Mixed Models Procedure Of SAS Research Articles

PSXII-28 Physiochemical and nutritional characteristics of the newly developed value-added blended fat stimulated feed product in comparison with commercial protein and energy feeds

Abstract The objectives of this study were to determine physiochemical and nutritional characteristics of the newly developed value-added blended fat stimulated feed product (BFSFP) in comparison with commercial protein and energy feeds. The new value-added BFSFB with three-batch samples (BFSFP1, BFSFP2, BFSFP3) were developed. Barley grain (n = 3) and canola meal samples (n = 3) were obtained from Canadian Feed Research Center. Chemical composition and nutrient profiles were determined using standard feed analysis methods (e.g., AOAC, NRC-energy). The treatment design was a one-way structure. The experimental design was a CRD with feed treatments as a fixed effect. The data were analyzed using the Mixed model procedure of SAS. Tukey’s method was used for multi-treatment comparison. The results showed that compared with commercially available energy-rich and protein-rich feeds, the BFSFP had greater (P < 0.05) ether extract (EE) than both canola meal and barley grain [4.8 vs. 1.0, 1.6 % dry matter (DM), respectively]. It had decreased ash content than canola meal but greater than barley grain (P < 0.05). For protein chemical profiles, the BFSFP had less (P < 0.05) CP (31.0 vs. 41.6, 12.5%DM), SCP (4.9 vs. 9.1, 3.4% DM), and NPN (11.0 vs. 18.2, 9.2% CP) than canola meal but greater than barley grain. The BFSFP had greatest NDICP (2.6 vs. 0.9, 0.4%CP) and ADICP (0.14 vs. 0.30, 0.06%DM) than both canola meal and barley grain. For carbohydrate chemical profiles, the BFSFP had greater (P < 0.05) carbohydrate (58.1 vs. 50.4, 83.7%DM) and starch (4.5 vs. 1.3, 55.9%DM) than canola meal but less than barley grain. The BFSFP had greater (P < 0.05) NDF (42.9 vs. 28.6, 18.9%DM) and hemicellulose (27.7 vs. 10.5, 12.9%DM) than both canola meal and barley grain. The BFSFP had had less (P < 0.05) ADF (12.7 vs. 17.5, 5.7%DM) and ADL (3.0 vs. 8.0, 0.8%DM) than canola meal but greater barley grain. As to energy profle, the BFSFP had no significant difference in NE for lactation when compared with barley grain and canola meal (1.80 vs 1.93 vs. 1.69 Mcal/kg DM, P > 0.05). The BFSFP had similar in NE for growth (1.29 Mcal/kg DM) when compared with canola meal (1.29 vs. 1.20 Mcal/kg DM, P > 0.05) but less than barley (1.29 vs 1.42 Mcal/kg DM, P < 0.05). In conclusion, the newly developed blended fat stimulated feed product differed in physiochemical and nutritional characteristics in comparison with commercially available energy-rich and protein-rich feeds.

PSVIII-6 Effect of adding plant extracted saponin (PES) on accumulative gas production kinetics and methane emission of the prairie blend pelleted feed products in ruminant system

Abstract The objectives of this study were to study the effect of adding plant extracted saponin (PES) as phytochemical feed additive on in vitro accumulative gas production kinetics and methane (CH4) emission of blend pelleted feed products in ruminant system. Four levels of PES (0, 1, 2, 3%) were added to canola meal and pea mixtures with two different ratios (CMP1: 50:50; CMP2: 70:30) which were used to make Prairie blend pellet feed products. The accumulative gas production kinetics and CH4 were determined using in vitro systems. Ruminal fluid for in vitro studies was obtained from rumen fistulated lactation dairy cows. The experimental design was a randomized complete block design with the PES level as a fixed effect and in vitro run with fistulated animals as a random effect. The data were analyzed using Mixed Model Procedure of SAS. Polynomial contract was used to determine linear and quadratic relationship. The results showed that adding PES did not significantly affect the asymptotic production (a) with an average of 104.06 ± 12.38 (SD) mL/g DM, the gas production fractional rate (c) with an average of 1.00 ± 0.90 %/h, the average production at one-half of asymptotic production (AP) with an average 11.26 ± 0.87 mL and lag time with an average of 2.08 ± 0.81 h. As to CH4 emission at different incubation times, the result showed that at short incubation times (2 h, 4 h, 12 h), adding PES showed numerically reduced CH4 from 277 to 1.08 mL/g (at 2 h) and 4.39 to 1.59 mL/g (at 4 h). With increasing PES level, CH4 was significantly linearly reduced (P = 0.019) from 8.31 to 6.30 mL/g at 12h incubation time. At long incubation (24 h), adding PES did not have significant impact on CH4. In conclusion, adding PES at the studied levels to Prairie blend pellet feed products did not significantly affect accumulative gas production kinetics but it had a high potential to decrease CH4 emission at short incubation times.

257 Total degradable and undegradable protein and carbohydrate supply to dairy cows from the newly developed blended fat stimulated feed product in comparison with commercial protein and energy feeds

Abstract The objectives of this study were to determine total rumen degradable and undegradable protein and carbohydrate supply to dairy cows from the newly developed value-added blended fat stimulated feed product (BFSFP) in comparison with commercial protein and energy feeds. The new blended fat stimulated feed products with three-batch samples (BFSFP1, BFSFP2, BFSFP3) were developed. Barley grain samples (n = 3) and canola meal samples (n = 3) were obtained from Canadian Feed Research Center. Total rumen degradable and undegradable protein and carbohydrate supply to dairy cows were determined using the updated Cornell Net Carbohydrate and Protein System. The treatment design was a one-way structure. The experimental design was a CRD with feed treatments as a fixed effect. The data were analyzed using the Mixed model procedure of SAS. Tukey method was used for mean separation. The results showed that compared with commercially available energy-rich and protein-rich feeds, the BFSFP had less (P < 0.05) total degradable protein supply to dairy cows (TRDP: 17.0 vs. 23.9, 7.4%DM) and total undegradable protein supply (TRUP: 13.9 vs. 17.8, 5.1%DM) than canola meal and greater than barley grain. For carbohydrate degradable and undegradable supply to dairy cows, the results showed that the BFSFP had greater (P < 0.05) total degradable carbohydrate supply to dairy cows (TRUC) than canola meal and less than barley grain (TRDC: 26.0 vs. 20.8, 56.6%DM, respectively). The BFSFP had greater total undegradable carbohydrate supply (TRUC) than canola meal and barley grain (supply (TRUC: 30.3 vs. 28.7, 26.6%DM, respectively, P = 0.09).

489 Antibiotic Resistance of cecal Escherichia coli isolates from Lohmann LSL lite pullets and laying hens fed omega-3 fatty acids or yeast bioactives, reared at different spacing allowance

Abstract Poultry diets provide components that alter gut microbiota composition. We investigated antimicrobial resistance (AMR) phenotypes of E. coli isolates from ceca digesta of pullets and hens reared at different spacing allowance (SA) and dietary source of omega-3 fatty acids (N-3 FA) and yeast bioactives (YB) from placement to 17 wk of age (woa). A total of 2,632-day old chicks were placed in cages at two SA (24 cages each): High SA (HSA, 348 cm2/bird; ~50 birds/cage) and Low SA (LSA, 284 cm2/bird; ~68 birds/cage). Birds were fed corn and soybean-based diets (C), C + 3% co-extruded full fat flaxseed and pulse mixture (N-3 FA) and C + 0.05% YB processed with β-1,3-glucan hydrolase. At 4, 16 and 35 woa, ceca samples were collected to isolate E. coli using Chromocult agar. Their susceptibility to 14 antibiotics were determined by automated Sensititre system according to CLSI and CIPARS guidelines to determine their antimicrobial susceptibility profile. Number of antibiotics resistant E. coli isolates were analyzed using general linear mixed model procedure of SAS with diets, SA, sampling age and associated interactions as fixed factors. Cochran-Mantel-Haenszel test was used to determine the relationship between these treatments, and differences between treatments were considered significant at P < 0.05. Out of 428 presumptive E. coli isolated, 153 of 428 isolates (35.7%) were resistant to one antimicrobial class but no resistance against ciprofloxacin, azithromycin and nalidixic acid were detected. The prevalence of antimicrobial resistant E. coli decreased as the birds aged from wk 4–35 (P < 0.05). At wk 4 (P = 0.002) and 16 (P = 0.011), the least prevalence of ampicillin (AMP) resistance was in ceca digesta from N-3 FA-fed birds. At 35 woa, no AMP and cefoxitin (FOX) resistance were detected in birds fed YB (Table 2). At 16 woa, the prevalence of streptomycin resistance was greater in N-3 FA-fed than in YB-fed birds (P = 0.02), which was less than control-fed birds. Of the 428 isolates, 59 (13.8%) were resistant to more than two antimicrobial classes, with most from TIO-FOX-AMP-TET and STR-SULF-TET. At wk-4, SA had a significant effect on multiple resistance spectrum with LSA having the lowest MDR E. coli (P = 0.02) mainly from N-3 FA-fed pullets. This study showed an overall low AMR prevalence which decreases with age of the bird. This study is the first to report that feed additives (N-3 FA or YB) influence the AMR profile of cecal E. coli in pullets and layers. Prevalence of AMP resistance was least in N-3 FA-fed birds, whereas least STEP- and SULF resistance was observed in YB-fed birds. Our next study would help understand the molecular and evolutionary aspect of this resistant E. coli and their potential to cause colibacillosis.

Saponin Extracts Utilization as Dietary Additive in Ruminant Nutrition: A Meta-Analysis of In Vivo Studies.

The present meta-analysis aimed to determine the underlying effects of different saponins extracted from different sources on the production performance, milk yield, digestibility, rumen fermentation, blood metabolites, and nitrogen utilization of ruminants. A total of 26 papers comprising 66 in vivo studies (148 data points of dietary treatments) were evaluated in the present study. The databases were statistically analyzed using the mixed model procedure of SAS, where experiments considered random effects and tannin-related factors were treated as fixed effects. Statistical procedures were then continued in comparing different sources of saponin extract through Mixed Model analysis, where experiments were also random factors and sources of saponin extract were fixed factors. The evidence revealed in the present meta-analysis that saponin supplementation of up to 40 g/kg DM appears to have no detrimental impact on feed intake across ruminant types, suggesting that it does not significantly affect diet palatability. However, the results indicated that there are species-specific responses to saponin supplementation, particularly in relation to palatability and nutrient absorption efficiency, with larger ruminants being better able to tolerate the bitterness induced by saponin extracts. Furthermore, the study found that saponin extracts can influence nutrient digestibility and rumen fermentation dynamics, with different effects observed in large and small ruminants. While some saponin extracts can enhance average daily weight gain and milk yield, others can have adverse effects, highlighting the importance of considering both saponin sources and animal physiological condition when developing nutritional strategies. Additionally, optimization of ruminant production by utilizing saponin extracts is necessary to avoid negative health implications, such as increased blood creatinine levels. Different saponin extracts utilization in ruminant nutrition and environmental management, have a distinct understanding associated to their various bioactive properties. However, among the saponin sources, saponin extracted from Quilaja saponaria is more likely to improve large ruminant production performance while maintaining ruminant health and metabolism, but negatively affect small ruminants. Further research is needed to unravel the intricate effects of different saponin sources on ruminant health and productivity, emphasizing the importance of tailored dietary strategies that consider the unique physiological and metabolic characteristics of the target livestock.

338 A Survey of Mycotoxin Occurrence in Us Corn and Corn By-Product Feed Ingredients from 2018 to 2022 Harvest Years

Abstract The aim of this survey was to compare the occurrence and contamination levels of six major mycotoxin categories found in corn and corn by-product feed ingredients harvested in the United States from 2018 through 2022. Mycotoxins are secondary fungal metabolites that can negatively impact animal health and performance and have been routinely found in a variety of feedstuffs including, but not limited to, cereal grains, by-products, silages, dry hays and pasture grasses. Mycotoxin categories evaluated in this survey included: aflatoxins (AFLA), type A trichothecenes (A-Trich), type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A (OTA). This study includes data from corn samples labeled as 2022 harvest and corn b-product feed ingredients submitted from October 2022 through March 2023 and were analyzed for 17 different metabolites via the Liquid Chromatography with tandem mass spectrometry (LC-MS/MS) method. Samples that tested above the limit of detection for each mycotoxin group were analyzed using the generalized linear mixed model procedure of SAS (SAS 9.4, Cary, NC) using harvest year as a fixed effect. The effect of harvest year on average contamination level for each mycotoxin is presented in Table 1. For 2022 harvest year, 260 corn samples and 66 corn by-product samples have been evaluated to date. Mean B-Trich, ZEN, FUM and AFLA levels (parts per billion, ppb) for corn grain samples were similar in 2022 as previous years (P > 0.05). However, for corn grain samples, FUM prevalence and concentration were numerically greater in 2022 than in 2021 and 2020. In the 66 samples of corn by-products, FUM was found in all the samples (100%) and B-Trich were found in the majority of the samples (97%). Mean concentration of FUM in 2022 corn by-product samples was greater (P < 0.001) compared with 2021. Preliminary results of this survey suggest mycotoxin occurrence and contamination remains similar to previous harvest years except for greater mean FUM concentration levels in corn and corn by-products feed ingredients.

Effects of Overfeeding on the DIGESTIVE Efficiency, VOLUNTARY Physical Activity Levels, and Fecal Characteristics and Microbiota of Adult Cats.

The incidence of feline obesity continues to rise despite it being a preventable disease. There are many risks and health perturbations associated with obesity, with several of those impacting a pet's quality of life, wellness, and longevity. Feline obesity is commonly studied, but most research has been focused on weight loss rather than weight gain. To our knowledge, feline studies have not examined the implications of overfeeding and weight gain on gastrointestinal transit time (GTT) nor the association it has with the fecal microbiota. Therefore, the objective of this study was to determine the effects of overfeeding and weight gain on apparent total tract digestibility (ATTD), GTT, blood hormones, serum metabolites, hematology, fecal microbiota populations, and voluntary physical activity of cats. Eleven lean adult spayed female cats [body weight (BW) = 4.11 ± 0.43kg; body condition score (BCS) = 5.41 ± 0.3; age = 5.22 ± 0.03 y] were used in a longitudinal weight gain study. After a 2-wk baseline phase, cats were allowed to overeat for 18wk. A commercially available complete and balanced diet was fed during the baseline phase to identify intake needed to maintain BW. Cats were then fed the same diet ad libitum to induce weight gain. Fecal samples, blood samples, and voluntary physical activity data were collected at baseline (wk 0) and 6, 12, and 18wk after weight gain. Fecal samples were collected for microbiota analysis, determination of ATTD, and GTT measurement while blood samples were collected for serum chemistry, hematology, and insulin and leptin measurements. Microbiota data were evaluated using QIIME2. All other measures were evaluated statistically using the Mixed Models procedure of SAS using repeated measures analysis, with time effects being the focus. A P<0.05 was considered significant. The ATTD of dry matter (P=0.0061), organic matter (P=0.0130), crude protein (P<0.0001), fat (P=0.0002) and gross energy (P=0.0002) and GTT (P=0.0418) decreased with overfeeding and weight gain. Fecal bacterial alpha diversity measures were unchanged, but fecal bacterial beta diversity was impacted (P<0.05) with overfeeding and weight gain. The relative abundances of 16 bacterial genera, including Bifidobacterium, Collinsella, Erysipelatoclostridium were affected (P<0.05) by overfeeding and weight gain. In conclusion, overfeeding and subsequent weight gain reduced ATTD, reduced GTT, and caused changes to the fecal microbial community of adult cats.

Amino acid digestibility and nitrogen-corrected true metabolizable energy of mildly cooked human-grade vegan dog foods using the precision-fed cecectomized and conventional rooster assays.

The pet food market is constantly changing and adapting to meet the needs and desires of pets and their owners. One trend that has been growing in popularity lately is the feeding of fresh, human-grade foods. Human-grade pet foods contain ingredients that have all been stored, handled, processed, and transported in a manner that complies with regulations set for human food production. While most human-grade pet foods are based on animal-derived ingredients, vegan options also exist. To our knowledge, no in vivo studies have been conducted to analyze the performance of human-grade vegan diets. Therefore, the objective of this study was to investigate the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TME n ) of mildly cooked human-grade vegan dog foods using precision-fed cecectomized rooster and conventional rooster assays. Three commercial dog foods were tested. Two were mildly cooked human-grade vegan dog diets (Bramble Cowbell diet (BC); Bramble roost diet (BR)), while the third was a chicken-based extruded dog diet (chicken and brown rice recipe diet (CT)). Prior to the rooster assays, both mildly cooked diets were lyophilized, and then all three diets were ground. Diets were fed to cecectomized roosters to determine AA digestibility, while conventional roosters were used to determine TME n . All data were analyzed using the mixed models procedure of SAS (version 9.4). The majority of indispensable and dispensable AA across all diets had digestibilities higher than 80%, with a few exceptions (BC: histidine, lysine, threonine, and valine; BR: histidine). The only difference in indispensable AA digestibility among diets was observed with tryptophan, with its digestibility being higher (P = 0.0163) in CT than in BC. TME n values were higher (P = 0.006) in BC and BR (4.55 and 4.66 kcal/g dry matter, respectively) than that in CT (3.99 kcal/g dry matter). The TME n /GE was also higher (P = 0.0193) in BR than in CT. Metabolizable energy (ME) estimates using Atwater factors accurately estimated the energy content of CT, but modified Atwater factors and the predictive equations for ME recommended by the National Research Council underestimated energy content. All calculations underestimated the measured TME n values of BC and BR, with Atwater factors being the closest. Although testing in dogs is required, these data suggest that mildly cooked human-grade vegan dog diets are well-digested. Moreover, TME n data suggest that existing methods and equations underestimate the ME of the mildly cooked human-grade vegan foods tested.

Effects of isochronal induced feed restriction during the transition period on mRNA abundance of the hepatic genes related to lipid metabolism in fat-tailed ewes.

The process of fat mobilization during the transition period (TP) requires deep re-orchestration of the energy indices, and understanding its mechanism has generated considerable interest among the TP-related studies. The present study aims to validate the effect of feed restriction and TP on the mRNA abundance of hepatic genes related to fat metabolism in fat-tailed sheep. Twenty pregnant ewes with the age of 40.8 ± 6.2 (mean ± standard error) month were randomly assigned to control (n = 10) or restriction (n = 10), and investigated from week - 5 to 5 relative to parturition. Control animals received 100% DM during the trial. Restriction animals received 100% DM through weeks - 5, - 1, 1 and 5 and were fed with 50, 65, and 80% DM in the weeks - 4, - 3, - 2 and 2, 3, and 4, respectively. On the third week of experiment (65%) during both pre- and post-partum, the hepatic tissue was biopsied, and the mRNA load of the fatty acid synthase, acetyl-CoA carboxylase, carnitine palmitoyltransferase (CPT) 1, CPT2, and acyl-CoA synthase long-chain family member-1 genes was quantified by the TaqMan qPCR technique. Data were analyzed using the mixed model procedure of SAS. The mRNA abundance of the target genes was not influenced by feed restriction, during the pre- and post-partum periods. Parturition suppressed the mRNA abundance of target genes in both groups. It can be concluded that the fat-tailed sheep are well adapted to feed scarcity in the harsh environment and would have a higher capacity for the metabolism of fat mobilization during the negative energy balance.

Effect of cool-season adapted chickpea varieties on physicochemical and nutritional characteristics in ruminant systems

The focus of this study was to evaluate the effect of varieties on structural, physicochemical, and nutritional characteristics of cool-season adapted chickpeas as an alternative source for protein and energy feed for ruminant livestock. The hypothesis of this study was that cool-season adapted CDC chickpeas varieties grown in Western Canada would have significant differences in nutritional characteristics and truly nutrient supply to dairy livestock. The Crop Development Center (CDC) at the University of Saskatchewan (Saskatoon, Canada) provided the experimental samples of cool-season adapted chickpeas used in this study. Three chickpea varieties, CDC Alma, CDC Cory, and CDC Frontier were collected from three locations in Saskatchewan: Elorse, Limerick, and Lucky Lake. The standard official methods from the Association of Official Analytical Chemists (AOAC) were used for chemical analyses. Energy parameters were determined using the NRC dairy-2001. An in situ technique in cannulated cows was used to evaluate rumen degradation kinetics. Intestinal digestibility was determined in vitro using the 12 h residual samples from in situ incubations. A randomized complete block design (RCBD) with variety as a fixed effect and location as a random effect was used for statistical analyses using the MIXED model procedure of SAS 9.4. Significance was declared at P < 0.05 and tendencies at 0.05 < P < 0.10. Varieties CDC Alma and CDC Cory had a higher carbohydrate content than CDC Frontier (P = 0.02). Conversely, CDC Frontier had higher crude protein (CP) (P = 0.02) and SCP (soluble crude protein) (P = 0.02) than the other chickpeas. The rumen undegraded crude protein (RUP) was higher in CDC Alma and CDC Frontier compared to CDC Cory (P = 0.01). The intestinal digested crude protein (IDP) was higher in CDC Frontier than CDC Alma and CDC Cory (P = 0.03). No differences were observed in the true protein supply (DVE value), metabolizable protein (MP), and Feed Milk Value (FMV) between the three CDC varieties (P > 0.05). In conclusion, the chemical and nutrient profiles, rumen degradation kinetics, intestinal digestibility, and true nutrient availability in lactating cows among the cool-season adapted CDC chickpea varieties have been obtained. The cool-season adapted CDC chickpea varieties had > 770 g/kg EDCP and < 230 g/kg RUCP. CDC Frontier showed better results with relatively higher CP, higher degraded protein balance (OEB, DPB), higher truly digestive protein nutrient supply (DVE, MP) to dairy cows, and higher FMV than other two varieties. In general, cool-season CDC chickpea varieties grown in western Canada can be used as an alternative energy and protein nutrient option for ruminants.

The Efficacy of Conventional Spray, Electrostatic Spray, and Dip with a Combination of Hydrogen Peroxide and Peroxyacetic Acid To Inactivate Listeria monocytogenes on Apples

This study aimed to evaluate the efficacy of a hydrogen peroxide (H2O2) and peroxyacetic acid (PAA) mixer delivered by conventional garden spray (GS), electrostatic spray (ES), and dip methods to inactivate Listeria monocytogenes on apples. Organic Honeycrisp, Fuji, and Pink Lady apples were dip inoculated with L. monocytogenes (two strains, serotype 1/2b), which were then kept untreated (control), sprayed with water only, or treated with the H2O2-PAA mixer (0.0064, 0.1, 0.25, and 0.50%) for 20 s via GS, ES, or dip, followed by draining (for 2 min) on aluminum foil. Surviving bacteria were recovered on modified Oxford agar. Atomic force microscopy was used to detect the structural changes of inactivation of L. monocytogenes in broth medium by the H2O2-PAA mixer solution. Data (two replicates, with six samples per replicate) were analyzed using the mixed model procedure of SAS (P = 0.05). Initial counts of L. monocytogenes on untreated apples were 6.80 to 6.90 log CFU per apple. The dip method was the most effective treatment (P < 0.05) for pathogen reductions (2.31 to 2.41 log CFU per apple), followed by GS (1.44 to 1.70 log CFU per apple) and then ES (0.84 to 1.20 log CFU per apple). Reductions of L. monocytogenes were greatest (P < 0.05) when apples were treated with H2O2-PAA mixer -0.25 and -0.50%. Atomic force microscopy analyses indicated that inactivation of L. monocytogenes cells in H2O2-PAA mixer solutions resulted from disruption of the outer membrane. The H2O2-PAA mixer-treated cells had increased width and height and decreased roughness compared with the untreated cells. Results suggested that applying a H2O2-PAA mixer by dip or GS methods is better for pathogen reduction than ES on apples.

Effects of dietary macronutrient profile on apparent total tract macronutrient digestibility and fecal microbiota, fermentative metabolites, and bile acids of female dogs after spay surgery

Obesity and estrogen reduction are known to affect the gut microbiota and gut microbial-derived metabolites in some species, but limited information is available in dogs. The aim of this study was to determine the effects of dietary macronutrient profile on apparent total tract macronutrient digestibility, fecal microbiota, and fecal metabolites of adult female dogs after spay surgery. Twenty-eight adult intact female beagles (age: 3.02 ± 0.71 yr, BW: 10.28 ± 0.77 kg; BCS: 4.98 ± 0.57) were used. After a 5-wk baseline phase (week 0), 24 dogs were spayed and randomly allotted to one of three experimental diets (n = 8 per group): 1) control (CO) containing moderate protein and fiber (COSP), 2) high-protein, high-fiber (HPHF), or 3) high-protein, high-fiber plus omega-3 and medium-chain fatty acids (HPHFO). Four dogs were sham-operated and fed CO (COSH). All dogs were fed to maintain BW for 12 wk after spay and then allowed to consume twice that amount for 12 wk. Fecal samples were collected at weeks 0, 12, and 24 for digestibility, microbiota, and metabolite analysis. All data were analyzed using repeated measures and linear mixed models procedure of SAS 9.4, with results reported as a change from baseline. Apparent organic matter and energy digestibilities had greater decreases in HPHF and HPHFO than COSH and COSP. Increases in fecal acetate, total short-chain fatty acids, and secondary bile acids were greater and decreases in primary bile acids were greater in HPHF and HPHFO. Principal coordinates analysis of weighted UniFrac distances revealed that HPHF and HPHFO clustered together and separated from COSH and COSP at weeks 12 and 24, with relative abundances of Faecalibacterium, Romboutsia, and Fusobacterium increasing to a greater extent and Catenibacterium, Bifidobacterium, Prevotella 9, Eubacterium, and Megamonas decreasing to a greater extent in HPHF or HPHFO. Our results suggest that high-protein, high-fiber diets alter nutrient and energy digestibilities, fecal metabolite concentrations, and fecal gut microbiota, but spay surgery had minor effects. Future research is needed to investigate how food intake, nutrient profile, and changes in hormone production influence gut microbiota and metabolites of dogs individually and how this knowledge may be used to manage spayed pets.

The use of an upgraded GreenFeed system and milk fatty acids to estimate energy balance in early-lactation cows

Measurements of energy balance (EB) require the use of respiration chambers, which are quite expensive and laborious. The GreenFeed (GF) system (C-Lock Inc.) has been developed to offer a less expensive, user friendly alternative. In this study, we used the GF system to estimate the EB of cows in early lactation and compared it with EB predicted from energy requirements for dairy cows in the Finnish feeding standards. We also evaluated the association between milk fatty acids and the GF estimated EB. The cows were fed the same grass silage but supplemented with either cereal grain or fibrous by-product concentrate. Cows were followed from 1 to 18 wk of lactation, and measurements of energy metabolism variables were taken. Data were subjected to ANOVA using the mixed model procedure of SAS (SAS Institute Inc.). The repeatability estimates of the gaseous exchanges from the GF were moderate to high, presenting an opportunity to use it for indirect calorimetry in EB estimates. Energy metabolism variables were not different between cows fed different concentrates. However, cows fed the grain concentrate produced more methane (24.0 MJ/d or 62.9 kJ/MJ of gross energy) from increased digestibility than cows fed the by-product concentrate (21.3 MJ/d or 56.5 kJ/MJ of gross energy). Nitrogen metabolism was also not different between the diets. Milk long-chain fatty acids displayed an inverse time course with EB and de novo fatty acids. There was good concordance (0.85) between EB predicted using energy requirements derived from the Finnish feed table and EB estimated by the GF system. In conclusion, the GF can accurately estimate EB in early-lactating dairy cows. However, more data are needed to further validate the system for a wide range of dietary conditions.

6 Immunological aspects of ovarian follicle ovulation and corpus luteum formation in cattle

Ovarian follicle ovulation and subsequent luteinization have been described as a controlled inflammatory event, comprising tissue damage and repair. To elaborate this further in cattle, the contribution of immune cells to dominant follicle luteinization, ovulation, and corpus luteum formation was investigated. Ovulation in beef heifers was synchronized using an 8-day progesterone-based synchronization program. Heifers were slaughtered at a local abattoir at 5 timepoints (T): (T1) 24h before ovulation (n=10); (T2) 2h before ovulation (n=9); (T3) 6h after ovulation (n=10); (T4) 24h after ovulation (n=10); (T5) 72h after ovulation (n=10), and ovarian tissue was collected and returned to the laboratory on ice. Follicular fluid, theca, granulosa, and corpus luteum (CL) tissues were recovered by dissection and processed for analysis. The concentrations of a panel of cytokines were measured using an antibody-conjugated magnetic bead immunoassay. The abundance of T-lymphocytes, mast cells, neutrophils, eosinophils, monocytes, macrophages, and dendritic cells was determined by immunohistochemistry. The mRNA relative abundance of candidate genes, including angiogenic growth factors, adhesion factors, chemokines and cytokines, was determined by quantitative real-time PCR analysis. The resulting datasets were analysed using the linear mixed model procedure of SAS and data are presented as least squares means; reported differences were deemed significant at P≤0.05. The cytokines IFNy, IP-10, IL-10, IL-36RA, MCP-1, MIP-1a, MIP-1b, and VEGF-A were detected in follicular fluid. The concentrations (pg mL−1) of IL-10 and VEGF-A were significantly higher in T1 follicular fluid samples compared with T2 (7.70 vs. 0.86 and 2193.33 vs. 293.93, respectively). Although dendritic cells were the most abundant cells in bovine ovulatory follicular and early corpus luteum tissue at all time points (P&amp;lt;0.05), their numbers peaked in ovulatory (T2) thecal tissue (261.5 cells/mm2). The greatest number of neutrophils was identified in thecal tissue at T1 (45/mm2); thereafter, their numbers declined to 1.1/mm2 in CL tissue by T5. Similarly, the numbers of T-lymphocytes, mast cells, monocytes, and macrophages declined in CL tissue at T4 and T5. Candidate gene mRNA expression profiles appeared to be time- and tissue-specific; for example, IFNA was highest in the preovulatory granulosa tissue (T1), IL8 was highest in peri-ovulatory thecal tissue (T2), VEGFA and MMP9 were highest in the early CL tissue (T4 and T5), MMP1, TIMP1, and VCAM1 expression was highest in theca, granulosa, and CL tissue collected on or after ovulation (T2, T4, T5), expression of the prostaglandin-related genes PTGES and PTGS2 was lowest in CL tissue, and that of PTGIS was highest. The current findings support the hypothesis that ovulation in heifers is characterised by an initial proinflammatory cascade followed by a dramatic switch to tissue repair, growth, and remodelling, all occurring within a 72-h period and commencing with the LH surge. Our results highlight the roles of neutrophils, dendritic cells, and macrophages as the key actors in this process.

Characterization of hypothalamo–pituitary–thyroid axis gene expression in the hypothalamus, pituitary gland, and ovarian follicles of turkey hens during the preovulatory surge and in hens with low and high egg production

Dysregulation of the preovulatory surge (PS) leads to lowered egg production. The hypothalamo–pituitary–thyroid (HPT) axis has been shown to influence plasma progesterone levels and follicle ovulation. The presence of thyroid hormone receptors (THR) in the reproductive axis suggests possible effects of thyroid hormone. To further understand the potential role of thyroid hormone on the PS, HPT axis plasma hormone concentrations and gene expression were characterized surrounding the PS in average egg producing hens (AEPH), low egg producing hens (LEPH), and high egg producing hens (HEPH) (n = 3 hens/group). Data were analyzed using the mixed models procedure of SAS, with significance indicated at P < 0.05. Average egg producing hens and HEPH displayed lower levels of triiodothyronine (T3) and higher levels of thyroxine (T4) inside of the PS, whereas LEPH showed inverse T3 and T4 levels relative to the PS. Expression of mRNA for hypothalamic thyrotropin-releasing hormone (TRH), pituitary thyrotropin (TSHB), and the main thyroid hormone metabolism enzyme (DIO2) were downregulated during the PS in AEPH and HEPH. Low egg producing hens displayed higher expression of mRNA for hypothalamic TRH as well as pituitary TSHB and DIO2 compared with HEPH. Average egg producing hens expression of THR mRNAs was upregulated during the PS in the hypothalamus but downregulated in the pituitary. High egg producing hens showed decreased expression of THR mRNAs in both the hypothalamus and pituitary when compared with LEPH. In ovarian follicles, THR mRNAs were more prevalent in the thecal layer of the follicle wall compared with the granulosa layer, and expression tended to decrease with follicle maturity. Minimal differences in follicular THR expression were seen between LEPH and HEPH, indicating that THR expression is unlikely to be responsible for steroid hormone production differences occurring between LEPH and HEPH. Generally, downregulation of the HPT axis was seen during the PS in AEPH and HEPH, whereas upregulation of the HPT axis was seen in LEPH. Further studies will be required to clarify the role of the HPT axis in the regulation of ovulation and egg production rates in turkey hens.

PSVII-9 Evaluating Performance Trends of the Four Most Represented Breeds of Bulls in the Utah Beef Improvement Performance Test

Abstract This study evaluated changes in performance of bulls enrolled in the Utah Beef Improvement Association’s (UBIA) annual performance tests conducted in accordance with central bull test standards established by the Beef Improvement Federation. Breeds with over 500 bulls enrolled over the period of 2004 to 2018 were included in the evaluation. The breeds with greater than 500 animals evaluated included the Angus, Red Angus, Hereford and Simmental Breeds. Traits evaluated included birth weight, initial weight, a 205-day adjusted weaning weight, final test weight, average daily gain, adjusted yearling weight, and weight per day of age. The mixed model procedure of SAS and interval regression analyses were utilized to evaluate the yearly rate of change for each breed and to determine if that rate of change was significantly different (P &amp;lt; 0.05) between the evaluated breeds. When evaluating all breeds represented across years, significant differences (P &amp;lt; 0.05) were observed for rate of change when evaluating birth weight and 205-day adjusted weaning weight. However, no differences were observed between breeds with more than 500 animals represented. Significant differences (P &amp;lt; 0.05) for rate of change were observed when comparing the top four represented breeds, for average daily gain, initial test weight, final test weight, adjusted yearling weight and weight per day of age. Specifically, a declining trend was noted for all breeds when evaluation all significant traits. When evaluating the previously described traits, the Angus breed was significantly different in its rate of decline when compared to the Red Angus and Hereford breeds. The lone increasing trend was observed in the Hereford breed which had a positive increasing trend for initial test weight which was significantly different (P &amp;lt; 0.05) from both the Angus and Red Angus breeds but not significantly different from the Simmental breed.

Free Calcium Concentration, Calpain-2 Activity, and Final Product Tenderness of Electrically Stimulated Beef

The objective of this study was to evaluate the effect of timing of electrical stimulation on free calcium concentration, calpain-2 activity, Warner-Bratzler shear force (WBSF), and consumer sensory analysis. Twenty-three beef steers were harvested and stimulated (S) using extra-low voltage or not stimulated (NS), at exsanguination and/or 1 h postmortem, resulting in 4 different stimulation treatments: NS-NS, NS-S, S-NS, or S-S. Samples were removed from the longissimus lumborum (LL) and semimembranosus (SM) for free calcium and calpain-2 analysis on days 1, 4, and 14 postmortem. WBSF and sensory analysis steaks were removed on day 4 and frozen (4 d) or aged to 14 d postmortem. Data were analyzed using the mixed model or generalized linear mixed model procedure of SAS (SAS Institute, Inc., Cary, NC), with significance determined at P < 0.05. There was a tendency for an aging-period-by-stimulation-treatment interaction for LL free calcium concentration (P = 0.05), and there was a significant difference between aging periods (P < 0.01). No difference was observed in free calcium concentration in the SM between stimulation treatments (P = 0.44); aging, however, significantly increased SM free calcium concentration (P < 0.01). Stimulation did not impact native calpain-2 activity in the LL (P = 0.71) or SM (P = 0.89). Stimulation treatment did not improve tenderness values for WBSF analysis for the LL (P = 0.69) or SM (P = 0.61) or consumer sensory analysis in the LL (P = 0.56) or SM (P = 0.36). A longer aging period tended to increase calpain-2 activity in the SM (P = 0.08), improve WBSF in the LL (P = 0.09), and significantly improve consumer tenderness scores in the SM (P < 0.01). In conclusion, the timing of electrical stimulation utilized in the current study tended to influence free calcium concentration in the LL but did not influence calpain-2 activity or beef tenderness. Aging, however, improved tenderness.

Differences in invitro responses of the hypothalamo–pituitary–gonadal hormonal axis between low- and high-egg-producing turkey hens

Low-egg-producing hens (LEPH) ovulate less frequently than high-egg-producing hens (HEPH) and exhibit differences in mRNA levels for components of the hypothalamo–pituitary–gonadal (HPG) axis, suggesting differential responsiveness to trophic stimulation. Ovulation frequency is governed by the production of the pituitary gonadotropins and feedback of the ovarian follicle steroid hormones, which are regulated by HPG axis stimulation and inhibition at the hypothalamic level. The pituitary and follicle cells from LEPH and HEPH were subjected to in vitro hormonal treatments to stimulate or inhibit the HPG axis, followed by expression analysis of mRNA levels for HPG axis genes and radioimmunoassays for steroid hormone production. Statistical analysis was performed using the mixed models procedure of SAS. The pituitary cells from HEPH showed upregulation of genes associated with ovulation stimulation, whereas cells from LEPH showed upregulation of genes associated with inhibition of ovulation. High-egg-producing hens’ follicle cells displayed a higher sensitivity and responsiveness to gonadotropin treatment. Level of egg production impacted ovulation-related gene expression in the pituitary cells as well as steroid hormone production in the follicle cells, with HEPH displaying a greater positive response to stimulation. These findings indicate that differences in egg production among turkey hens likely involve differential responsiveness of the cells within the HPG axis.

Characterization of the hypothalamo–pituitary–gonadal axis in low and high egg producing turkey hens

Variation in egg production exists in commercial turkey hens, with low egg producing hens (LEPH) costing more per egg produced than high egg producing hens (HEPH). Egg production correlates with ovulation frequency, which is governed by the hypothalamic–pituitary–gonadal (HPG) axis. Ovulation is stimulated by a preovulatory surge (PS) of progesterone and luteinizing hormone, triggered by gonadotropin releasing hormone release and inhibited by gonadotropin inhibiting hormone. Differences between LEPH and HEPH were characterized by determining HPG axis plasma hormone profiles and mRNA levels for key genes, both outside and inside of the PS (n = 3 per group). Data were analyzed with a 2-way ANOVA using the mixed models procedure of SAS. In the HPG axis, plasma progesterone levels were not affected by egg production level but were elevated during the PS. In contrast, plasma estradiol levels were higher in HEPH than in LEPH but were not associated with the PS. LEPH exhibited decreased gene expression associated with ovulation stimulation and increased gene expression associated with ovulation inhibition in the hypothalamus and pituitary. In ovarian follicle cells, LEPH displayed decreased gene expression associated with progesterone, androgen, and estradiol production in the F1 follicle granulosa cells, F5 theca interna cells, and small white follicle cells, respectively. Different degrees of stimulation and inhibition within all tissues of the HPG axis were noted between LEPH and HEPH turkey hens, with HEPH showing higher expression of genes related to ovulation and steroidogenesis.

PSIII-17 The effects of a yeast product on apparent total tract macronutrient digestibility, fecal characteristics, fecal fermentative end products, fecal microbiota, and immune responses of adult dogs

Abstract Research in various animal species has demonstrated the effectiveness of yeast products to improve health and performance. However, little research on yeast products are available for dogs. The objective of this study was to investigate the effects of a yeast product on apparent total tract macronutrient digestibility (ATTD), fecal characteristics, fecal microbiota, and immune responses of adult dogs. Twelve adult female beagles (age: 4.8±0.9 yr; BW: 13.3±0.7 kg) were fed the same diet, but supplemented with a yeast product (165 mg/d) or a placebo (125 mg cellulose/d) via gelatin capsules in a crossover design. In each period, a 21-d adaptation phase was followed by 5 d of total fecal collection for ATTD measurement. Fresh fecal samples (within 15 min defecation) were collected on d 22 for fecal dry matter, pH, fermentative end-products, and fecal microbiota measurements. Blood samples were collected on d 27 and peripheral blood mononuclear cells were isolated for evaluations of immune cell populations and immune cell responsiveness. Except for microbiota data, data were analyzed using Mixed Models procedure of SAS 9.4. Microbial sequence data were analyzed using QIIME 1.9.1. and STAMP 2.1.3. ATTD, fecal characteristics and fermentative end-products were not altered by treatment (P &amp;gt; 0.05). Microbial alpha- and beta-diversity and specific microbial taxa were not affected by treatment (P &amp;gt; 0.05). Immune cell populations and immune cell responsiveness of toll-like receptors were not altered by treatment (P &amp;gt; 0.05). However, the strong period effect reported for all parameters may have mitigated the yeast product expected benefits. In conclusion, the yeast product tested in this study did not significantly alter the outcomes measured in healthy adult dogs. Future studies testing higher yeast product dosages, studying dogs undergoing stress, antibiotic administration or immune challenge, or studying dogs most susceptible to gastrointestinal distress (weanling; geriatric), may be of interest.