14-d Period Research Articles

59 Effects of serial harvest on growth and carcass characteristics of beef x dairy crossbred steers

Abstract Beef x dairy crossbred feedlot steers [n = 707; body weight (BW) at initial processing = 148 kg] were utilized in a randomized complete block design to evaluate effects of three serial harvest endpoints on growth performance and carcass characteristics. Allocation to treatment occurred after 204 d-on-feed (DOF), at which point steers weighed 484 kg (SEM = 3.2 kg). Treatments consisted of three serial harvest endpoints: 326, 347, and 368 DOF, as measured from initial processing at 148 kg. Twelve pens, with approximately 59 steers/pen and four pens/treatment were utilized. Final BW measured 696, 730, and 744 kg at 326, 347, and 368 DOF, and increased (P < 0.01) with DOF. Dry matter intake (DMI) from allocation to harvest did not differ among treatments (11.4 kg/d; P = 0.36). Average daily gain (ADG) from allocation to harvest measured 1.82, 1.79, and 1.64 kg at 326, 347, and 368 DOF, respectively and was greater (P < 0.01) at 326 and 347 DOF than at 368 DOF. Feed efficiency (FE) from allocation to harvest measured 0.162, 0.151, and 0.143 at 326, 347, and 368 DOF, respectively and was greater (P < 0.01) at 326 and 347 DOF than at 368 DOF. Hot carcass weight (HCW) measured 438, 459, and 472 kg at 326, 347, and 368 DOF, respectively and increased (P < 0.01) with DOF. Across the 42-d serial harvest period live and carcass ADG averaged 1.09 and 0.78 kg, respectively, with a carcass transfer of 71.6%. Backfat thickness measured 1.35, 1.63, and 1.47 cm at 326, 347, and 368 d, respectively and was greater (P < 0.01) at 347 and 368 d than at 326 d. Marbling score measured 508, 529, and 550 at 326, 347, and 368 DOF, respectively and was greater (P = 0.03) at 368 and 347 DOF than at 326 DOF. Distribution of USDA quality grades (QG) did not differ (P = 0.45) among treatments and averaged 6.3% Prime and 83.1% Choice. Ribeye area and dressing percentage (P = 0.11) did not differ among treatments. Distribution of USDA yield grades (YG) was affected by treatment (P < 0.01), with a shift toward more YG 4 and 5 carcasses with increasing DOF. Liver abscess occurrence averaged 62.9% and did not differ (P = 0.61) among treatments. Results from this experiment indicate a BW gain of 1.09 kg/d and a HCW gain of 0.78 kg/d across the 42-d serial harvest period. There were no differences in DMI as DOF progressed but ADG and FE decreased in the longest-fed cattle. Distribution of QG was not affected by DOF, but YG increased with increasing DOF.

PSIII-16 Effects of dietary corn origin (U.S., Argentina, and Brazil) on pig growth performance

Abstract Corn is an important global commodity. Understanding its nutritional value and practically utilizing different corn sources and varieties in swine diets is important to U.S. corn and swine production. Globally, the U.S. “dent” corn variety is presumed to be of lesser quality compared with “harder” flint-type corn (the preferred varieties in Argentina and Brazil) due to differences in whole kernel structure when shipped long distances. In fact, official work from the US Grains Council indicates that US corn produces more ethanol per bushel when compared with flint-type varieties of corn. This indicates a greater concentration of starch in US corn and increased starch content should mean a greater quantity of energy and nutrients. Therefore, swine producers globally benefit from understanding the feeding value of different varieties and origins of corn. The objective of this study was to assess the performance of pigs fed corn from three exporting countries: U.S., Argentina (ARG), and Brazil (BRZ). Two similar studies were conducted comparing the effect of 3 corn sources on late nursery pig growth performance. Study 1 used 96 nursery pigs [body weight (BW) = 8.8 ± 1.7 kg] split between 24 pens and study 2 used 114 nursery pigs (8.0 ± 1.3 kg) split between 24 pens. Three experimental diets were formulated with corn sources from: 1) U.S.; 2) ARG; and, 3) BRZ. The U.S. corn diet was considered the control diet and was balanced to meet or exceed all nutrient requirements for the pigs. The U.S. corn was replaced with ARG corn and BRZ corn on a kg for kg basis in the diets. Pigs were assigned in a randomized block design based on initial body weights (BW) and sex. Feed and water were offered ad libitum over a 28-d period, pig BW and feed disappearance were measured each week. Average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency [gain to feed ratio (G:F)] were determined after weeks 1, 2, and 4. Performance data were analyzed using PROC MIXED procedure in SAS considering dietary treatment as a main effect and pen as experimental unit. There were no significant differences (P > 0.05) in BW, ADFI, ADG, and feed efficiency between the three corn sources throughout all weeks and the overall 28 d. Overall performance values for the three treatments were: US corn ADG (0.66 kg), ADFI (0.91 kg), and G:F (0.72): Argentina corn, ADG (0.65 kg), ADFI (0.92), and G:F (0.70); and Brazil corn, ADG (0.65), ADFI (0.92), and G:F (0.71). In conclusion, the value of US corn is similar in nutrient content and nutritional quality as demonstrated by equivalent performance in nursery pigs. The aesthetics of whole kernels are not indicative of feeding value to swine.

27 Standardized ileal digestible lysine to metabolizable energy ratio equations for 12 to 127 kg boars, gilts, immunocastrated gilts and boars

Abstract We aimed to determine the standardized ileal digestible (SID) lysine (Lys) to metabolizable energy (ME) ratio equations for 12 to 127 kg boars, gilts, immunocastred gilts (IC gilts), and barrows (IC barrows). An average of 3,545 split-gender pigs (PIC 337×Camborough, initially 11.98 ± 1.26 kg) were used in a 21-d trial followed by a 21-d wash-out period in 2 replicates, totaling six feeding periods. In feeding phase 6, both genders were immunized against gonadotropin-releasing hormone (administrated with Vivax, Zoetis, São Paulo, SP, Brazil). Pens of pigs were weighed, blocked by body weight, and randomly allotted to 1 of 5 treatments consisting of 80, 90, 100, 110, and 120% of PIC SID Lys:Mcal of ME recommendations for mixed gender between boars, barrows, and gilts for each phase. The treatment diets were corn-soybean-meal-based and contained 3,300 Kcal of ME/kg. There were six split-gender pens•treatment-1•replicate-1 •phase-1 and 30 pigs/pen. Data were analyzed using generalized linear and nonlinear mixed models with a pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ) for average daily gain (ADG) and gain to feed ratio (G:F). There was no significant gender by quadratic coefficient interactions in all phases of this study (P > 0.05), then the mixed gender equation was determined, and the intact boars and gilts equation was estimated by the PIC overall difference in efficiency between genders. In the immunocastrated phase, after second dose, the mixed gender optimum level was determined and the equations for IC gilts and barrows was estimated by the differences in efficiency observed in the phase 6 of the two replicates. The SID Lys to calorie ratio recommended is based on the average for ADG and G:F (Table 1). Approximately 98.4% and 99.2% of maximum ADG and G:F were achieved at these levels, respectively, and these equations were similar compared with previous PIC biological requirements (Orlando et al., 2021).

PSIV-20 Evaluation of pectinase on nursery pig performance

Abstract Non-starch polysaccharidases have been widely employed in swine production to enhance fiber digestion and nutrient utilization, yielding mixed results. Our objective was to evaluate the effects of an exogenous pectinase on performance of early nursery pigs. The study utilized 320 mixed sex freshly weaned pigs, 19-21 d of age [5.4 ± 1.1 kg body weight (BW), Camborough (1050) x 337, (PIC, Hendersonville, TN)], sourced from a commercial sow farm. Upon arrival, pigs were randomly allotted to four dietary treatments (10 pens/treatment, 6 gilts and 2 barrows/pen). All diets were fed in two phases consisting of 7 and 14 d over a 21-d study period. Phase 1 basal diets consisted of 40% soybean meal, 1.45% SID Lys, and 3,396 kcal/kg ME. Phase 2 basal diets consisted of 40% soybean meal, 1.375% SID Lys, and 3,396 kcal/kg ME. In both phases, exogenous pectinase was included at 0, 8, 40, and 80 (g/MT). Pen bodyweights and feed disappearance were collected at the start and end of each phase to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Fecal consistency was scored for diarrhea presence daily. In all analyses, pens served as the experimental units. Growth performance and mortality/removals data were analyzed within phase and overall with the fixed effect of pectinase level, including the linear and quadratic effects of varying pectinase levels across the diets. No discernible health impacts were identified based on observations of mortality/removals and fecal consistency scores (P > 0.10). There were no notable main, linear, or quadratic effects observed on pig bodyweights during the trial. Overall, the diet had a significant impact on ADG (P < 0.05), showing a positive trend associated with pectinase inclusion (linear P = 0.08). This trend was supported by a 14% increase in the ADG of pigs that consumed the diet with 80 g/MT of pectinase, in contrast to pigs fed the control diet. Phase 1 did not exhibit any notable effects on performance in terms of main, linear, or quadratic trends. In contrast, during phase 2, the diet significantly affected the ADG of pigs, with all pectinase-containing diets promoting greater body weight gain compared with control-fed pigs (P < 0.05). Additionally, there was a tendency for a diet effect on GF in phase 2 (P = 0.09). Pigs that were fed the diet with 80 g/MT of pectinase observed a 14-22% improvement in feed efficiency compared with all the other dietary groups. In conclusion, the addition of pectinase to early nursery pig diets had the capacity to enhance pig performance without any adverse effects on pig health when feeding high soybean meal.

233 Inclusion of a multispecies fungal feed additive in forage-based diets fed to beef cattle: Effects on growth performance and ruminal fermentation

Abstract The objective was to evaluate the effect of adding a multispecies fungal feed additive (MFA; Aspergillus flavus, Aspergillus niger, Aspergillus oryzae) to forage-based diets fed to beef cattle on growth performance and ruminal fermentation. Experiment 1 evaluated the effect of supplementing Angus × SimAngus-crossbred steers [n = 80; initial body weight (BW) = 370 ± 44 kg] with varying doses of an MFA in a randomized complete block design. Steers were blocked by BW and housed in 8 feedlot pens (randomly assigned 2 pens per treatment) where a hay-based diet was fed for 122 d. The hay-based diet was offered with the inclusion of the MFA at 0.02, 0.04, and 0.08 % of the diet dry matter (DM), or without the inclusion of the MFA (CON). Steers were weighed at 28-d intervals. For experiment 2, ruminally cannulated Angus × SimAngus cows (n = 4; initial BW = 569 ± 21 kg) were used in a crossover design with two 21-d study periods to evaluate the effect of dietary inclusion of an MFA on in situ digestion and rumen metabolites. Treatments consisted of a forage-based diet with (WFA) or without (CON) the inclusion of the MFA. In situ digestion was evaluated on d 5, 10, and 20 throughout each period. In-situ bags were incubated in the rumen for 0 to 36 h, sampling every 4 h. On d 20, samples of ruminal fluid were collected to analyze short-chain fatty acids (SCFA) concentration. All data were analyzed using the PROC MIXED procedure of SAS. For experiment 1, a polynomial contrast was used. For experiment 2, the interaction between period and treatment was not significant (P > 0.45). In Experiment 1, the final BW, average daily gain (ADG), and gain to feed ratio (G:F) changed cubically (P ≤ 0.04; Table 1) as dietary inclusion of the MFA increased. Steers supplemented with the MFA at a rate of 0.02% of the diet DM were heavier at the end of the 122-d study period and had the greatest ADG and G:F among treatments. No differences between treatments (P ≥ 0.37) were observed for dry matter intake. In Experiment 2, no treatment × time interactions and treatment effects were detected (P ≥ 0.17; Table 2) for the in-situ disappearance rate and degradation kinetics of the diet DM, neutral detergent fiber, and acid detergent fiber. In addition, MFA supplementation did not affect (P ≥ 0.13; Table 3) the SCFA profile and the total SCFA content in the rumen fluid. Results from these studies indicate that dietary inclusion of an MFA might be an effective alternative to increase the feed efficiency of beef cattle-fed forage-based diets. However, the precise mode of action warrants further investigations.

68 Serological comparisons of IBR-BVD-PI3-BRSV- Mannheimia haemolytica toxoid vaccines

Abstract The objective of this study was to compare serological responses in low-risk calves vaccinated with various IBR-BVD-PI3-BRSV-Mannheimia haemolytica toxoid vaccines. Bovine herpes virus-1 (BHV-1) and M. haemolytica (MH) leukotoxin titers were analyzed to investigate any potential BHV-1 antigen interference to MH leukotoxin levels when administering multi-valent vaccines. Serology responses of BVD, BRSV, and PI3 were not within the scope of this study. Before enrolling in the study, weaned calves born to dams at two University of Arkansas beef cattle research stations that were not previously vaccinated with MH toxoid or BHV-1 were bled and sera harvested. Crossbred steer and heifer calves [n = 364; steers = 168, heifers = 196; body weight (BW) = 187.9 ± 2.8 kg] were used for this study at the two locations. Calves were stratified by MH titers, BHV-1 titers, and sex, and allotted to 1 of 5 treatments: 1) “BS GOLD” = IBR-BVD-PI3-BRSV-MH (Bovi-Shield GOLD One Shot, 2 mL/SQ; Zoetis); 2) “P5 + PRE” = IBR-BVD-PI3-BRSV-MH (Pyramid 5 + Presponse SQ, 2 mL/SQ; Boehringer Ingelheim Animal Health); 3) “BV Once” = IBR-BVD-PI3-BRSV-MH-PM (Bovilis Vista Once SQ, 2 mL/SQ; Merck Animal Health); 4) “IF3 + One Shot” = IBR-BVD-PI3-BRSV (Inforce 3, 2 mL/intranasal; Zoetis) and BVD-MH (One Shot BVD, 2 mL/SQ; Zoetis); and 5) “BN + BV” = IBR-BVD-PI3-BRSV (Bovilis Nasalgen 3-PMH, 2 mL/intranasal; Merck Animal Health) and BVD (Bovilis Vista BVD CFP, 2 mL/SQ; Merck Animal Health). Cattle were weighed on d 0, 7, 14, and 28 and blood samples were taken for MH leukotoxin titers. Serum samples were collected on d 0 and 28 for BHV-1 titers. For statistical analyses, data were analyzed using the PROC MIXED procedure of SAS. Statistical significance was determined at P ≤ 0.05, with tendencies at 0.05 < P ≤ 0.1. There was an overall treatment effect for MH serum antibody titers with BV Once and BN + BV vaccinated calves exhibiting decreased MH serum titers compared with calves vaccinated with BS GOLD, P5 + PRE, and IF3 + One Shot (P = 0.0457). There was a treatment by day interaction for BHV-1 titers (P = 0.0336). On d 28, BHV-1 serum titers were greatest in BS GOLD and BN + BV vaccinated calves, least in calves that received IF3 + One Shot vaccines, and intermediate for BV Once vaccinated calves. Morbidity and average daily gain did not differ between treatments (P > 0.27) throughout the 28-d study period.

PSIV-A-8 Effects of meal frequency on heart rate in horses

Abstract In humans, meal size has been shown to affect heart function with meal ingestion being associated with an increase in heart rate (HR) and cardiac output lasting significantly longer when larger meals are consumed. In horses, HR spikes at the sight of feed due to anticipation, but no studies have specifically evaluated the effect of meal frequency or size on HR. Heart rate has also been used as a measure both positive and negative stress. Domesticated horses are often meal fed, with small frequent meals requiring more labor than large infrequent meals. Fewer larger meals may have negative welfare implications for a grazing species. As part of a larger project investigating the effects of meal frequency on the behavior and metabolism of horses, the objective of this study was to evaluate equine HR in response to feeding frequencies commonly practiced in the field [once (1x), twice (2x), or thrice (3x) per day]. Feeding times were at 0800 (1x, 2x, and 3x), 1300 (3x), and 1800 (2x and 3x) h. The 12 adult clinically healthy horses [average ± SD; 14 ± 6 yr and 572 ± 32 kg body weight (BW)] were separated into two equal groups before completing a 14-d acclimation period to the diet during which they were fed 2x. The diet was provided at 2% BW on a dry matter (DM) basis (1.55% BW grass hay in a slow feed hay net plus 0.45% BW complementary fortified feed). During the study the same diet was fed but the meal frequency, and therefore meal size, differed between the treatments. The order of treatments, lasting 1 wk each, was decided at random for each group. On d 6 of each treatment HR was measured using individual H10 Polar HR monitors, which recorded every second from 0700 to 1900 h yielding 1,514,799 data points. During this time the aisleways housing the stalled horses were blocked off to minimize exposure to human presence other than at feeding time(s). After removing outliers, the mode was calculated for HR of each horse, which was considered to be the resting HR for that horse and ranged from 31 to 46 beats/min. The percentage of data above, below, or at the mode was calculated for each horse over the 12 h period and evaluated using Chi Square tests for statistical significance. The proportion of HR values above, below, or at the mode differed between treatments (P = 0.02). When fed 1x, 69 ± 14% of the HR readings were above the mode on average, as compared with 42 ± 18% and 44 ± 18% for 2x and 3x, respectively. These results suggest that the increase in HR was more than anticipatory and that there may be sustained stress when horses are fed at fewer frequency, such as once daily.

257 Estimating bone mineral replenishment following phosphorus deficiency in growing pigs

Abstract Available phosphorus (avP) is essential for bone health and strength in growing pigs. Our objective was to evaluate growth performance and replenishment of bone mineral in avP deficient pigs when fed diets adequate in avP. Over a 42-d test period, mixed sex pigs [n = 48; initial body weight (BW) = 13.1 ± 0.7 kg], were randomly assigned to one of three dietary treatments consisting of two experimental periods. In period 1(28 d), 8 pens/trt (2 pigs/pen) were fed diets formulated to 0.36, 0.17 and 0.08% avP and at a total calcium to avP ratio of 2.91, 3.15 or 6.40, respectively, representing adequate, marginally deficient, or deficient avP. In period 2 (14 d), marginally deficient and deficient pigs were then fed diets formulated to be above requirement at 0.54% avP and a 2.19 Ca:avP, while the adequate pigs staying on the same period 1 diet (n = 8 pens/trt). Pig BW and pen feed disappearance were recorded during each phase to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency gain to feed (G:F). At the end of each period, 1 pig per pen was removed to assess whole body, femur, and 3rd metatarsal bone mineral content (BMC) and bone mineral density (BMD) via dual-energy X-ray absorptiometry (DXA). All data were analyzed with pen as the experimental unit and the fixed effect of diet within each period. At the end of period 1, adequate avP and marginally deficient fed pigs were heavier than the deficient avP fed pigs (41.9 and 41.2 vs 33.4 kg, respectively, P < 0.001). Consequently, ADG and ADFI were significantly reduced as avP decreased (P < 0.001). Compared with the adequate avP pigs, whole body BMD was reduced by 22% and 65% in marginal and deficient avP pigs (P < 0.001), respectively. At the end of period 2, adequate, marginal, and deficient avP pigs weighed 53.4, 53.2 vs 43.1 kg (P < 0.001), respectively. Within period 2, ADG, ADFI, and G:F did not differ. However, adequate avP fed pigs continued to have a greater body BMD compared with marginal and deficient avP pigs (0.928, 0.850, and 0.732 g/cm2; P < 0.001), respectively. Whole body BMD and BMC increased from period 1 to peiod 2, resulting in period 2 whole body BMC accretion rates of 2.31, 23.28, and 9.30 g/d (P < 0.007) for deficient, marginal, and adequate diets, respectively. In conclusion, pigs fed marginally deficient avP diets reduced body BMD while pigs fed deficient avP diets reduced body BMD and performance. Following this period of deficiency, marginal deficient avP pigs recovered growth and BMC within 14 d when fed increased dietary avP. However, compared with adequate avP fed pigs, the deficient pigs only partially recovered BMC and BW within the 14-d replenishment period.

243 Effects of body weight change in pre-production Duroc boars on semen collection training, semen production parameters, and longevity in a commercial boar stud

Abstract Our objective was to assess the effects of percentage body weight (BW) change in developing Duroc boars on semen collection training, semen production parameters, and longevity in a commercial boar stud. Retrospectively, 164 boars were divided into one of three groups based on their percentage BW change from arrival to the boar stud until the end of the 42-d isolation period. The one-third of boars that had the greatest percentage of BW change during the isolation period gained 36.1% to 10.1% (TOP). The middle one-third of boars that were intermediate in percentage BW change during isolation gained 9.7% to 2.6% (MIDDLE). The final group consisted of one-third of boars that either minimally gained or lost BW (2.5% to -9.5% change in BW; BOTTOM). During the isolation period boars in the TOP group lost the least amount of backfat (indicated by ultrasound or caliper score; P < 0.05), while boars in the BOTTOM group lost the most backfat. Average boar age at the time of successfully becoming a working boar (successfully mounting the collection dummy and producing an ejaculate with a motility ≥ 70% and percent normal morphology ≥ 65%) and the proportion of boars that were successful at become working boars did not differ between groups (P > 0.05). Among working boars, the concentration of sperm in ejaculates tended to differ (P = 0.0740) between groups (Table). Boars in the TOP group had a greater percentage of sperm with normal morphology (P = 0.0337) than boars in the BOTTOM group. There was a group by production week interaction (P < 0.0001) for semen ejaculate volume, total number of sperm, and total number of sperm with normal morphology. Boars in the TOP and MIDDLE groups produced more total sperm and normal sperm than the BOTTOM group from wk 8 to 20 of being working boars, resulting in production of considerably more doses for artificial insemination. During their time as working boars, removal from the stud by cull or death was not different between groups (P >0.05). There was also no difference (P > 0.05) between groups on the average week of removal from the stud, with each group having boars most frequently removed at wk 22 of production. While percentage BW change during isolation did not affect semen collection training and longevity in the stud, the increase in production of total normal sperm in the TOP and MIDDLE groups compared with the BOTTOM group could have substantial economic benefits for boar stud. Our study suggests that managing boars individually to ensure they stay in a positive metabolic state is ideal for optimal semen production at a boar stud.

187 Polyphenols as a partial replacement for vitamin E in nursery pig diets

Abstract A total of 300 pigs [241×600; DNA, Columbus, NE; initial body weight (BW) = 6.0 ± 0.01 kg] were used in a 42-d trial to determine the effects of vitamin E levels and partially replacing vitamin E with a polyphenol (Cabanin CSD, R2 Argo, Denmark) on growth performance, complete blood count (CBC), serum thiobarbituric acid reactive substances (TBARS), serum superoxide dismutase (SOD), and serum cytokines. Sixty pens of pigs were weighed and allotted to 1 of 5 dietary treatments in a completely randomized design with 12 pens/treatment with 5 pigs/pen. A control treatment was formulated to provide 15 IU/kg of vitamin E. This control treatment was then used as a base for 3 replacement strategies to determine the effects of replacing an additional 60 IU/kg of vitamin E above baseline with polyphenol in diets containing a basal level of vitamin E (15 IU/kg). First, an additional 60 IU/kg of vitamin E was added for a total of 75 IU/kg of vitamin E. Second, 50% of the additional vitamin E (30 IU/kg) was replaced with the vitamin E equivalency of polyphenol. Third, all 60 IU/kg of the additional vitamin E was replaced with the equivalency of polyphenol. To evaluate whether there are negative effects of feeding nursery pigs a high level of polyphenol, a fifth treatment was formulated to provide 575 IU/kg of vitamin E equivalence with 75 IU/kg from vitamin E and 500 IU/kg from polyphenol. Whole blood and serum samples were collected on d 10 and 42, and pig BW and feed disappearance measured on d 10, 21, 31, 38, and 42. For growth performance, there was no evidence of differences (P > 0.10) in average daily gain (ADG) and average daily feed intake (ADFI) as vitamin E equivalence increased or between replacement strategies throughout the entire 42-d experimental period (Table). From d 10 to 21, increasing vitamin E equivalence from 15 to 75 IU/kg increased (quadratic, P = 0.086) gain to feed ratio (G:F) with no further increase at 575 IU/kg. From d 21 to 42 and overall, there was a tendency for increased (linear, P < 0.10) G:F as the vitamin E equivalence increased. There was a vitamin E equivalence × day interaction (P = 0.050) for serum SOD activity where increasing vitamin E equivalence increased (linear, P < 0.05) serum SOD activity on d 42, but not on d 10 (P > 0.10). For serum TBARS, there was no evidence of differences (P > 0.10) between treatments, vitamin E equivalence levels, or day, and negligible differences in complete blood count parameters and serum cytokines. In summary, increasing vitamin E equivalence tended to increase G:F, which may be related to the improved SOD activity. These data indicate that when diets contain requirement levels of vitamin E, additional vitamin E equivalency can be provided by polyphenol or vitamin E to achieve similar levels of performance.

71 Growth and reproductive responses to gonadotropins in gilts fed on ad libitum (AD) or restricted (RS) bases using an electronic sow feeder (ESF)

Abstract Previous work in our laboratory showed that age at puberty was similar for replacement gilts fed on either RS or AD bases using an ESF. The objective of this investigation was to determine the effects of feeding (RS vs. AD) on growth and sexual development in gilts treated with gonadotropins (P.G. 600; Merck Animal Health, Rahway, NJ). Prepubertal crossbred gilts were moved at 150 d of age to an open pen with an ESF (ACCUTEAM, Osborne Industries, Osborne, KS) located in an environmentally controlled, curtain-sided building. A 10-d training period to the ESF ensued, during which all gilts received feed on AD basis. At 160 d of age, gilts were allocated to treatments in a 2-by-2 factorial design. Treatments were RS plus P.G. 600 (n = 9), RS without P.G. 600 (n = 10), AD plus P.G. 600 (n = 8), or AD without P.G. 600 (n = 8). The P.G. 600 treatment was administered at 170 d of age. Estrus detection commenced at d 171 and continued for 32 d. Puberty onset was not affected by feeding basis (P = 0.85), P.G. 600 (P = 0.56), or feeding basis x P.G. 600 (P = 0.25). Time in estrus and body weight (BW) at puberty were also similar between treatments. Estrous cycle length was shorter (P < 0.01, 20.0 vs. 21.2 d, SE = 0.54) for RS compared with AD gilts. Bodyweights throughout the trial were similar between treatments but were affected by day (P < 0.01), typical of growing gilts. Feed disappearance was affected by feeding basis (P < 0.01, 2.30 vs. 4.54 kg/d, SE = 0.03 for RS and AD, respectively) and day (P < 0.01). For pubertal gilts, gain to feed ratio was improved (P < 0.01, 0.29 vs. 0.21, SE = 0.03) in RS compared with AD gilts, but average daily gain (ADG) was greater in AD gilts (P = 0.05, 0.75 vs 0.88 kg/d, SE = 0.09). Data were normalized for the 20-d period before second estrus. Feed disappearance was affected by feeding basis x day, and decreased in AD, but not RS gilts, as gilts approached estrus (P = 0.04). Feeding visits (P < 0.01) and feeding visit duration (P < 0.01) were affected by feeding basis with AD gilts consuming feed more frequently and spending less time eating per visit. In this study, RS feeding did not delay, and P.G. 600 did not hasten puberty onset. Moreover, RS gilts grew slower but were more feed efficient than AD gilts. We continue to find that employment of an ESF may support current estrus detection methods by monitoring feeding behavior in AD-fed gilts.

87 Evaluating the effects of an amino acid-formulated diet on ruminal fermentation in vitro

Abstract The objective was to determine the effect of an amino acid-formulated diet on ruminal fermentation in vitro. While most amino acid-formulated diets focus on improving the amino acid composition of rumen undegradable protein, additional benefits to microbial fermentation within the rumen are unknown. The experiment was a completely randomized design with a factorial treatment arrangement (2 donor diets and 2 substrates). Four ruminally cannulated steers were fed one of two donor diets: control (CON; 55% dry rolled corn, 20% corn silage, 15% dry distiller’s grain, and 10% supplement) and amino acid-formulated (AAF; 51% dry rolled corn, 15% corn silage, 14% dry distillers grain, 10% heat-treated soybean meal, and 10% supplement). After a 30-d diet adaptation period, rumen fluid was collected and pooled by donor diet for the in vitro fermentation. Additionally, two different substrates were used to represent each donor diet. Flasks contained 2.5 g dry matter (DM) of substrate and 150 mL of rumen fluid mixture (2 McDougall’s buffer:1 rumen fluid). Treatments were evaluated in triplicate flasks in two replicated runs for a total of six observations per treatment. Four sealed Ankom F57 bags were filled with 0.25 g DM of substrate each to facilitate measuring in vitro DM disappearance (IVDMD). Flasks were incubated at 39°C with sample aliquots collected at h 0, 4, 8, 12, and 24 to determine pH, ammonia, and volatile fatty acids (VFA). Data were analyzed using the MIXED procedure of SAS 9.4 with a repeated measures analysis. Ammonia, pH, and VFA were analyzed with effects of donor diet, substrate, time, and all interactions. A treatment by hour interaction was detected (P < 0.01) for pH; fluid from steers fed CON was greater than AAF at h 4, 8, 12, and 24. A treatment by hour interaction was also detected (P = 0.02) for ammonia; fluid from steers fed CON was greater than AAF at h 24, but was not different at other time points. Total VFA was affected by hour (P < 0.01) as it increased over time, but substrate did not have an effect (P = 0.21). A treatment by hour interaction (P = 0.06) tended to be observed for molar proportions of acetate as AAF and CON were similar at h 0 but AAF was increasing greater than CON over time. A treatment by hour interaction was observed (P = 0.01) for molar proportions of propionate; at h 4 at 8, CON was greater than AAF. No effect (P ≥ 0.32) of donor diet, substrate or their interaction were observed on IVDMD. Overall, an amino acid-formulated diet for cannulated steers did impact ruminal fermentation in vitro, mostly altering molar proportions of volatile fatty acids and ammonia release from protein degradation.

88 Ruminal degradation profiles of dry matter, organic matter, and crude protein of finishing diets with different levels of inclusion of dried distiller’s grains plus solubles and soybean meal

Abstract The objective of this study was to estimate the ruminal degradation profile of dry matter (DM), organic matter (OM), and crude protein (CP) in concentrate-based diets with different levels of inclusion of dried distiller’s grains plus solubles (DDGS) and soybean meal (SBM). Red Angus steers [n = 4; body weight (BW) = 360 ± 9 kg] with ruminal, duodenal, and ileal cannulas, were used in a 4 × 4 latin square. Diets (TMR) consisted of dry-rolled corn (70%), hay (10%), liquid supplement (5%), and test ingredients (15%). Treatments were (DM basis): 1) 15.0% DDGS (CON); SBM in replacement of 50% of DDGS (SBM50); SBM in replacement of 75% of DDGS (SBM75), and SBM in replacement of 100% of DDGS (SBM100). Each period lasted 18-d, consisting of a 7-d diet adaptation followed by an 11-d collection period. An in situ ruminal incubation of each TMR was performed from d 8 to 11 of each period. Ingredients were weighed separately, maintaining their proportion in the TMR. Air-dried TMR sample (6 g, 2 mm grind) was ruminally incubated in a nylon bag (Ankom, 10 × 20 cm) using the same steer from the in vivo study. Samples were incubated for 0, 2, 4, 8, 16, 24, 48, and 72 h. The number of bags varied as a function of the incubation time to guarantee enough residual samples after incubation, where more bags per sample were incubated for the longer incubation times relative to the shorter incubation times (72 and 48 h, n = 5; 24 h, n = 4; 16 h, n = 3; 8 h and 4 h, n = 2; 2 h and 0 h, n = 1). DM, OM, and CP degradation were estimated by using the following model: Yt = a + b × (1 − e(−kd × t)), The NLIN procedure of SAS 9.4 was used and restricted and full models were compared by a likelihood ratio test. Rumen degradable protein (RDP) of each TMR was calculated as follows: RDP = a + b + [kd/(kd + kp)], where kp was 0.05 h−1). There were no differences (P ≥ 0.47) on the fractions a, b, and kd, or RDP (55%) between treatments for DM, OM, and CP. According to our analysis, approximately 13 h of incubation is necessary to accurately estimate the RDP content of the TMR. The NASEM (2016) adopts 35 and 75% of RDP for DDGS and SBM, respectively, based on fixed incubation time of 16 h. Most studies have evaluated degradation profiles of individual feed and not TMR; however, animals are fed complete diets, made up by feedstuff that vary in physical characteristics, nutrient composition, and consequently RDP. In this study, the similar degradation profiles between diets suggest that RDP of complete diets differs from that of individually assayed ingredients.

80 Substitution of dried distiller’s grains with soybean meal on beef cattle diets: Effects on ruminal ammonia and volatile fatty acid concentrations

Abstract The objective of this study was to evaluate the effects of substitution of dried distiller grains with soybean meal on beef cattle diets in ruminal ammonia and volatile fatty acid (VFA) concentrations. Red Angus steers [n = 4; body weight (BW) = 360 ± 9 kg] with ruminal, duodenal, and ileal cannulas, were used in a 4 × 4 latin square. Diets (TMR) consisted of dry-rolled corn (70%), hay (10%), liquid supplement (5%), and test ingredients (15%). Treatments were [dry matter (DM) basis]: 1) 15.0% DDGS (CON); SBM in replacement of 50% of DDGS (SBM50); SBM in replacement of 75% of DDGS (SBM75), and SBM in replacement of 100% of DDGS (SBM100). Each period lasted 18-d, consisting of a 7-d diet adaptation followed by an 11-d collection period. Rumen fluid was collected at -2, 0, 2, 4, 6, 8, 10, and 12 h post-feeding on d 16. Ruminal digesta was strained through two layers of cheesecloth and two 10-mL aliquots of ruminal fluid were collected and stored at −20°C until further analysis of ammonia and VFA concentrations. Data were analyzed as repeated measures using the MIXED procedure of SAS with treatment, sampling time, and their interaction as fixed effects, and animal and period as random effects. No treatment by day interactions (P ≥ 0.84) were observed for ammonia or VFA. Ammonia concentrations were greater (P ≤ 0.01) for SBM75 compared with SBM100 and CON, with intermediate values observed for SBM50 (Table 1). Moreover, ammonia was greater (P ≤ 0.01) at 0h compared with 6, 8, and 12h post-feeding. Acetate was greater (P ≤ 0.01) for SBM75 and SBM100 compared with CON and SBM50. Concentrations of propionate were greatest (P ≤ 0.01) for SBM100 and least for CON, with SBM50 and SBM75 being intermediate. Further, propionate was greater (P ≤ 0.01) at 16h compared with 0 and 2 h post-feeding, with all other times being intermediate. Isobutyrate was less (P ≤ 0.01) for CON than all other treatments, and greater concentrations (P ≤ 0.01) were observed at -2 compared with 14 and 16 h post-feeding. Butyrate was greatest (P ≤ 0.01) in SBM75, followed by CON and SBM50; SBM50 was similar to SBM100. Butyrate concentrations were similar -2 and 0 h post feeding, which were less (P ≤ 0.01) than all other times. Isovalerate was greater (P ≤ 0.01) for CON than SBM50 and SBM75, and similar to SBM100. Valerate was greatest (P ≤ 0.01) for SBM75 and SBM100 followed by SBM 50 and CON which had the least valerate value. Overall, our results show that SBM75 resulted in greater concentrations of ammonia, acetate, propionate, butyrate, isobutyrate, and valerate compared with CON. These data suggest that 75% substitution of DDGS with SBM has the potential to optimize microbial fermentation. To complement these results, we are currently evaluating rumen protein degradation profiles and amino acid flow to small intestine.

PSV-9 Effects of increasing amounts of high-oleic or conventional soybeans in diets fed to mid-lactation dairy cows on measures of dry matter intake and lactation

Abstract The objective of the study was to determine effects of increasing amounts of conventional (CONV) or high-oleic (HO) soybean in diets fed to mid-lactation dairy cows on dry matter intake (DMI) and performance. Rumen and duodenally cannulated cows (n = 8) were split into two groups and placed in a split-plot design. The whole plot factor was type of soybean (CONV vs. HO) and was provided to cows in a crossover arrangement so that each cow was provided both types of soybeans throughout the experiment. The subplot factor was amount of soybeans (0, 4, 8, 12%). Each group of cows receiving the same type of soybean were placed in a 4 x 4 Latin square with treatment sequences balanced for carryover effects. Diets were formulated to contain 18.5% crude protein and to slightly exceed requirements for ruminally degradable protein. Additions of soybeans replaced soybean meal and soybean hulls so that diets provided similar amounts of soy-based protein and fiber. During the last 4 d of each 14-d period, spot samples of feed, orts, and milk were collected together with measures of milk production and feed intake. Data were analyzed using the MIXED procedure of SAS. There were no interactions of soybean type and amount on lactation or DMI except for measures of milkfat, milk energy concentration and milkfat yield. Increasing amounts of HO resulted in a quadratic response in milkfat and energy concentration together with measures of milkfat yield. Specifically, these measures were greater (P ≤ 0.02) when cows were fed diets containing 4 and 8% HO compared with diets containing 0 or 12% HO; increasing amounts of CONV had no impact (P ≥ 0.32) on milkfat and energy concentration or milkfat yield. Measures of milk yield were not affected by type or amount of soybean (P ≥ 0.54), but measures of energy corrected milk yield (ECM) tended to respond differently to increasing amounts of soybean from either CONV or HO (P = 0.07). Interestingly, ECM responded quadratically (P = 0.02) to increasing amounts of HO but not to increasing amounts of CONV (P ≥ 0.58). Overall, however, ECM tended (P = 0.06) to be slightly greater with HO compared with CONV (42.5 vs. 41.1 kg/d). Yet, DMI was also greater (P ≤ 0.01) with HO compared with CONV (26.6 vs. 24.4 kg/d). Differences in DMI, therefore, resulted in a tendency (P = 0.07) for greater efficiency of ECM production when cows were fed CONV vs. HO. Overall, treatments had no effect on measures of milk protein, urea-nitrogen, solids-not-fat or lactose concentrations or yields. These data seem to indicate that performance responses among lactating cows to increasing amounts of HO are dynamic but that responses to CONV are not.

No Effect of High Eating Frequency Compared with Low Eating Frequency on Appetite and Inflammation Biomarkers: Results from a Randomized Crossover Clinical Trial

BackgroundEating frequency (EF) focuses on the total number of eating occasions per day and may influence metabolic health. ObjectivesWe sought to examine the effect of high compared with low EF on appetite regulation and inflammatory biomarkers among healthy adults. MethodsData are from a randomized, crossover trial (the Frequency of Eating and Satiety Hormones study). Participants (n = 50) completed 2 isocaloric 21-d study periods of low EF (3 eating occasions/d) and high EF (6 eating occasions/d) in random order with a 14-d washout period in between. Participants were free-living and consumed their own food, using study-directed, structured meal plans with identical foods and total energy in both study periods. On days 1 and 21 of each EF period, fasting blood was collected during in-person clinic visits to assess plasma concentrations of ghrelin, leptin, adiponectin, and high-sensitivity C-reactive protein (hs-CRP). Linear mixed models with EF, diet sequence, and period as fixed effects and participant as random effect were used to estimate the intervention effect. Interaction effects between EF and body fat percentage were examined. ResultsAmong the 50 participants who completed the trial, 39 (78%) were women, 30 (60%) were Non-Hispanic White, and 40 (80%) had a body mass index of <25 kg/m2, and the mean age was 32.1 y. The differences between high and low EF in fasting ghrelin (geometric mean difference: 17.76 ng/mL; P = 0.60), leptin (geometric mean difference: 2.09 ng/mL; P = 0.14), adiponectin (geometric mean difference: 381.7 ng/mL; P = 0.32), and hs-CRP (geometric mean difference: −0.018 mg/dL; P = 0.08) were not statistically significant. No significant interaction was observed between EF and body fat percentage on appetite regulation and inflammatory biomarkers. ConclusionsNo differences was observed in fasting ghrelin, leptin, adiponectin, and hs-CRP comparing high and low EF. Future studies are needed to understand the physiology of EF and appetite as they relate to metabolic health.This trial was registered at clinicaltrials.gov as NCT02392897.

Effects of sanitary conditions with lipopolysaccharide injection and dietary valine supplementation on growth performance, immune response, bacterial profile, and microbial metabolites in weaned pigs

ABSTRACT This study investigated the effects of dietary L-valine (Val) supplementation and sanitary conditions with lipopolysaccharide injection on growth performance, immune response, and intestinal bacterial profiles and metabolites in weaned pigs. Thirty-two weaned pigs (6.98 ± 0.47 kg) were randomly assigned to treatments in a 2 × 2 factorial arrangement based on dietary Val levels and sanitary conditions (low or high). The pigs were fed either a basal diet containing the standard levels of Val suggested by (NRC), (2012) or a basal diet supplemented with 0.1% L-Val. A room designated as a high sanitary room was washed weekly, whereas the designated low sanitary room was not washed throughout the experiment and 5 kg of manure from the nursery pig barn was spread on the pen floors on day 1. All data were analysed using a mixed procedure of SAS, with the individual pen as the experimental unit. The pigs raised in low sanitary conditions exhibited a lower (p < 0.05) average daily gain, average daily feed intake, and gain-to-feed ratio and a higher (p < 0.05) incidence of diarrhoea than those raised in high sanitary conditions during the 14-d experimental period. The pigs in the low sanitary group also had a lower (p < 0.05) concentration of butyrate in the jejunum and a higher (p < 0.05) concentration of NH3-N in the colon than those in the high sanitary group. Dietary Val supplementation was reduced (p < 0.05) plasma interleukin (IL)-1β and IL-1 receptor antagonist concentrations as well as isovalerate and NH3-N concentrations in the colon, regardless of sanitary conditions. Interactions between dietary Val supplementation and sanitary conditions were observed in the abundances of mRNA-encoding β-defensins 113, 125 and 129 (p < 0.05). In conclusion, dietary Val supplementation beneficially modulates inflammatory responses and microbial metabolites regardless of sanitary conditions while transcriptional levels of β-defensins are regulated by dietary Val supplementation in a manner dependent on housing hygiene conditions.

The effectiveness of a virtual fencing technology to allocate pasture and herd cows to the milking shed

Virtual fencing technology provides an opportunity to rethink the management of intensive grazing systems in general, yet most studies have used products developed and applied to more extensive livestock systems. This research aimed to assess the application of a virtual fencing technology developed for the intensive pastoral dairy industry. The Halter system uses 2 primary cues, sound and vibration, and one aversive secondary cue, a low energy electrical pulse, to confine cows to a pasture allocation and remotely herd cows. Two groups of 40 mid-lactation multiparous dairy cows were studied (Bos taurus, predominantly Friesian and Friesian × Jersey, parity 1-8). Cows were milked twice per day and provided 9 kg pasture DM/day in a 24-h allocation, supplemented with 7 kg silage and 6 kg grain DM/day. Training to the Halter system occurred over 10 d after which cows were managed with the technology for a further 28 d. The type and time of cues delivered was recorded by each collar and communicated via a base-station to cloud data storage. Cows took less than a day to start responding to the sound cues delivered while held on a pasture allocation and were moving to the milking parlor without human intervention by d 4 of training. On training d 1, at least 60% of sound cues resulted in an electrical pulse. Across training d 2-10, 6.4% of sound cues resulted in a pulse. After the 10-d training period, 2.6% of sound cues resulted in a pulse. During the management period, 90% of cows spent ≤1.7 min/d beyond the virtual fence, received ≤ 0.71 pulse/d in the paddock and received ≤ 1 pulse/d during virtual herding to the parlor. By the final week of the management period, 50% of cows received zero pulses/week in the paddock and 35% received zero pulses/week during virtual herding. The number of pulses delivered per day and the pulse:sound cue ratio was lower in this study than that previously reported using other virtual fencing technologies. We conclude that the Halter technology is successful at containing lactating dairy cows in an intensive grazing system as well as at remotely herding animals to the milking parlor.

Responses of selected plasma metabolites to a 2-day nutritional challenge of goats divergently selected for functional longevity

Understanding the extent to which genetics × environment plays a role in shaping individual strategies to environmental challenges is of considerable interest for future selection of more resilient animals. Accordingly, the objective of this study was to evaluate the metabolic responses to a nutritional challenge of goats divergently selected for functional longevity based on plasma metabolites and the repeatability of these responses across 2 experimental farms and years. We carried out 6 different experimental trials from years 2018 to 2022 (4 trials on site Bourges (2018-21) and 2 trials (2021-22) on site Grignon) in which 267 first kidding goats, daughters of Alpine bucks divergently selected for functional longevity, longevity plus (n = 137), and longevity minus (n = 130), were exposed to a 2-d nutritional challenge in early lactation. The experiments consisted of a 5 or 7-d control period (pre-challenge) on a standard lactation diet followed by a 2-d nutritional challenge with straw-only feeding and then a 7 or 10-d recovery period on a standard lactation diet, for site Bourges and Grignon, respectively. During the challenge plasma metabolite composition was recorded daily. Linear mixed-effects models were used to analyze all traits, considering the individual as a random effect and the 2x2 treatments (i.e., genetic line and year nested in site) and litter size as fixed effects. The linear mixed-effects model using a piecewise arrangement was used to analyze the response/recovery profiles to the nutritional challenge. Random parameters estimated for each individual, using the mixed-effects models without the fixed effects of genetic line, were used in a Sparse Partial Least Square Discriminant Analysis (sPLS-DA) to compare the goat metabolism response to the challenge on a multivariate scale. The plasma metabolites, glucose, β-hydroxybutyrate (BHB), and nonesterified fatty acids (NEFA), and urea concentrations responded to the 2-d nutritional challenge. Selection for functional longevity did not affect plasma glucose, NEFA, BHB, and urea response/recoveries to a 2-d nutritional challenge. However, site, trial, and litter size affected these responses. Moreover, the plasma metabolites seem not to fully recover to prechallenge levels after the recovery phase. The sPLS-DA analysis did not discriminate between the 2 longevity lines. We observed meaningful between-individuals' variability in plasma BHB, especially on the prechallenge and rate of response and rate of recovery from the 2-d nutritional challenge (CV = 26.2%, 36.1%, and 41.2%, repeatability = 0.749, 0.322, and 0.741, respectively). Plasma NEFA recovery from challenge also demonstrated high between-individuals' variability (CV = 16.4%, repeatability = 0.323). Selection for functional longevity did not affect plasma metabolites responses to a 2-d nutritional challenge in dairy goats. Plasma NEFA and BHB response/recovery presented high between-individuals' variability, indicating individual adaptative characteristics to nutritional challenges not related to the environmental conditions but to inherent individual characteristics.

Diurnal shifts of rumen fermentation and microbial profiles revealed circadian rhythms of rumen bacteria, methanogens, and protozoa under high-grain and high-forage diets

In this study, we investigated how the composition and population of rumen microbiota shifted in response to diurnal oscillations under 2 different diets (high grain vs high forage). Five multiparous Holstein dairy cows with similar body weight, days in milk, and parity were enrolled in this study. The cows were fed high-grain (HG) diet for 21 d and then shifted to high-forage (HF) diet in the next 21 d (7-d washout and 14-d experimental period). During the experimental period, dry matter intake (DMI) and rumination activity were recorded, and rumen fluid was collected 8 times post-feeding every 6 h during the last 2 d of each dietary feeding period. The rumen microbial (bacterial, archaeal, and protozoal) population and composition were assessed using quantitative PCR and amplicon sequencing respectively. The daily dynamic of measurements was assessed using cosinor model. The associations between microbial taxa and rumen fermentation profiles were assessed using linear mixed model, in which the cows were termed as random intercept effects. Daily rhythmicity was observed for DMI, rumination activity, and rumen fermentation profiles under both diets. Additionally, rumination time, rumen pH, and acetate/propionate ratio had a higher mesor (the average level of diurnal fluctuations) under HF diet than in HG diet. The amplitude (the distance between the peak and mesor) of DMI, rumen pH, ammonia nitrogen, and total volatile acid concentration were higher under HG diet than in HF diet. Although no significant diurnal oscillation was observed in rumen microbial population, the relative abundance of 14 bacterial genera, one protozoal genus, and 2 archaeal species had significant diurnal oscillations under both HF and HG diets. Among them, the bacterial genera Ruminococcus and Colidextribacter had time at peak of rhythm within 0 to12 h after feeding, which were also negatively associated with the rumen acetate/propionate ratio. The bacterial genus Rikenellaceae_RC9_gut_group had time at peak of rhythm within 12 to 24 h after feeding, which was also positively associated with the rumen acetate/propionate ratio. Our study illustrated the daily dynamic on the rumen microbiota population and composition under different diets, and also identified the feeding-responsive rumen microbiota, highlighting a more targeted approach is needed to manipulate rumen microbiota.