Influence of Season on Immunoglobulin Absorption and Status in Young Calves

A high rate of calf mortality can represent a major economic loss to the dairy farmer. Despite increased knowledge in calf rearing, mortality rates of 10 to as high as 25% are not uncommon. The loss of heifer calves alone cost dairymen an estimated $81 million in 1975. This figure does not include the additional costs of extra labor, medication and veterinary expenses, and the loss of genetic potential. The most critical period for calf survival is the first 2 to 3 wk of life. During this time, the calf depends upon colostral immunoglobulins absorbed during the first 24 h of life for protection against pathogenic microorganisms. Antigenic stimulation after birth activates the calf\u27s own immune system, but significant endogenous synthesis of immunoglobulin does not occur until about the fourth week of life. Studies on the newborn calf have shown that age at first feeding, amount of colostral immunoglobulin consumed, and mothering by the dam, all exert a strong influence on the amount of immunoglobulin absorbed. Attainment of an adequate level of circulating maternal immunoglobulins is of utmost importance for survival of the calf, since calf losses to infectious disease are highly correlated with low levels of serum immunoglobulins. Season of the year has been related to the immunoglobulin status of young calves. A survey of serum immunoglobulin levels in 1-wk-old market calves in Scotland showed a marked seasonal variation in mean serum immunoglobulin concentration, with high mean values during summer months (21). Lowest mean values occurred during winter months and coincided with the time of highest calf mortality. However, the observed seasonal variation may have been managemental in origin since the summer calves in this survey were born on pasture and nursed, while most winter calves were removed from their darn and bucket fed. A later study in Scotland (64), conducted from January thru July under uniform management conditions, showed no seasonal variation in- immunoglobulin status of neonatal calves. The influence of high temperature on immunoglobulin absorption was recently investigated (72) in Arizona. Newborn calves were housed under shade, cooled shade, or in hutches. Hutch-housed calves were exposed to higher ambient temperature and had lower serum immunoglobulin concentrations and a higher mortality rate. This study examined the influence of season of the year (winter vs. summer) and the related factors of temperature and humidity on colostrum immunoglobulin absorption and immunoglobulin status of dairy calves raised in outdoor hutches in South Dakota. Other relationships studied included (1) influence of lactation number and season of the year on immunoglobulin concentration in colostrum, and (2) influence of season on feed intake and weight gain of calves

Insects and arachnids associated with rapeseed, Brassica napus ssp. oleifera, in western Tennessee

Rapeseed is a member of the crucifer genus Brassica (Cruciferae; Brassiceae), a genus with more than 50 plant species utilized for fodder, food, oilseed, or vegetable production (Fribourg et al. 1989). Rapeseed represents both summer and winter forms of rape, Brassica napus ssp. oleifera L., and turnip rape, Brassica campestris ssp. oleifera L., and both species frequently occur in common geographical areas (Appelqvist 1972). Rape, a native to Europe and Northwestern Africa, was first introduced into Canada in 1942, where cultivation is limited to summer forms due to extreme climatic conditions. Until the mid-1980\u27s, rapeseed cultivation in the United States was limited to the Pacific Northwest and the Northern Great Plains (Fribourg et al. 1989). Usage of rapeseed is dependent upon the level of unsaturated erucic acid and sulfur-containing glucosinolates (Ohlson 1972). High erucic acid rapeseed (HEAR) is a plant cultivar with an oil content of \u3e50% erucic acid and \u3e30 μmol glucosinolates per gram of meal (Fribourg et al. 1989). HEAR oil cultivars are desirable because the oil is used for rubber stabilization, machine lubrication, and textile manufacturing (Ohlson 1972). From 1986 to 1988, field trial experiments were conducted at the Milan Experiment Station in western Tennessee to determine the suitability of local environmental conditions for rapeseed production (Fribourg et al. 1989). This research demonstrated that the rapeseed species, winter rape, Brassica napus ssp. oleifera forma biennis. could be cultivated in western Tennessee to produce HEAR oil. Because rapeseed is a new crop in western Tennessee, the species composition and seasonal incidence of arthropods are unknown; therefore, a two-year study beginning in the spring of 1990 was initiated to address these research areas. Rapeseed and other crucifers are hosts to more than 150 insect species, with many pest species representing the orders Coleoptera, Diptera, Hemiptera, Homoptera, and Lepidoptera (Hill 1987) . Most homopteran and lepidopteran pests attack the foliage tissues of crucifers; whereas, many coleopteran and hemipteran pests attack the reproductive tissues of crucifers, including rapeseed (Bonnemaison 1965). Dipteran pests are primarily root and foliage feeders (Hill 1987). During this study, approximately 111 species or groups were collected from rapeseed in western Tennessee. Fortyseven families representing ten insect orders, including Coleoptera, Diptera, Hemiptera, Homoptera, and Lepidoptera, and five families representing one arachnid order were collected and identified. The most extensive diversity of arthropods occurred during the flowering and ripening stages of rapeseed. The turnip aphid, Lipaphis erysimi (Kaltenbach) (Homoptera: Aphididae), was the predominant aphid species. The turnip aphid was present on the first sampling date (March 9 and 19) in 1990 and 1991, respectively. Turnip aphid populations increased most rapidly during the flowering stage of rapeseed, with population peaks coinciding with rapeseed flowering. Feeding damage in heavily-infested fields caused stunted growth, reduced pod production, and delayed seed maturity. Perhaps due to heavy spring rains, turnip aphid populations in 1991 were 78.8% lower than populations in 1990 as estimated by sweep-net sampling. In all fields sampled in 1990 and 1991, turnip aphids were frequently attacked by a wasp parasitoid [Diaeretiella rapae (M’Intosh) (Hymenoptera: Aphidiidae)]. Wasp populations in 1991 were 95.8% lower than in 1990, reflecting the reduced level of aphid infestation. Parasitized aphids ceased feeding, attached themselves to plant stems, and became brown mummies. The coleopteran species, the cabbage seedpod weevil, Ceutorhynchus assimilis (Paykull) (Curculionidae), was collected in sweep-net samples in 1990 and 1991 and was the most common (98.8%) curculionid species collected. Adults were first collected as rapeseed began to flower in early April, when adults were observed to feed and mate on flowers. Damaged seedpods were characterized by the presence of a small, black puncture, with larvae later damaging three to five seeds per pod. During both years of this study, overwintering adult populations peaked during or shortly after the peak flowering of rapeseed. The summer generation (F1) adults emerged three to four weeks later during the ripening (5.1 to 5.5) stage of rapeseed, and were observed to feed on any remaining green tissue. Several thysanopterans attracted to rapeseed flowers included flower thrips, Frankliniella tritici (Fitch), tobacco thrips, F. fusca (Hinds), and soybean thrips, Neohydatothrips variabilis (Beach) (all Thripidae). Flower thrips was the most abundant species (87.8%) in 1990 and (97.9%) in 1991. Flower thrips were most abundant during the flowering (4.1 to 4.4) and early ripening (5.1) stages, and numbers of flower thrips decreased rapidly after flowering terminated. No visual damage to infested plants was observed, and plants appeared to develop normally. The implication of thrips infestation in rapeseed is that the crop may serve as an early-season host for later infestation of other crops (e.g., cotton). In western Tennessee, the tarnished plant bug, Lvous lineolaris (Palisot de Beauvois) (Miridae), was the most frequently (\u3e95%) collected pod-feeding hemipteran. During both years of this study, tarnished plant bug populations peaked during the ripening (5.1 to 5.3) stage of rapeseed. The tarnished plant bug is believed to utilize rapeseed as an early-season host in western Tennessee; therefore, the tarnished plant bug may build up populations in rapeseed, and later infest other crops (e.g., cotton)

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis

The Effect of Socializing During Exercise on Psychological Need Satisfaction, Motivation to Exercise, and Wellbeing

Previous research has indicated that exercising with other people improves interest and engagement in physical activity (e.g., Christensen, Schmidt, Budtz-Jorgensen, & Avlund, 2006; Estabrooks & Carron, 1999). However, the degree of socializing with other people engaged in by exercisers has not been manipulated in previous studies. In the present study, the amount of socializing during exercise was manipulated in order to evaluate the effect of social connection on motivation to exercise. Two perspectives on the role of socializing in exercising were considered and discussed – Social Facilitation (Zajonc, 1965) and Self-Determination Theory (SDT; Deci & Ryan, 2000). In order to test the importance of social contact during exercise, previously inactive women between the ages of 18-30 were randomly assigned to exercise for 12 sessions in one of three conditions. In the “social partner condition”, two participants exercised together and also discussed personal topics. In the “non-social partner condition”, two participants exercised together, but did not discuss personal topics. Lastly, in the “exercise alone condition”, participants exercised alone. In general, it was hypothesized that the social partner condition would lead to the greatest improvements in satisfaction of the psychological need for relatedness, subjective vitality, motivation to exercise, amount of physical activity, fitness level, affect, interest, and effort in exercise. Non-social partners were expected to experience some benefits from exercising with a partner, but not to the same extent as those in the social partner condition. Participants who exercised alone were expected to experience the fewest improvements. The partner relationships were also examined more closely, with the expectation that pairings that were more interpersonally complementary (that is, more similar on affiliation, and reciprocal on dominance) would positively affect outcomes. Further, partners were expected to become more similar in their exercise behaviour and motivation due to their repeated interactions over the course of the study. A one-month follow-up session assessed whether motivation and exercise behaviour observed at the end of the study changed or were sustained over time. The hypotheses were partially supported. Overall, exercise contributed to improved vitality, fitness, and affect, with few differences amongst the conditions. Participants in both partner conditions reported greater relatedness, or social connection, after a month of exercising together, than the exercise alone condition participants. Some interesting motivational patterns emerged at the end of the study and at a one-month follow-up, with some indication that the social partner condition most greatly benefited motivation. Interpersonal complementarity positively impacted competence, relatedness, and fitness, but surprisingly had a negative impact on vitality. Partners did not become more similar to one another over the course of the study, suggesting a lack of mutual influence. The findings are discussed within the context of Self-Determination Theory and Social Facilitation. These findings contribute to a growing body of literature that indicates that the social aspects of physical activity are essential for physical and mental wellbeing. Further research is required to evaluate how social factors can be utilized to promote greater enjoyment of and adherence to physical activity

Developmental and Situational Factors Contributing to Changes in Eating Behaviour in First-Year Undergraduate Women

The purpose of the present study was to evaluate the importance of developmental history and current life events in predicting changes in eating behaviour in undergraduate women. The developmental variables tested were parents’ general parenting style and also how parents interacted with their daughter around food in childhood. Within the current situational model, I considered the variables of current family and peer dieting, as well as participants’ stressors and coping styles. Importantly, this study utilized a longitudinal design in which women provided information regarding their stressful experiences and eating behaviours over the previous week for nine weeks during their first semester of university. Results showed that it is possible to evaluate short-term changes in eating behaviours, and that both the situational factors as well as developmental history contribute to the understanding of these changes. A greater number of stressful academic and interpersonal events and perceived stress were both related to increases in dietary restriction over the semester, and also to periods of emotional over-eating. Past parenting style in childhood, including excessive control or very permissive parenting, were both related to a higher occurrence of current eating problems in daughters. Parental focus on the relationship between food and weight while their daughters were children was also related to more problematic eating behaviours in adulthood. As well, the more that peers and parents dieted or encouraged dieting presently, the more likely the participant was to exhibit restrictive dieting, as well as over-eating. The findings from this study suggest that the first year of university is a time when many changes occur in women’s eating behaviours, and further research on eating behaviour in this population is warranted

Impact of Insecticides on Predators of the Soybean Looper, Pseudoplusia Includens (Walker).

Insecticide toxicity to hemipteran predators (i.e. Geocoris punctipes (Say), Nabis capsiformis Germar, Nabis roseipennis Reuter, and Podisus maculiventris (Say)) was evaluated using three different routes of insecticide exposure (direct contact, indirect insecticide toxicity through consumption of treated prey, and residue uptake). Pirate 3SC\sp\circler (chlorfenapyr) had direct contact toxicity equal to Ambush 2E\sp\circler (permethrin) and Methyl Parathion 4E\sp\circler to most hemipteran predators tested. Exposure to foliage treated with Proclaim 0.16E\sp\circler (emamectin benzoate) usually resulted in lower mortality as compared to Pirate. Condor OF 100F\sp\circler (Bacillus thuringiensis) had the lowest contact toxicity to hemipteran predators of all insecticides tested. Pirate at 0.224 kg AI/ha had significantly greater toxicity through consumption of treated prey than Proclaim to adult N. roseipennis and greater toxicity than Admire 2FS\sp\circler (imidacloprid) and Tracer 4SC\sp\circler (spinosad) to adult G. punctipes. Pirate displayed greater residual toxicity in the field than the standard insecticide, Ambush, to adult G. punctipes and N. roseipennis and both adult and third-instar nymphs of P. maculiventris. Proclaim had lower residual toxicity than Pirate to G. punctipes and N. roseipennis, but greater residual toxicity than Admire and Tracer to adult G. punctipes adults when foliage was collected 48 hours after insecticide applications. Generally, older classes of insecticides, such as organophosphates and pyrethroids, were more toxic to natural enemy populations than newer insecticides in field tests. Total predator populations were significantly lower in plots treated with organophosphates as compared to populations in untreated plots in 1993 and 1995. In 1993, plots treated with Orthene 75S\sp\circler (acephate) had the lowest predator populations, and in 1995, plots treated with Karate 1E\sp\circler (lamba-cyhalothrin) had the lowe st populations among insecticides tested. In general, newer classes of insecticides were less toxic to hemipteran predators than older, standard compounds. These results demonstrate that these newer, more selective compounds may enable soybean producers to use these insecticides to combat pests and preserve a larger proportion of resident beneficial arthropod populations which in turn should slow pest resurgence and prevent secondary pest outbreaks

Effect of caffeinated gum on a battery of rugby-specific tests in trained university-standard male rugby union players

BACKGROUND: Caffeine has been shown to enhance strength, power and endurance, characteristics that underpin performance in rugby. Caffeinated gum has attracted interest as a novel vehicle for delivering caffeine, because absorption of caffeine from gum is quick. Rapid absorption of caffeine may be useful during rugby matches when there is limited time for supplementation such as at half-time or when substitutes enter play. The purpose of this study was to determine whether a low dose of caffeine in gum improves performance in a battery of rugby-specific tests. METHODS: In a double-blind, randomized, placebo-controlled, crossover design, 17 male university-standard rugby players (mass: 85.6 ± 6.3 kg; height: 179.4 ± 6.2 cm; age: 20.4 ± 1.2 years) chewed caffeinated gum (200 mg caffeine) or a placebo gum on two occasions separated by a week. After a standardized warm-up, gum was chewed for 5 min. Subsequently, participants performed three countermovement jumps, followed by an Illinois agility test, 6 × 30 m repeated sprints, and the Yo-Yo IR-2 test; each test was separated by short rest periods. RESULTS: Caffeinated gum enhanced countermovement jump by 3.6% (caffeine: 43.7 ± 7.6 cm vs. placebo: 42.2 ± 6.2 cm; d = 0.22, 95% CI [0.006, 0.432]; p = 0.044). There was a greater resistance to fatigue during the 6 × 30 m repeated sprint test (fatigue index caffeine: 102.2 ± 0.9% vs. placebo: 103.3 ± 1.2%; d = 1.03, 95% CI [0.430, 1.613]; p = 0.001), and performance on the Yo-Yo IR2 was improved by 14.5% (caffeine: 426 ± 105 m, placebo: 372 ± 91 m; d = 0.55, 95% CI [0.130, 0.957]; p = 0.010). Caffeine gum had no significant effect on the Illinois agility test (caffeine 16.22 ± 1.08 s vs. placebo 15.88 ± 1.09 s; d = - 0.31, 95% CI [- 0.855, 0.240]; p = 0.271). CONCLUSIONS: In university-standard rugby players, a low dose of caffeine (200 mg) supplied in chewing gum enhanced performance on the Yo-Yo IR-2 test and the countermovement jump test and reduced fatigue index during repeated sprints. These improvements in a battery of rugby-specific tests may transfer to enhanced performance in rugby matches