Effect Of Day Research Articles

PSIII-25 The effects of varying levels of trace mineral supplementation on mineral balance and antibody concentrations in feedlot cattle

Abstract Trace mineral (TM) supplementation is critical for optimal performance and health. The objective was to determine the effects of varying levels of TM supplementation on feedlot cattle TM status and antibody concentrations. Angus steers (n = 240; BW = 291 kg ± 27.4) were stratified by arrival BW and source and assigned to 1 of 4 treatments (12 pens/treatment; 5 steers/pen). Treatments included a negative control (CON) in which cattle received no TM supplementation, a requirement treatment (1X) in which cattle received added TM at 2016 Nutrient Requirements of Beef Cattle required levels, a 2 times requirements (2X), and a 4 times requirements (4X) treatment. Selenium was included at 0.1, 0.2, and 0.3 mg/kg for 1X, 2X, and 4X respectively. Treatments were chosen based on reported TM supplementation levels from the 2015 Feedlot Consulting Nutritionist Survey. One steer was chosen at random from each pen to be evaluated for serum and liver TM status and antibody concentrations to respiratory viruses. There was treatment × day interaction for serum Co, and liver Cu and Se (P < 0.0001). Serum Co was greatest for the 4X treatment from d 28 through harvest. Liver Cu was greatest for the 2X and 4X treatments from d 56 through harvest. Liver Se was greatest for 2X and 4X from d 28 through harvest. There was an effect of day on liver Co, Fe, Mn, Mo, and Zn (P < 0.0001) and serum Cu, Mn, Mo, Se, and Zn (P < 0.0019). Concentrations for individual TM had different trends over time, however, all reported values were within normal ranges. Serum Zn was greater at harvest (P = .02). There was an effect of time on Bovine Viral Diarrhea Virus Type 1A, Bovine Herpesvirus Type 1, Bovine Parainfluenza 3 virus antibody titer concentrations (P < 0.0001).

177 Ad Libitum Consumption of a 1:1 Blend of inorganic:organic Se by Steers Grazing Endophyte-infected Tall Fescue Increases Serum Prolactin and Alkaline Phosphatase Activity, but Not Average Daily Gain

Abstract To test the hypothesis that average daily gain (ADG) and clinical parameters of steers grazing novel non-toxic (NTE) or toxic KY-31 (TE) endophyte-infected tall fescue would be improved by ad libitum intake of vitamin-mineral mixes (V-M) that contain 27 ppm Se as a 1:1 blend of SELPLEX:sodium selenite (MIX) vs sodium selenite (ISe), 32 TE-naïve beef steers depleted of Se were randomly assigned to ad libitum consumption ISe vs MIX for 35 d and fed enough of a NTE/alfalfa/grain diet to achieve 0.57 kg BW gain/d. Within Se-form treatments, 2 steers were randomly assigned to each of 4, 2-acre NTE (ISe = 316 ± 31 kg, MIX = 315 ± 22 kg) or TE (ISe = 316 ± 37 kg, MIX = 314 ± 39 kg) paddocks for 84 d and had ad libitum access to their respective V-M. The MIXED procedure of SAS was used to assess effects of day, Se-form (ISe, MIX) and endophyte (NTE, TE) treatments, and their interactions. Whole blood Se decreased (P < 0.01) 31% from d 0 to 84 and was 6.2% greater (P < 0.01) for MIX steers. Serum prolactin decreased (P < 0.01) 18% for NTE and 48% for TE steers from d 0 to 84 and was 17% greater (P = 0.01) for MIX vs. ISe TE steers. Alkaline phosphatase activity (AP) decreased (P < 0.02) 27% from d 0 to 84 and was 15% greater (P < 0.02) for MIX steers. Serum urea nitrogen increased (P < 0.02) 8.2% from d 0 to 84 for TE but not NTE steers. Average daily gain (kg/d) was less (P < 0.01) in TE (-0.18) vs NTE (0.09) steers. We conclude that the ad libitum intake of MIX ameliorated the negative effects of consuming TE on serum prolactin and AP but not ADG.

PSX-A-2 Late-Breaking: Acute Endotoxinemia May Increase Intercostal Temporary Mechanical Nociception in Wethers

Abstract Systemic inflammation induced by lipopolysaccharide (LPS; endotoxin) is associated with generalized hyperalgesia in humans and some animal models. However, the effects of endotoxin-induced inflammation on pain threshold in livestock, such as sheep, is unknown. Eight wethers [~1 year of age; 61.3 ± 0.5 kg BW] were administered saline (2 mL; n = 4) or endotoxin (2 mL; 400 ng of LPS / kg BW; n = 4) intravenously. A handheld algometric unit was used to administer temporary mechanical nociception (TMN) before (Day -2) and after (Day 1) treatment administration by the same person three times at two locations on the right thorax (intercostal spaces 6 and 9). Two-way ANOVA was completed in SAS v9.4 (Cary, NC). There were effects of day (P < 0.001) and location (P < 0.0001) on TMN, such that the force needed to induce TMN on Day -2 (2.04 +/- 0.15 kgF) was less than on Day 1 (2.93 +/- 0.15 kgF) and the force needed to induce TMN at intercostal space 6 (1.81 +/- 0.15 kgF) was less than at intercostal space 9 (3.15 +/- 0.15 kgF). While there was no effect of treatment (P = 0.96), or interaction of treatment and location (P = 0.19), day and location (P = 0.25), or treatment and day and location (P = 0.49), there was a tendency for an interaction of treatment and day (P = 0.06), such that TMN was not different on Day 1 (2.73 +/- 0.30 kgF) and Day -2 (2.24 +/- 0.30 kgF) for animals receiving saline but was greater on Day 1 (3.12 +/- 0.30 kgF) than Day -2 (1.83 +/- 0.30 kgF) for animals receiving LPS. While systemic inflammation is associated with reduced pain threshold in some models, acute LPS-induced inflammation may increase intercostal TMN in castrated sheep.

527 Late-Breaking: Objective Assessment of Behaviour, Pain, and Lameness Due to Digital Dermatitis in Beef Cattle

Abstract Digital dermatitis (DD) is an infectious disease affecting cattle feet causing ulcerative and necrotic skin lesions. Most lesions are painful when palpated, some cause lameness and significantly impact animal welfare and productivity. Our objectives were: to determine if changes in behaviour were associated with DD in cattle, to quantify pain associated with DD lesions, and to determine the relationship between pain sensitivity and lameness, and DD and lesion temperature. In total, 255 animals across three feedlots were enrolled. A subset of 120 animals were fitted with accelerometers to record behaviour. Cattle were scored for lameness (Step-Up Locomotion Scoring System), both hind feet scored for DD (M-stage scoring system), the pressure pain threshold of lesions determined using pressure algometry and lesion temperature using thermal images. Animals and feet were classified as DD absent or present. Further, DD present was divided into active or chronic. Behaviour, 5 to 2 days before DD identification was analyzed. Animals with DD ruminated 3% less daily compared to animals without DD (P < 0.05). Further, animals with active lesions ruminated 5% less daily (P < 0.05). Daily inactivity time was greater in animals with DD and the effect of day depended on type of lesion (P < 0.05). Feet without DD lesions withstood 5.6N more pressure (P < 0.001). Active lesions were most sensitive withstanding 8.1N less pressure and chronic lesions 4.1N less pressure than DD absent feet (P < 0.05). Moderate to severely lame animals withstood 3.1N less pressure than sound animals (P < 0.001). Median maximum temperature (MMT) was higher in feet with DD compared to those without (P < 0.001) with MMT being highest in active lesions (P < 0.05). In conclusion, rumination is depressed, and inactivity increased in DD affected animals. Both active and chronic lesions are painful, lame animals have a lower pain threshold and DD is associated with higher lesion temperatures.

PSX-B-19 Behaviour of cows while being tested for methane emissions using the greenfeed system

Abstract Increased focus on sustainability is driving a need for environmental efficiency traits in dairy cattle breeding. Breeding for reduced emission of methane, an inevitable product of fermentation in ruminants, is increasingly being explored. Methods to measure methane emissions vary but can be impacted by cow behaviour. As part of an on-going project to develop genomic tools for breeding resilient dairy cows, we explored changes in cow behaviour over time during methane emission measurements. First lactation heifers (n = 49) were tested in tie-stall housing at a research herd in Ontario, Canada. Animals were tested over 5 consecutive days at 08:00h, 12:00h, and 16:00h each day for a 10-min period using the GreenFeed system (C-Lock Inc., Rapid City, SD, USA). The frequency of movement (body shifts and leg lifts) and the number of seconds the cow removed her head from the machine were recorded. The effect of day on the average frequency of movements or time the cow’s head was outside of the machine was assessed using a repeated measures model. In general, cows moved their legs the most on day 1 of testing (76 ± 5.0 movements per 10 min), after which it numerically decreased (e.g., day 5: 68 ± 5.0 movements per 10 min, P = 0.1110). A similar effect was observed for seconds the cow had her head out of the machine (P = 0.0650). Cows spent an average of 39 ± 5.7 sec with their head outside of the machine on day 1 versus 25 ± 3.6 sec on day 5 (P = 0.0499). These preliminary results suggest that cows adapt to the testing conditions; however, changes in their behaviour were minor and do not intervene with recording of methane emissions using the GreenFeed system.

Physiological role of circadian clock gene on the energetic metabolism in horses

The aim of the present study was to investigate the linkage between the molecular clock and the metabolic processes in horses. Ten clinically healthy Italian Saddle horses of 8-11 years old (body weight of 480 ± 25 Kg) were housed in individual boxes under natural photoperiod (sunrise at 6:10 h, sunset at 18:10 h) and natural environmental conditions (T max 18°C, T min 16°C, Rh 70%). They were fed 3 times a day (07.00, 12.00, and 19.00) and water was available ad libitum. On each horse, blood sample collections were performed every 4 hours over a 48-hour period. Glucose, total proteins, total lipids levels and clock genes (Clock and Bmal1) expression were assed. The method of single Cosinor was applied to evaluate the daily rhythmicity of the texted parameters. Glucose, total proteins and total lipids showed a robust daily rhythmicity; diurnal for glucose and total lipids, and nocturnal for total proteins and Bmal1. Clock no showed daily rhythmicity in horses. Two ways ANOVA was applied to compare acrophase and robustness of rhythm. Only Clock no showed an effect of time. No effect of day was observed on each tested parameter, acrophase and robustness. Statistical differences in acrophase were observed among diurnal and nocturnal parameters. Further studies are necessary to better understand the peripheral circadian rhythmicity in this species.

P090 The Effect of Workload, Sleep Deprivation and Time of Day on Simulated Driving Performance

Abstract Sustained operations expose individuals to long work periods, which deteriorates their ability to sustain attention. Biological factors, including sleep deprivation and time of day, have been shown to play a critical role in the ability to sustain attention. However, a gap in the literature exists regarding external factors, such as workload. Therefore, the aim of this study was to investigate the combined effect of sleep deprivation, time of day, and workload on sustained attention. Twenty-one participants (18–34y, 10 F) were exposed to 62 hours of sleep deprivation within a controlled laboratory environment. Every 8 hours, sustained attention was measured using a 30-minute monotonous driving task, and subjective workload was measured using the NASA-Task Load Index (TLX). Workload, defined as time on task was assessed by splitting the drive into two 15-minute loops. A mixed model ANOVA revealed significant main effects of day (sleep deprivation) and time of day on lane deviation, number of crashes, speed deviation and time outside the safe zone (all p<.001). There was a significant main effect of workload (time on task) on lane deviation (p=.042), indicating that a longer time on task resulted in greater lane deviation. NASA-TLX scores significantly increased with sleep deprivation (p<.001), indicating that subjective workload increased with sleep loss even though the task remained constant. Workload, sleep deprivation and time of day produced a deterioration in sustained attention. With this, countermeasures that not only consider sleep deprivation and time of day, but also workload (time on task) can be considered.

149 Examining the Relationship Between Markers of Emergency Department Crowding and Physician Wellbeing

Literature on emergency department (ED) crowding and boarding has primarily focused on adverse patient outcomes including increased patient mortality, and longer hospital length-of-stay. Few studies have explored relationships between ED crowding, boarding and physician wellbeing (burnout, professional satisfaction) despite evidence demonstrating that EM specialists are consistently among those with the highest rates of burnout. Therefore, we sought to evaluate the relationships between markers of ED crowding and boarding and physician wellbeing. Data for this prospective, observational study were collected from resident and attending emergency physicians employed at our Level-I, tertiary care referral center ED. Participants completed the 7- item Physician Well-Being Index (PWBI) twice weekly for three months following clinical shifts. The PWBI assesses physician distress across several dimensions using a score from 0 to 7 and has previously demonstrated validity with similar physician groups. For the same period, we collected markers of ED crowding and boarding: ED volume, numbers of arriving and boarding patients by shift, and average census by shift. Generalized Estimating Equations (GEE) analyses were performed to examine relationships between ED crowding and boarding markers and physician PWBI scores. Hierarchical regression models were constructed to control for the potentially confounding effects of the day of the week, shift type, and provider role (resident/attending). 42 emergency physicians (18 (43%) resident, 24 (57%) attending) participated in the study, providing 273 PWBI assessments. Data for 4, 318 ED patient encounters were summarized for the same period. Mean PWBI scores were 2.3 (SD 1.53, 95% CI: 2.1-2.5); no significant differences between the resident and attending groups were noted (2.0, ±1.50, 95% CI: 1.5-2.6 vs. 2.5, ±1.52, 95% CI: 1.9-3.0, respectively). After adjusting for the effects of day of week, shift type, and provider role, we did not observe statistically significant relationships between PWBI scores and count of arrivals in 24 hours (b=-0.089, SE=0.0593, CI: -0.206-0.027, p=0.133), patient arrivals by shift (b=-0.006, SE=0.013, CI: -0.031-0.02, p=0.667), average census by shift (b=0.004, SE=0.019, CI: 0.041-0.047, p=0.829), or average boarding census by shift (b=-0.161, SE=0.1051, CI: -0.367-0.045, p=0.127). In this study, ED crowding and boarding were not significantly related to physician wellbeing, as measured by the PWBI. Findings suggest further research is needed to validate the PWBI in capturing ED physician wellbeing during periods of ED crowding and boarding. Next steps are to explore the relationships between individual dimensions of wellbeing (fatigue, mental quality of life) and ED busyness, given the important impact of dimensions of burnout on care team wellbeing and patient outcomes.

Impact of digital dermatitis on feedlot cattle behaviour

Digital dermatitis (DD) is an infectious disease affecting the bovine digital skin which can cause lameness and significantly affect animal welfare and economics. Digital dermatitis has emerged in feedlots and early identification of DD lesions is difficult using traditional visual methods. The objective of this study was to determine if changes in behaviour: rumination, feeding, inactivity and activity could be associated with DD in beef heifers and if these behaviours differed among DD M-stages (‘M′ for Mortellaro; 6-point classification describing the life cycle of DD). On arrival at the feedlot 120 heifers were fitted with accelerometers (CowManager system) attached to their Radio-frequency identification (RFID) tags to measure time spent ruminating, feeding, activity (walking and movement) and inactivity (lying and standing) throughout the feeding period. The study was conducted from November 2018 to November 2019 with heifer placements in fall 2018 and winter 2019. Biweekly pen walks were conducted to assess hind feet for presence or absence of DD using the M-stage scoring system and for altered gait using a lameness score. Detailed foot examination was conducted for heifers selected during pen walks, at routine re-handling events and prior to transport to the abattoir. In total 51 of 114 (44.74%) heifers were afflicted with DD. Among DD affected heifers 26 were classified as having active lesions and 25 as having chronic lesions. Behaviour pattern 5–2 days before detailed foot examination was analysed. Mean time spent ruminating ranged from 16% to 20%. Rumination time was significantly greater in heifers without DD lesions (P = 0.008) compared to DD affected heifers that ruminated 3% less per day. The effect of Day on mean daily rumination time depended on whether heifers had active DD lesions, chronic DD lesions or no lesion present (P = 0.034). Heifers with active DD lesions ruminated 5% less (P = 0.002) than heifers with no lesions. Mean time spent inactive ranged from 46% to 49% and was significantly greater in heifers with DD lesions (P = 0.035). The effect of Day on mean inactivity time depended on whether heifers presented with an active DD lesion, a chronic DD lesion or no lesion (P = 0.047). In conclusion, rumination is depressed, and inactivity increased in heifers with DD, 5–2 days before diagnosis. Taken together, our results describe the impact of DD on beef heifer behaviour and the potential utility of behaviour for early detection of DD.

Effects of parity order on performance, metabolic, and hormonal parameters of grazing beef cows during pre-calving and lactation periods

BackgroundMetabolic profile evaluation is a tool widely used in ruminant nutrition as metabolic cues that relate nutrition to physiology. Metabolic and hormonal traits change during pre-partum and lactation according to parity in dairy cows, but studies of beef cows under grazing are scarce. The present study aimed to evaluate how metabolic and hormonal traits change over time, their relationship to performance, and determine if these factors differ according to the parity order of grazing beef cows. Thirty-six pregnant Nellore cows (12 nulliparous, 12 primiparous, and 12 multiparous) were used. The study started at 60 d prepartum until 203 d of lactation.ResultsThe initial body weight (BW) and final BW were higher for multiparous cows (P > 0.05). An interaction occurred between parity and day (P < .0001) for body condition score. Nulliparous and primiparous body condition score were reduced from − 60 prepartum to 30 postpartum, then stabilized 60 postpartum (P < 0.05), while multiparous maintained body condition score from − 60 days until 60 days postpartum (P > 0.05). Calf BW, final BW, and average daily gain did not differ between parities (P > 0.05). Effect of day (P < 0.05) was detected for non-esterified fatty acids, triglycerides, total cholesterol, LDL, VLDL, progesterone, and insulin. An interaction was observed between parity and days for glucose, HDL, β-hydroxybutyrate, creatinine and IGF-1 (P < 0.05). Parity affected serum urea nitrogen, total proteins, albumin, and globulins (P < 0.05). Parity and day relative to calving did not impact total T3 and T4 (P > 0.05).ConclusionsHormonal and metabolic profile is strongly influenced by the stage of lactation. Time effects (pre-partum and lactation period) were more pronounced in nulliparous since they displayed more unbalanced metabolic and hormonal traits and lowered BCS pre- and postpartum.

Adverse Events following AstraZeneca COVID-19 Vaccine in Saudi Arabia: A Cross-Sectional Study among Healthcare and Nonhealthcare Workers

Introduction: Many COVID-19 vaccines have been emerging with different efficacy and safety profiles. So far, very little attention has been paid to severity and reactogenicity of COVID-19 vaccine among healthcare workers. Thus, the aim of this study is to investigate the side effects associated with the first dose of AstraZeneca COVID-19 vaccine among healthcare workers (HCWs) and nonhealthcare workers (non-HCWs). Method: This is an observational cross-sectional study conducted at King Abdullah bin AbdulAziz University Hospital, Saudi Arabia, between February 28 and March 12, 2021. The major outcomes were the reported side effects of day 1, day 2, and day 3 after vaccination among HCWs and non-HCWs. Other outcomes included the onset and the duration of the reactions or the side effects that were reported. Results: A total of 526 participants completed the survey with 173 (32.8%) HCWs and the remaining majority were non-HCWs. Some of the most frequently reported side effects among the participants on the first day were muscle aches (49%), followed by fever (42%) and headache (40%). HCWs experienced more muscle aches, headache, sore throat, and abdominal pain, which were statically significant, compared to non-HCWs. The mean onset of symptoms was 16 (±15.3) h in the HCW arm compared with 12.2 (±10.2) h in non-HCWs (p = 0.0024). Furthermore, the mean duration of symptoms in the HCW group was 37 (±19) h compared with 32.3 (±13) h in the non-HCW group (p = 0.067). Conclusion: The reported side effects were common but not pressing in both groups. HCW respondents appeared to have more COVID-19 vaccine-associated symptoms.

Meat Quality of Nellore Young Bulls-Effects of Different Days on Feed and Zilpaterol Hydrochloride Supplementation.

Simple Summaryβ-adrenergic agonists have been widely used to improve meat production efficiency and can be a valuable tool for increasing world meat supply. They act as nutrient repartitioning agents, increasing lean tissue deposition but negatively affecting meat quality, notably reducing palatability. While this metabolic modifier improves the growth performance of Zebu breeds, they can impair even more meat quality in feedlot-finished cattle. This study was developed to evaluate the impact of zilpaterol hydrochloride (ZH) feeding duration and time on feed (90 or 117 days), on meat quality, and on composition properties of meat from young Zebu bulls. Supplementing ZH resulted in a leaner and less tender and juicy meat compared to non-supplemented animals, with few differences in fatty acid composition. Feeding animals for 90 or 117 days had a small impact on meat quality attributes. Feeding ZH to Zebu bulls would require additional tenderization practices to reduce the negative effects of ZH on meat quality.Ninety-six Nellore young bulls were fed (90 or 117 day) diets containing ZH (8.33 mg/kg) for 0, 20, 30, or 40 days to evaluate the effects of days on feed (DOF) and length of zilpaterol hydrochloride (ZH) supplementation on meat quality. At the end of feeding period, animals were slaughtered, and samples of the Longissimus muscle were collected to evaluate the chemical composition, fatty acid profile, color stability, shear force, and sensory profile. DOF did not affect chemical composition, shear force, sensory tenderness, and most of fatty acids; however, animals fed for 90 d had lower redness (p < 0.01), sustained juiciness (p < 0.01), and more flavor (p = 0.03) than those fed for 117 d. The ZH supplementation decreased lipid content and redness (p < 0.01), initial and sustained tenderness (p < 0.01), initial and sustained juiciness (p < 0.01), but increased protein (p < 0.01) and shear force (p < 0.01) as compared to non-supplemented animals. The ZH supplementation increased total PUFA, c9,c12-18:2, and 20:4-n6, and decreased c9-20:1 (p < 0.05). Feeding ZH impairs meat quality attributes of Nellore young bulls, regardless of duration of supplementation, while DOF has a small effect on meat quality properties.

Impairments in glycaemic control do not increase linearly with repeated nights of sleep restriction in healthy adults: a randomised controlled trial.

Evidence suggests reduced glycaemic control following sleep restriction in healthy individuals. However, it remains unknown if impairments in glycaemic control increase with each additional night of sleep restriction in a linear manner. This randomised crossover study aimed to determine if the impairment in glycaemic control increases with each additional night of sleep restriction. Ten healthy individuals underwent 4 nights of control sleep (8 hours in bed) and 4 nights of sleep restriction (4 hours in bed) in a sleep laboratory. An oral glucose tolerance test was conducted each morning. Serum glucose and insulin were measured. Glucose and insulin area under the curve were higher overall in the sleep restriction trial compared with control (p < 0.001 and p = 0.033); however, no effect of day (p = 0.620 and p = 0.863) or interaction effect (p = 0.152 and p = 0.285) were observed. This supports previous literature showing a detrimental impact of sleep restriction on glucose regulation. The present findings, however, suggest the impairment in glycaemic control does not increase in a linear manner with an increasing number of nights of sleep restriction. This may have implications for the design of future studies examining sleep restriction and glycaemic control. Novelty: Four nights of sleep restriction impaired glycaemic control in healthy individuals, but did not do so in a linear manner. No effect of number of nights of restriction was found for glucose or insulin, which may have implications for future studies.

English

Although tomato is the leading vegetable crop in Kenya, not much work has been done to develop improved tomato varieties with farmer preferred and market demanded traits. This study aims to characterize ten tomato genotypes for morphological and agronomic traits and to identify potential parental lines for use in the breeding program. The experiments were conducted in Kenya during the 2017 long and short rain seasons. Trials were laid out in a randomized complete block design with three replicates. Study materials were AVTO1429, AVTO1424, AVTO1314 from World Vegetable Center, four commercial varieties namely; Riogrande, Cal J, Roma VF, UC82 and three farmer selections namely; Valoria, Danny and Eden select. Genotype effects, genotype x environment interactions and location effects for days to flowering, plant height, maturity, fruit yield and related traits were highly significant (P&lt;0.01). Duration of flowering varied from 36 to 42 days; plant height from 66.37 to 182.57cm, duration to maturity from 85 to 100 days, and fruit yield from 18.3 to 55.7 t ha-1. All the genotypes showed a determinate growth habit except AVTO1314 which had indeterminate growth habit. Genotype AVTO1429, AVTO1424 and AVTO1314 had green stem while commercial varieties and farmers&rsquo; selection had purple stem. The high genetic variation observed among the test genotypes for the traits evaluated can be exploited in developing the tomato breeding program. Key words: Tomato, accessions, characterization, flowering, morphological traits, agronomic traits.

English

Eight sunflower inbred lines were crossed in 8&times;8 diallel fashion (without reciprocal) and 28 F1 were developed at Oilseed Research Centre (ORC), Bangladesh Agricultural Research Institute (BARI), Gazipur in Rabi season, 2018. All F1 and their parents were planted in Rabi season 2019 to estimate general combining ability (GCA) and specific combining ability (SCA) effects for yield and yield attributes. The highly significant mean squares for genotypes for all the studied characters indicating wide variability in the parental materials. The highly significant GCA effects for stem diameter, days to maturity, number of seeds/head, 1000-seed weight and SCA effects for days to 50 flowering, days to maturity, head diameter, number of seeds/head, 1000-seed weight and seed yield were observed. The greater ratio of GCA/SCA implies the predominance of additive gene effect for all the studied characters. The parents, P1, P2, P3, P6 and P8 were found as good general combining parents for short duration, early maturity, lodging resistant, and 1000 seed weight. Crosses with the best SCA effects for some characters were found from the interaction of low &times; low, high &times; low, low &times; high or high &times; average combining parents. Further investigation on superiority and stability of good combining parents and hybrids over different years and locations is needed. Key words: Sunflower, Griffing&rsquo; method, general combining ability (GCA), specific combining ability (SCA).

Higher Baseline Aerobic Fitness Influences Jumping Performance During Military Operational Stress

Vertical jump (VJ) testing via force plate technology serves as a field-expedient indicator of fatigue and readiness in the military. PURPOSE: To determine if higher baseline aerobic fitness is protective against declining unloaded and loaded jump performance during simulated military operational stress (SMOS). METHODS: Eighteen military men (27 ± 6 y, 84.4 ± 12.7 kg, 177.8 ± 7.6 cm) completed a 5-day SMOS protocol characterized by frequent cognitive testing, marksmanship assessments, and a ~ 90 min Tactical Mobility Test (TMT) daily. The schedule was the same each day except that subjects had four instead of eight hours of sleep and 50% instead of 100% of their caloric needs on days 2-3. Participants performed VJ testing in unloaded (UL) and loaded (LD) (16-kg) conditions at three time points during the TMT: 1) pre, 2) following 2-min water can carry, fire and movement, casualty drag, and 300-m shuttle runs (UL and LD, 16-kg) (mid), and 3) after a 4-mile ruck march (post). Subjects were divided into groups using a median split based on baseline VO2peak (HIGH vs. LOW) assessments. Three-way ANOVAs for UL and LD conditions were used to examine the effect of group*time*day on jump height (JH). RESULTS: The three-way interactions were not statistically significant. A significant group*day interaction was observed for UL condition JH (p = .035). The main effect of day from the simple two-way ANOVA was not statistically significant at each level of group (HIGH: p = .111, np2 = .218; LOW p = .312, np2 = .132), but this effect was in opposite directions. Adjusted means on days 1 to 4 declined for LOW (M: 24.7 cm, SE: 2.0 to M: 22.9 cm, SE: 1.9) but increased for HIGH (M: 27.1 cm, SE: 1.2 to M: 28.9 cm, SE: 1.3). In the LD condition, no significant interactions were observed, but there was a significant main effect of time (p = .001). For the LD condition, pre-JH (M: 21.1 cm, SE: 1.0) was significantly higher than mid-JH (M: 19.1 cm, SE: 1.1, p = .001) and post-JH (M: 19.6 cm, SE: 1.0, p = .031). CONCLUSION: We demonstrate that higher levels of aerobic fitness was protective against declining JH performance in the UL, but not LD, condition across acute SMOS, suggesting that other factors (e.g., strength/power) may be important for maintaining jump performance in the LD condition. Funded by the Department of Defense (Award # W81XWH-17-2-0070).

GENETIC DIVERGENCE AMONG MAIZE (ZEA MAYS L.) INBRED LINES USING MORPHOMETRIC MARKERS

Genetic divergence study is imperative in breeding programmes in order to select distant parents. Forty maize inbred lines were assessed using morphometric markers to identify the potential inbred lines for yield and its component traits. The inbred lines were raised in α-RBD design replicated twice during kharif 2019. The morphological diversity analysis was done as per the standard statistical procedures using Mahalanobis D2-statistic. Analysis of variance revealed significant mean sum of squares due to genotypes for all the traits suggesting ample amount of genetic variability present among them. Moderate PCV, GCV and high heritability coupled with moderate genetic advance was observed for grain yield per plant, plant and cob placement height. Grain yield per plant exhibited significant positive correlation with all the traits except days to 50 per cent pollen shed and silking. Path analysis revealed high direct effects of days to 50 per cent pollen shed, harvest index, grains per row and 100 grain-weight on grain yield per plant therefore these morphometric traits would be the best selection indices to select high yielding genotypes. D2-statistics grouped 40 maize genotypes into three clusters. Cluster III has the highest cluster mean values for all the traits.Seven genotypes viz., 4186-4-05-1-1, LM-14, BAJIM-08-27, BIOM 10, LQPM24×1114-5, 9180-2, LDH 5(Vivek-21-1) were superior over the best check on the basis of mean performance and disease resistance and were diverse therefore, could be used in maize improvement program.

Evaluation of sustained release mineral boluses as a long-term nutrient delivery method for beef cattle

Two studies were conducted to evaluate the efficacy of sustained release mineral boluses as an alternative nutrient delivery method for beef cattle. For both studies 16 ruminally-cannulated cows were used in a completely randomized design. In study 1, we evaluated degradation rates of two bolus prototypes and cow age (2-yr-old versus 3-yr-old cows) over an 87-d study period. In study 2, we evaluated two bolus types (90-d degradation target versus 180-d degradation target), as well as two diet qualities contrasting a low-quality high-fiber forage (> 600 g/kg neutral detergent fiber and < 80 g/kg crude protein, dry matter basis) and high-quality low-fiber forage (< 500 g/kg neutral detergent fiber and> 150 g/kg crude protein, dry matter basis). For both Study 1 & 2, intake and digestion periods were conducted to evaluate cow age (study 1) or diet quality (study 2) effects on intake and rumen/reticulum function. In study 1, models containing an asymptotic effect of day and an interaction between day and bolus type were the best supported of the candidate models for bolus degradation rate. Cow age did not affect (P= 0.48) bolus degradation rates (β^ = -0.81 ± 1.13) and degradation rates were greater (P < 0.01) for bolus prototype B compared to bolus A (β^prototype B = -20.39 ± 1.13; β^prototype A = -9.64 ± 0.81). Bolus degradation rate displayed an asymptotic relationship (P < 0.01) to bolus surface area for prototype A (β^ = 5.83 ± 0.57) and a linear relationship (P < 0.01) for prototype B (β^ = 0.001 ± 0.0001). In study 2, models containing a linear effect of day and an interaction between day and diet were the best supported of the candidate models for the degradation rate of the 90-d and 180-d prototype. In addition, both bolus protoypes displayed a diet quality × time interaction (P < 0.01) for bolus degradation rate. Cattle treated with the 90-d bolus and fed a high-quality diet had a greater (P < 0.01) degradation rate (β^High-quality = -2.64 ± 0.08; β^Low-quality = -1.97 ± 0.10) than the cows that were fed a low-quality diet. In contrast, cattle treated with the 180-d bolus had an inverse effect (P < 0.01), with bolus degradation rates greater (β^Low-quality = -0.09 ± 0.007; β^High-quality = -0.04 ± 0.005) with cows on the low-quality diet versus the high-quality diet. Across both studies, two of four bolus prototypes met target release rates at 90 days. However, bolus prototype degradation characteristics varied and were influenced by diet quality.

Effect of Some Non-Genetic Factors on 305-day Milk Yield and Lactation Persistency in Holstein Friesian Cows

This study was performed on productive data collected from private farm of Holstein Friesian cows. The objective of this study was to evaluate the effect of days in milk (DIM), peak milk yield (PMY), dry period (DP), calving interval (CI), parity, and season of calving on 305-day milk yield (305-DMY). And the effect of 305- day milk yield (305-DMY), peak milk yield (PMY), days in milk (DIM), parity, and season of calving on lactation persistency. We found that DIM, parity, and PMY had significant effect on 305-DMY, the highest milk production was obtained when DIM more than 357 days and in the 1st lactation. Moreover, PMY, 305-DMY, and season of calving had significant effect on lactation persistency. In addition, average estimated breeding value (EBV) for 305-DMY, PMY and CI was higher in sire than in cow and dam. Also, Average estimated breeding values for lactation persistency, DP, and DIM were higher in dam than in cow and sire.

PHYSIOLOGICAL MECHANISM OF FATIGUE. Review

Relevance. Fatigue, both intellectual and physical, reduces the efficiency of daily activities and quality of life, in addition, fatigue is one of the factors contributing to the development of various pathological conditions, such as cardiovascular disease and others. Therefore, it is important to understand the mechanisms underlying the development of fatigue, which will improve prevention and development.&#x0D; Objective: to analyze the physiological and biochemical mechanisms underlying the development of fatigue.&#x0D; Methods. Analysis of scientific publications of the international scientific database PubMed by keywords. The following research methods were used in writing the paper: systematization of material, analysis and generalization.&#x0D; Results. In this article we discussed the physiological and biochemical mechanisms of fatigue. The correlation between fatigue and the general mental condition, physiological, biochemical processes, activity of neurotransmitters, intellectual and physical activity, food has been defined. The central and peripheral mechanisms of fatigue were considered. Central fatigue is divided into spinal and supraspinal and involves the neuromuscular junction. Peripheral fatigue occurs at the level of the muscles and mainly involves muscle bioenergetics or an excitation-contraction coupling.&#x0D; Currently fatigue is considered as a general reaction to stress that lasts for a period of time, taken in an account the cumulative effects of days, weeks or months, and the effects of sleep disorders are also very important, because the effects of fatigue are closely linked to sleep deprivation. Therefore, the time required for recovery depends on the severity of fatigue. There are currently many research methods, such as electromyography, transcranial magnetic stimulation, magnetic resonance imaging, and spectroscopy, which are useful in undestending the physiological correlates of fatigue.&#x0D; In turn, psychological, behavioral or physical triggers can have a beneficial effect against the development of acute fatigue and improve performance, as well as provide a better understanding of the function of neurotransmitters, physiological and biochemical processes important in the development of body fatigue in general.