Finisher Diets Research Articles

Changes in the intestinal microbiota of broiler chicken induced by dietary supplementation of the diatomite-bentonite mixture

BackgroundDiatomite is a source of biologically available silicon but in feed industry its insecticide and anti-caking properties have been also widely recognized. The aim of the study was to evaluate the effect of dietary diatomite-bentonite mixture (DBM) supplementation on the quantitative and qualitative composition of the bacterial microbiome of the broiler chicken gut. The trial was carried out on 960 Ross 308 broiler chickens divided into 2 experimental groups throughout the entire rearing period lasting 6 weeks. The birds were fed complete granulated diets without (group C) or with DBM (group E) in an amount of 1% from the 11 day of life. Two nutritionally balanced diets were used, tailored to the age of the broilers: a grower diet (from day 11 to 34) and a finisher diet (from day 35 to 42 of life).ResultsDiatomite used in a mixture with bentonite significantly altered the microbiome. Restricting the description to species that comprise a minimum of 1% of all analyzed sequences, 36 species in group E (with diatomite) and 30 species in group C (without diatomite) were selected. Several bacteria species were identified in intestinal contents of chickens for the first time. Thirteen species occurred only in group E: Agathobaculum butyriciproducens, Anaerobutyricum hallii, Anaerobutyricum soehngenii, Blautia producta ATCC 27,340 = DSM 2950, Gordonibacter pamelaeae 7-10-1-b, Helicobacter pullorum NCTC 12,824, Lactobacillus crispatus, L. helveticus DSM 20,075 = CGMCC 1.1877, Mucispirillum schaedleri, Phascolarctobacterium faecium, Phocaeicola coprocola DSM 17,136, P. massiliensis, and Ruthenibacterium lactatiformans.ConclusionsThe findings highlight the intricate and potentially consequential relationship between diet, specifically diatomite-bentonite mixture supplementation, and gut microbiota composition.

Gut response to the dietary supplementation with sodium butyrate in broiler chickens: morphology and microbiota composition and predictive functional groups

This study investigated the effects of Na-butyrate supplementation (0 vs. 150 vs. 300 mg/kg) and the dietary fat level (7.7% vs. 6.7% in the grower diet; 8.9% vs. 7.7% in the finisher diet) in 900 broiler chickens of both sexes, out of which 108 were used to evaluate gut morphology and immune response on jejunum tissues at 14, 28, and 40 days of age, and caecal microbiota composition according to 16S rRNA gene multi-amplicon sequencing and the predictive functional bacteria groups at 40 d of age. Villi height and crypts depth changed only according to the age of chickens. Microbiota analysis revealed Firmicutes as the dominant phylum, with sex-related differences in microbial diversity indices (Simpson index, p < .05). The Na-butyrate dietary supplementation and dietary fat level affected the abundance of specific bacterial genera related with short fatty acids production, without changes in the bacterial metabolic pathways. Under the good health conditions of chickens in the present trial, Na-butyrate supplementation and the dietary fat level did not modify the overall gut equilibrium of broiler chickens.

Optimising compensatory growth in pastoral beef production systems: insights into feed efficiency, body composition, carcass characteristics and meat quality attributes.

Exploitation of compensatory growth (CG) is a widely practised management strategy in beef production, especially under pastoral conditions due to its potential to reduce feed costs. The aim of this experiment was to evaluate the effect of nutritional restriction during backgrounding in Angus steers slaughtered at either similar age and/or similar BW on feed efficiency, body composition, carcass characteristics and meat quality attributes under either a forage or feedlot-based finishing diet. Eighty steers (BW: 444±39kg, age: 18±1months) were blocked and randomly assigned within block to either an optimal (0.6-0.7kg/day) or suboptimal (0.3-0.4kg/day) growth rate, during 97days of backgrounding. Following, half of the steers in each group were finished on a forage diet while the other half were finished on feedlot-based diet. Half of the steers in each treatment were then slaughtered at similar age (24months), whilst all remaining steers were slaughtered at similar BW (∼620kg). Two extra slaughters were done with other representative steers on day 0 and day 97, to provide baseline parameters for carcass and non-carcass measurements. During the backgrounding period, optimal steers gained more than suboptimal (P<0.01), resulting in higher BW and hot carcass weight (HCW; P<0.01). During the finishing period, the suboptimal group increased BW gain (P<0.01) and displayed an improved feed conversion ratio (FCR; P<0.01). Differences (P<0.01) in BW and HCW remained between the treatments when slaughtered at a similar age. When the steers were slaughtered at similar BW, after additional days of finishing for the suboptimal groups, no differences (P>0.05) in backgrounding treatment on HCW, carcass grading, body composition or FCR for the entire period (backgrounding and finishing) were apparent. Indeed, no differences (P>0.05) by backgrounding growth strategy were observed for any meat quality variables assessed using instrumental or sensory evaluations. During the finishing period, feedlot steers had increased (P<0.01) BW and HCW gains, improved (P<0.05) FCR and carcass grading, and had higher (P<0.05) HCW compared to forage finished steers. However, no differences (P>0.05) were observed for any meat quality variables assessed by finishing system. Overall, exploiting CG within pasture-based beef cattle production systems improves growth rate and FCR in both forage and feedlot finishing. Suboptimal backgrounded steers required additional days on feed to achieve similar BW to their contemporaries. Nevertheless, at similar BW, there were no residual differences in body composition, FCR during the entire period, meat tenderness or overall meat liking because of the backgrounding conditions.

Effect of 3-Nitrooxypropanol Combined with Different Feed Additives on Growth Performance, Carcass Traits, Enteric Methane Emissions, and Physiological Responses in Feedlot Beef Cattle Fed a High-Concentrate Finishing Diet.

The objective of this study was to evaluate the effect of 3-nitrooxypropanol (3-NOP) in combination with different feed additives on growth performance, carcass traits, meat quality, enteric methane (CH4) emissions, nutrient intake and digestibility, and blood parameters in feedlot beef cattle. In experiment (Exp.) 1, one hundred sixty-eight Nellore bulls (initial bodyweight (BW) 410 ± 8 kg) were allocated to 24 pens in a completely randomized block design. In Exp. 2, thirty Nellore bulls (initial BW 410 ± 3 kg) were allocated to a collective pen as one group, and treatments were allocated in a completely randomized design. Three treatments were applied: Control (CTL): monensin sodium (26 mg/kg of dry matter, DM); M3NOP: CTL with 3-NOP (100 mg/kg DM); and Combo: 3-NOP (100 mg/kg DM) with essential oils (100 mg/kg DM), 25-Hydroxy-Vitamin-D3 (0.10 mg/kg DM), organic chromium (4 mg/kg DM), and zinc (60 mg/kg DM). In Exp. 1, bulls in the Combo group had greater (p < 0.01) dry matter intake (DMI) at d 28 compared to the CTL and M3NOP groups. During d 0 to 102, bulls' final BW and average daily gain (ADG) were greater (p ≤ 0.03) for the Combo group compared to the CTL. The bulls in the Combo and M3NOP groups had better (p < 0.01) feed conversion (FC) and feed efficiency (FE) compared to the CTL. Hot carcass weight (HCW), carcass ADG, and carcass yield were greater (p ≤ 0.05) for bulls in the Combo group compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.01) dressing compared to the M3NOP group. Combo bulls had better (p = 0.02) biological efficiency compared to the CTL. The bulls in the Combo group had lower (p < 0.01) carcass pH compared to the CTL and M3NOP groups. In Exp. 2, bulls in the Combo group had greater (p = 0.04) DMI at d 28 compared to the CTL and had greater (p < 0.01) DMI at d 102 compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.04) HCW compared to the CTL and M3NOP groups and carcass ADG was greater (p = 0.04) for bulls in the Combo group compared to the M3NOP group. The bulls in the Combo and M3NOP groups had lower (p < 0.01) CH4 production (38.8%, g/d), yield (41.1%, g/kg DMI), and intensity (40.8%, g/kg carcass ADG) and higher (p < 0.01) H2 emissions (291%, g/d) compared to the CTL. Combo bulls had lower (p < 0.01) blood glucose and insulin, and higher nutrient intake and digestibility (p ≤ 0.05) compared to the CTL and M3NOP groups. Combining 3-NOP with different feed additives improved FC and FE, and reduced enteric CH4 emissions. Combo treatment improved growth performance, carcass traits, nutrient intake, and digestibility, and improved glucose and insulin responses in feedlot beef cattle on a high-concentrate finishing diet.

Exploring the Linkage Between Ruminal Microbial Communities on Postweaning and Finishing Diets and Their Relation to Residual Feed Intake in Beef Cattle.

Feed efficiency significantly impacts the economics of beef production and is influenced by biological and environmental factors. The rumen microbiota plays a crucial role in efficiency, with studies increasingly focused on its relationship with different rearing systems. This study analyzed 324 rumen samples from bulls and steers categorized as high and low efficiency based on residual feed intake. The animals were fed two diets (postweaning and finishing) and rumen samples were sequenced using a reduced representation sequencing (RRS) based approach. The results indicated that diet significantly affected microbial diversity and abundance. In postweaning diets, Actinomycetota, particularly Bifidobacterium, were prevalent, aiding carbohydrate fermentation. In contrast, Acetoanaerobium was identified in finishing diets, likely contributing to acetate production. Additionally, Bacteroides and Butyrivibrio were abundant during postweaning, known for fiber degradation and volatile fatty acid production. Notably, Prevotella and Fibrobacter succinogenes were associated with high feed intake and nutrient utilization, indicating their potential as microbial biomarkers. However, alpha diversity indices showed no significant relationship with feed efficiency, suggesting that diversity alone may not adequately reflect the complexity of feed efficiency phenotypes. These findings highlight the importance of diet and microbial interactions on feed efficiency and suggest further research to explore these microbial contributions to precision feeding strategies.

Effects of cashew nutshell extract inclusion into a high-grain finishing diet on methane emissions, nutrient digestibility, and ruminal fermentation in beef steers.

By 2050, the U.S. beef industry must produce an extra 40 million tons of beef to satisfy the global demand. Such an increase in inventory will undoubtedly enhance methane (CH4) production from livestock, which should be reduced by over 20%. The addition of plant secondary metabolites, such as anacardic acid present in cashew nutshell extract (CNSE), has shown promising results in reducing CH4 yield, although its effects seemed to be diet dependent. This study evaluated the addition of CNSE to a high-grain diet (85:15 Grain: forage) on in vivo CH4 emissions, nutrients digestibility, performance, feeding behavior, and ruminal fermentation parameters of beef steers. Sixteen Angus crossbred steers [599 ± 40kg of bodyweight (BW)] and six ruminally cannulated crossbred steers (490 ± 51kg of BW) were utilized in a crossover design with 2 experimental periods of 56 d each, composed by 14 d of adaptation, 35 d of measurement, and 7 d of washout. Following adaptation, steers were sorted by BW, and assigned to receive no additive (CON) or CNSE at 5g/steer/d. Data were analyzed using the MIXED procedure of SAS. Inclusion of CNSE increased (P < 0.05) propionate concentration and molar proportion (MP; mol/100mol), tended to decrease acetate MP (P = 0.10), reduced the acetate: propionate (A:P) ratio (P = 0.05), and MP of branched chain volatile fatty acids (P < 0.01). Neither in vitro organic matter digestibility nor in vitro CH4 yield were affected by CNSE inclusion (P > 0.05). Steers receiving CNSE exhibited greater (P < 0.05) final BW, dry matter intake (DMI), and average daily gain (ADG) but lesser (P < 0.05) in vivo CH4 emission rate (g/d), yield (g/kg of DMI), and intensity (g/kg of ADG). Meal length, bunk visit duration, and apparent total tract digestibility of DM increased (P < 0.05) after CNSE addition. Considering CNSE-supplemented steers spent more time in the feedbunk and exhibited higher DMI, CH4 mitigation was unlikely associated with intake reduction. The addition of CNSE to a high-grain diet in beef steers demonstrated significant improvements in animal performance and reduced CH4 emissions, as the result of shifts in ruminal fermentation patterns, favoring propionate instead acetate concentration, leading to a reduction in the A:P ratio. CNSE shows promise as a strategy to enhance beef industry sustainability.

Anatomical and carcass traits, partition of fat deposits, and meat quality in culled adult goats finished with high-fat diet

The objective of this study was to examine the impact of a high-fat finishing diet on the in vivo performance, anatomical and carcass characteristics, and meat quality of adult culled goats. Over a period of 28 days leading up to slaughter, eighteen adult culled goats were subjected to a finishing diet provided in quantities sufficient to meet 3.0 times the nutritional requirements of adult non-dairy maintenance goats. The female goats were divided into two groups: one fed with the baseline diet without fat supplementation (n = 9) and the other fed a diet concentrated supplemented with whole full-fat linseed (n = 9). The diets varied in fat content (2.8% vs. 8.4% DM). The high-fat group exhibited a higher dry matter intake compared to the control group (+37%), along with elevated plasma cholesterol and triglyceride levels. The control group experienced a significant decrease in daily weight gain between the second and final week of the finishing period (-70%), in contrast to the increase observed in the high-fat group (+59%). At slaughter, no differences were noted between the groups in anatomical and carcass characteristics. Additionally, no differences were found between the diets regarding proximate composition, pH, yellow color component, and lightness of loin. The high-fat group exhibited a higher redness of loin. The inclusion of high-fat levels in finishing diets for culled adult goats allows for increased feed intake and performance but does not appear to affect carcass or meat quality.

Effect of Long-Term Supplementation of AZOMITE (Hydrated Sodium Calcium Aluminosilicate) in Finishing Diets on Growth Performance, Dietary Energy, and Carcass Yield of Hairy Lambs.

The aim of this study was to evaluate growth performance, dietary energy utilization, and carcass characteristics (carcass weight, dressing percentage, and visceral organ mass) of feedlot lambs fed different levels of AZOMITE (AZO), a source of volcanic clay composed of hydrated sodium calcium aluminosilicate, the same as that included in a finishing diet. For this reason, 36 Pelibuey × Katahdin crossbred intact male lambs (18.81 ± 3.04 kg initial weight) were used in a feeding trial lasting 81 d. Lambs were grouped by initial weight and assigned within six weight groupings to 18 pens in a randomized complete block design. Diets, offered ad libitum, were corn-based finishing diets with an 88:12 concentrate-to-forage ratio supplemented as follows: 1) no AZO inclusion (CTRL), 2) AZO inclusion at a 0.75% level (0.75AZO) in diet dry matter, 3) AZO inclusion at a 1.50% level (1.5AZO) in diet dry matter. Cracked corn was replaced by AZO. After the feeding trial was finished, lambs were slaughtered and carcass weight was registered and dressing percentage was calculated. The data were analyzed as a randomized complete block design, with the pen as the experimental unit. Water consumption and dry matter intake were not affected (p ≥ 0.11) by supplemental AZO. The incorporation of AZO into the diet increased gain efficiency and observed dietary net energy (NE), being maximal with 0.75% AZO inclusion (quadratic effect, p = 0.02). The observed-to-expected dietary NE in the control group was as anticipated (1.00) according to the estimated energy based on the ingredient composition in diet, while in the 0.75AZO group, the observed dietary energy was 6% above expected, indicating a greater efficiency in energy utilization destined to growth (quadratic effect, p = 0.006). Lambs that were fed the AZO treatment showed an improvement (linear effect, p = 0.04) in hot carcass weight (HCW), and tended (linear effect, p = 0.06) to improve dressing percentage (DP) as AZO was increased in the diet. Visceral organ mass was not affected by the treatments. It is concluded that AZOMITE clay can be included up to 1.5% in finishing diets for lambs without negative effects on the intake of water and feed. Lambs that received diets supplemented with 0.75% AZO showed greater improvements in feed efficiency and dietary energy utilization, but an inclusion of 1.50% resulted in greater improvements to HCW and DP. This is the first report regarding the effects of AZO supplementation in the dietary energy utilization of fattening hairy lambs. Further research about the effects of AZO supplementation on ruminal and total tract digestion, carcass and meat quality, and the health of lambs is needed in order to more deeply understand the effects of AZO on its productivity performance.

Performance and sensory properties of broilers fed finisher diet supplemented with onion skin extract

Performance and sensory properties of broilers fed finisher diet supplemented with onion skin extract

The Relationship between the Infrared Eye Temperature of Beef Cattle and Associated Biological Responses at High Environmental Temperatures.

Cattle in regions with high ambient temperatures are at risk of heat stress. Early detection is important to allow action to be taken to minimise the risks to cattle exposed to thermal stress. This study aimed to investigate the impact of heat stress on IRT-Eye temperature and its association with the behavioural and physiological responses of heat-stressed Angus steers (n = 24) on finisher and or substituted diets. Overall, 2 cohorts of 12 Angus steers were individually housed in a climate-controlled facility to examine responses to heat stress when fed on a standard finisher diet, based on a high percentage of cereal grains, and on a substituted diet in which 8% of the grains were replaced by an isoenergetic amount of lucerne hay. Exposing feedlot cattle to hot environmental conditions increased IRT-Eye temperature, which had a strong association with behaviour and physiology. There was no evidence of differences between the different dietary cohorts. The cattle with increased IRT-Eye temperature showed stress-related responses, including a downward-facing head, ears directed backwards, and other indicators of heat stress such as increased panting, standing, and increased rumen temperature. The strong association of IRT-Eye temperature with stress-related behaviours, as well as with rumen temperature and panting behaviour, highlights the potential for IRT-Eye to be utilised as a non-invasive tool to assess cattle responses in hot conditions.

PSXII-26 The influence of protein supplementation in beef cows during early lactation on growth performance, carcass characteristic and meat quality of progeny

Abstract At 11 ± 4 d of lactation, 30 multiparous Angus cows [body weight (BW) = 476 ± 17 kg, body condition score (BCS) = 4.5 ± 0.3) were stratified by BW and allotted in 6 pens (5 cows/pen). During 75 d of experiment, all pens received ad libitum low quality hay (Panicum italicum; 54.7% TDN, 6.1% CP DM basis) and were randomly assigned to one of two treatments: 1) PS; cows received ad libitum 30% CP supplement including an intake limiter component (Controlmix, Nutralmix SRL, Argentina), or 2) NS; cows were not supplemented. After the experimental period, dams and their calves (PS: 7 males and 8 females; NS: 8 males and 7 females) were managed on improved pastures as a single group until weaning at 213 d of age. After weaning, heifer and steer calves were reared on improved pastures until 448 d of age, then placed into a feedlot with a finishing diet during 73 d until slaughter. Pens were considered the experimental unit and data were analyzed using the PROC MIXED of SAS, considering treatment and sex as a fixed effects and pen as a random effect. Overage dry matter intake (DMI) of hay was not affected by treatments (P &amp;gt; 0.10), and DMI of supplement in PS cows was 4.4 kgּ cow-1ּ d-1. Milk production was greater in PS than NS cows (PS: 5.3, NS: 3.6 kgּ cow-1ּ d-1; P &amp;lt; 0.01). Progeny from PS cows increased BW at weaning (PS: 180, NS: 141 kg; P &amp;lt; 0.01), BW at initial feedlot phase (PS: 300, NS: 252 kg; P = 0.01) and final BW (PS: 415, NS: 354 kg; P = 0.01). After slaughter, progeny from PS cows tended to have increased dressing percentage (PS: 59.0, NS: 58.1%; P = 0.09), had an increased hot carcass weight (PS: 227, NS: 191 kg; P &amp;lt; 0.01), and increased Longissimus muscle (LM) area (PS: 68.5, NS: 60.1 cm2; P = 0.02), while rib fat thickness was not affected by treatments (PS: 7.8, NS: 7.6 mm; P = 0.68). There was no effect of protein supplementation on color (L*, a*, b*) and pH of LM at 24 h postmortem (P &amp;gt; 0.10). In addition, moisture, ether extract and shear force of LM after 4 d of aging were similar between treatments (P &amp;gt; 0.10). There was no treatment × sex interaction for any variables (P &amp;gt; 0.10). This study showed that protein supplementation during early lactation improved growth performance and carcass quality, but did not result in enhanced meat quality of progeny.

PSIII-14 Cotton gin byproduct in growing diets for beef steers

Abstract The purpose of this study was to evaluate the performance of beef cattle during the stocker phase when fed different concentrations of cotton gin byproduct (CGB). Angus steers [n = 50; initial body weight (BW) = 349 ± 66 kg) were stratified by BW and grouped in slatted floor pens (10 steers/pen). Steers were assigned randomly within pen (2 per pen) to one of five diets containing 0, 10, 20, 30, and 40% CGB (dry matter basis). Diets were balanced for protein and energy, and the steers were fed for 84 d. Steers were weighed on d -1, 0, 28, 56, 83, and 84 for the stocker phase with d -1 and 0, 83 and 84 averaged to give start and end BW. Following the growing period, steers were switched to the same finishing diet and fed for an additional 55 d prior to being transported to PA for harvest and carcass data collection. Data were analyzed using procMIXED of SASv9.4 to determine the significance of linear, quadratic, cubic, and quartic trends. During the growing phase, dry matter intake increased linearly (P = 0.0017) with 10.16, 11.23, 11.59, 11.86, and 11.96 kg/d for 0, 10, 20, 30, and 40% CGB, respectively. Average daily gain tended to increase (P = 0.0631) with a cubic trend, increasing with the first addition of CGB, declining at the intermediate levels, and then increasing again at the 40% level (1.34, 1.54, 1.36, 1.39, and 1.52 kg/d for 0, 10, 20, 30, and 40% CGB, respectively). Feed efficiency showed a similar cubic trend (P = 0.10) with 0.133, 0.138, 0.119, 0.117, and 0.128 for 0, 10, 20, 30, and 40% CGB, respectively. Within the finishing phase, average daily gain was significant (P = 0.026) as a quadratic trend with 1.54, 1.25, 1.18, 1.20, and 1.33 kg/d for 0, 10, 20, 30, and 40% CGB, respectively. Diets did not differ (P &amp;gt; 0.10) for dry matter intake (10.08 kg/d), feed conversion (8.31), or feed efficiency (0.130). Treatment did not influence (P &amp;gt; 0.10) marbling or other carcass measurements. Data suggest CGB supported good animal gains with only minor impact on feed intake and feed efficiency for stocker steers up to an inclusion rate of 40%.

PSX-20 The inclusion of a tannin-based product evaluated in a typical feedlot diet under tropical conditions increases the molar proportion of propionate in a dual-flow continuous-culture system

Abstract The objective of the present study was to evaluate increasing levels of a tannin-based product and a monensin (positive control; unique dose) using a dual-flow continuous-culture system. Diets were randomly assigned to ten fermenters in a replicated 5 x 5 Latin square with three, 10-d experimental periods consisting of 7 d for adaptation and 3 d for sample collection. Four different levels were tested independently, resulting in 5 treatments: tannin at levels of 0 (negative control), 0.07, 0.14, and 0.21 (% of DM of the total diet) and monensin as positive control at 28 mg/kg DM. The tannin-based product was a specific blend of tannin and saponins, composed of quebracho and chestnut tannin extracts, SilvaFeed-BX). Diets were prepared as concentrate mixes that were combined with sugarcane bagasse, corn grain, dry distillers grain, citrus pulp, peanut meal, and urea. Liquid and solid flow rates were adjusted to 10 and 5.0%/h, respectively. Samples were collected for digestibility, ruminal fermentation, and microbial growth. The basal diet consisted of a typical finishing diet for beef cattle (16:84 roughage:concentrate ratio). All results were assessed for residual normality and variance homogeneity. All variables were fitted through generalized mixed models (GLIMMIX procedure) and compared by using Tukey test (multiple comparison) and polynomial regressions (tannin concentrations, which were analyzed for linear and quadratic responses. Partial data were presented in the table below. Total VFA concentration, molar proportion of butyrate, and total Branched-chain VFA were not affected by treatments (P &amp;gt; 0.05). Molar proportion of acetate of the tannin-based product at 0.07 % of DM tended to be decreased compared with all other treatments. Molar proportion of propionate increased quadratically (P = 0.05) reaching the peak at the level of 0.07 % of DM, which were greater than monensin treatment. In conclusion, our results indicate that a smaller dose of a tannin-based product (0.07 g/kg of DM) might manipulate ruminal fermentation by increasing molar proportion of propionate in typical feedlot diet fed under tropical conditions. This is important from an energetic standpoint for the animal host, since propionate is the precursor of glucose synthesis in ruminants.

PSIII-7 Effects of Saccharomyces cerevisiae fermentation product on total tract digestibility, ruminal fermentation, and plasma metabolome of beef steers fed a finishing diet

Abstract Saccharomyces cerevisiae fermentation product (SCFP) has been widely studied; however, its mode of action on high-concentrate diets has not been fully elucidated. This study evaluated the impact of SCFP on total tract digestibility, fecal excretions of N, P, Zn, and Cu, rumen fermentation, and plasma metabolome of finishing beef steers. Ruminally cannulated Holstein steers [n = 8; body weight (BW) = 580 ± 29.2 kg] were enrolled in a crossover design study with 25-d treatment periods and a 24-d washout period. Steers were fed ad libitum a finishing diet consisting of 20% corn silage and 80% concentrate (on DM basis). Steers were blocked based on initial BW and randomly assigned to two treatments in period 1 and switched to the other treatment in period 2. The treatments were CON (Control, basal diet only) and SCFP (basal diet top-dressed with 12 gּ steer-1ּ ּ d-1 SCFP, NaturSafe, Diamond V, Cedar Rapids, IA). Feed and fecal samples were collected during d 22 to 24 for determination of digestibility. Blood was collected before morning feeding on d 25. Plasma samples were analyzed for metabolome with liquid chromatography-mass spectrometry (LC-MS). Rumen fluid was collected via the rumen cannula at 0, 4, 8, and 12 h post-morning feeding on d 25 and analyzed for pH, volatile fatty acids (VFA), and NH3-N. Performance and ruminal fermentation characteristics data were analyzed using the GLIMMIX procedure of SAS 9.4. Metabolomic data analysis was conducted with Metaboanalyst 6.0. Supplementing steers with SCFP reduced DMI (10.6 vs. 11.4 kg/d, P = 0.05) without affecting (P &amp;gt; 0.05) average daily gain, feed efficiency, and digestibility of organic matter, crude protein, and neutral detergent fiber. Treatment did not affect (P &amp;gt; 0.10) fecal excretions of N, P, Cu, and Zn. Feeding SCFP increased ruminal pH (6.29 vs. 6.01, P = 0.01), numerically reduced concentrations of NH3-N (5.01 vs 6.25 mM, P = 0.16), and total VFA (96.8 vs. 102.5 mM, P = 0.15). SCFP also reduced the ruminal molar proportion of butyrate (11.2 vs. 12.8 molar %, P = 0.01) and tended to increase those of isobutyrate (1.03 vs. 0.90, molar %, P = 0.06) and isovalerate (2.62 vs. 2.29, molar %, P = 0.10). Supplementation of SCFP enriched (P ≤ 0.05) purine metabolism, amino sugar and nucleotide sugar metabolism, and lysine degradation pathways in the plasma. Additionally, tryptophan metabolism and pyrimidine metabolism pathways tended to be enriched (0.05 &amp;lt; P ≤ 0.10) by SCFP. Our findings indicate that feeding SCFP improved the ruminal pH of finishing cattle, which may be beneficial for preventing subacute ruminal acidosis in feedlot cattle. Additionally, SCFP enriched several important plasma nitrogen metabolism pathways, potentially associated with microbial nitrogen metabolism in the rumen, warranting further research.

PSVII-5 Heat shock protein 70 gene expression and association with morphometric and heat tolerance traits in three plumage colors of Noiler chicken exposed to acute heat stress

Abstract Heat stress is one of the most difficult climatic conditions chickens faces and is a direct result of climate change. It is important to research poultry thermotolerance because it may help find genetic lines resistant to heat stress. This study investigated the influence of plumage colors on heat shock protein 70 gene expression in Noiler chickens exposed to acute heat stress. Noiler is a dual-purpose breed developed for smallholder poultry production in Nigeria. A total of 150 birds of three plumage colors (black, brown and white) of mixed sexes were used for the experiment. The birds were raised in deep litter house separated into six groups of 25 birds each and fed with commercial broiler diets from 0-8 wk and broiler finisher diets from 8 to 12 wk old. The birds were shared into treatments in 3 x 2 x 2 factorial arrangements with 3 plumage colors (black, brown, white), two temperature regimens (Control/thermoneutral, Heat stress) and sex of birds (male, female). The heat stressed birds were exposed to 41oC for 8 h from 0600 h to 1400 h for 7 d while control group maintained a thermoneutral temperature range of 30 oC to 32 oC for the same period. At 13 wk old, two birds were selected per treatment, slaughtered and the spleen removed and stored in RNA later for heat shock protein (HSP) 70 gene expression. Data collected were analyzed with Microsoft excel code for fold expression of HSP70 gene while GLM procedure in SAS was used to determine difference in expression of gene. The relative expression of HSP70 brown plumage was greater, upregulated compared with black and white. White plumage birds in control/thermoneutral group were significantly greater in HSP70 expression than other plumage colors and heat stressed birds. Association of HSP70 delta threshold cycle (DCT) values with morphometric and heat tolerance traits were investigated (Figure 1). High negative correlations emerged between HSP70DCT expression and body weight (-0.65), body temperature (-0.73) with moderate positive correlation for rectal temperature (0.55) in black birds (Table 1). HSP70 DCT positively correlated with body weight (0.70), breast/leg circumferences but negatively with wing length, suggesting reduced surface area during heat stress and a supportive role in maintaining protein integrity (Figure 2). For white Noiler birds, HSP70DCT associated negatively with body weight (-0.94) and positively with rectal temperature during heat stress (Table 2). Thermoneutral birds were positively correlated with heat tolerance traits except temperature while heat stressed birds showed low positive correlation with respiratory and pulse rates and very low positive relationship with body and rectal temperatures (Table 4). Sex-based differences emerged, with potential compromise between HSP70-mediated growth/composition in males versus muscle maintenance in females, although leg length/circumference showed shared developmental regulation (Figure 3, Table 3). These findings highlight HSP70’s versatile roles in systemic heat tolerance mechanisms influenced by plumage color, temperature regime and sex.

PSXIII-22 Intake, digestibility, and ruminal parameters of Nellore cattle fed with amylolytic and fibrolytic enzymes in feedlot

Abstract This study was carried out to evaluate the use of dietary exogenous enzyme (ENZ) products with amylolytic and fibrolytic activity on nutrient intake, digestibility, and ruminal volatile fatty acids production (VFA) of Nellore cattle in feedlot. Rumen-cannulated Nellore steers [n = 10; body weight (BW) = 543 kg ± 28.6 BW] were distributed in a replicated Latin-square design (5 × 5) in individual pens. The treatments consisted of a negative control (CON; without ENZ); Amylase (AML; Amaize, Alltech, 0.5 g/kg of DM); Xylanase (FBL, Fibrozyme, Alltech, 0.9 g/kg of DM); Half dose (HD; AML 0.25 g/kg of diet DM and FBL 0.45 g/kg of diet DM); and Full dose (FD; AML 0.5 g/kg of diet DM and FBL 0.90 g/kg of diet DM; Table 1). The experimental period lasted 19 d (14 d of adaptation and 5 d of collection). Between d 15 and 18, total fecal collection was performed and on d 19 rumen fluid was collected at 0, 4, 8, 12, and 16 h post-feeding for ammonia, VFA, and pH determination. The data were analyzed as orthogonal contrasts using SAS: (C1) CON vs. ENZ, (C2) AML vs. FBL, (C3) HD vs. FD, and (C4) AML + FBL vs. HD + FD. There were no C1 differences for nutrient digestibility, total VFA, or ruminal pH (P &amp;gt; 0.10). However, a tendency effect in neutral detergent fiber (NDF) intake (P = 0.065) was observed, where animals fed ENZ had reduced values compared with animals kept in CON group. In the same way, ENZ reduced ther extract (EE) intake (P = 0.023), ruminal ammonia (P &amp;lt; 0.001), and isovalerate proportion (P = 0.080) as well as increased proportion of acetate (P &amp;lt; 0.001), valerate (P &amp;lt; 0.001) and acetate:propionate ratio (P = 0.030). No differences were observed in nutrient intake between AML and FBL (P &amp;gt; 0.10), but AML had greater organic matter (OM) digestibility (P = 0.097) and ruminal valerate (P = 0.039) and decreased butyrate proportion (P = 0.068). Animals that received FD had greater values of dry matter (DM; P = 0.009) and OM (P &amp;lt; 0.001) digestibility than HD. The enzyme combination resulted in greater DM (P = 0.026), OM (P = 0.062), crude protein (P = 0.018), EE (P = 0.063) and NDF (P = 0.040) intake and reduced OM digestibility (P = 0.008) compared with AML and FBL alone. The addition of exogenous enzymes in feedlot diets affected nutrient utilization and ruminal fermentation of Nellore cattle fed a feedlot finishing diet.

124 Effects of Saccharomyces cerevisiae and dietary type offered to beef cattle on intake, feeding behavior, nutrient digestibility, and ruminal fermentation

Abstract The effects of live yeast and diet type offered to beef steers on intake, feeding behavior, nutrient digestibility, and ruminal fermentation profile were evaluated. Ruminally cannulated beef steers [n = 8; body weight (BW) = 550 ± 20 kg] were used in a duplicated 4 × 4 Latin square design following a 2 × 2 factorial arrangement of treatments: A) presence of live-yeast [Saccharomyces cerevisiae (CNCM I-1077), at 1 × 1010 CFUּ animal-1ּ d-1]; and B) diet type [steam-flaked corn-based grower or finisher diets (ad libitum intake)]. Live yeast was delivered with gel-capsules (0.25 g, as is) twice daily via ruminal-cannula. Four, 35 d periods were used. Feed refusal was subtracted from offered (dry matter basis) to calculate feed intake (DMI). The 24 h feeding behavior assessment was conducted on d 31 by trained personnel (time spent eating, ruminating, chewing, drinking, resting, and meal size/number). A 5-d fecal collection (twice daily) was used for the digestibility assessment. Ruminal pH was continuously measured (7 d, intra-ruminal Dascor wireless data loggers). Ruminal ammonia-N and volatile fatty acids (VFA) were analyzed at 0, 2, 4, 8, 16, and 23 h on d 35. The GLIMMIX procedure of SAS was used with animals as the experimental unit. No live yeast × diet interactions (P ≥ 0.17) were observed. Intake was not affected (P = 0.83) by live yeast, while steers offered the grower diet consumed more (P ≤ 0.01) NDF, ADF, and hemicellulose compared with the finisher diet. Live yeast increased (P ≤ 0.02) the dietary NDF, ADF, and hemicellulose digestibility of the grower diet by 13.7, 12.8, and 14.6%, and on the finisher diet by 6.7, 9, and 6.4%, respectively. Live yeast did not affect (P ≥ 0.23) major feeding behavior activities measured. Steers offered grower diet spent more time (P ≤ 0.01) on each meal, ruminating, eating, and chewing and less time (P &amp;lt; 0.01) resting. Live yeast did not affect (P ≥ 0.81) ruminal pH variables measured. Steers offered the grower diet had a greater (P &amp;lt; 0.01) ruminal pH pattern compared with the finisher diet. The ruminal ammonia-N and volatile fatty acids were not affected (P ≥ 0.16) by live yeast, while steers offered the finisher diet had a greater (P ≤ 0.01) total VFA and propionate molar proportion, while a lower (P ≤ 0.01) ammonia-N and acetate molar proportion compared with the grower diet. Regardless of the diet type, live yeast improved digestibility of fiber fractions, while dry matter intake was unaffected. Grower diets were more prone to stimulate feeding behavior activities than finisher, while live yeast seemed to not affect such variables. Expected effects of diet type on ruminal fermentation were ratified, while live yeast inclusion did not affect the ruminal fermentation variables evaluated.

125 Could yeast derivatives change beef cattle water intake in different scenarios?

Abstract Adequate water intake is linked to greater dry matter intake, heat loss, and productivity. To measure the water intake of beef cattle reared in groups, two experiments were carried out in Brazil (South East/Middle East) using water throughs coupled with scales (Intergado, Betim, Brazil) and RFID individual identification systems, allowing the recording of individual water intake of animals. In experiment 1, young bulls (n = 96; 105 d on feed - feedlot) were randomly assigned to four treatments: 1) Control, no yeast derivative; 2) AY – 7 g·animal⁻¹·d⁻¹, Autolyzed Yeast grown on sugarcane molasses (RumenYeast, ICC, Brazil); 3) YM – 3 g·animal⁻¹·d⁻¹, yeast rich in soluble Yeast Metabolites; 4) YB – 5 g·animal⁻¹·d⁻¹, Yeast Blend (live Yeast plus autolyzed Yeast). Diets (adaptation, growing, and finishing) x treatments were treated as fixed effects on the complete randomized design. In experiment 2, backgrounding bull calves (n = 32) reared on grazing and 710 g/d of protein supplements (90 d) were randomly assigned to two treatments: 1) Control, no yeast derivative; 2) AY – 7 g·animal⁻¹·d⁻¹, Autolyzed Yeast (RumenYeast), the means were subjected to ANOVA analyses. In both experiments, additives were inserted into the diet (mineral premix or supplement), animals were the experimental unit, and differences were declared significant at P &amp;lt; 0.05. Yeast derivatives increased (P &amp;lt; 0.05) water intake in both experiments (Figure 1). The average increment in water intake (L·animal⁻¹·d⁻¹ was 13.9%. Interestingly, the increment in relation to control was noted for all yeast derivatives and scenarios covered by the experiments (feedlot adaptation diet, feedlot growing diet, feedlot finishing diet, and grazing system). Until now, there seems to be no literature explanation for our findings. However, these results could help to explain the positive effects of yeast derivatives on rumen pH, protein microbial flow, and thermal stress since greater water intake increases the passage rate of rumen fluid and body heat loss. Statistical correlations may not be understood as a cause-consequence link. However, when dealing with a new question, correlations may give us a path to go on and investigate. Malheiros et al. (2023) noted a negative correlation between water intake and rumen dimethylamine. Autolyzed yeast can strongly decrease the concentration of rumen methylamines in cows facing subacute acidosis (Humer et al., 2018). Niacin metabolism should also be investigated since its supplementation enhances cows’ blood niacin levels and water intake. Yeast derivatives are rich in niacin, and autolyzed yeast supplementation can increase blood niacin and body heat loss during summer (Dias et al., 2018), probably increasing water need. In conclusion, yeast derivatives increased the water intake of beef cattle, and this finding adds to the understanding of how yeast derivatives supplementation benefits ruminants.

PSII-8 The effects of diet and finishing phase on the behavioral time budgets of feedlot cattle

Abstract Feedlot cattle undergo many transitions in diet, social group structure, and environment during the finishing period. Little is known about how their behavior may be altered by these transitions. The objective of our pilot project was to compare the behavior of younger feedlot cattle fed a low-concentrate diet to that of finishing cattle, and to create 24-h time budgets for activity and oral behaviors in these groups. Cattle [n = 20; body weight (BW) = 305 ± 21 kg, mean ± SD] were fed a low-concentrate feedlot diet (60:40, concentrate:forage; ST) and cattle (n = 20; BW = 522 ± 45 kg) received a finishing diet (90:10, concentrate:forage; FI) twice daily. Animals were separated by diet and housed in groups of 10. Trained observers recorded behaviors of each group by live instantaneous recording every 5 min for a continuous 48 h, resulting in 192 h of data collected. We predicted that ST cattle would spend more time eating and ruminating due to the higher forage diet. We also expected that FI animals would rest more and spend less time standing and walking as a result of being more familiar with the environment and their social group structure. We also quantified a wide range of oral behaviors including rumination, grooming and manipulation of non-feed items in the pen. Behaviors were summarized by 24-h period, animal, group, and diet, then averaged by animal, and then averaged again by group (n = 2/diet). Missing values accounted for 3% of the activity data and 11% of the oral behaviors. T-tests revealed that ST cattle ruminated more than FI (352 ± 3 vs. 304 ± 1 min/d, mean ± SE, P = 0.02), but differences between treatments were not detected for time spent eating (196 ± 15 vs. 131 ± 3 min/d), standing (584 ± 13 vs. 588 ± 29 min/d), walking (46 ± 10 vs. 35 ± 5 min/d), or lying (768 ± 16 vs. 772 ± 7 min/d; P ≥ 0.13). When fed the ST diet, cattle spent 5 ± 2 min/d grooming group mates, while FI cattle groomed others for 11 ± 1 min/d, although this was not analyzed statistically because it was rare. Similarly, there were numerical differences in the amount of time spent orally manipulating non-food items (8 ± 3 and 18 ± 1 min/d for ST and FI animals, respectively) that have not been previously described. These results suggest that behavioral differences might be more apparent with larger sample sizes, but with the present experimental design, the predictions were not supported. Nonetheless, these are the first behavioral observations of feedlot cattle and provide a comprehensive time budget of their activity, including a range of oral behaviors over a 48-h period.

133 Effect of feeding two different feed additives (Prime Force and Optipartum C+) on finishing cattle performance and carcass characteristics

Abstract A feedlot study was conducted to evaluate the effect of two feed additives, Prime Force (Furst-McNess Company, Rockford, IL) and Optipartum C+ (AB Vista, Plantation, FL), on finishing cattle performance and carcass characteristics. In this experiment, steers [n = 320; 390 ± 9.5 kg of body weight (BW)] were used and four treatments were evaluated in a total of 32 pens, with 10 steers per pen and 80 steers per treatment. Treatments were arranged in a 2 × 2 factorial and included a control diet with no additives; a diet containing Prime Force targeted at 68 g/steer daily; a diet containing Optipartum C+, targeted at 20 g/steer daily; and a diet containing a combination of both products (68 g/steer Prime Force and 20 g/steer Optipartum C+). Cattle were fed for 151 d, but treatments were imposed the last 67 d before slaughter (i.e., fed control diet to all cattle until d 84). Performance is for the total 151-d feeding period. No interaction between feed additives was observed for performance or carcass traits (P ≥ 0.41), therefore main effects are presented. Feeding Prime Force increased final BW (P &amp;lt; 0.04) when compared with cattle not fed Prime Force. A tendency was observed for greater adjusted final BW (P = 0.06) and ADG (P = 0.08) for cattle fed Prime Force compared with cattle fed no Prime Force. Cattle fed Prime Force had numerically greater intake (P = 0.11) than cattle fed no Prime Force, therefore gain to feed (G:F) was not impacted (P = 0.54). Ribeye area and fat depth were not different (P ≥ 0.17) for cattle fed Prime Force versus cattle that had no Prime Force added to the diet, but marbling was numerically improved (P = 0.11) due to Prime Force. Carcass-adjusted final BW (P = 0.11) was numerically greater for cattle fed Optipartum C+ and ADG tended (P = 0.09) to be greater for cattle fed Optipartum C+ compared with cattle fed no Optipartum C+. Dry matter intake was not different (P = 0.54) for cattle fed Optipartum C+ versus cattle with no Optipartum C+ in the diet, therefore G:F was numerically improved (P = 0.13) by the increase in ADG for cattle fed Optipartum C+. Ribeye area, fat, and marbling were not different (P ≥ 0.30) between cattle fed Optipartum C+ and those that did not receive Optipartum C+ in the diet. Incidence of liver abscesses was not affected by feeding either additive (P = 0.40). Based on results from this study, adding Prime Force to a finishing diet tended to improve BW and ADG compared with cattle not fed Prime Force. Feeding Optipartum C+ tended to increase ADG and improve G:F due to equal DMI when compared with diets with no Optipartum C+ added.