Translational Animal Science最新文献

Formaldehyde has been found to decrease virus concentrations in feed and ingredient matrices. Continued research is needed to identify the appropriate inclusion levels and application time for different viruses in these matrices. The objective was to evaluate different inclusion levels of formaldehyde when applied either pre- or postinoculation of porcine epidemic diarrhea virus (PEDV), type 2 porcine reproductive and respiratory syndrome virus (PRRSV), and Seneca Valley virus 1 (SVV1) to complete feed or soybean meal. The experiment was designed in a 2 × 2 factorial with a formaldehyde-based product (Termin-8, Anitox Corporation, Lawrenceville, GA) applied either before virus inoculation (preinoculation) or after inoculation (postinoculation) at either a 2 or 3 kg/MT. On day 0, samples of the respective matrices were weighed in 50 g aliquots and added to 500 mL bottles. Formaldehyde was applied to the preinoculation samples at the respective inclusion levels and 50 µL of each virus were added to the postinoculation samples. All bottles were shaken and allowed to sit at room temperature for 24 h. On day 1, virus was added to the preinoculation samples and formaldehyde was added to the postinoculation bottles. Half of the samples were immediately processed (0 h) and the other half were incubated at room temperature for an additional 24 h. Samples were processed and aliquots were analyzed via triplex PCR. An application time × inclusion level interaction was observed for PEDV at 0 h and SVV1 and PEDV at 24 h in complete feed, where less viral RNA (P < 0.05) was detected in the postinoculation samples at either inclusion level as compared to the positive controls. In soybean meal, the same interaction was observed in PEDV and PRRSV at 0 h and SVV1 and PEDV at 24 h with less detectable RNA observed (P < 0.05) in the postinoculation samples regardless of inclusion level than the preinoculation counterparts and the controls. Overall, an application time effect was noticed in each matrix where less RNA was detected in the postinoculation samples at 0 h (P < 0.05) compared to the preinoculation samples and the control, and at 24 h, both the pre- and postinoculation samples had less detectable RNA (P < 0.05) than the control. Overall, formaldehyde can reduce detectable RNA immediately in contaminated complete feed and soybean meal, with greater decreases observed as mitigant contact time increases.

Twelve horses weighing 570 ± 35 kg were split into two groups (standard protein, STD, and balanced protein, BAL) to evaluate the effect of balanced vs. unbalanced protein on muscle mass. Groups were fed grass hay and a 12% CP feed (one formulated for balanced protein). Horses were out of work for 14 wk prior and participated in 1 to 2 h of light-to-moderate exercise 5 d/wk for 12 wk. A 4-d total urine and feces collection period was conducted at the start and end of the study. Urine and feces samples were analyzed for nitrogen (N) to calculate N balance. Muscle mass status was evaluated using histochemistry, muscle scoring, and body measurements at the start and end of the study. Muscle biopsies were analyzed for free amino acid concentrations. An ANOVA was done using the Proc MIXED function of SAS (2006). Nitrogen retention was greater and urine nitrogen as a percent of intake less for the STD group at the end of the study (P = 0.01). Muscle free concentrations of methionine, leucine, phenylalanine, and arginine were greater in the BAL group at the end of the study compared to the STD group (P < 0.04) while muscle free histidine, threonine, and valine were less for the STD group at the end of the study compared to the start of the study (P < 0.05). Muscle fiber diameters were greater at the start of the study for the STD group (P = 0.004) but greater for the BAL group at the end of the study (P = 0.001). There is some evidence of improved muscle mass for the BAL group with greater muscle free amino acids (arginine, leucine, methionine, phenylalanine, and valine) as well as greater type II muscle fiber areas and diameters. While changes did not appear evident between groups at the "whole body" level, changes at the tissue level appear more evident.

The global population is projected to increase, indicating that there will be greater demand for animal protein to meet the associated food needs. This demand will place additional pressure on livestock systems to increase output while also minimizing natural resource inputs. Insect protein has emerged as a potential alternative to conventional protein feeds, such as soybean meal. Mealworm larvae (MWL; Tenebrio molitor) have been studied in poultry and swine as an alternative protein source; however, there is no research currently evaluating MWL for cattle. Black soldier fly larvae (BSFL; Hermetia illucens) have also received attention for their potential use in livestock feed due to their scalability and nutritional value, but research in cattle is limited. The objective of this study was to evaluate the effects of whole-dried MWL and defatted BSFL as protein supplements for cattle consuming forage. Five ruminally cannulated steers were utilized in a 5 × 5 Latin square experiment to determine how MWL and BSFL supplementations affect forage utilization. Steers consuming ad libitum low-quality forage (76.5% neutral detergent fiber [NDF], 4.2% crude protein) were provided one of the five treatments each period: 1) control with no supplement (CON), 2) soybean meal (CONV), 3) BSFL, 4) MWL, or 5) 50/50 by-weight blend of BSFL and MWL (MIX). All treatments were provided at 100 mg N/kg BW and periods included 8 d for treatment adaptation, 5 d for intake and digestion, and 1 d for ruminal fermentation measures. Protein supplementation stimulated forage organic matter intake (FOMI; P ≤ 0.01) relative to CON (3.28 kg/d). There was a significant difference in FOMI (P ≤ 0.01) between BSFL (4.30 kg/d) and CONV (4.71 kg/d), but not between CONV and MWL (P = 0.06, 4.43 kg/d). Total digestible OM intake (TDOMI) was also stimulated by the provision of protein (P ≤ 0.01), from 1.94 kg/d for CON to an average of 3.24 kg/d across protein supplements. Organic matter digestibility (OMD) and NDF digestibility (NDFD) were not affected by treatment (P ≥ 0.37), for an average OMD of 66.5% and NDFD of 62.7%. There was also no treatment effect on ruminal volatile fatty acid (P = 0.96) or ammonia-N (P = 0.22) concentrations. These data indicate that MWL may stimulate forage utilization by beef cattle to a greater extent than BSFL, but both are viable protein supplements.

Ruminants produce one-third of the anthropogenic methane (CH ₄ ) emissions worldwide, and 47% of the CH₄ emissions result from ruminants under grazing conditions. However, there is limited information regarding the appropriate number of visits to accurately determine enteric CH₄ emissions using the automated head-chamber system (AHCS) from growing beef cattle under intensive grazing conditions. Data from one experiment were analyzed to determine the number of visits to assess gas flux (CH₄, carbon dioxide [CO ₂ ], and oxygen [O ₂ ]) from Angus-crossbreed steers grazing in a pivot-irrigated improved pasture. A total of 110 steers (324 ± 37.3 kg initial body weight) were selected and divided into two blocks. Steers were under intensive grazing management for 84 d. Depending on forage availability, steers were rotated at 2- to 4-d intervals. Pastures were predominately composed of cool-season forages. Two different databases using the same animals (n = 16) were defined to calculate the gas flux using the first 100 visits to an AHCS with 2 or more or 3 or more minutes of visitation length. The mean gas flux was estimated as the average for increasing (forward) or decreasing (reverse) the gas flux of 5-visit intervals starting with the first or the last 5 visits and increasing or decreasing until the full 100-visit dataset was utilized, respectively. Spearman and Pearson correlations were computed between the maximum visits and each shortened visit interval. Concurrently, the residual variance and the residual variance change were determined for each interval by fitting a mixed model. The minimum number of visits was defined when correlations with the total visits were greater than 0.95, and the residual variance was stabilized. The results indicated that the minimum number of visits needed to determine CH₄ production varied between 45 and 70, while CO₂ production and O₂ consumption varied between 45 and 50 according to the visitation length. Additionally, steers that visited the AHCS for 2 or more minutes in visit duration required a greater number of visits than those that visited for 3 or more minutes. Thus, based on the average daily visitation in this experiment (1.4 visit/d), the assessment of CH₄ emissions requires 32 d, while CO₂ production and O₂ consumption require between 32 and 36 d using 3 or more minutes of visit length from growing steers under intensive grazing conditions.

This study investigated the potency of bird eye pepper (BEP) of varying proportion and sieve size on growth performance and meat quality of broiler chickens. Two hundred and forty-six 2-wk-old broiler chicks were randomly allotted to six treatment groups (basal diet (B) inclusive × 2) in a 2 × 3 factorial arrangement each replicated four times (10 × 10 × 10 × 11) in a completely randomized design. Diets containing BEP of varying proportion (0, 150, and 300 g) and sieve size (0.05 and 0.1 mm) were offered in two phases, starter (14 d) and finisher (17 d). Postfeeding, 48 birds (two per replicate) were sacrificed to further evaluate performance and assess the quality of meat produced. Result obtained indicates chicks fed 150 g BEP consumed less feed compared to 300 g BEP. Also, 0 and 150 g BEP groups had better (P < 0.05) feed conversion ratio (FCR) than 300 g BEP, while 0.05 mm BEP diet improved (P < 0.05) FCR as against 0.1 mm BEP. Interaction of proportion and sieve size effects of BEP increased (P < 0.05) the final weight of the birds and suppressed (P < 0.05) feed intake for all groups as against 300 g (0.1 mm) BEP (1,576.00 g/bird; 964.20 g/bird). Feeding 150 and 300 g BEP diets lowered (P < 0.05) superoxide dismutase (SOD) production compared to 0 g BEP, while 150 g BEP diet increased (P < 0.05) catalase production over 0 g BEP. Interactive effect of proportion and sieve size of BEP reduced (P < 0.05) SOD production in 150 g (0.05 and 0.1 mm) BEP and 300 g (0.05 mm) BEP groups, followed by 300 g (0.1 mm) BEP group that had lower (P < 0.05) SOD than both basal groups. Birds fed B + 150 g (0.05 mm) BEP diet produced more (P < 0.05) catalase compared to both basal groups. Meat pH for 150 and 300 g BEP groups was significantly (P < 0.05) reduced than 0 g BEP. The Hue angle corresponds with a high value (P < 0.05) to 0 g BEP, while 300 g BEP showed a low value. This study has shown BEP at low concentration (150 g) screened with 0.05 and 0.1 mm sieves enhanced chick welfare, while a higher concentration (300 g) screened at 0.05 mm improved overall growth performance (endogenous antioxidant profile) at finisher phase. Broiler chickens, farmers, and meat processors will benefit from diet containing BEP screened through 0.05 mm sieve.

The objectives of this project were to measure the effect of SeaFeed, a canola oil infused with Asparagopsis armata, on methane emissions, animal health, performance, and carcass characteristics of feedlot cattle. Angus steers (n = 160) with an initial body weight of 474.4 kg were fed a steam-flaked wheat and barley ration for 200 d in a large, commercial feedlot. A single-blinded randomized complete block design compared two treatments including control and SeaFeed included at a rate of 25 mg bromoform per kg dry matter intake (DMI). Monthly testing of bromoform levels in the canola demonstrated that SeaFeed maintained a stable bromoform concentration for 6 mo. The inclusion of SeaFeed had no effect on daily DMI. However, steers fed SeaFeed were more efficient with a 6.6% higher (P < 0.01) gain-to-feed ratio as compared to control steers over the 200-d feeding period. This improved efficiency resulted in 0.094 kg higher (P < 0.01) average daily gain and 19.7 kg higher (P < 0.01) live exit weight in steers fed SeaFeed as compared to control steers. Steers fed SeaFeed produced 51.7% less (P < 0.01) methane and yielded 50.5% less (P < 0.01) methane over the 200-d feeding period as compared to cattle fed the control ration. Peak methane inhibition occurred on day 29 on feed with 90.6% less methane production in cattle fed SeaFeed as compared to control animals. SeaFeed reduced (P < 0.01) methane intensity by 55.4% over the 200-d feeding period. Hot carcass weight tended (P = 0.097) to be 6.9 kg heavier in cattle fed SeaFeed as compared to controls. Cattle fed SeaFeed had similar (P > 0.20) marbling, meat color, eye muscle, area, and ultimate pH to control cattle. Interestingly, cattle fed SeaFeed tended (P = 0.054) to have slightly higher fat color scores. Rumen papillae from cattle fed SeaFeed were more (P < 0.01) gray in color and more oval (P < 0.01) in shape as compared to control animals; however, rumen damage was not different between treatment groups. In regards to food safety and residues, all muscle, fat, and kidney samples were free from bromoform residues. Bromine residues in kidney and meat samples were higher (P < 0.01) in the SeaFeed group as compared to controls. Cattle fed SeaFeed produced strip loin steaks similar (P > 0.05) in eating quality to control cattle. These results demonstrate that SeaFeed reduced methane emissions, improved performance, and produced safe beef with similar eating quality to conventional beef.

Alga 1.0, a product containing bromoform, was fed to cattle to evaluate its effects on methane (CH ₄ ) and carbon dioxide (CO ₂ ) emissions and diet digestibility. Twelve nonlactating, nonpregnant Jersey cows (490 ± 19 kg body weight) were used in four replicated 3 × 3 Latin squares with three periods, each consisting of 21 d. Cows were blocked by feed intake (averaged intakes over 4 wk prior to trial) and assigned randomly to one of three treatments. Treatments included Alga 1.0 fed at 0, 69, and 103 g/d in a 0.454 kg/d dry matter (DM) top-dress daily in a modified distillers grains plus solubles (MDGS) carrier. Diet consisted of 60% dry-rolled corn, 20% corn silage, 15% modified distillers grains, and 5% supplement (DM basis). Headbox-style indirect calorimeters were utilized to evaluate gas production from individual cows with two nonconsecutive 23-h collections in each period. Data were analyzed using the GLIMMIX procedure of SAS with cow within square as experimental unit and as a random effect, and treatment and period as fixed effects. Linear and quadratic contrasts were used to compare treatments. Feeding Alga 1.0 linearly reduced dry matter intake (DMI, P < 0.01) by 10.1% for 69 g/d inclusion and 13.3% for 103 g/d inclusion compared to the control. Nutrient intakes decreased linearly (P < 0.01) due to lower DMI, but nutrient digestibility was not impacted (P ≥ 0.28). Inclusion of Alga 1.0 did not impact gross energy or digestible energy concentration of the diets expressed as Mcal/kg DM (P ≥ 0.22) but did linearly reduce energy intake (Mcal/d; P < 0.01). Feeding Alga 1.0 linearly reduced enteric CH₄ emissions measured as g/kg DMI (P < 0.01) by 39 and 64% for 69 g/d and 103 g/d inclusion, respectively. Linear reductions (P < 0.01) of 64% to 65% were also observed in enteric CH₄ emissions when expressed per kilogram of DM or organic matter digested. Respired CO₂ as g/d linearly decreased (P = 0.03) for cattle fed Alga 1.0 but did not differ when expressed as g/kg of DMI (P ≥ 0.23). Oxygen consumption did not differ between treatments for g/d and g/kg DMI (P ≥ 0.19). In conclusion, feeding Alga 1.0 reduced DMI up to 13.3%, did not impact digestibility, and significantly reduced CH₄ emissions up to 63%.

The primary objective of this experiment was to evaluate the effects of a growth-hormone implant (Revalor-G, Merck Animal Health., Rahway, NJ, USA) and tannin supplementation (Silvafeed BX, Silva Team, San Michele Mondovi CN, Italy) on enteric methane (CH₄) emissions and estimated nitrogen (N) excretion in grazing steers. Steers (n = 20; initial body weight [IBW] = 343 ± 14 kg) were acclimated to use a portable automated head-chamber system (AHCS) to measure CH₄ and a SmartFeed Pro automated feeder for dietary supplementation (C-Lock Inc., Rapid City, SD, USA). After the training period, steers were randomly assigned to a 2 × 2 factorial arrangements of treatments, with 2 levels of growth-hormone implants, no-implant (NO-IMP) or implanted (IMP), and 2 levels of tannin supplementation, no tannin supplementation (NO-TAN) or tannin supplementation (TAN). This created 4 treatment groups: (1) NO-TAN and NO-IMP, (2) TAN and NO-IMP, (3) IMP and NO-TAN, and (4) TAN and IMP. Tannin was offered daily at 0.30% dry matter intake (DMI) through 0.5 kg/hd/d sweetfeed supplement (Sweetfeed Mix, AgFinity., Eaton, CO, USA) with a targeted tannin intake at 48 g/hd/d. No (P ≥ 0.05) implant × tannin interaction was detected for any dependent variable, so only the main effects of implant (NO-IMP vs. IMP) and tannin supplementation (NO-TAN vs. TAN) are discussed. Implant status did not affect (P ≥ 0.56) final body weight (FBW) or average daily gain (ADG) during the 90 d grazing period. There was no effect (P ≥ 0.15) of growth implant on CH₄ production or emission intensity (EI; g CH₄/kg gain). Additionally, IMP steers tended (P ≤ 0.08) to have less CH₄ yield (MY; g CH₄/g DMI) and higher blood urea nitrogen (BUN) than NO-IMP steers. Tannin supplementation did not impact (P ≥ 0.26) FBW or ADG. However, NO-TAN steers tended (P = 0.06) to have a greater total DMI than steers supplemented with tannin. No effect (P ≥ 0.22) of tannin supplementation was observed for CH₄ production and EI. Nitrogen utilization as measured through BUN, urine N, fecal N, or fecal P was similar (P ≥ 0.12) between TAN and NO-TAN animals. The findings indicate that low-level dietary supplementation to reduce enteric emissions is difficult in grazing systems due to inconsistent animal intake and that growth implants could be used as a strategy to improve growth performance and reduce EI of steers grazing improved pasture.

The objective of this study was to evaluate growth and reproductive performance of heifers developed using 3 different winter systems in the midwestern U.S. Spring-born heifers (n = 1,156; 214 d of age; SD ± 17 d) were used in a 3-yr study to evaluate performance in winter development systems, which utilized cover crop (CC) and corn residue grazing. Heifers were assigned to 1 of 3 treatments: grazing corn residue with 0.77 kg/d dried distillers grains (CD) or 1.69 kg/d wheat midds (CW) supplementation followed by a grower ration in the drylot, or grazing late summer planted oat-brassica CC followed by corn residue grazing with 0.35 kg/d dried distillers grains supplementation (CC). Supplementation during the corn residue phase was targeted to result in a common body weight (BW) (276 kg; ~45% of mature BW) by the end of the winter development period. Grazing of corn residue (CD and CW) and CC began in early November. After 63 d, heifers assigned to CC were moved to corn residue; on day 77 heifers assigned to CD and CW began receiving a grower ration in the drylot. In mid-February (day 98), heifers were comingled and managed in a single group. Breeding season began in June and lasted for 29 d. The ADG of heifers assigned to CC when grazing CC (days 1 to 63) was greater (0.76 kg/d; P < 0.01) than those assigned to CD or CW (0.58 kg/d and 0.49 kg/d, respectively). Gain during the last 35 d of the winter period for heifers assigned to CC (0.36 kg/d) was less (P < 0.01) than those assigned to CW (0.49 kg/d) but not different from CD heifers (0.41 kg/d). Overall (days 1 to 98), winter ADG was greater (P < 0.05) for heifers assigned to CC (0.62 kg/d) than CD (0.53 kg/d) or CW (0.50 kg/d), which did not differ (P = 0.42). Percent of mature BW in May (27 d pre-breeding) was greater (P < 0.01) for heifers assigned to CC (52%) than for those on CD and CW (50%), which did not differ (P = 0.64). Pregnancy rates were affected by treatment (P < 0.03), with heifers assigned to CC (76%) being greater than CW (64%) and CD heifers being intermediate (70%). When accounting for the differences in cost and the value of open and bred heifers, the economic return tended to differ (P = 0.07) among treatments, with CC and CW not differing (P ≥ 0.20) from CD but return for CC being $73 greater than CW (P = 0.02). Utilizing oat-brassica CCs early in the winter followed by a slower rate of gain while grazing corn residue with distillers supplementation appears to be as effective for developing beef heifers in the midwestern U.S. as supplementing distillers grains.