Effect of seasonal environmental changes on selected reproductive parameters in mares

2021 ◽  
Vol 24 (2) ◽  
pp. 208-218
Author(s):  
Z. Vilhanová ◽  
F. Novotný ◽  
I. Valocký ◽  
V. Hura ◽  
P. Horňáková ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Seasonal Changes ◽  
Environmental Changes ◽  
Jugular Vein ◽  
Day Length ◽  
Reproductive Parameters ◽  
Spearman Correlation ◽  
Microsoft Excel ◽  
Average Temperature ◽  
Preovulatory Follicles

The aim of this study was to monitor and evaluate the seasonal changes on selected reproductive parameters in mares. Ninety-six mares of different breeds, aged 3 to 23 years were evaluated during the breeding season 2015–2018 at the Equine clinic at University of Veterinary Medicine and Pharmaco­logy in Košice, Slovakia (48°42´N, 21°15´E). The beginning of the estrus was determined by history or observation, mares were examined every 6 hours, blood for progesterone analysis was taken from the jugular vein. Correlation analyses were performed using both the Pearson and the Spearman correlation coefficient. Statistical analysis was performed using the functions of Microsoft Excel and GraphPad Prism. The day length (r = -0.708, P<0.0001) and the average ambient temperature (r = -0.754, P<0.0001) had a statistically significant effect on the duration of estrus. The shortest estrus was recorded in July with day length of 15 hours 40 minutes at an average temperature of 21.4 ± 0.52 °C, with duration 4.67 ± 0.58 days. The longest estrus was recorded in April with day length of 11 hours 48 minutes at average temperature of 6.9 °C. The environmental factors did not affect the size of the preovulatory follicles, the concentration of progesterone, the internal changes of uterus and the external manifestations of estrus.

Temperature/light interactions and the effect of seed source on germination of annual ryegrass (Lolium rigidum Gaud.) seeds

1976 ◽  
Vol 27 (6) ◽  
pp. 779 ◽  
Author(s):  
D Gramshaw
Keyword(s):  
Constant Temperature ◽  
Day Length ◽  
Maximum Temperature ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Average Temperature ◽  
Seed Sources ◽  
Alternating Temperature ◽  
Germinating Seeds ◽  
Temperature Optima

Germination of Lolium rigidum seeds, in the light (12 hr day length) and in the dark, was studied at constant and alternating (12/12 hr) temperatures in the range 8–35°C. Seeds had after-ripened for 22 weeks. Different constant temperature optima for germinability were found: 27° in light and 11° in dark. Germinability at alternating temperatures in darkness was determined solely by the minimum temperature of the alternation, and there was no response to thermoperiodicity per se. In contrast, light and alternating temperature appeared to interact to increase germinability, although the highest germinability occurred only when the maximum temperature was close to the optimum constant temperature, i.e. about 27°. Germination in both light and dark was most rapid where either the constant or the average temperature of an alternating regime was between 18 and 29°. Below 18° germination rates decreased markedly, and at 8°, rates were one-third of those at 18°. Seeds germinated more slowly in light than in darkness at all temperatures, but the differences were small relative to the effects of low temperatures.In another study, seeds collected from plants naturalized in eight different localities in the cereal belt of Western Australia and subsequently planted together in two contrasting environments were examined for germinability at 24/12°C in light and dark 18 weeks after harvest. Dark germinability differed between seed sources but not between planting sites, and ranged between 78 and 93%. Exposure of germinating seeds to light substantially alleviated dormancy in seeds from all sources.

Temperature modulation of photoperiodism and the timing of late-season changes in life history for an aphid, Acyrthosiphon pisum

2011 ◽  
Vol 143 (1) ◽  
pp. 56-71 ◽  
Author(s):  
M.A.H. Smith ◽  
P.A. MacKay ◽  
R.J. Lamb
Keyword(s):  
Sexual Reproduction ◽  
Seasonal Changes ◽  
Acyrthosiphon Pisum ◽  
Late Summer ◽  
Day Length ◽  
Temperature Modulation ◽  
Four Seasons ◽  
Aphid Clone ◽  
Photoperiodic Responses

AbstractWhere winters are severe, aphids reproduce parthenogenetically and viviparously in summer, switch to sexual reproduction in late summer, and produce winter-hardy eggs by the end of the season. The role of day length and temperature in initiating seasonal changes from parthenogenetic to sexual reproduction by pea aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), are described and the selection pressures that affect the timing of this transition are investigated. Over four seasons, a pea aphid clone was sampled from field cages through late summer in southern Manitoba, Canada, and reared in the laboratory to determine the phenotypes of progeny produced as the season progressed. The timing of transitions from one phenotype to another under natural day length and temperature, and the critical day lengths that caused the transitions, coincided with expectations from laboratory studies of photoperiodic responses. Males and mating females appeared later when the weather in August was warm than when it was cool. The timing of seasonal changes was adapted to minimize the physiological time to the end of the season, which maximized the number of asexual summer generations. Ambient temperature modulated the response to day length and fine-tuned the timing of sexual reproduction to adapt for annual variation in autumn weather.

scholarly journals Comparing citrated native, kaolin-activated, and tissue factor–activated samples and determining intraindividual variability for feline thromboelastography

2011 ◽  
Vol 23 (6) ◽  
pp. 1109-1113 ◽  
Author(s):  
Amrita Banerjee ◽  
Shauna L. Blois ◽  
R. Darren Wood
Keyword(s):  
Veterinary Medicine ◽  
Tissue Factor ◽  
Blood Test ◽  
Jugular Vein ◽  
Point Of Care ◽  
Alpha Angle ◽  
Maximum Amplitude ◽  
Intraindividual Variability ◽  
Significant Difference ◽  
Kappa Value

Thromboelastography (TEG) is a point-of-care whole blood test of hemostasis. While TEG is becoming more widely used in veterinary medicine, few studies describe the use of TEG in cats. The objectives of the current study were to: 1) document the range of TEG variables produced in healthy cats using 3 sample types (citrated native, kaolin-activated, and tissue factor–activated), and 2) determine if there was a significant difference between 2 separate samples obtained from individual healthy cats on the same day. Jugular venipuncture was performed in 20 cats, and citrated blood collected for TEG. TEG analysis was performed on citrated native, kaolin-activated, and tissue factor–activated blood for each sample. Two hours later, the procedure was repeated from the opposite jugular vein, yielding a total of 120 analyses. Reaction time ( R), alpha angle (α), kappa value (κ), and maximum amplitude (MA) were recorded from each tracing. No significant differences were found between TEG tracings from the first and second venipuncture samples. Significant differences were found between sample types for R, α, κ, and MA. Means for citrated native/kaolin-activated/tissue factor–activated methods were R = 4.1/3.7/0.6 min; κ = 2.5/1.8/2.2 min; α = 59.9/65.1/70.4 degrees; MA = 47.4/49.9/44.7 mm. A limitation of this study was the small number of cats used. Thromboelastography analysis may be a suitable method of evaluating hemostasis in cats.

scholarly journals Photoperiodic regulation of prolactin secretion: changes in intra-pituitary signalling and lactotroph heterogeneity

2004 ◽  
Vol 180 (3) ◽  
pp. 351-356 ◽  
Author(s):  
JD Johnston
Keyword(s):  
Environmental Conditions ◽  
Seasonal Changes ◽  
Mammalian Species ◽  
Prolactin Secretion ◽  
Day Length ◽  
Pars Tuberalis ◽  
Photoperiodic Regulation ◽  
Pituitary Lactotroph

Many mammalian species utilise day-length (photoperiod) to adapt their physiology to seasonal changes in environmental conditions, via secretion of pineal melatonin. Photoperiodic regulation of prolactin secretion is believed to occur via melatonin-mediated changes in the secretion of a putative prolactin secretagogue, tuberalin, from the pituitary pars tuberalis. Despite the in vivo and in vitro evidence in support of this intra-pituitary signalling mechanism, the identity of tuberalin has yet to be elucidated. This paper reviews recent advances in the characterisation of tuberalin and the regulation of its secretion. Furthermore, the hypothesis that pituitary lactotroph cells display heterogeneity in their response to changing photoperiod and tuberalin secretion is examined.

Modelling seasonal changes in the temperature-dependency of CO2 photosynthetic responses in two Vitis vinifera cultivars

2018 ◽  
Vol 45 (3) ◽  
pp. 315 ◽  
Author(s):  
Dennis H. Greer
Keyword(s):  
Vitis Vinifera ◽  
Seasonal Changes ◽  
Vitis Vinifera L ◽  
Temperature Dependency ◽  
Seasonal Climate ◽  
Average Temperature ◽  
Internal Co2 ◽  
Photosynthetic Responses ◽  
Temperature Optima ◽  
Cultivar Difference

A study of photosynthesis of two grapevine cultivars, Vitis vinifera L. cv. Chardonnay and cv. Merlot in relation to the seasonal climate and internal CO2 (Ci) concentration at leaf temperatures from 15 to 45°C was undertaken. Average rates of photosynthesis at saturating CO2 concentrations and all leaf temperatures were higher in Merlot compared with Chardonnay leaves. This was attributable to higher rates of ribulose 1,5-bisphosphate (RuBP) carboxylation (Vcmax) and regeneration (Jmax) in Merlot leaves. These differences in photosynthesis were extended as the season progressed, partly because rates of RuBP carboxylation and regeneration of Chardonnay leaves declined markedly whereas rates for Merlot leaves remained high. Although there was no cultivar difference in the seasonal average temperature optima for assimilation (34°C) and the underlying metabolism (40°C for Vcmax and 35°C for Jmax), for temperatures above 35°C, the Merlot leaves had 50% higher rates. Across the season, activation energies of the temperature sensitivity of Vcmax and Jmax declined in response to the seasonal climate but were consistently lower in Merlot than Chardonnay. This suggested some apparent differences in the biochemistry occurred between the two cultivars that limited assimilation in Chardonnay leaves, especially at higher temperatures, but did not limit assimilation in Merlot leaves.

scholarly journals Effects of Climatological Parameters on the Outbreak Spread of COVID-19 in Highly Affected Regions of Spain

2020 ◽  
Author(s):  
Khurram Shahzad ◽  
Umer Shahzad ◽  
Najaf Iqbal ◽  
Farrukh Shahzad ◽  
Zeeshan Fareed
Keyword(s):  
Air Quality ◽  
Pearson Correlation ◽  
Rank Correlation ◽  
Spearman Correlation ◽  
Pm 2.5 ◽  
Average Temperature ◽  
Castilla Y Leon ◽  
Panel Regressions ◽  
La Mancha ◽  
Rapid Spread

Abstract The Coronavirus (COVID-19) pandemic is infecting the human population, killing people, and destroying livelihoods. This research sought to explore the associations of daily average temperature (AT) and air quality (PM 2.5) with the daily new cases of COVID-19 in the top four regions of Spain (Castilla y Leon, Castilla-La Mancha, Catalonia, and Madrid). We apply Pearson correlation, Spearman correlation, Kendall’s rank correlation, and panel regressions to quantify the overall co-movement between temperature, air quality, and daily cases of COVID-19 from February to 17th April 2020. Overall empirical results show that temperature and air quality exert pressure to increase new COVID-19 infections. Our findings are contrary to the earlier studies, which show a significant impact of temperature in reducing the COVID-19 spread. The conclusions of this work can serve as an input to mitigate the rapid spread of COVID-19 in Spain and reform policies accordingly.

scholarly journals An assessment of the interactions between climatic conditions and genetic characteristic on the agricultural performance of soybeans grown in Northeast Asia

2018 ◽  
Author(s):  
Myoung Ryoul Park ◽  
Chunmei Cai ◽  
Min-Jung Seo ◽  
Hong-Tae Yun ◽  
Soo-Kwon Park ◽  
...  
Keyword(s):  
Northeast Asia ◽  
Climatic Conditions ◽  
Day Length ◽  
Stem Length ◽  
Genetic Characteristic ◽  
Average Temperature ◽  
Agricultural Performance ◽  
Positive Correlations ◽  
Highly Correlated ◽  
100 Seed Weight

AbstractGlycine max, commonly known as soybean or soya bean, is a species of legume native to East Asia. The interactions between climatic conditions and genetic characteristic affect the agricultural performance of soybean. Therefore, an investigation to identify the main elements affecting the agricultural performances of 11 soybeans was conducted in Northeast Asia, China [Harbin (45°12′N) Yanji (42°53′N) Dalian (39°30′N) Qingdao (36°26′N)] Republic of Korea [Suwon (37°16′N) and Jeonju (35°49′N)]. The days to flowering (DTF) of soybeans with the e1-nf and e1-as alleles and the E1e2e3e4 genotype, except Keumgangkong, Tawonkong, and Duyoukong, was relatively short compared to soybeans with other alleles. Although DTF of the soybeans was highly correlated to all climatic conditions, days to maturity (DTM) and 100-seed weight (HSW) of the soybeans showed no significant correlation with any climatic conditions. The soybeans with a dominant Dt1 allele, except Tawonkong, had the longest stem length (STL). Moreover, the STL of the soybeans grown at the test fields showed a positive correlation with only day length (DL) although the results of our chamber test showed that STL of soybean was positively affected by average temperature (AVT) and DL. Soybean yield (YLD) showed positive correlations with latitude and DL (except L62-667, OT89-5, and OT89-6) although the response of YLD to the climatic conditions was cultivar-specific. Our results show that DTF and STL of soybeans grown in Northeast Asia are highly affected by DL although AVT and genetic characteristic also affect DTF and STL. Along with these results, we confirmed that the DTM, HSW, and YLD of the soybeans vary in relation to their genetic characteristic.

Integration of Peripheral and Central Systems in Control of Ingestive and Reproductive Behavior

2020 ◽  
Author(s):  
Jill E. Schneider
Keyword(s):  
Energy Expenditure ◽  
Reproductive Behavior ◽  
Environmental Changes ◽  
Brain Area ◽  
Hormone Secretion ◽  
Peripheral Circulation ◽  
Ingestive Behavior ◽  
Day Length ◽  
Survival And Reproduction ◽  
Strong Candidate

During the evolution of animals, survival and reproduction depended upon mechanisms that maintained internal homeostasis in the face of environmental change. These environmental changes included fluctuations in ambient temperature, food availability, humidity, day length, and population density. Most, if not all, of these variables have effects on the availability of energy, and most vertebrate species have mechanisms that sense energy availability and adjust behavioral priorities accordingly. For example, when the availability of food and potential mating partners is stable and abundant, brain mechanisms often inhibit ingestive behavior, increase energy expenditure, and give priority to courtship and mating. In response to severe energy shortages, brain mechanisms are likely to stimulate foraging, food hoarding, and overeating. These same deficits often delay reproductive development or inhibit adult reproductive behavior. Such adaptations involve the integration of sensory signals with peripheral hormone signals and central effectors, and they are key to understanding health and disease, particularly obesity, eating disorders, and diabetes. The link between energy balance and reproduction recurs repeatedly, whether in the context of the sensory-somatic system, the autonomic nervous system, or the neuroendocrine cascades. Peripheral signals that are detected by receptors on vagal and splanchnic nerves are relayed to the caudal hindbrain. This brain area contains the effectors for peripheral hormone secretion and for chewing and swallowing, and this same brain area contains receptors for humoral and metabolic signals from peripheral circulation. The caudal hindbrain is therefore a strong candidate for integration of multiple signals that control the initiation of meals, meal size, energy storage, and energy expenditure, including the energy expended on reproduction. There are some differences between the reproductive and ingestive mechanisms, but there are also many striking similarities. There are still gaps in our knowledge about the nature and location of metabolic receptors and the pathways to their effectors. Some of the most promising research is designed to shed light on how hormonal signals might be enhanced or modulated by the peripheral energetic condition (e.g., the level of oxidizable metabolic fuels).

scholarly journals Photoperiod-Induced Neuroplasticity in the Circadian System

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Alessandra Porcu ◽  
Malini Riddle ◽  
Davide Dulcis ◽  
David K. Welsh
Keyword(s):  
Seasonal Changes ◽  
Phase Distribution ◽  
Light Exposure ◽  
Brain Regions ◽  
Day Length ◽  
Light Conditions ◽  
Seasonal Adaptation ◽  
Circadian Oscillators ◽  
Plastic Changes ◽  
Mood And Cognition

Seasonal changes in light exposure have profound effects on behavioral and physiological functions in many species, including effects on mood and cognitive function in humans. The mammalian brain’s master circadian clock, the suprachiasmatic nucleus (SCN), transmits information about external light conditions to other brain regions, including some implicated in mood and cognition. Although the detailed mechanisms are not yet known, the SCN undergoes highly plastic changes at the cellular and network levels under different light conditions. We therefore propose that the SCN may be an essential mediator of the effects of seasonal changes of day length on mental health. In this review, we explore various forms of neuroplasticity that occur in the SCN and other brain regions to facilitate seasonal adaptation, particularly altered phase distribution of cellular circadian oscillators in the SCN and changes in hypothalamic neurotransmitter expression.

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