome structure.

Post-weaning management of modern dairy cattle genetics for beef production: a review.

The contribution of dairy steers to the U.S. fed beef supply has increased from 6.9% to 16.3% over the last two decades; in part, due to declining beef cow numbers and the increased use of sexed dairy semen to produce genetically superior replacement heifers from the best dairy cows. Raising dairy cattle for beef production offers unique opportunities and challenges when compared with feeding cattle from beef breeds. Dairy steers offer predictable and uniform finishing cattle performance (ADG, DMI, G:F) as a group and more desirable quality grades on average compared with their beef steer counterparts. However, dairy steers have lesser dressing percentages and yield 2%-12% less red meat compared with beef steers due to a greater ratio of bone to muscle, internal fat, organ size, and gastrointestinal tract weight. In addition, carcasses from dairy steers can present problems in the beef packing industry, with Holstein carcasses being longer and Jersey carcasses being lighter weight than carcasses from beef breeds. Beef × dairy crossbreeding strategies are being implemented on some dairy farms to increase the income generated from dairy bull calves, while beef × dairy crossbreeding strategies can also improve the G:F and red meat yield of beef produced from the U.S. dairy herd. This alternative model of beef production from the dairy herd is not without its challenges and has resulted in variable results thus far. Successful adoption of beef × dairy crossbreeding in the cattle industry will depend on the proper selection of beef sires that excel in calving ease, growth, muscling, and marbling traits to complement the dairy genetics involved in beef production.

The number of dairy steers contributing to the U.S. fed beef supply has increased from 6.9% to 16.3% over the last two decades. Raising dairy cattle breeds for beef production offers unique opportunities and challenges when compared with feeding beef cattle breeds. Dairy steers offer predictable and uniform finishing cattle performance (ADG, DMI, G:F) as a group and more desirable quality grades on average compared with their beef steer counterparts. Dairy steers yield less red meat compared with beef steers due to a greater ratio of bone to muscle, internal fat, organ size, and gastrointestinal tract weight. The use of growth-promoting technologies such as hormonal implants and ß-adrenergic agonists can help improve finishing cattle performance and increase the red meat yield of dairy-influenced steers. In addition, beef × dairy crossbreeding strategies are being implemented on some dairy farms to increase the income generated from bull calves, while beef × dairy crossbreeding strategies can also improve the gain:feed and red meat yield of beef produced from the U.S. dairy herd. Successful adoption of beef × dairy crossbreeding in the cattle industry will depend on the proper selection of beef sires to complement the challenges and opportunities experienced with dairy genetics for beef production. Early calfhood management practices should be investigated further to determine their impacts on the subsequent finishing performance and carcass characteristics of calves produced by dairy farms for beef production.

Board Invited Review: Crossbreeding beef × dairy cattle for the modern beef production system.

Current trends in the United States dairy industry suggest that crossbred beef × dairy calves are replacing a proportion of the calf-fed Holstein steers slaughtered for beef each year. Economic pressures value preweaned beef × dairy calves at a premium over preweaned dairy bull calves; however, there is little modern data to support that intensively fed crossbred calves maintain their premium value over dairy steers across the supply chain. Data from international production systems and from historic research suggests that beef × dairy cattle had greater average daily gains and converted feed to gain more efficiently than dairy steers. Regarding carcass characteristics, across the literature crossbreds consistently yielded heavier carcasses that had lower proportions of trim than dairy steers. Fewer comparisons of beef × dairy and dairy steers exist in the literature for other economically relevant carcass characteristics such as ribeye area, backfat, marbling, tenderness, and eating quality. Existing published data are inconsistent among studies, highlighting the necessity for more research tailored to the United States beef production system.

Effects of rubber matting on feedlot cattle growth performance, locomotion, and carcass characteristics in slatted floor facilities.

The objective was to determine effects of old and new rubber matting in a slatted, indoor cattle feeding facility on cattle growth performance, locomotion, and carcass characteristics. In experiment 1, fall-born Angus × Simmental steers (N = 207; body weight = 222 ± 38 kg) were blocked by weight and assigned to 32 pens. Pens were randomly assigned to 1 of 4 treatments: no matting/concrete (CONC1), 12-yr-old Animat Pebble matting (OLD1), new Animat Maxgrip matting (MG), and new Animat Pebble matting (PEB1). Steers were fed a common diet for 209 d with a minimum stocking density of 3.40 m2 per animal. Final body weight (BW) and average daily gain (ADG) were affected (P = 0.02 and P < 0.01, respectively) by treatment with steers on PEB1 finishing heaviest with the greatest growth, MG and CONC1 intermediate, and OLD1 finishing at the lightest final BW with the least growth. Flooring treatment did not affect overall dry matter intake (DMI; P = 0.16) or gain to feed ratio (G:F; P = 0.94). Flooring treatment did not affect (P ≥ 0.19) any carcass traits. Locomotion scores (LS) were affected (P < 0.01) by flooring treatment with CONC1 having the worst mobility while OLD1, MG, and PEB1 were similar (P ≥ 0.24). Locomotion score had a day effect (P < 0.01) where cattle gait and mobility worsened as days on feed increased. In experiment 2, fall-born Angus × Simmental steers (N = 189; BW = 352 ± 43 kg) were blocked by weight and assigned to 21 pens. Pens were randomly assigned to 1 of 3 treatments: no matting/concrete (CONC2), 15-yr-old Animat Pebble matting (OLD2), and new Animat Pebble matting (PEB2). Steers were fed a common diet for 152 d with a stocking density of 2.65 m2 per steer. After 152 d on feed, flooring treatment did not affect (P ≥ 0.30) BW, ADG, or DMI nor did treatment affect (P ≥ 0.17) carcass traits. However, steers housed on OLD2 or PEB2 had improved locomotion scores (P = 0.02) compared with steers housed on CONC2. Locomotion score had a day effect (P < 0.01) as cattle gait and mobility worsened with greater number of days on feed, regardless of treatment. Overall, results suggest that new rubber matting increased ADG and HCW during a 209-d trial when cattle were stocked at 3.4 m2 in small pens and that rubber matting regardless of age improved cattle locomotion scores in slatted indoor feeding facilities.

Many feedlots in the Midwest have constructed slatted indoor cattle feeding facilities to improve winter pen conditions and decrease land requirements. Finishing cattle in indoor feeding facilities can increase cattle growth and carcass value, but greater prevalence of cattle lameness is a concern. Rubber matting is commonly used in these facilities, but it is a consumable product with a variable lifespan. This study evaluated the effects of old and new rubber matting in a slatted, indoor cattle feeding facility on cattle growth performance, locomotion, and carcass characteristics in two experiments. In experiment 1, steers in pens with new Animat Pebble matting had increased growth compared with steers in pens with no matting and 12-yr-old Animal Pebble matting. Furthermore, steers in pens with no matting had the poorest locomotion scores. In experiment 2, flooring treatments did not affect cattle growth or carcass traits, but steers in pens with old or new rubber matting had more desirable locomotion scores than cattle in pens with no matting. Therefore, new rubber matting can improve cattle growth in small pens with slatted floors when cattle were stocked at 3.4 m2 per steer (experiment 1) and that rubber matting regardless of age improved cattle locomotion.

Effect of feeding dry-rolled corn or whole shelled corn during the finishing phase on growth performance and carcass characteristics.

The objectives of this trial were to evaluate the effect of corn processing during the finishing phase on feedlot cattle performance and carcass characteristics. We hypothesized that steers fed dry-rolled corn would have better feed efficiency (less feed necessary to the same amount of gain) than steers fed whole shelled corn. Ninety-five backgrounded Angus-cross cattle (initial body weight [BW] = 263 ± 9.8 kg) were used in a randomized complete block design in a feedlot setting. Cattle were divided in to 3 blocks: heifers (n = 31, 4 pens; initial BW = 267 ± 1.3 kg), light steers (n = 32, 4 pens; initial BW = 253 ± 1.3 kg), and heavy steers (n = 32, 4 pens; initial BW = 279 ± 1.4 kg). Diets contained 70% corn (experimental treatment), 15% dried distiller's grains with solubles, 7% grass hay, and 8% supplement, on a dry matter basis. Cattle were fed for 217, 224, and 231 ± 8 d for the heifer, heavy steer, and light steer blocks, respectively. Two pens within each block were randomly assigned to one of the following treatments: (1) dry-rolled corn (DRC) or (2) whole-shelled corn (WSC). Animal growth performance and carcass characteristics were analyzed using the MIXED procedure of SAS, including the fixed effect of treatment. Pen and block were included as random effects. Carcass characteristics USDA Yield Grade and Quality Grade distributions were compared using the GLIMMIX procedure of using the same model than the growth performance data. Data are presented as LSMeans. Cattle fed DRC had greater average daily gain (ADG; P = 0.02) and final BW (P < 0.01) when compared with cattle fed WSC. Even though ADG was greater for the DRC treatment, feed efficiency was similar (P = 0.45) because dry matter intake was also greater (P = 0.04) for DRC when compared with the WSC treatment. Cattle fed DRC also had greater hot carcass weight (P < 0.01), dressing percentage (P < 0.01), and Longissimus dorsi muscle area (P < 0.01) than cattle fed WSC. No differences (P ≥ 0.18) were observed for marbling score, USDA Yield Grade or USDA Quality Grade. In conclusion, feeding DRC to feedlot cattle improved ADG, hot carcass weight, and Longissimus dorsi muscle area, without affecting feed efficiency or meat quality.

Effects of forage inclusion and cattle breed on apparent digestibility and ruminal pH of steers fed a whole shelled corn-based diet.

Objectives were to evaluate the effects of cattle breed, Holstein or Angus, and forage inclusion on total tract digestibility and ruminal pH in cattle fed a whole shelled corn-based diet. Six Holstein and six Angus steers were assigned to a 2 × 3 factorial arrangement of treatments. Factors included breed, Holstein or Angus, and forage inclusion at 0%, 8%, or 16% forage (dry matter [DM] basis). Steers were fed in a replicated 3 × 3 Latin square, split-plot design. Each period consisted of 14 d diet adaptation followed by 7 d of sample collection. Data were analyzed using the MIXED procedures in SAS (v9.4 SAS Inst. Inc., Cary, NC). Repeated measures were used to analyze changes in ruminal pH over time. There was no interaction of breed × diet (P ≥ 0.19) on dry matter intake (DMI) or digestibility; however, Holstein steers had greater (P = 0.03) DMI than Angus steers. Despite the impact of breed on intake, there was no effect (P ≥ 0.33) of breed on diet digestibility. Digestibility of DM increased (linear; P < 0.01) as forage was removed from the diet, but there were no differences (P ≥ 0.32) in Neutral Detergent Fiber (NDF) and starch digestibility. However, due to the change in diet, NDF intake digested on a grams per day basis increased (P ≤ 0.01) and starch intake digested (g/d) decreased (P = 0.01) as forage inclusion increased. There was a tendency for breed × diet interaction (P = 0.08) on ruminal pH. Holstein steers fed 8% or 16% forage had greater ruminal pH than Holstein steers fed 0% forage; but, ruminal pH of Angus steers was not altered by diet.

Effects of coated and noncoated steroidal implants on growth performance, carcass characteristics, and serum estradiol-17ß concentrations of finishing Holstein steers.

The objectives of the study were to determine the effect of coated or noncoated hormone implants on growth performance, carcass characteristics, and serum estradiol-17ß (E2) concentrations of Holstein steers fed a grain-based diet for 112 d. Seventy-nine Holstein steers [average initial body weight (BW) = 452 ± 5.5 kg] were stratified by BW and allotted to one of two treatments: 1) Holstein steers implanted with a coated implant containing 200 mg of trenbolone acetate (TBA) and 40 mg E2 (Revalor-XS (Merck Animal Health; Summit, NJ)] on day 0 (XS) or 2) Holstein steers implanted two times (days 0 and 56) with a noncoated implant containing 80 mg of TBA and 16 mg of E2 [(2IS) Revalor-IS (Merck Animal Health)]. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). There was no effect (P ≥ 0.71) of implant strategy on initial, middle, and final BW. No effect (P ≥ 0.12) of implant strategy was observed on average daily gain, dry matter intake, or gain-to-feed ratio. There were no effects (P ≥ 0.11) of implant strategy on carcass characteristics. There was an implant × day interaction (P < 0.01) for the circulation of serum E2 concentrations. Serum E2 concentration increased similarly 14 d after Holstein steers were implanted, regardless of implant strategy. At 28 d, after steers were implanted, steers in the XS group had less serum E2 concentration than Holstein steers in the 2IS group. However, at 56 d after the first implantation, both groups, once again, had similar serum E2 concentrations and E2 concentrations were less on day 56 than day 28 for both strategies. Holstein steers implanted with 2IS had greater serum E2 concentration on day 70 and E2 concentrations remained greater than serum E2 of Holstein steers implanted XS for the duration of the trial (day 112). In summary, there was no effect of coated or two doses of noncoated implant on growth performance or carcass characteristics of Holstein steers.

Erratum: Effects of steroidal implants on feedlot performance, carcass characteristics, and serum and meat estradiol-17ß concentrations of Holstein steers.

[This corrects the article DOI: 10.1093/tas/txz186.].

In vitro and in situ techniques yield different estimates of ruminal disappearance of barley.

Objectives were to compare in vitro and in situ disappearance of dry matter (DM), neutral detergent fiber (NDF), and starch of traditional (unprocessed and rolled) and hulless (unprocessed) barley. Experiment 1: three barley sources were compared using in vitro techniques. The sources were: 1) traditional barley that was not processed, 2) traditional barley processed through a roller mill, and 3) hulless barley that was not processed. For in vitro incubation, each barley source was ground through a 1-mm screen. Ground barley sources were weighed into bags (25 micron porosity) and incubated in ruminal fluid from two steers fed 80% rolled corn for 3, 6, 12, 24, 48, or 72 h. Intact bags were assayed for NDF; remaining bags were opened and the residual was removed and analyzed to determine disappearance of DM and starch. Experiment 2: the barley sources used in Exp. 1 were compared using in situ techniques. For in situ analysis, each barley source was ground in a Wiley mill with no screen to mimic mastication. Artificially masticated samples were weighed into Dacron bags (50 ± 10 micron porosity) and incubated in eight ruminally fistulated steers (n = 8) for 3, 6, 12, 24, 48, and 72 h. Residual contents were analyzed to determine in situ disappearance of DM, NDF, and starch. Data were analyzed using the MIXED procedures of SAS (9.4 SAS Institute, Cary, NC) with repeated measures. DM disappearance was greatest (P < 0.05) for hulless barley in vitro and for rolled barley in situ, regardless of time postincubation. For both trials, NDF disappearance was greatest (P < 0.05) for hulless barley, regardless of time postincubation. Starch disappearance at all time points was greatest (P < 0.05) for rolled barley in situ. Starch disappearance was greater (P < 0.05) for hulless barley at 6 h of in vitro incubation compared to rolled and unprocessed barley, whereas starch disappearance in vitro was comparable (P = 0.60) between barley sources. When the grains were compared in vitro, minor differences were noted, presumably because barley sources were finely ground prior to incubation. Compared to in vitro estimates, in situ techniques had greater variation in ruminal degradation estimates. Differences observed between in situ and in vitro techniques are driven largely by differences between the procedures. Although laboratory methods are widely used to estimate ruminal degradation, these techniques did not provide comparable estimates of ruminal degradation of barley.

Effects of steroidal implants on feedlot performance, carcass characteristics, and serum and meat estradiol-17ß concentrations of Holstein steers.

The objectives of the study were to determine the effect of steroidal implants on growth performance, carcass characteristics, and estradiol-17ß (E2) concentrations in the blood and longissimus muscle of Holstein steers fed a grain-based diet. Seventy Holstein steers (average initial BW = 275 ± 6.4 kg, 10 to 12 mo of age) were assigned to treatments: (i) implanted with 80 mg of trenbolone acetate (TBA) and 16 mg of E2 (Component TE-IS with Tylan; Elanco Animal Health, Greenfield, IN) at the start of the trial (day 0), and reimplanted with 120 mg of TBA and 24 mg of E2 (Component TE-S with Tylan; Elanco Animal Health) on day 84 of the experiment; or (ii) no implant. Implanted Holstein steers were heavier (P ≤ 0.01) than nonimplanted Holstein steers in the middle (day 84) and at the end of the experiment (day 186). Implanting Holstein steers increased (P < 0.01) average daily gain (ADG) and dry matter intake (DMI) without affecting gain-to-feed ratio compared with nonimplanted animals. Carcasses from implanted Holstein steers had greater (P < 0.01) hot carcass weight (HCW) and longissimus muscle (LM) area than carcasses from nonimplanted steers. Implanting did not affect (P ≥ 0.21) other carcass characteristics. There was an increase (P = 0.03) of 1.3 pg of E2/g of muscle in implanted Holstein steers compared with that from nonimplanted Holstein steers. There was an implant × day interaction (P < 0.01) in serum E2 concentrations. Serum E2 concentrations were not altered in nonimplanted Holstein steers, whereas E2 concentration increased (P < 0.01) after steers were implanted, regardless of implant characteristics. Serum E2 peaked at 28 days after the first implant and then rapidly declined after day 56. In summary, steroidal implants administered on days 0 and 84 increased DMI, ADG, HCW, and LM area in Holstein steers compared with nonimplanted steers due to increased serum E2 concentrations. However, these changes did not improve feed efficiency or other carcass characteristics.

Effect of corn processing on growth performance, carcass characteristics, and plasma glucose-dependent insulinotropic polypeptide and metabolite concentrations in feedlot cattle.

The objectives of this trial were to evaluate the association between corn processing, glucose-dependent insulinotropic polypeptide (GIP) concentration, and intramuscular (IM) fat deposition. We hypothesized that steers fed whole shelled corn (WSC) would have a greater IM fat deposition than steers fed cracked corn (CC) due to an increase in plasma GIP concentration. Backgrounded, Angus-cross cattle (initial body weight [BW] = 279 ± 9.8 kg) were used in a randomized complete block design in a feedlot setting for an average of 230 d. Cattle were allotted in 12 pens (6 pens per treatment with 8 animals per pen). There were three blocks: heifers (n = 32, initial BW = 265 ± 1.3 kg), small steers (n = 32, initial BW = 262 ± 1.3 kg), and large steers (n = 32, initial BW = 310 ± 1.4 kg). Two pens within each block were randomly assigned to one of the following treatments: 1) CC or 2) WSC. Animal growth performance, carcass characteristics, and plasma hormone and metabolite concentrations were analyzed using the MIXED procedure of SAS, including the fixed effects of treatment, or treatment, time, and their interaction. Pen and block were included as random effects. Carcass yield and quality grade distributions were compared using the GLIMMIX procedure of SAS. including the fixed effects of treatment and time with pen and block as random effects. Linear regression was used to evaluate the association of plasma GIP concentration and IM fat content. Average daily gain (P = 0.57) and final BW (P = 0.34) were similar, regardless of treatment. Cattle fed CC had reduced (P < 0.01) dry matter intake (DMI) when compared with those fed WSC. This lesser DMI resulted in improved gain:feed ratio (P < 0.01) for cattle fed CC compared with cattle fed WSC. There was no effect (P ≤ 0.33) of corn processing on plasma glucose, plasma GIP concentrations, hot carcass weight, dressing percentage, or marbling score. There was a positive linear relationship (P = 0.03) between IM fat concentration and plasma GIP concentration. In conclusion, feeding CC increased gain:feed ratio compared with WSC, but there was no difference in plasma GIP concentration, whereas plasma GIP concentration appears to be related to IM fat deposition.

Impacts of Time-Fed Concentrate-Based Diets on Plasma Metabolites, Rumen Histology, and mRNA Expression of Hepatic Enzymes of Wethers.

Transition to grain increases inflammation and causes parakeratosis, which can decrease growth performance in fattening animals. It is unknown if ruminants adapt to these inflammatory responses over time. In a three-phase, 49-day experiment, all wethers (n = 13, BW = 50.6 ± 4.7 kg; 4.9 ± 0.3 months of age) were fed an 80% forage diet during P1(day 0 to 21). On day 21, 4 wethers were slaughtered to obtain baseline liver and rumen tissue. During P2 (day 22 to 25), the remaining wethers were fed an 80% concentrate diet. Four wethers were slaughtered on day 25 to obtain P2 liver and rumen tissue. During P3 (day 22 to 49), the remaining five wethers were fed 80% concentrate diets and were slaughtered on day 49 to obtain P3 liver and rumen tissue. Rumen parakeratosis was greater (p ≤ 0.02) in wethers sampled in P2 and P3 when compared to those sampled in P1. Among positive acute phase reactants, expression of serum α-amyloid (SAA) and haptoglobin (HPT) tended (p ≤ 0.12) to be 6- and 10-fold greater, respectively, in wethers sampled in P2 compared to wethers sampled in P1; however, SAA and HPT expression was not different between wethers sampled in P3 and P1. Plasma glucose and ß-hydroxybutyric acid (BHBA) increased (p ≤ 0.03) in wethers sampled in both P2 and P3 compared to the wethers sampled in P1, while total protein and cholesterol decreased (p ≤ 0.06) only in wethers sampled from P2 compared to those sampled in P1. Hepatic acute phase responses suggest that the wethers adapted to an 80% concentrate diet over time.

Effect of cattle breed and basal diet on digestibility, rumen bacterial communities, and eating and rumination activity.

The objectives of this study were to compare ruminal total tract digestibility, bacterial communities, and eating and rumination activity between Holstein and Angus steers fed grain- or forage-based diets. Six Holstein steers (average body weight [BW] = 483 ± 23 kg) and six Angus steers (average BW = 507 ± 29 kg), previously fitted with rumen cannulae, were fed in a crossover design with a 2 × 2 factorial arrangement of four treatments: 1) Holsteins fed a grain-based diet, 2) Holsteins fed a forage-based diet, 3) Angus fed a grain-based diet, and 4) Angus fed a forage-based diet. Each period was 35 d with 26 d of diet adaptation and 9 d of sample collection. On days 1 and 2 of collection, feeding activity was recorded for 48 h. On day 3, rumen contents were sampled to measure ruminal pH at 0, 3, 6, 12, and 18 h after feeding. A portion of the strained ruminal fluid was subsampled at 0, 3, and 6 h for volatile fatty acids (VFA) analysis. Rumen contents were subsampled at 3 h for analysis of bacterial communities. From day 4 to 8, total fecal excretion, feed, and refusals samples were collected and analyzed for dry matter (DM), neutral detergent fiber (NDF), and starch. On days 8 and 9 (0 and 3 h post-feeding, respectively), total reticulorumen evacuation was conducted and contents were weighed. Data were analyzed using the MIXED procedures in SAS (v9.4 SAS Inst. Inc., Cary, NC). Repeated measures were used to analyze changes in ruminal pH and VFA over time. There were no interactions of diet × breed (P ≥ 0.07). While the main effects of diet were expected, unique to these data is the fact that bacterial diversity and richness were reduced (P < 0.01) in cattle fed grain-based diets. There was no main effect (P > 0.34) of breed on total tract DM, organic matter, and starch digestibility, but Angus cattle had greater (P = 0.01) NDF digestibility than Holsteins. The increased NDF digestibility may be associated with a numerical (P = 0.08) increased numbers of bacterial species in Angus steers compared with Holstein steers. Holstein steers also spent more time (P ≤ 0.05) ruminating than Angus steers. There was no effect (P > 0.80) of breed on reticulorumen content at feeding time; however, Holstein steers had greater (P = 0.04) reticulorumen content on a wet basis 3 h post-feeding. Although Holstein steers spent more time ruminating, Angus steers were better able to digest NDF when compared with Holsteins, regardless of basal diet, and this improvement may be related to changes in bacterial communities in the rumen or to rumination activity.

Effect of high-pressure-jet processing on the physiochemical properties of low-fat ice cream mix.

The objective of this study was to use high-pressure-jet (HPJ) processing to produce functional properties in a low-fat (4.5% fat) ice cream mix similar to those seen when emulsifiers are used. Ice cream mix or serum (nonfat portion of the ice cream mix) were subjected to 200 or 400 MPa HPJ processing and compared with a non-HPJ-treated control. A similar non-HPJ-treated formulation but containing polysorbate 80 (0.075% wt/wt) was also used as a control. The mix samples were characterized in terms of their particle size, density, flow properties, stability, crystallization kinetics, and fat-protein interactions. The sample from the mix subjected to 400 MPa HPJ processing (HPJ-M-400) had increased consistency coefficient (5°C; 228 ± 102.7 mPa·s) and particle size (D[4,3]; 16.0 ± 2.5 µm) compared with the non-HPJ-treated control sample, with viscosity and particle size (volume-moment mean diameter, D[4,3]) values of 7.5 ± 0.4 mPa·s and 0.50 ± 0.1 µm, respectively. These differences were attributed to an increase in casein-fat interactions and casein-casein interactions caused by the 400 MPa HPJ treatment, which were observed using confocal scanning laser microscopy and inferred from an increase in protein and fat concentrations in the sediment after ultracentrifugation. Interestingly, the density of HPJ-M-400 was also lower (0.79 ± 0.17 g/mL) than that of the control (1.04 ± 0.00 g/mL) because bubbles were trapped within these complexes. The large casein-fat complexes formed in the HPJ-M-400 sample also appeared to act as steric barriers that slowed ice crystal growth during quiescent freezing. The alterations in physiochemical properties and apparent ice crystal growth induced by the 400 MPa treatment of low-fat ice cream mix have many potential applications, including clean-label confections.

Efficacy of sheep as a digestibility model for cattle when fed concentrate-based or forage-based diets.

The objectives were to determine the efficacy of sheep as a digestibility model for cattle feeding two diets, forage or concentrate based, under current genetics. Twelve Suffolk wethers were blocked into two periods with six wethers in each period. Within each period, wethers were fed a forage-based diet (n = 3) or a concentrate-based diet (n = 3). Six angus steers were also fed a forage-based diet (n = 3) or a concentrate-based diets (n = 3) in switchback design with two periods. All animals were adapted to diets for a minimum of 3 wk, then feed intake, refusals, and feces were collected. Feed and fecal dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and starch were analyzed. Refusals were analyzed for DM. Data were analyzed using Proc Mixed in SAS with diet and species as fixed and period as a random effect. Dry matter intake as percentage of body weight for each animal within each period was used as a covariable. There was an interaction (P < 0.01) between species and diet for DM and OM digestibility. When fed the concentrate-based diet, DM and OM digestibility were similar between wethers and steers (P > 0.18); however, when fed the forage-based diet, DM and OM digestibility was less (P < 0.01) for wethers than steers. Like DM and OM, an interaction (P < 0.05) between species and diet was present for starch digestibility. When fed the forage-based diet, starch digestibility did not differ (P = 0.66) between wethers and steers; however, when fed concentrate-based diet, wethers had a greater starch digestibility (P < 0.05) than steers. There was no interaction (P > 0.45) between species and diet for NDF and ADF digestibility. Regardless of the diet fed, NDF and ADF digestibilities were greater (P < 0.05) in steers than wethers. Present day sheep were not a good model for cattle when fed forage-based diets, but sheep were an acceptable model for cattle when fed concentrate-based diets.

Effects of increasing dietary level of a commercial liquid supplement on growth performance and carcass characteristics in feedlot steers.

Feeding cattle liquid supplements has become increasingly popular in the feedlot industry; however, optimal inclusion of liquid supplements in feedlot cattle diets is not known. The objectives of this study were to determine the optimal inclusion of liquid supplementation to maximize growth performance and improve carcass characteristics, as well as estimate the energy value of liquid supplementation when used as a direct corn replacement, for feedlot steers fed a concentrate-based diet. Two hundred and eighty steer calves were stratified by BW into light (BW = 208 ± 9 kg; n = 24) and heavy (BW = 275 ± 8 kg; n = 16) pens. Pens within BW block were randomly assigned to 1 of 4 supplements: 1) dry at 4.5% inclusion (0LIQ), 2) liquid (a proprietary blend from Quality Liquid Feeds; Dodgeville, WI) at 4.5% inclusion (4.5LIQ), 3) liquid at 9% inclusion (9LIQ), or 4) liquid at 13.5% inclusion (13.5LIQ). The remainder of the diet was 47.5% to 55.5% dry rolled corn, 20% corn silage, and 20% modified wet distillers grains with solubles (DM basis). Data were analyzed as a randomized complete block design and linear and quadratic were examined to determine effects of increasing dietary concentrations of liquid. Steers fed 4.5LIQ and 9LIQ had greater (quadratic; P ≤ 0.05) final BW, HCW, and NEm and NEg, and less DMI as a percent of BW compared to steers fed 13.5LIQ. Steers fed 0LIQ were intermediate and not different from other treatments. However, ADG and total BW gain did not differ (P ≥ 0.15) among treatments. Despite the lack of treatment effect on live measures of gain, feeding steers 4.5LIQ and 9LIQ resulted in greater carcass ADG (quadratic; P = 0.03), total carcass gain (quadratic; P = 0.04), and more efficient carcass gain (quadratic; P ≤ 0.01) compared to carcasses from steers fed 13.5LIQ. Feeding steers a liquid supplement at 9% of the diet, DM allowed for the greatest final BW and ADG in this study; however, there was no benefit of increasing liquid to 13.5%.

Effect of haylage and monensin supplementation on ruminal bacterial communities of feedlot cattle.

The objective of this study was to investigate the ruminal bacterial communities as affected by monensin, haylage, and their interaction of feedlot cattle fed 60 % dried distillers grains with solubles in a replicated 4 × 4 Latin square design. Pyrosequencing analysis of the V1-V3 region (about 500 bp) of 16S rRNA gene from the four dietary treatments (3 treatment plus one control diets) collectively revealed 51 genera of bacteria within 11 phyla. Firmicutes and Bacteroidetes were the first and the second most predominant phyla, respectively, irrespective of the dietary treatments. Monensin supplementation decreased the proportion of Gram-positive Firmicutes while increasing that of Gram-negative Bacteroidetes. However, the monensin supplementation did not reduce the proportion of all genera of Gram-positive bacteria placed within Firmicutes and lowered that of some genera of Gram-negative bacteria placed within Bacteroidetes. Haylage supplementation appeared to attenuate inhibition of monensin on some genera of bacteria. Factors other than monensin and haylage could affect ruminal bacterial communities.