Applied Animal Science最新文献

Objectives

Our objectives were to evaluate prediction of macromineral concentrations in a TMR by various meters compared with laboratory macromineral analyses, to determine whether these meters could estimate DCAD in the TMR for close-up and lactating-cow pens, and to determine whether meters could estimate uniformity of TMR.

Materials and Methods

Meters used were Cl (Oakton SaltTestr, Oakton Instruments, Vernon Hills, IL), K (Laqua Twin K Meter, Horiba Scientific, Kyoto, Japan), S (Hanna Instruments Smithfield, RI), and Ca and Mg (Hanna Instruments Ca/Mg Photometer, Smithfield, RI). The TMR samples were collected from close-up and lactating-cow pens in 10 dairies. Ten subsamples of TMR were collected per pen at the time of feeding and sent to Analab (Agri-King Inc., Fulton, IL) for analysis, and another 10 were used to measure mineral concentrations with the meters. Mineral concentrations analyzed by the laboratory were regressed on meter mineral concentrations.

Results and Discussion

Prediction of Cl and K concentrations in TMR were best (R² = 0.53 and R² = 0.66, respectively). The combination of K and Cl meter concentrations was able to predict TMR DCAD (R² = 0.72). The Cl meter was also able to predict TMR coefficient of variation (R² = 0.57) to evaluate TMR uniformity.

Implications and Applications

Chloride and K meters can aid in identifying the source of TMR DCAD failure and can predict overall TMR uniformity delivered by the mixer wagon.

Objective

The objective of this analysis was to determine whether an online bidding format affects the price of female beef cattle along with several factors such age, months bred, and her sire’s EPD.

Materials and Methods

This analysis uses annual sales data from 2017 to 2022 from a registered Angus cow and heifer sale in Crossville, Tennessee, that occurs in November at the University of Tennessee Plateau Research and Education Center. A hedonic pricing model was used to determine the value of these factors on sale price.

Results and Discussion

The results indicate heifer lots were sold for less than cows lots. The sale price of bred females increases until they are approximately 5 and 6 mo bred, and then the prices start declining. These results were expected based on the literature. The primary finding of this analysis is that having a sale to have online bidding increased the sale price by approximately $379 per head.

Implications and Applications

This research extends the literature by considering the effects of an online bidding presence on female sale prices. This article also builds on the growing literature examining how various factors affect female sale prices in the southeastern United States. These results are useful for producers with small and medium-sized herds who market cattle in their farm; they might consider implementing an online bidding com ponent when marketing their cattle.

Objective

Our objective was to evaluate the effects of pre-finishing plane of nutrition of stocker steers on subsequent feedlot performance and carcass characteristics over 2 years.

Materials and Methods

Crossbred steers (n = 140/ yr) without supplement (FC), 1.2 kg/d supplemental dried distillers grains (DDG) cubes (FS) on fertilized pastures, or 0.75% of BW per day of supplemental DDG cubes on unfertilized pastures (SP) were followed through the finishing phase in a commercial feedyard to evaluate carryover effects on performance.

Results and Discussion

Supplementation increased initial feedlot BW (P < 0.01) versus FC. Steers in FC gained faster (P = 0.02) before re-implanting in yr 1 and tended (P = 0.09) to gain faster in yr 2. Although ADG from re-implant to slaughter in yr 1 (P = 0.89) did not differ, FC tended (P = 0.08) to gain faster than FS and SP from re-implant to slaughter in yr 2. Steer BW at slaughter did not differ (P ≥ 0.23), but FC required (P < 0.01) greater days on feed than FS and SP. Overall, FS and SP consumed less feed (P < 0.01) and had lower feed costs (P < 0.01) relative to FC steers. Total system net returns were greater (P ≤ 0.04) for FS and SP than FC.

Implications and Applications

Enhancing the plane of nutrition with an extruded DDG cube during grazing affected subsequent feedlot performance and carcass characteristics, which increased overall profitability when producers retain ownership through finishing.

Objectives

The objective of this experiment was to determine the effects of strategic supplementation on year- ling performance and effects on economic return.

Materials and Methods

Predominantly Red Angus- crossbred steers and heifers (12–14 mo old; initial BW = 316 kg, SD = 8.6 kg) grazed crested wheatgrass at 4.3 ha/ yearling for an average of 112 d in a 3-yr study. Treatments were (1) dried distillers grains (DDGS) supplemented at 1.59 kg/yearling per day fed 6 d/wk throughout the entire grazing season (full season, FS), (2) 1.59 kg/ yearling per day supplemented for 6 d/wk only during the latter part of the grazing season (late season, LS), or (3) no supplement (control, CONT). Economic data from 2012 to 2021 were applied to experimental data to create potential yearling marketing scenarios and a partial budget analysis. Costs of both DDGS and live cattle were included. Pasture was the experimental unit (4 replicates in yr 1 and 2; 3 replicates in yr 3) in a randomized complete block design.

Results and Discussion

There were no significant year × treatment interactions (P > 0.53) for performance. Supplement increased (P < 0.01) ADG 0.23 kg/d over CONT. Ending BW and ADG did not differ (P = 0.31) between FS and LS. There was a tendency for a treatment × year interaction (P = 0.08) for return to management. A significant increase (P < 0.01) in return to management over CONT was observed in yr 2 for FS and yr 2 and 3 for LS. Overall, FS returned $14.96 more and LS returned $32.21 more per yearling than CONT. Return from LS and FS was greater (P ≤ 0.05) than CONT in all years except 2012, 2019, and 2021.

Implications and Applications

Strategically timed supplementation with DDGS as forage quality declined resulted in similar yearling performance as supplementing through the entire grazing season and increased economic return to management.

Objective

Variation in DMI over time could be associated with performance and metabolic disorders in feedlot cattle, but methods of measuring DMI variation have not been adequately defined. Our objective was to evaluate methods of assessing DMI variation using simulated data, as well as data from a published feedlot experiment.

Materials and Methods

Two data sets were created to simulate DMI by pens of cattle over 100 d: one with the same mean DMI (9 kg/d) and SD that varied from 0.125 to 0.5 kg/d and the other with different mean DMI (9, 10, and 11 kg/d) and the same SD (0.25 kg) or CV (2.78%). Approaches to assess DMI variation included (1) the sum of daily Euclidean distance between DMI values (DIST); (2) the average of the absolute daily deviations in DMI (DEV); and (3) repeated measures analysis of DMI over days on feed to estimate variance and covariance. The DIST and DEV metrics were analyzed by ANOVA, with model residuals tested for normality. Treatments in the published feedlot experiment included management for ad libitum intake versus slick bunk management, factored with different bulk densities of steam-flaked corn (335 vs. 425 g/L).

Results and Discussion

All 3 methods identified differences (P ≤ 0.05) among SD groups with the same mean, whereas with different mean DMI that had the same SD, no differences (P ≥ 0.80) in DMI variation were observed. When the CV was held constant among the different mean DMI, all 3 methods identified differences (P≤ 0.05) between the greatest and least CV values. For the published data, all 3 methods detected an effect of bunk management on DMI variance (P ≤ 0.05), with greater variance for ad libitum versus slick bunk management.

Only repeated measures detected an effect of bulk density on DMI variance, with greater variance (P ≤ 0.05) for the 425 g/L treatment.

Implications and Applications

Results suggest that all 3 methods can provide a tool for statistically assessing variation in DMI over time, potentially allowing for a greater understanding of how such variation affects growth performance and metabolic health of feedlot cattle.

Objective

This study evaluated the effects of the in- clusion of either monensin (Rumensin 90, Elanco Animal Health) or propionate salt (NutroCal 100, Kemin Indus- tries) in protein supplements on BW change, BCS, en- ergy metabolism, reproduction, milk production, and calf weaning BW in young 2- and 3-yr-old postpartum range cows.

Materials and Methods

In a 3-yr study at the Gud- mundsen Sandhills Laboratory near Whitman, Nebraska, March-calving, young range cows (n = 189) were individu- ally supplemented 908 g/d with a 30% CP supplement with the addition of either (1) 160 mg·cow⁻¹·d⁻¹ monensin (MON) or (2) 40 g·cow⁻¹·d⁻¹ propionate salt (CAP). Sup- plementation started approximately 10 d after parturition and continued for an average of 70 d postpartum. Cow BW and BCS data were collected weekly. Weekly blood samples were taken beginning 45 d postpartum. A com- pletely randomized design was used and data were ana- lyzed using MIXED procedure (SAS Institute Inc., Cary, NC). All binomial data were analyzed using PROC GLIM- MIX. Cow served as experimental unit, with supplemental treatment, year, and cow age set as fixed effects.

Results and Discussion

Cow BW (P ≥ 0.19) and BCS (P ≥ 0.11) were not affected by postpartum supple- mentation during the study. However, BW change from calving to breeding was influenced (P = 0.04; −7 vs. −2 kg for CAP and MON; respectively) by supplementation, with cows receiving CAP losing greater BW. Calf BW at birth, weaning, or 205 d were not affected (P ≥ 0.68) by the postpartum supplementation strategy. Cows fed CAP had lower (P = 0.01; Table 4) circulating blood serum BHB concentrations than their counterparts. Cows receiving CAP supplementation had an increase (P = 0.04; 89% vs. 80% for CAP and MON; respectively) in overall pregnancy rate.

Implications and Applications

This study implies that feeding young postpartum cows additional glucogenic precursors in the form of propionate salts increased re- productive efficiency without affecting BW or BCS. This increase in reproductive performance may have been en- hanced by improved dietary energy utilization as seen by decreased blood serum BHB concentration. In addition, economic efficiency was increased due to the increased re- productive performance and timing of when cows were bred.

Objective

Our objectives were to evaluate the effects of random metaphylaxis administered at feedlot arrival to 0, 33, 66, or 100% of high-risk beef cattle on clinical health, growth performance, complete blood cell counts, and antimicrobial use during a 35-d receiving period.

Materials and Methods

Crossbred beef steers (n = 216; arrival BW = 197 ± 6.4 kg) were used in a general- ized complete block design consisting of 2 source blocks, each with 4 BW blocks, and 4 treatments. Experimen- tal treatments and steers were randomly assigned to pen within source block: (1) negative control, s.c. injection with sterile saline (0M); (2) 33% of steers per pen giv- en metaphylaxis at random with tildipirosin (33M); (3) 66% of steers per pen given metaphylaxis at random with tildipirosin (66M); and (4) positive control; conventional metaphylaxis given to 100% of steers with tildipirosin (100M). Body weight and blood samples for quantification of complete blood count were collected on d 0, 14, and 35. Metaphylactic treatment was included in the model as a fixed effect, and BW block within source block was included as a random effect.

Results and Discussion

The percentage of steers treated with an antimicrobial for bovine respiratory dis- ease once was greater (P < 0.01) for 0M and 33M than for 66M and 100M. Neither BW on d 35 nor ADG from d 0 to 35 differed among treatments (P ≥ 0.65), but DMI and DMI as a percentage of BW from d 0 to 35 was greater (P ≤ 0.03) for 66M and 100M than for 0M and 33M. No dif- ferences in hematological variables were detected among treatments (P ≥ 0.19), whereas most complete blood count variables were affected by day (P < 0.01). Most notably, the neutrophil:lymphocyte ratio was greater (P < 0.01) on d 0 than on d 14 and 35.

Implications and Applications

These data suggest that arrival metaphylaxis can be randomly administered to 66% of cattle without increasing bovine respiratory dis- ease morbidity, while simultaneously increasing DMI simi- lar to conventional metaphylaxis. Random metaphylaxis to 66% of steers at arrival decreased antimicrobial use for metaphylaxis while simultaneously maintaining health outcomes and growth performance of high-risk beef cattle.

Objectives

The objectives of this experiment were to optimize fecal sample protocols using internal markers (acid detergent insoluble ash [ADIA], indigestible NDF [INDF] and ADF [IADF]) to estimate DM digestibility (DMD), CP digestibility (CPD), and DE.

Materials and Methods

Steers (n = 6; 754 ± 20.5 kg of BW) used in this experiment were housed in individual pens and were fed a starter and finisher diet in 2 periods. Fecal bags were fitted to steers for 4 d during each period. Fecal samples were collected every 12 h for 2 d. The fecal sampling regimens evaluated were (1) one sample collected on one morning (AM-1d); (2) samples collected on 2 mornings (AM-2d); (3) a morning and evening sample collected on 1 d (AM&PM-1d); or (4) a morning and evening sample collected on 2 d (AM&PM-2d).

Results and Discussion

The ADIA marker was found to be inadequate under the current experimental and this was largely driven by improvements in precision rather than accuracy.

Implications and Applications

Researchers will need to determine whether the improvements in method precision are worth the increased requirements in labor, time, and animal handling. This decision should be driven by experimental design limitations.

Objective

The objective of this study was to evaluate the effects of sorghum-based diets with or without phytase superdosing on broiler performance.

Materials and Methods

A 42-d grow-out trial with 1,500 male broiler chicks that were a day old (Ross 708) was conducted. The experiment included 30 pens of 50 birds, with 10 replicate pens per treatment. The 3 dietary treatments were as follows: T1—corn-based diet with 550 phytase units (FTU)/kg phytase (standard), T2—sorghum-based diet with 550 FTU/kg phytase, and T3—sorghum-based diet with 2,000 FTU/kg phytase (superdose). The diets were formulated to be isocaloric, isonitrogenous, and to contain the same levels of available phosphorus and calcium (Ca) across all treatments. Birds were fed ad libi- tum following a phase-feeding program. Cumulative BW, BW gain, feed intake, and adjusted feed conversion ratio were calculated. One-way ANOVA followed by Fisher’s LSD was used for statistical analysis. Significant differences were considered when P-values were less than 0.05, and trends were considered when P-values were between 0.1 and 0.05.

Results and Discussion

No differences in feed intake were observed (P > 0.05). At 14 d of age, birds fed T3 tended to gain around 6% more weight (0.368 vs. 0.346 kg) and be 3% more efficient (1.23 vs. 1.27 kg:kg) than birds fed T1 (P < 0.10). Similarly, by 21 d, birds fed the T3 diet were 2% more efficient (1.284 vs. 1.313 kg:kg; P < 0.05) and tended to gain 4% more weight than T1 birds (0.799 vs. 0.767 kg; P < 0.10). Also, at 28 d, birds fed T3 were 1.7% more efficient than those fed T1 (1.301 vs. 1.324 kg:kg; P < 0.05). Analysis of the dietary nutrient composition had 0.03% more methionine concentration in the sorghum-based diets during the starter and grower phases. This, in conjunction with the phytase superdose, might have helped birds fed T3 achieve a better nutrient uptake and, consequently, growth performance earlier in life, especially in the grower phase.

Implications and Applications

A full replacement of corn with American sorghum is possible without negatively affecting bird performance, and phytase superdosing in sorghum-based diets might help birds to achieve better performance.