Applied Animal Science最新文献

Objective

Materials and Methods

Results and Discussion

Implications and Applications

Objectives

Materials and Methods

Results and Discussion

Conclusions and Applications

Objective

Materials and Methods

Results and Discussion

Implications and Applications

Objective

Our objective was to quantify differences in carcass fabrication yield and allometric coefficients of carcass components from implanted and non-implanted steers.

Materials and Methods

Steers (n = 80; initial BW 271 ± 45 kg) were paired and randomized to slaughter date (d 0, 42, 84, 126, 168, 210, 252, 294, 336, 378). Individuals were randomized to treatment of negative control (CON) or Revalor-XS on d 0 and 190 (REV). One side of each animal was fabricated after a 48-h chill into primals, denuded subprimals, lean trim, trimmed fat, and bone. Weights (g) of non-carcass and carcass components were log-transformed and consolidated to arithmetic means by treatment and slaughter date. Growth coefficients were calculated using the allometric equation.

Results and Discussion

Cattle administered REV had increased cold side weights (CSW) 7.7%, bone yield 4.9%, and red meat yield 8.5%, with no differences in fat yield. Forequarter primal weights (chuck, brisket, foreshank, rib) increased 8.4%, 6.9%, 7.2%, and 5.2%, respectively, for REV cattle. Hindquarter primals (loin, flank, round) increased by 7.0%, 8.6%, and 6.3%, respectively, for REV steers. Length of feeding period notably did not affect chuck or loin yields proportionate to CSW. Fat as percentage of CSW increased at 0.04% per day, whereas bone and red meat yield decreased at −0.013% and −0.024% per day, respectively. Allometric growth coefficients were greater for REV in 2 carcass components (chuck eye roll, eye of round), whereas CON was greater in 1 component (flank steak). All primals except the round (0.81) and foreshank (0.87) exhibited growth coefficients greater than the empty body.

Implication and Applications

These data indicate that REV steers are more likely to have heavier side weights, greater bone yield, and increased red meat yields than CON steers. Additionally, minimal differences were observed in allometric growth coefficients between CON and REV steers. Steers administered REV greatly improved carcass yield over CON during a 378-d finishing period.

Objective

Our objective was to characterize the effects of lubabegron (Experior 10; Elanco Animal Health, Greenfield, IN) on ammonia gas emissions, growth and carcass merit, and animal mobility of feedlot steers.

Materials and Methods

Crossbred beef steers were used in a randomized complete block with a 4 × 3 factorial arrangement of dietary lubabegron concentrations. (LUB; 0, 1.5, 3.5, or 5.5 mg/kg of DM) and duration of feeding (28, 56, or 84 d before slaughter). Blocks were slaughtered after an equal time on feed.

Results and Discussion

Calculated cumulative ammonia gas emissions per kilogram of hot carcass weight decreased after 28 d (linear) as LUB increased and responded quadratically after 56 and 84 d (LUB × duration). Steer DMI (LUB × duration) decreased linearly as LUB increased after 28 and 56 d. Final shrunk BW and ADG (LUB × duration) increased (linear) as duration increased and increased (quadratic) as LUB increased. The increase in G:F (LUB × duration) as LUB increased was linear within each duration, with an increasingly smaller magnitude as duration increased. Steer G:F increased linearly as duration increased when 0, 1.5, and 3.5 mg/kg of DM was fed. Steer DP (LUB × duration) increased quadratically as duration increased and linearly as LUB increased. Marbling score (LUB × duration) decreased quadratically as LUB increased when fed for 84 d and decreased linearly when 1.5 or 3.5 mg/kg of DM was fed. Average YG decreased (LUB × duration) linearly as LUB increased. Neither LUB nor duration altered the distribution of mobility scores at lairage before slaughter.

Implications and Applications

Feeding lubabegron resulted in lesser calculated ammonia emissions per kilogram of output, ≤0.3 kg/d lesser DMI, up to 19 kg more hot carcass weight, and leaner carcasses with a lesser marbling score after 56 d and did not alter health status or animal mobility after transport to slaughter.

Objective

The objectives of this study were to assess the effects of feeding Lubabegron (LB; Experior, Elanco, Greenfield, IN) for 0, 28, 56, or 84 d on live growth, car- cass, and mobility in Holstein steers.

Materials and Methods

Holstein steers (n = 438; 521 kg ± 35.5 kg) were used in a completely randomized study with 4 duration treatments: control, LB for 28 d, LB for 56 d, and LB for 84 d. Feed intake, BW, and car- cass data were all measured and analyzed on an individual basis.

Results and Discussion

In the pooled analysis, steers fed LB had greater total gain, ADG and G:F on a live and yield-adjusted basis relative to the controls. Lubabegron treated cattle had greater hot carcass weight, dressing per- cent and ribeye area, and decreased marbling score and average yield grade compared with the control treatment. There were no differences detected between LB or control steers in mobility at either shipment to abattoir or in lai- rage.

Implications and Application

Supplementation with LB favorably altered growth and carcass responses. Steers fed LB had no differences in mobility or other health maladies during the feeding period. These results indicate that feedyard producers can utilize LB without negatively affecting feeding performance or carcass quality.

Objective

A commercial feedlot experiment evalu- ated the effects of implanting heifers with an extended- release implant (Synovex One Feedlot) compared with a re-implant strategy (Synovex Choice followed by Synovex Plus) on finishing heifer performance, animal health, and carcass characteristics.

Materials and Methods

Using a randomized com- plete block design, crossbred heifers (n = 1,737; initial BW = 313 kg ± 15.3 kg) were randomly assigned to 24 pens across 2 treatments for an average of 181 d experi- ment. Treatments included a single extended-release im- plant administered on d 0 (Synovex One Feedlot; ONE) or a re-implant strategy of Synovex Choice (d 0) followed by Synovex Plus (CH/PLUS) on d 93 to 95.

Results and Discussion

There were no differences in live final BW or ADG between the 2 implant strate- gies; however, heifers implanted with CH/PLUS had 2.5% greater carcass-adjusted feed efficiency than ONE heif- ers. The CH/PLUS strategy produced heavier hot carcass weight (387 vs. 384 kg), larger LM area (87.9 vs. 85.3 cm²), and greater DP (62.30% vs. 61.96%) compared with ONE. Heifers implanted with ONE had greater marbling score, calculated YG, and 12th-rib fat (1.97 vs. 1.89 cm) compared with CH/PLUS heifers, resulting in a difference in QG and YG distribution between the 2 implant strate- gies. No differences were observed between treatments in morbidity, mortality, or pen removals.

Implications and Applications

These results indi- cate that heifers receiving a more aggressive re-implant strategy have heavier hot carcass weight, greater yield, and larger LM area, but reduced marbling compared with heifers that received an extended-release implant.

Objective

Our objective was to evaluate the effects of exogenous melatonin on the immune response and growth performance of beef calves during a vaccination series at weaning.

Materials and Methods

Crossbred beef calves (n = 48, initial BW = 176 ± 21.7 kg) were enrolled in a completely randomized design with a 2 × 2 factorial arrangement of treatments: vaccinated with 0.5 mg of ovalbumin (d 0 and 21) or not, and a 24-mg injection of melatonin (d 0 and 21) or not. Treatments were placebo injections only (CON), vaccination only (VAC), melatonin only (MEL), and both melatonin and vaccination (MVAC). Calves were weaned on d 0 and fed for 63 d. Calf BW and blood samples were collected on d 0, 2, 4, 8, 21, 42, and 63.

Results and Discussion

On d 8, MEL-treated calves had a greater percentage of cells performing oxidative burst and a greater percentage of cells performing phagocytosis, and these were at a greater intensity. On d 21, MEL-treated calves also had greater burst intensity than other treatments. Melatonin alone may bolster the innate immune response. Anti-ovalbumin IgG response was different on d 63, where MVAC calves had greater circulating anti-ovalbumin IgG compared with VAC calves. Calves who received VAC treatment had greater DMI than calves who received MVAC, and MVAC-treated calves tended to have a greater G:F than VAC calves. The administration of melatonin at the time of vaccination resulted in greater feed conversion and greater IgG than VAC alone.

Implications and Applications

Melatonin may bolster the immune response of calves at weaning and improve feed conversion, incentivizing its adoption as a management protocol.

Objective

This study was conducted to (1) determine the economic potential of field peas relative to corn distillers dried grains with solubles (DDGS) in diets of growing heifers and (2) identify price points for competitive utilization of field peas as an alternative to corn DDGS in diets of growing heifers.

Materials and Methods

In a 2-yr study, 162 heifers/ yr were kept in 6 dry lot pens and fed isocaloric and isonitrogenous corn DDGS-based or field pea-based TMR in the fall and winter. Animal performance (final BW, total gain, and ADG) data analysis considered the fixed effects of diet (DDGS or peas), season (fall and winter), and diet × season interaction. Base-case ration costs were calculated using prices of $325∙t⁻¹ and $366∙t⁻¹ for corn DDGS and field peas, respectively. To understand market situations where field peas are more cost effective than DDGS, and vice versa, sensitivity analysis was conducted to calculate relative total cost of feeding peas versus DDGS for several combinations of prices of DDGS and field peas.

Results and Discussion

Heifer performance was not affected by dietary treatment, which was expected because diets were formulated to be isocaloric and isonitrogenous. Therefore, the relative economics of diet (DDGS vs. field peas) is based on evaluation of costs. Base-case results indicated that field pea-based rations cost $6.89∙head⁻¹ more than DDGS-based rations. Sensitivity analysis suggests that field peas only have a lower cost relative to corn DDGS in situations where the price of peas are between 30% and 50% less than the base-case price of peas at the same time that the prices of corn DDGS are at base-case prices and below. The breakeven price of field peas was $231.15∙t⁻¹ ($7.64∙bushel⁻¹), or 71% of the base-case price of DDGS. Overall, the value of field peas was mainly driven by the amount of field peas incorporated into diets and the price of field peas relative to DDGS.

Implications and Applications

Results from this study offer useful economic information to the field pea processing industry about the range of prices that beef cattle producers can afford to pay for peas relative to DDGS. This information will help the industry to develop a reliable supply chain for field peas as a feed source for beef cattle.