CON Treatment Research Articles

Does the distribution of light intensity within the barn impact broiler production and welfare?

ABSTRACT 1. The objective of this study was to determine if rearing broilers under variable light intensity (VLI) impacted their welfare or productivity. 2. Ross 308 broilers (n = 7,256) were reared until 35 d of age and exposed to a uniform intensity of 10 lux (CON) or VLI with low intensity areas of 2–5 lux proximal to the walls and high intensity areas of 84–133 lux proximal to feeders. 3. The data were analysed as a complete randomised design using an analysis of variance. Significance was declared when p ≤ 0.05. 4. Applying VLI resulted in increased feed intake early in life but had no impact on body weight. Overall efficiency was improved in the CON treatment. Mortality diagnoses of skeletal problems were reduced under VLI. Treatment had no impact on footpad, hock or gait score, heterophil to lymphocyte ratio or melatonin concentration. Birds performed certain behaviours in specific locations within the room, independent of light intensity treatment. 5. In conclusion, raising broilers under VLI had little impact on production or most welfare parameters assessed in this study. However, satisfying the bird’s preference for different light intensities may improve welfare.

Effect of training method and dairy cow personality traits on adaptation to an automated milking system

Training dairy cows on the automated milking system (AMS) can improve their performance, however, the ideal training method and how their individual personality relates to training is unknown. The objectives of this study were to determine: 1) the effect of AMS training method on adaptation of primiparous cows to an AMS, 2) whether the personality of a cow affects their adaptation to the AMS, and 3) whether certain personality types adapt better based on the type of training they receive. Forty-eight primiparous Holstein dairy cows, who had not previously been milked by an AMS, were enrolled in the study at ∼85 DIM and were assessed for personality traits using a combined arena test comprised of 3 parts: a novel arena test, a novel object test, and a novel human test. Cows were allocated into 1 of 4 AMS training treatments (n = 12): control (CON; no training), environment exposure only (ENV), environment and AMS concentrate provision (PEL), and environment and mechanics exposure (MEC). Cows in the ENV, PEL, and MEC treatments were subjected to training 4 × /d for 4 d, and then cows from all 4 treatments were milked on the AMS in the evening of the 4th training d. Milking activity and production were recorded for the first 14 d on the AMS. PEL cows had fewer visits to the AMS, fewer milkings, and fewer voluntary milkings compared with CON cows across the 14 d. Cows on all experimental treatments had more fetching events than CON cows, while MEC and ENV treatment cows had a higher milk yield compared with those on the CON treatment. Principal component analysis of the behaviors recorded during the personality assessment revealed 2 factors interpreted as personality traits, "explore-active" and "bold." Across all cows, more "explore-active" cows had greater milk yield. Only the performance of ENV cows was associated with personality; ENV cows who scored low for "explore-active" differed from CON cows, through increased visits and voluntary milkings. Overall, the results demonstrate that providing concentrate on its own during AMS training may not be motivating enough to improve adaptation and performance. However, exposing cows to the mechanics (e.g., the robotic arm and sounds of the AMS) before first milking may improve milk yield. Finally, cow personality may influence the performance of cows trained using less complicated training methods, such as only exposing them to the environment of the AMS.

PSXIII-26 Effects of Lentilactobacillus lactis and Lentilactobacillus buchneri on fermentation and aerobic stability in corn grain silages

Abstract The inclusion of corn grain silages (early-harvest and reconstitute grain) in the diets has gained wide acceptance in the last decade among Brazilian farms. Thus, reducing losses in these silages is one of the main goals. The objective of this study was to evaluate the effects of an inoculant containing Lentilactobacillus lactis O224 and Lentilactobacillus buchneri LB1819 on fermentation, microbial counts, and aerobic stability in reconstituted corn grain (RCG) and high-moisture corn (HMC). Two experiments were carried out, which tested the inclusion of no additive (CON) and the addition of L. lactis and L. buchneri. For both trials, the inoculant was added at a theoretical rate of 1.5 x 105 CFU/g of feed. For HMC, corn kernels (30.1% of moisture) were processed and ensiled in 5-L jars for 44 or 64 d. For RCG, corn kernels were purchased at 14% moisture, ground, and water was added to reach 35% moisture. Afterwards, ground kernels were ensiled in 5-L jars for 21 or 42 d. Measurements included fermentation end-products (acids, alcohols, and NH3-N), microbial counts (LAB, yeasts, and molds), and aerobic stability. Both trials were set up as a completely randomized design using a 2 x 2 factorial arrangement. Data were analyzed using MIXED procedure of SAS, followed by a Tukey test at P ≤ 0.05. In both experiments, inoculated silages had reduced concentrations of lactic acid and greater concentrations of acetic acid and 1,2-propanediol. These three fermentation end products increased over time for both treatments. In HMC, there was an interaction between inoculation and time of conservation for propionic acid concentrations. Also, the concentration of NH3-N was greater in treated silages. In both experiments, the population of LAB was greater in inoculated silages. For RCG, yeast population was greater in CON treatment. During aerobic exposure, treated silages remained more stable in both trials. In HMC, the aerobic stability was > 240 h for treated silages, whereas CON silages had 94 h of stability. Still in HMC, the peaks of temperature were 39.5 and 28.2 oC and the pH values (after 10 d of aerobic exposure) were 6.81 and 4.38 for CON and inoculated silages, respectively. In RCG, the aerobic stability was more pronounced at 42 d of conservation (35 vs 66 h for CON and inoculated silages, respectively). Overall, the combination of L. lactis and L. buchneri modulates corn grain silages fermentation and improves aerobic stability.

362 Nutrikinetic evaluation and modeling of 25-hydroxyvitamin D3 in beef cattle

Abstract The objective of this study was to evaluate serum 25-hydroxyvitamin D3 [25(OH)D3] status in beef cattle when 1) fed diets with supplemental 25(OH)D3 or calcidiol (HyD, dsm-firmenich, Plainsboro, NJ), and 2.) a single dose of calcidiol was administered to cannulated heifers on nutrikinetic evaluation and predictive modeling simulations. In experiment 1, crossbred heifer calves [n = 96, initial body weight (BW) = 222 ± 12.4 kg] were assembled from auction markets near Dickson, TN and transported ~1,069 km to Manhattan, KS. Heifers (n = 12 per pen) were stratified by BW and randomly allocated to a corn-based receiving diet with one of four dietary treatments: 1) No supplemental D3 or calcidiol (CON, n = 24), 2) 3,000 IU supplemental D3·heifer⁻¹·d⁻¹ (D3, n = 24), 3.) 0.5 mg calcidiol/h/d (Hy D Low, n = 24), or 4.) 1.0 mg calcidiol·heifer⁻¹·d⁻¹ (Hy D High, n = 24) for 60 d. Blood samples were collected from each heifer prior to transport (d -1), on arrival (d 0) and on d 14, 31, and 60 of dietary treatment period. Data were analyzed using the GLIMMIX procedure of SAS using animal as experimental unit and treatment as fixed effect. HyD High calves had greater (P < 0.001) serum 25(OH)D3 concentrations than HyD Low at d 14 and 31 (Figure 1 and 2). At d 14, 31 and 60, HyD High and HyD Low calves had greater (P < 0.001) serum 25(OH)D3 concentrations than CON or D3 treatments. In experiment 2, cannulated crossbred heifers (n = 8, initial BW = 289 ± 44.9 kg were randomly assigned to one of two treatments: 1.) 3 mg/272 kg BW calcidiol, or 2.) 5 mg/272 kg BW calcidiol in a single dose administered via rumen cannula at h 0. Serial blood samples were collected at baseline out to 70 d post-dose. Serum 25(OH)D3 concentrations were analyzed via HPLC coupled with tandem MS (dsm-firmenich, Belvidere, NJ). Predictive modeling simulations of serum 25(OH)D3 concentrations used non-parametric superposition (Certara Phoenix WinNonlin 64, St. Louis, MO) from applying non-compartmental analysis with the assumptions of linearity, independent calcidiol dose response, and the rate of absorption and the average systemic clearance were consistent for each calcidiol dosing interval. The elimination half-life (t1/2) of calcidiol was determined to be an average of 7.1 d and area under change in concentration-time curve time 0 to the last time point that measured above baseline concentration post dose (AUC0-last) averaged of 32.6 d (Table 1). Non-parametric dosing simulations using nutrikinetic parameters from experiment 2 suggest that administration of two 5 mg oral doses of calcidiol with daily feeding of 1 mg would result in a rapid and sustained increase in serum 25(OH)D3. However, simulations should be confirmed in vivo before implementation.

335 Effects of feeding an immunomodulatory feed additive (NutraGen) on serum cytokine and antibody concentrations in calves following exposure to a combination bovine respiratory disease challenge

Abstract Two 89-d experiments (Exp 1 and Exp 2) evaluated the effects of feeding an immunomodulatory feed additive (NutraGen; NG) in calves following exposure to bovine viral diarrhea virus (BVDV) on d -3 and Mannheimia haemolytica (MH) infection on d 0. For each experiment, steers [body weight (BW = 251 ± 38.2 kg were randomly allocated to 1 of 3 treatments. Treatments included a placebo (CON; Exp 1 n = 5; Exp 2 n = 5), a placebo fed from d -18 to d -3 followed by NG fed from d -3 to d 28 (CHLG; Exp 1 n = 5; Exp 2 n = 6), and NG fed from d -18 to d 28 (PREC; Exp 1 n = 6; Exp 2 n = 5). Data were analyzed using the GLIMMIX procedure of SAS Version 9.4 (SAS Institute, Cary, N.C.). Animal served as the experimental unit and time served as a repeated measure. Treatment, time, and the treatment × time interaction served as fixed effects. Block was included as a random effect. Cytokine data were tested for normality using the Shapiro-Wilk test, determined to be non-normal, and logarithm (base 10) transformed as a result prior to statistical analysis. Multiple time effects and treatment × time interactions occurred for serum MH, BVDV 1, and BVDV 2 antibody concentrations in both experiments (P ≤ 0.05). In Exp 1, there was a tendency for an overall treatment effect for calves assigned to the CON treatment to exhibit the greatest MH serum antibody concentrations (P = 0.06). While no differences were detected between treatment groups, BVDV 1 and BVDV 2 antibody concentrations peaked on the same day in both experiments, d 28 post-challenge. There were no treatment × time interactions, treatment effects, or time effects for serum TNF-α, IFN-γ, or IL-17A concentrations (P ≥ 0.13) in either experiment. In Exp 1, there was a treatment effect for serum IL-10 (P ≤ 0.0001), where calves assigned to the PREC treatment had increased serum IL-10 concentrations when compared with calves in the other treatment groups. In Exp 2, there was a tendency for a treatment effect for IL-10 concentrations, where calves assigned to the PREC treatment displayed decreased IL-10 concentrations when compared with calves in the other treatment groups (P = 0.07). These data suggest that feeding NG to calves prior to a stress experience may alter cellular responses. Overall, these experiments suggest that NG impacted antibody concentrations and cytokine expression during a bovine respiratory disease challenge.

Integrated farming optimization ensures high-yield crop production with decreased nitrogen leaching and improved soil fertility: The findings from a 12-year experimental study

Context or problemSustainable farming practices, including precision fertilization, water-saving irrigation and recycling of organic materials, have been implemented worldwide in recent decades to achieve high crop yields and minimize nonpoint source pollution. However, the comprehensive impacts of these agricultural practices have seldom been systematically evaluated in field production. As agricultural intensification started in the 1980s, most previous studies focused on a single practice in the context of low land productivity. Objective or research questionThe objective of this research is to investigate and evaluate how holistic farming practices affect both crop production and environmental quality. MethodsWe reported findings from a 12-year experiment (2008–2020) in the highly intensive North China Plain (NCP) farming region, and conventional and optimized farming measures were compared. Three field treatments with annual double cropping (winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.)) were chosen in the study, i.e., control without nitrogen (N) application (CK), farmers’ conventional practices (CON), and optimized practices (OPT), were chosen for this study. ResultsCompared with the CON treatment, OPT reduced N fertilizer input by 41.4 % and irrigation water by 27.1 % but produced similar grain yields; OPT increased the N recovery efficiency (REN) and N utilization efficiency (NUT2E) by 90.4 % and 53.0 %, respectively; these values were much greater than the increases in REN (+56.1 %) and NUT2E (+25.5 %) when soil N change was not considered. Similarly, compared with those in the CON treatment, the soil N stock (0–60 cm) in the OPT treatment increased by 8.4 %, and the N loss via leaching, ammonia volatilization and N2O + NO + N2 decreased by 47.1 %, 11.4 % and 28.6 %, respectively. ConclusionsOur study revealed that the integration of optimized practices of organic material recycling, precision fertilization and water-saving irrigation substantially reduced N losses, mainly through decreased N leaching, but maintained fertilizer N in the root-zone soil layer, which is important for a sustainable and high-yield crop production. Implications or significancesThe dissemination of these optimized practices to other regions in China and beyond will be highly important for achieving the dual goals of food security and environmental protection.

Impact of dietary fat types on expression levels of dopamine and serotonin transporters in the ileum of broiler chickens

Various types of dietary fats undergo distinct fermentation processes by gut microbes, potentially leading to the production of neurotransmitters that can influence the gut. Serotonin and dopamine are recognized neurotransmitters with positive effects on gut function. A broiler chicken trial was conducted to evaluate the influence of dietary fat types on protein expression of 2 neurotransmitter transporters, dopamine (DAT) and serotonin (5-HTT). A total of 560 day-old (Ross 708) male broiler chicks were randomly assigned to 7 dietary treatments. The experimental treatments included a basal diet of corn-soybean meal (SBM), supplemented with 3% of various fats: poultry fat (CON), olive oil (OLIV), fish oil (FISH), canola oil (CANO), lard (LARD), coconut oil (COCO), or flaxseed oil (FLAX). Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Ileal tissues were aseptically collected to determine the expression levels of DAT and 5-HTT through western blot analysis. In addition, plasma samples were analyzed for reactive oxygen metabolites (d-ROM) tests on d 55. Results showed that dietary fat type inclusion did not have any detrimental effect on growth performance parameters. The expression levels of DAT were higher (P < 0.05) in FLAX treatments compared to CON treatments on d 20 and d 55, respectively. Similarly, with 5-HTT levels, FLAX, CANO, and LARD treatments were higher (P < 0.05) than CON treatments on d 20 and d 55. However, higher levels of oxidative stress (d-ROM values) were recorded in COCO (32.75 Carr U), CANO (29 Carr U), and CON treatments (25.5 Carr U) compared to FLAX (18.5 Carr U; P < 0.05) treatment. These findings suggest that incorporating dietary flaxseed oil at a 3% level in the diet has significant potential to elevate the expression levels of intestinal DAT and 5-HTT without inducing oxidative stress.

Effects of different ratios of soluble to insoluble dietary fiber on growth performance and intestinal health of piglets

This study investigated the impact of different ratios of soluble to insoluble dietary fiber (SDF:IDF) formulations by sugar beet pulp (SBP) supplementation on piglet growth performance, nutrient digestibility, immune function, intestinal morphology, intestinal microbiota and intestinal health. A total of 60 crossbred piglets (Duroc × [Landrace × Yorkshire]) at 40 d old with body weight of 10.0 ± 0.3 kg were randomly assigned to 5 treatments with 6 replicates per treatment and 2 piglets per replicate in a 21-d trial. The dietary treatments included a corn-soybean meal diet (0% SBP supplementation; CON), and diets supplemented with 2%, 4%, 6%, and 8% SBP, representing different SDF:IDF ratios at 10.16%, 13.53%, 16.79%, 19.86%, and 24.81%, respectively. The results indicated that the 8% SBP treatment had a negative effect on feed-to-gain ratio (linear, P = 0.009) compared with the CON treatment (P = 0.021). The apparent total tract digestibility (ATTD) of crude protein was lower in treatments supplemented with SBP (P = 0.002) and showed a linear decrease (P = 0.001), while the ATTD of IDF showed a linear increase (P = 0.037) in four SBP treatments compared to the CON treatment. The 4% SBP treatment increased serum concentrations of triglyceride (quadratic, P = 0.019) and K (linear, P < 0.0037), and decreased alanine transaminase concentration (quadratic, P = 0.015) compared with the CON treatment. The concentrations of Cit, Cys, Ile, Leu, Orn, Arg, taurine, urea, 1-methylhistidine, α-aminoadipic acid, α-aminobutyric acid and cystathionine in the 4% SBP treatment were highest among all treatments (P < 0.05). The serum concentrations of interleukin-6, interleukin-8, interleukin-10, transforming growth factor-β, and tumor necrosis factor-α in the 6% SBP treatment were higher than those in the CON treatment (P < 0.05), which also increased mucin-2 and G protein-coupled receptor 41 mRNA expression (P < 0.05) in colonic mucosa compared with the CON treatment and improved the intestinal barrier function. Diets containing more than 19.86% SDF:IDF could impair the intestinal health in piglets when SBP was used as the SDF source. Supplementing nursery piglet diets with 16.79% to 19.86% SDF:IDF is recommended for improving intestinal barrier function, increasing short-chain fatty acids concentrations, and improving intestinal microbiota composition.

Dietary incorporation of brown seaweed spent oyster mushroom substrate alters growth performance, physiological responses and meat quality parameters in Boschveld roosters

Use of brown seaweed (Ecklonia maxima) as a nutraceutical source in indigenous chicken diets is limited by high dietary fibre levels. Inoculating seaweeds with oyster mushroom (Pleurotus ostreatus) spawn (OMS) could enhance the utility of the spent mushroom substrate (SMS). This study investigated the effect of feeding incremental levels of brown seaweed SMS on growth performance, physiological responses, and meat quality parameters in Boschveld roosters. A total of 324, 4-week-old Boschveld roosters were weighed and randomly allotted to 36 pens (9 birds per pen) to produce six replicates per dietary treatment. The diets were formulated as follows: a standard grower diet (CON); and CON containing 150 g/kg of brown seaweed inoculated with OMS at 0 (SMS0), 20 (SMS20), 30 (SMS30), 40 (SMS40) and 50% (SMS50). Birds fed diet CON had the least feed intake (p < 0.05) than all the other SMS treatment levels in weeks 7, 8, 12, 14 and 15. Diet SMS40 promoted higher (p < 0.05) body weight gain (BWG) than CON in weeks 6, 7, 9 and 14. Gain-to-feed ratio linearly increased in weeks 7 [R2 = 0.288; p = 0.010], 11 [R2 = 0.581, p = 0.0001] and 14 [R2 = 0.389, p = 0.004], respectively. Quadratic responses (p < 0.05) were observed for BWG in week 5, white blood cells, heterophils, platelets, lymphocytes, monocytes, and relative spleen and large intestine weights as OMS levels increased. Linear increases were recorded for slaughter [R2 = 0.197, p = 0.017] and breast weights [R2 = 0.197, p = 0.020] as OMS levels increased. Diet SMS0 promoted higher (p < 0.05) relative caeca weights than the CON and SMS treatment groups. Neither quadratic nor linear responses (p > 0.05) were observed for breast meat quality parameters. In conclusion, feeding brown seaweed SMS improved growth performance and slaughter weight, altered some blood parameters and internal organs, without affecting breast meat quality of Boschveld roosters. Based on the quadratic response for BWG, the optimum OMS level was deduced at 20% in a brown seaweed-based Boschveld rooster diet.

Contour furrowing reduces erosion and enhances soil moisture on semiarid hillslopes

Water scarcity and soil erosion are global problems with socioeconomic consequences for small-scale farmers, especially in semiarid areas. Small-scale farmers scarcely consider techniques for reversing this situation due to uncertain outcomes and high costs. In this study, we hypothesized that contour furrowing, a simple and accessible technique, would effectively increase soil moisture and mitigate soil erosion. In addition, we hypothesized that vegetation is also a contributing factor. We performed a field experiment to evaluate the effect of four treatments on soil moisture (until 1 m depth) and soil loss: bare and unmanaged soils (CON); bare soils managed with contour furrowing (CF); soils with shrub cover (VEG); and CF + VEG. Each treatment was monitored on six hillslopes of agricultural communities in a semiarid area of central Chile for one year. We found that the minimal soil water content recorded in the soil profiles of the CF, VEG, and CF + VEG plots was significantly greater than in the CON plots (with increases of 16%, 22%, and 13%, respectively, compared to CON). The CF and VEG treatments conserved soil moisture during the dry season and demonstrated more effective soil–water recharge after the first rain. However, the combined CF + VEG treatment retained less water in the soil profile than the single treatments. On the other hand, all treated plots showed lower soil loss than the CON treatment (mean of 0.68 t ha−1 year−1). We concluded that contour furrowing effectively enhances soil and soil-water conservation on bare hillslopes. Moreover, it is a low-cost technique that engaged those farmers looking to enhance sustainability and productivity on their lands.

Effects of Long-Term Fertilizer Managements on Soil Organic Carbon Mineralization Under the Double-Cropping Rice System in Southern China

ABSTRACT Soil organic carbon (SOC) plays an important role in maintaining or increasing soil fertility and quality in paddy field, but there is limited information about how SOC mineralization responds to different fertilizer managements under the double-cropping rice system in southern China. Therefore, this study was designed to explore changes in SOC content, soil enzyme activities, SOC mineralization at 0–10 cm and 10–20 cm layers, and its relationship with long-term fertilizer managements in a double-cropping rice system of southern China. The experiment included four fertilizer treatments: chemical fertilizer alone (CF), rice straw and chemical fertilizer (RS+F), 30% organic manure and 70% chemical fertilizer (OM+F), and without fertilizer input as a control (Con). These results showed that SOC and labile organic carbon contents at 0–10 cm and 10–20 cm layers in paddy field with RS+F and OM+F treatments were increased, compared to CF and Con treatments. Compared with Con treatment, SOC mineralization rate and accumulation with CF, RS+F, and OM+F treatments were increased. SOC accumulation and potential mineralization at 0–10 cm and 10–20 cm layers with RS+F and OM+F treatments were increased, compared with CF and Con treatments. SOC mineralization rate and accumulation at 0–10 cm layer with CF, RS+F, OM+F, and Con treatments were higher than that of 10–20 cm layer. These results indicated that soil invertase, cellulose and urease activities in paddy field with RS+F and OM+F treatments were significantly higher than that of CF and Con treatments. There was a significant positive relationship between SOC accumulation and SOC content, soil invertase, cellulose, urease activities but were significant negative correlated with soil pH, bulk density. As a result, these were beneficial practices for improving SOC content and SOC mineralization in a double-cropping rice field of southern China by combined application of rice residue or organic matter with chemical fertilizer managements.

Incremental supply of fat, lactose, or protein influences the diurnal pattern of heat production and substrate oxidation in preweaning calves

Increasing nutrient supply to dairy calves has well known benefits; however, the effects of milk replacer (MR) composition when supplied in higher amounts are not fully understood, particularly in the first weeks of life. To better understand the metabolism of macronutrient supply in young calves (21 d old), we investigated diurnal patterns of heat production and substrate oxidation in young calves fed MR with an incremental supply of fat, lactose, or protein. Thirty-two groups of 3 mixed-sex Holstein-Friesian newborn calves (3.4 ± 1.6 d of age), were randomly assigned to one of 4 dietary treatments and studied for 21 d. Diets consisted of a basal MR (23.3% CP, 21.2% EE, and 48.8% lactose of DM) fed at 550 kJ/kg BW0.85 per day (CON; n = 24), or the basal MR incrementally supplied with 126 kJ of digestible energy/BW0.85 per day as milk fat (+FAT; n = 23), lactose (+LAC; n = 24), or milk protein (+PRO; n = 23). Calves were fed MR in 2 daily meals and had ad libitum access to water, but were not supplied with any calf starter nor forage. After 2 weeks of adaptation to the diets, groups of 3 calves were placed for 1 wk in an open-circuit respiration chamber for nitrogen and energy balance measurements (lasting 7 d). On d 3, glucose oxidation kinetics was estimated by using [U-13C]glucose. Measurements included total heat production (total energy [HP], activity [Hact] expenditure, resting metabolic rate [RMR]), respiration quotient (RQ), carbohydrate (COX) and fat oxidation (FOX) in 10 min. intervals and averaging these values per hour over days. Incremental supply of lactose and fat increased body fat deposition, with observed patterns in RMR indicating that this increase occurred primarily after the meals. Specifically, the average daily RMR was highest in the +PRO group and lowest in the CON treatment. The HP was higher in the +PRO group and throughout the day, hourly means of HP were higher in this treatment mainly caused by an increase in Hact. The recovery of 13CO2 from oral pulse-dosed [U-13C]glucose was high (77%), and not significantly different between treatments, indicating that ingested lactose was oxidized to a similar extent across treatments. Increasing lactose supply in young calves increased fat retention by reduction in fatty oxidation. Calves fed a MR with additional protein or fat raised RMR persistently throughout the day, whereas the extra lactose supply only affects RMR after the meal. Dietary glucose was almost completely oxidized (77% based on (13C) glucose measurement) regardless of nutrient supplementation. Extra protein supply increased HP and FOX compared with similar intakes of fat and lactose. Fasting heat production (FHP) of young, group-housed calves is comparable to literature values and unaffected by energy intake. Overall, these findings deepen our understanding of how different nutrients affect metabolic processes, fat retention, and energy expenditure in young dairy calves.

PSV-10 Evaluation of the effect of probiotic feed additives in the diet to improve dairy production and quality measures

Abstract There is limited information regarding the effectiveness of probiotic feed additives in the diet of lactating dairy cows. This study aimed to determine the effect that Fastrack probiotic had on the yield and milk quality measures of lactating dairy cows. To accomplish this goal, lactating Holstein cows (n = 80) were equally divided into two treatment groups: one supplemented with a probiotic (PRO) and one that did not receive the probiotic supplement (CON). The cows remained in their treatment groups for the duration of the 120-d study and were given ad libitum access to a total mixed ration consisting of 35% corn silage, 30% rolled corn, 10.5% soybean meal, 23% DDGS, and 1.5% mineral supplement. Cows on the PRO treatment were given 1 kg of DDGS once a day at milking that had the probiotic mixed in while the CON treatment were given 1 kg of the same DDGS that did not have the probiotic included. Preliminary results of this study show a decrease in individual treatment records for cows on the PRO treatment and an increase of 2 kg of milk yield per day.

182 Evaluation of the effects of F18 enterotoxigenic Escherichia coli intestinal attachment in nursery pigs

Abstract Enterotoxigenic Escherichia coli (ETEC) infections are a leading cause of post-weaning diarrhea and poor performance in nursery pigs. ETEC fimbriae regulate binding to epithelial cells and subsequent intestine colonization, commonly F18 in post-weaned pigs. The objective of this study was to evaluate F18 ETEC ileal attachment in relation to growth performance and intestinal integrity and function around peak infection. Following 10 d of acclimation to a common diet, 24 individually housed, mixed sex weaned pigs [initial body weight (BW) = 5.7 ± 0.44 kg] were randomly allotted across 4 treatment groups (n=6/treatment). On day post inoculation (dpi) 0, pigs were non-inoculated (CON) or orally inoculated with 5 mL of F18 ETEC (LT, STb, Stx2, STx2e positive) at either 107 colony-forming units [CFU)/mL (LOW), 108 CFU/mL (MED] or 109 CFU/mL (HIGH). Over a 5-dpi period, fecal scores [scale: 0 (dry) – 3 (watery)] and feed intakes were measured daily. Body weights were recorded on dpi 0 and 5 to calculate average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). On dpi 5, all pigs were euthanized, ileal contents and feces was assessed for F18 gene abundance via PCR, and fixed ileal sections were evaluated for morphology changes, stem cell proliferation (Ki67), and F18 ETEC attachment via in situ hybridization. Further, ex vivo ileal tissue integrity and function was assessed via Ussing chambers by measuring transepithelial resistance (TER), 4.4 kDa FITC-Dextran (FD4) flux and active glucose and glutamine transport. Pig was considered the experimental unit, and data were analyzed for the fixed effects of treatment. Over this 5 dpi challenge period, ADG, ADFI, and G:F did not differ between treatments (P &amp;gt; 0.05). Compared with the CON, mean fecal scores were greatest in MED followed by the LOW and HIGH treatments (P = 0.028). Ileal pH tended to be greater in the HIGH compared with the MED, LOW and CON (7.8, 7.6, 7.5 and 7.3, respectively, P = 0.08). Compared with the CON, decreased Ct values were reported for the LOW, MED, and HIGH groups for fecal (32, 19, 18, 20, respectively; P &amp;lt; 0.001) and ileal (28, 19, 19, 18, respectively; P = 0.019) F18 gene abundances, respectively. Ileal F18 attachment was greatest in the HIGH group compared with CON, with LOW and MED being intermediate (P = 0.011). The immunohistochemistry stem cell marker Ki67 was lleast in HIGH compared with CON, LOW and MED treatments (P &amp;lt; 0.01). Ileal histology, active glucose and glutamine, TER and FD4 did not differ (P &amp;gt; 0.05). F18 attachment was negatively correlated with ileal (R = -0.706, P &amp;lt; 0.001) and fecal (R = -0.713, P &amp;lt; 0.001) F18 CT values, and positively correlated with ileal pH (R = 0.536, P &amp;lt; 0.01). In conclusion, F18 ileal attachment increased as challenge dose increased. However, at 5-dpi no effect on growth performance or ileal function and integrity was observed.

PSIII-21 Impact of high zinc oxide supplementation or lignocellulose supplement on chronic markers of intestinal inflammation and growth of weaned piglets

Abstract The objective of this project was to study the effects of high zinc oxide (ZO) supplementation and fiber supplement from lignocellulose (LIGCEL) on chronic markers of intestinal inflammation and growth of weaned piglets. At weaning (21 d), 150 piglets (body weight = 6.39 ± 0.276 kg) were transferred from a farrowing farm to a nursery farm where they were divided into 30 pens of 5 piglets per pen according to their weanling weight. Each pen was assigned to one of the following three treatments: Control (CON, 150 mg/kg of zinc), ZO (2,500 mg/kg of zinc), and LIGCEL (CON+3% lignocellulose). The ZO and LIGCEL supplements were added to a phase 1 diet. The experimental diets (phase 1) were distributed for 14 d. Subsequently, all piglets received the same diets from phases 2 and 3 for two periods of 14 d. During the experiment, piglets were weighed upon arrival and after phases 1, 2, and 3. The feed was distributed every day and the total quantities calculated for each of the feeding phases. The average daily gain (ADG), average daily feed intake (ADFI) and feed conversion (FC) were subsequently calculated (Table 1). On d 6 and 13, the blood of two piglets per pen was collected to determine the content of D-lactate and diamine oxidase (DAO). Fecal samples from these two piglets were also taken to evaluate the calprotectin and neopterin contents. During phase 1, ADG was greater for ZO piglets compared with the CON animals with an intermediate value for the LIGCEL group (P &amp;lt; 0.001). The ADFI was greater for the ZO compared with the CON and LIGCEL treatments (P &amp;lt; 0.003). Piglets in the ZO and LIGNOCELL treatments had less FC than those in the CON group (P &amp;lt; 0.001). During phase 2, only the FC was greater for the ZO and LIGCEL treatments compared with CON animals (P &amp;lt; 0.013). During phase 3, growth performances were not affected by the dietary treatments. For the entire experiment, ZO piglets had greater ADG than those in the CON group with an intermediate value for LIGCEL treatment (P &amp;lt; 0.019). D-lactate decreased from d 6 to 13 while DAO increased (P &amp;lt; 0.001). The DAO was also greater for ZO and LIGCELL piglets compared with CON animals (P &amp;lt; 0.001). Neopterin was greater for ZO treatment but only on d 13 (Trt × day, P &amp;lt; 0.010). Finally, calprotectin decreased from d 6 to 13 (P &amp;lt; 0.001) but was not affected by dietary treatments. In conclusion, ZO and LIGCEL fiber act positively on growth by modulating markers of intestinal inflammation. LIGCEL fiber could, therefore, be an alternative to ZO in the diet of weaned piglets.

Effects of abomasal infusion of soybean or sunflower lecithin on nutrient digestibility and milk production in lactating dairy cows

The fatty acid (FA) and phospholipid composition of dietary lecithin may influence FA digestibility and milk production in cattle. Eight multiparous Holstein cows (99.4 ± 9.2 DIM; 48.9 ± 3.8 kg of milk/d) were enrolled in a 3 × 3 incomplete Latin square design with 3 treatments provided as continuous abomasal infusates spanning 14-d experimental periods: water (CON), soybean lecithin (SBL; 74.5 g of deoiled soy lecithin), or sunflower lecithin (SFL; 133.5 g of hydrolyzed sunflower lecithin). Cows were fed the same diet, which contained (% DM) 27.0% NDF, 15.6% CP, 26.2% starch, and 5.87% FA. Treatments did not modify BW, milk fat, protein, or lactose contents, or the efficiency of producing ECM. Cows infused with SFL had greater milk yields than those receiving SBL or CON treatments. Cows infused with SFL had higher total solids, protein, and lactose yields than cows receiving the SBL or CON treatments. Sunflower lecithin enhanced feed efficiency (milk yield/DMI) relative to SBL or CON. Treatment did not affect intakes or apparent total-tract digestibilities for NDF, CP, starch, or 16-carbon (16C) FA. Cows receiving SFL had greater total FA and 18-carbon (18C) FA intakes than SBL or CON, but treatments did not affect their digestibility. Milk FA composition was modified by treatment. Cows receiving SFL had a greater concentration of PUFA and lower concentrations of SFA and MUFA in milk relative to SBL or CON. In conclusion, the abomasal infusion of SFL improved milk production and milk FA composition, indicating potential benefits for dairy cow nutrition and milk quality.

Enhanced efficiency nitrogen fertilizers (EENFs) can reduce nitrous oxide emissions and maintain high grain yields in a rain-fed spring maize cropping system

ContextEnhanced efficiency nitrogen fertilizers (EENFs) have provided opportunities for the simultaneous mitigation of nitrous oxide (N2O) emissions and increases in crop productions. However, the practice of combining EENFs with optimal fertilization under conditions of misaligned water and fertilizer inputs in rain-fed spring maize systems remains inadequately understood. ObjectiveThis study aims to determine the factors controlling N2O emissions under the soil climatic conditions in rain-fed plastic mulching cropping systems treated with different nitrogen (N) fertilization rates and EENFs, and to determine the most effective N fertilization measure to reduce N2O emissions while maintaining crop yields. MethodsA 3-year field experiment was conducted in a spring maize system located in the semiarid rain-fed region of the Loess Plateau, applying two types of EENFs: a nitrification inhibitor dicyandiamide (DCD) and a slow-release fertilizer (SRF). It comprised five fertilization treatments: unfertilized (CK), conventional N rate (CON, 200 kg N ha−1), optimal N rate (OPT, 160 kg N ha−1), OPT with the addition of DCD (OPT+DCD), and OPT using SRF (OPT-SRF). ResultsThe average annual cumulative N2O emissions over the 3-year experimental period ranged from 0.74 to 1.87 kg N2O-N ha–1. Fertilizer N contributed 26−60% to annual N2O emissions. The highest N2O fluxes (50–161 μg N2O-N m–2 h–1) typically occurred within the initial 10 days following fertilization, likely induced by strong nitrification processes, constituting 12–19% of the annual N2O emissions during this brief period. In comparison to the CON treatment, the OPT, OPT+DCD, and OPT-SRF treatments resulted in significant reductions in annual N2O emissions of 24%, 46%, and 34%, respectively, without causing any significant decrease in maize grain yields. The application of DCD led to increased ammonium (NH4+-N) concentrations while reducing nitrate (NO3–-N). Conversely, using SRF resulted in a decrease in both NH4+-N and NO3–-N concentrations. ConclusionsUsing EENFs at the ideal fertilization rate significantly curtailed yearly N2O emissions without adversely affecting maize yields in a rain-fed plastic mulching spring maize system prevalent in the Loess Plateau. Most N2O emissions occurred post-fertilization, with rainfall events further influencing these emissions. ImplicationsOur findings recommend the incorporation of nitrification inhibitors, such as DCD, as the most effective fertilizer measure for reducing N2O emissions in the rain-fed region of the Loess Plateau.

Effects of yeast culture on in vitro ruminal fermentation and microbial community of high concentrate diet in sheep.

This research aimed to investigate effects of different yeast culture (YC) levels on in vitro fermentation characteristics and bacterial and fungal community under high concentrate diet. A total of 5 groups were included in the experiment: control group without YC (CON), YC1 (0.5% YC proportion of substrate dry matter), YC2 (1%), YC3 (1.5%) and YC4 (2%). After 48h of fermentation, the incubation fluids and residues were collected to analyze the ruminal fermentation parameters and bacterial and fungal community. Results showed that the ruminal fluid pH of YC2 and YC4 groups was higher (P < 0.05) than that of CON group. Compared with CON group, the microbial protein, propionate and butyrate concentrations and cumulative gas production at 48h of YC2 group were significantly increased (P < 0.05), whereas an opposite trend of ammonia nitrogen and lactate was observed between two groups. Microbial analysis showed that the Chao1 and Shannon indexes of YC2 group were higher (P < 0.05) than those of CON group. Additionally, YC supplementation significantly decreased (P < 0.05) Succinivibrionaceae_UCG-001, Streptococcus bovis and Neosetophoma relative abundances. An opposite tendency of Aspergillus abundance was found between CON and YC treatments. Compared with CON group, the relative abundances of Prevotella, Succiniclasticum, Butyrivibrio and Megasphaera elsdenii were significantly increased (P < 0.05) in YC2 group, while Apiotrichum and unclassified Clostridiales relative abundances were decreased (P < 0.05). In conclusion, high concentrate substrate supplemented with appropriate YC (1%) can improve ruminal fermentation and regulate bacterial and fungal composition.

Effect of hay nets on horse bodyweight, body condition score, hay usage, and dental health in mature adult horses

Hay nets are a commonly used management practice to increase intake time and reduce hay waste but may impact horse health. The objectives were to compare hay usage, dental wear, and dental conditions between horses fed with (NET) or without (CON) hay nets during a 2-year cross-over study. In September 2021, 13 mature adult horses were blocked by bodyweight (BW) and randomly assigned to the NET or CON treatments for one year. After one year (September 2022), horses switched treatments and the trial concluded in September 2023. Horses were housed in adjacent dry lots with shelter, ad libitum water, and free choice access to round bales with or without hay nets (4.45 cm openings). Blinded dental work, including incisor length measurements and recording of dental abnormalities and conditions, and recording of horse BW and body condition score (BCS) were completed in September 2021, 2022, and 2023. Digital images were taken monthly to determine rostral oral cavity scores (ROCS). Round bales were weighed prior to being placed in the dry lot and the date fed was recorded to calculate hay usage. Significance was set at P≤0.05. Horse BW, BCS, and hay usage were greater in horses consuming hay without hay nets (P<0.05). No differences were observed in incisor length, presence of incisor bevels, ROCS, or dental abnormalities and conditions (P>0.05). These data suggest that hay nets do not result in negative impacts on dental health but can reduce hay usage and help to control horse BW and BCS.

Exogenous silicon applied at appropriate concentrations is effective at improving tomato nutritional and flavor qualities

Silicon can mitigate biotic and abiotic stresses in various plants; however, its effects on tomato quality under normal growth conditions are remain unclear. We used a randomized design with four Si treatments, CON (0 mmol/L), T1 (0.6 mmol/L), T2 (1.2 mmol/L), and T3 (1.8 mmol/L) on tomato fruit components Chlorogenic acid and rutin, among polyphenolic components, were increased by 56.99% and 20.31%, respectively, with T2 treatment compared to CON concentrations. T2 increased the sugar–acid ratio by 19.21%, compared to that with the CON treatment, and increased fruit Ca and Mg contents, compared to those with other treatments, improving the characteristic aroma. Furthermore, silicon application reduced the abscisic acid content by 112%, promoting ripening. Endogenous gibberellin, auxin, and salicylic acid, which retard fruit ripening and softening, were increased by 34.96%, 14.56%, and 35.21%, respectively. These findings have far-reaching implications for exogenous Si applications to enrich tomato nutritional and flavor qualities.