Effect of different seasons on concentration of plasma luteinizing hormone and seminal quality vis-à-vis freezability of buffalo bulls (Bubalus bubalis)

Seasonal variations in semen quality, freezability and plasma luteinizing hormone (LH) levels were studied between summer and spring. Semen volume, density and initial sperm motility did not differ significantly between different seasons. Plasma LH decreased between summer and spring but the differences were, however, not significant. Pre-freezing motility did not differ significantly but post-freezing motility varied significantly (P<0.01) between seasons. Post-freezing motility was lowest during summer and highest during winter. It can be concluded that summer spermatozoa may be fragile and cannot withstand freezing stress. To increase reproductive efficiency in buffalo during summer, semen should be frozen during winter and spring and used during hot weather conditions. Seasonal variations in plasma LH levels were insignificant.     

Effect of feeding a docosahexaenoic acid-enriched nutriceutical on the quality of fresh and frozen-thawed semen in Holstein bulls

The aim of the current study was to investigate the effect of feeding a DHA-enriched nutriceutical on the in vitro quality and sperm motility parameters of fresh and frozen-thawed bull semen assessed by CASA. Samples were obtained from nineteen Holstein bulls used for semen collection at Semen Production Center, Karaj, Iran. Control group (n = 10) were fed a standard concentrate feed while treatment group bulls (n = 9) had this standard feed top dressed with 100 g of a commercially available DHA-enriched nutriceutical. Semen quality was assessed on ejaculates collected at the baseline and after 5, 9, and 12 weeks of supplementation. Classical semen evaluation, assessment of sperm motility (subjective and computer-assisted), viability (eosin-nigrosin), and hypo-osmotic swelling test (HOST) were conducted. Semen volume, sperm concentration, and consequently total sperm output were not affected by dietary treatment (P > 0.05). Feeding the nutriceutical was indeed found to affect sperm motility parameters assessed by CASA after 9 weeks of trial. The treatment has improved total motility (P < 0.01), progressive motility (P < 0.05), average path velocity (P < 0.05), HOST-positive (P < 0.01), and proportion of rapid spermatozoa (P < 0.01) in the fresh semen of bulls. Moreover, the proportion of viable spermatozoa increased (P < 0.05) in the ejaculates collected from nutriceutical-fed bulls compared to the control after 12 weeks of feeding trial. The post-thawed HOST and sperm motility data obtained by CASA did not differ between two groups (P > 0.05). On the other hand, dietary supplementation did not affect body weight, BCS and scrotal circumference. Consequently, it can be concluded that dietary DHA supplementation or its precursors, improve in vitro quality and motility parameters of fresh semen assessed by CASA in Holstein bulls. However, this effect was not pronounced in frozen-thawed semen.     

Effect of feeding a docosahexaenoic acid-enriched nutriceutical on the quality of fresh and frozen-thawed semen in Holstein bulls

The aim of the current study was to investigate the effect of feeding a DHA-enriched nutriceutical on the in vitro quality and sperm motility parameters of fresh and frozen-thawed bull semen assessed by CASA. Samples were obtained from nineteen Holstein bulls used for semen collection at Semen Production Center, Karaj, Iran. Control group (n = 10) were fed a standard concentrate feed while treatment group bulls (n = 9) had this standard feed top dressed with 100 g of a commercially available DHA-enriched nutriceutical. Semen quality was assessed on ejaculates collected at the baseline and after 5, 9, and 12 weeks of supplementation. Classical semen evaluation, assessment of sperm motility (subjective and computer-assisted), viability (eosin-nigrosin), and hypo-osmotic swelling test (HOST) were conducted. Semen volume, sperm concentration, and consequently total sperm output were not affected by dietary treatment (P > 0.05). Feeding the nutriceutical was indeed found to affect sperm motility parameters assessed by CASA after 9 weeks of trial. The treatment has improved total motility (P < 0.01), progressive motility (P < 0.05), average path velocity (P < 0.05), HOST-positive (P < 0.01), and proportion of rapid spermatozoa (P < 0.01) in the fresh semen of bulls. Moreover, the proportion of viable spermatozoa increased (P < 0.05) in the ejaculates collected from nutriceutical-fed bulls compared to the control after 12 weeks of feeding trial. The post-thawed HOST and sperm motility data obtained by CASA did not differ between two groups (P > 0.05). On the other hand, dietary supplementation did not affect body weight, BCS and scrotal circumference. Consequently, it can be concluded that dietary DHA supplementation or its precursors, improve in vitro quality and motility parameters of fresh semen assessed by CASA in Holstein bulls. However, this effect was not pronounced in frozen-thawed semen.     

Season of the year influences semen output and concentrations of testosterone in circulation of yaks (Poephagus grunniens L.)

Seasonal changes in plasma testosterone concentration and semen quality were evaluated in yak bulls throughout a 1-year period. Blood samples were collected every week from adult yak bulls (n = 15). These blood samples were analyzed for testosterone using a highly sensitive enzyme-linked immunoassay. Ejaculates were collected from five representative bulls each week. Ejaculate volume, progressive motility, live sperm count and sperm concentrations were determined. Mean testosterone in plasma was 1.03 ± 0.25 ng/ml. Concentrations of testosterone changed throughout the year (P < 0.05) and were found to be highest during the winter. It was also higher during the autumn than in summer and spring (P < 0.05). Mean ejaculate volume, progressive motility, live sperm count and spermatozoa concentration were 2.7 ± 0.3 ml, 72.8 ± 1.4%, 82.3 ± 0.9% and 968 ± 233 × 10⁶ ml⁻¹, respectively. Ejaculate volume and sperm concentration were higher (P < 0.05) in autumn than in other seasons. To conclude, a highly sensitive EIA for testosterone was developed and validated for yak plasma. Seasonal changes in semen quality were associated with changes in the concentration of testosterone in plasma from yak bulls.     

Effects of <Emphasis Type="Italic">Mbo</Emphasis>II and <Emphasis Type="Italic">BspM</Emphasis>I polymorphisms in the gonadotropin releasing hormone receptor (<Emphasis Type="Italic">GnRHR</Emphasis>) gene on sperm quality in Holstein bulls

The hypothalamic gonadotropin-releasing hormone receptor (GnRHR) plays an essential physiological role in reproductive function, which triggers the synthesis and release of luteinizing hormone and follicle stimulating hormone in the pituitary. The objective of this study was to investigate the effects of polymorphisms of GnRHR gene on the quality of fresh and frozen semen in Holstein bulls. The PCR-RFLP method was applied to detect G286A and T340C transitions determining MboII and BspMI polymorphisms, respectively, in the exon I of bovine GnRHR gene and evaluated its associations with sperm quality traits in 131 Holstein bulls. In polymorphic locus 286, bulls with the GA genotype had significantly higher sperm motility in frozen semen (FMOT) than GG genotype (P < 0.01). In polymorphic locus 340, bulls with heterozygote CT genotype had significantly higher sperm motility (MOT), semen volume per ejaculate (VOL), and lower abnormal spermatozoa rate (ASR) than homozygote TT genotype (P < 0.05). Bulls contained one A allele or C allele had a favorable, positive effect on sperm quality traits. These results indicate that GnRHR gene can be a potential marker for improving sperm quality traits, and imply that bulls with GA or CT genotype should be selected in breeding program.     

Exposure by males to light emitted from media devices at night is linked with decline of sperm quality and correlated with sleep quality measures

ABSTRACT

The last several decades have been characterized by the widespread usage of digital devices, especially smartphones. At the same time, there have been reports of both decline in sleep duration and quality and male fertility decline. The aim of this study was to assess the relationship between evening exposure to the light-emitting screens of digital media devices and measures of both sleep and sperm quality. Semen samples were obtained from 116 men undergoing fertility evaluation for the following sperm variables: volume (mL), pH, sperm concentration (million/mL), motility percentage (progressive% + non-progressive motility%), and total sperm count. Exposure to the screens of electronic devices and sleep habits was obtained by means of a questionnaire. Smartphone and tablet usage in the evening and after bedtime was negatively correlated with sperm motility (?0.392; ?0.369; p < .05), sperm progressive motility (?0.322; ?0.299; p < .05), and sperm concentration (?0.169; p < .05), and positively correlated with the percentage of immotile sperm (0.382; 0.344; p < .05). In addition, sleep duration was positively correlated with sperm total and progressive motility (0.249; 0.233; p < .05) and negatively correlated with semen pH (?0.349; p < .05). A significant negative correlation was observed between subjective sleepiness and total and progressive motility (?0.264; p < .05) as well as total motile sperm number (?0.173; p < .05). The results of this study support a link between evening and post-bedtime exposure to light-emitting digital media screens and sperm quality. Further research is required to establish the proposed causative link and may lead to the future development of relevant therapeutic and lifestyle interventions.     

The seasonal fertility of North American bison (Bison bison) bulls

The objective of this study was to determine the presence and magnitude of seasonal fluctuations in semen quality and other reproductive indices in bison bulls. Testicles from 288 commercially slaughtered bison bulls were collected monthly over a 1-year period. Carcass and testicle weight were determined and measurements of seminiferous tubule lumen, diameter, and epithelial thickness were made. Sperm cell morphology and defects were described and quantified using epididymal semen from each testicle. Twenty-one Plains (Bison bison bison) and Wood bison (Bison bison athabascae) breeding bulls, averaging 6.0 years of age (range 2.5-8.0), from three farms were selected for semen collection and evaluation on the basis of producer co-operation. Semen was collected by electro-ejaculation on four seasonal occasions during a 12-month period. Ejaculate quality was judged on the basis of volume, density, gross and individual motility, morphology, live/dead ratio, and concentration. Sperm cell morphologies were evaluated microscopically and classified according to criteria used for bovine semen. Fecal testosterone was measured at each semen collection using a commercial competitive binding radioimmunoassay. There was an increase in carcass weights over the study period and testis weights were moderately correlated (r=0.44) with carcass weights. However, mean testes weights were heavier (P<0.05) in the summer than in winter, spring, or fall periods. There were no differences in the proportion of normal and abnormal epididymal sperm between seasons but there were seasonal changes in the testicular parenchyma. Seminiferous tubule and lumen diameter, and epithelial thickness were greatest (P<0.05) in summer. Live bulls gained weight between April and November, but lost weight over the winter. Normal sperm cell percentages as well as individual sperm cell motility in electro-ejaculated sperm samples were higher (P<0.05) at the pre-breeding collection relative to other collections, but no change in sperm cell concentrations occurred over the study period. Fecal testosterone concentrations were highest at the pre-breeding period (June) but decreased (P<0.05) in each subsequent collection to reach their lowest levels in the April. While many changes in seen characteristics were not significant, overall results indicate the presence of some reproductive seasonality and increased testicular capacity in the summer breeding season. Bulls showing marginal semen quality in the winter but otherwise carrying desirable genetic traits may warrant another evaluation in late spring prior to being culled from a breeding program.     

Impact of seasonality,storage of semen,and sperm head‐shape on whole tissue methylation and expression of methylation responsive candidate genes in swine placenta and fetal livers from summer and winter breedings

Epigenetics includes the study of external factors that can influence the expression of genes by altering the accessibility of DNA through methylation. To investigate the epigenetic influence of season, sperm head shape, and semen storage on placental and fetal tissues, pregnancies were generated in the summer or winter using boar semen from either least or most sperm head shape change, collected during cool or warm seasons, and stored as cooled‐extended or cryopreserved. The lowest (p < 0.05) ratios of 5‐methylcytosine to 5‐hydroxymethylcytosine activity (5mC:5hmC) in fetal liver were from summer breedings and in placental tissues from winter breedings. The relative expression of placental CDH1 tended ( p < 0.10) to be greater in placenta generated from cryopreserved semen or semen collected during cool periods. The relative expression of placental GNAS was affected ( p < 0.05) by the interaction of breeding and semen collection seasons. Cryopreserved semen increased ( p < 0.05) the placental relative expression of GNAS. Placental MEST and RHOBTB3 tended ( p < 0.10) to have a greater relative expression from pregnancies generated using semen collected during cool periods used during winter breedings. Within fetal liver, the relative expression of GNAS and HGF was greater ( p < 0.05) from winter breedings. Interaction of winter breedings and least sperm head shape change tended ( p < 0.10) to have the greatest fetal liver expression of CDH1. Seasonality of semen collection, breeding, and the effect on sperm head shape change had an influence on the expression of genes with known differentially methylated regions or response to methylation activity from embryonic and extraembryonic tissues.     

The contribution of bulls and cows to the seasonal differences in the fertility of dairy cattle in Israel

Semen collected from dairy Israeli-Friesian bulls in the winter and summer was pelleted-frozen and used for inseminations in the collection season, in the other season, and after a 12-month storage period.The semen quality, as assessed by the percentage of ejaculates with initial poor motility and low sperm density and the percentage of spermatozoa surviving the freezing-thawing process, and those revealing acrosomal and tail abnormalities after thawing, was slightly and non-significantly lower in summer than in winter.The fertility of semen collected in both seasons was not affected by a 12-month storage period. The use of winter semen in summer did not improve the low fertility of cows in that season compared with those inseminated with summer semen.It appears from the results of this study that the summer decrease in the fertility of the inseminations is due to the adverse effect of this season on the fertility of the cows.     

Flaxseed oil modulates testicular biometrics,hormone, libido,antioxidant and semen profiles in endangered Teressa goat of Andaman and Nicobar Islands

Teressa goat is a unique goat breed in Andaman and Nicobar Islands (ANI) of India. Effects of Flaxseed oil (FSO) supplementation in body weight (BW), scrotal circumference (SC), testicular volume (TV) and testicular weight (TW), endocrinological profiles, sex behavioural profiles (SBPs), oxidative stress markers and semen production and its quality profiles in rainy and dry summer season were studied in Teressa goat. Male goats (n = 12) of 3–4 years old were equally divided into control and treated groups. Treated animals received 25 mL FSO per day. Oral drenching of FSO was done in the morning before feeding the concentrate ration. Body weight, scrotal circumference, TV and TW were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Blood follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), cortisol and prolactin, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Libido score (LS), mating ability score (MAS) and sex behavioural score (SBS) were estimated at time of semen collection in bucks of FSO treated and untreated during rainy and dry summer seasons. Semen samples (n = 100; 50 semen samples from each season; each 25 semen samples from control and treatment groups per season) were collected and analysed for semen quality profiles. One-way ANOVA (control rainy, control dry, treated rainy and treated dry) revealed that BW, SC, TV and TW, FSH, LH, testosterone, TSH, T3 and T4 were higher (P < 0.05) and cortisol and prolactin were lower (P < 0.05) in FSO treated bucks of rainy season followed by untreated bucks of rainy season, FSO treated bucks of dry summer season and were lower (P < 0.05) in untreated bucks of dry summer season. Similarly, TAC, CAT, SOD and GSH, LS, MAS and SBS, and volume, pH, sperm concentration, mass activity, total motility (TM), viability, acrosomal integrity (AcI), plasma membrane integrity (PMI) and nuclear integrity (NI) were higher (P < 0.05) and MDA and TSA were lower (P < 0.05) in FSO treated bucks of rainy season followed by FSO treated bucks of dry summer season, untreated bucks of rainy season and were lower (P < 0.05) in untreated bucks of dry summer season. The results of the present study indicated that the breeding bucks suffered physiological stress (higher cortisol), oxidative stress (higher MDA and deficiency of antioxidants), hormonal imbalance (higher prolactin and cortisol and deficiency of gonadotropins, gonadal hormone and thyroid hormones) and infertility due to poor libido and poor semen production and its quality profiles during dry summer season. Thus, dry summer was more stressful season compared to rainy season for the goat bucks. FSO supplementation mitigated these stresses and improved the scrotal and testicular biometrics, libido, antioxidants, hormones and semen quality profiles in Teressa goat bucks. The current study concluded that FSO effectively improved the hormones, libido, antioxidant profiles, and scrotal and testicular biometrics with cascading beneficial effects on semen quality profiles in Teressa goat bucks under humid tropical island ecosystem of Andaman and Nicobar Islands.     

Seasonal variation in in vitro immune activity of milk leukocytes in elite and non-elite crossbred cows of Indian sub-tropical semi-arid climate

Immunity of mammary gland in terms of in vitro activity of milk leukocytes has been evaluated during hot-humid, summer, and winter season in elite (n = 10) and non-elite (n = 10) crossbred cows. Milk samples were collected from all the cows throughout the year at 15-day interval. Milk somatic cell counts (SCC) and differential leukocyte counts (DLC) were evaluated microscopically. Milk neutrophils, macrophages, and lymphocytes were isolated and cultured in vitro. In vitro PI of milk neutrophils and macrophages was evaluated by colorimetric NBT (nitro-blue tetrazolium) reductive assay. Mitogen-induced milk lymphocyte blastogenic response was measured by colorimetric MTT (thiazolyl blue tetrazolium bromide) assay. Milk SCC was found to be significantly (p < 0.01) higher in elite cows compared to non-elite cows irrespective of season. There was significant (p < 0.05) increase in milk SCC during hot-humid season compared to winter season in both the group of the cows. There was no significant difference between group and season in terms of DLC. In vitro phagocytic index of elite cows was significantly (p < 0.01) higher than non-elite cows. The phagocytic index was significantly (p < 0.01) decreased in summer and hot-humid season compared to winter season in both the group of animals. Macrophages isolated from elite cows having significantly (p < 0.01) lower phagocytic index than non-elite cows which significantly (p < 0.01) decreased during summer and hot-humid season compared to winter. In vitro milk lymphocyte proliferative response was significantly (p < 0.01) lower in elite cows. Activity of B-lymphocytes decreased significantly (p < 0.01) during summer and hot-humid season than winter, but activity of T-lymphocytes remains unaltered during different seasons. In conclusion, the mammary immunity in terms of in vitro activity of milk leukocytes is compromised during summer and hot-humid season in elite crossbred cows; therefore, better care and management should be taken in high-yielding cows during summer and hot-humid season to minimize intramammary infections.     

Seasonal variation in serum testosterone, testicular volume and semen characteristics in coatis (Nasua nasua)

The objective was to characterize seasonal changes in serum testosterone concentration, testicular volume and sperm quantity and quality in captive coatis (Nasua nasua) from Pantanal, MT, Brazil. Sampling was done once monthly for 1 y. Mean (± SEM) serum testosterone concentrations (767.37 ± 216.2 ng/ml) and total and progressive sperm motility (79.6 ± 3.9%; 3.8 ± 0.3, on a scale of 0 to 5) peaked in July. The highest combined testis volume (10.3 ± 0.4 cm³) and sperm concentration (403 million ± 102 sperm/ml) occurred in August, at the peak of the winter breeding season. No seasonal effects on percentages of morphologically normal sperm, acrosome integrity, or live sperm were detected; however, the percentage of secondary sperm defects was higher in the winter. In conclusion, intricate relationships between testosterone concentration, testis volume, semen concentration and total and progressive sperm motility with high levels of breeding activity were observed during the dry season in the winter (June, July, August), followed by a subsequent decline in these activities during the wet season (i.e., summer: December, January, February). There was no seasonal pattern for production of functionally intact and morphologically normal sperm.     

Collection method, season and individual variation on seminal characteristics in the llama (Lama glama)

The objective of the present study was to evaluate the effect of semen collection method (electroejaculation "EE" as compared with the artificial vagina "AV"), the season (summer versus winter) and the male used on macroscopic and microscopic characteristics of ejaculates in llamas. A total of 110 ejaculates were collected from six males and 92 of them were analyzed. Ejaculate volume, concentration, total sperm and the following sperm characteristics were studied: motility, membrane function (HOS test), membrane integrity (CFDA/PI fluorochromes) and morphology. A mixed linear model, that considered season and collection method as the fixed variables and the male as the random variable, was used for the statistical analysis. Variability was found between males (p相似文献   

Impact of season on antioxidants,nutritional metabolic status,cortisol and heat shock proteins in Hariana and Sahiwal cattle

The aim of this study was to evaluate the effects of summer and winter seasons on antioxidant status, body reserve mobilization and biomarkers of stress in Hariana and Sahiwal cows. Twelve lactating cows (six of each Hariana and Sahiwal cows) were included in summer (May to July) and winter season (November to January) study. Microclimatic observations were recorded on daily basis during the experimental period. In both seasons, blood samples were collected at fortnightly intervals for analysis of total antioxidant activity, non-esterified fatty acids (NEFA), β-Hydroxybutyric acid (BHBA), heat shock protein 70 and 90 (HSP70 and HSP90). Antioxidant activity reduced significantly (p < 0.05) in Hariana cattle during summers as compared to winters; whereas, seasonal variation exerts no effect on antioxidant activity in Sahiwal. Blood NEFA concentration was similar among both the breeds over both the seasons but reduced significantly (p < 0.05) during summer season as compared to winters in both the breeds. BHBA concentration was significantly higher (p < 0.05) in Hariana cows than Sahiwal cows during winters, however, no effect on BHBA level was observed during summer season in both the breeds. Significantly, lower plasma cortisol level (p < 0.05) was found during winter season in Sahiwal as well as Hariana cows. Further, Sahiwal exhibited lower plasma cortisol as compared to Hariana in both the seasons. HSP 70 and 90 showed non-significant differences between breeds within both the seasons. However, significantly, lower plasma HSP 70 levels (p < 0.05) were reported during winter season in Sahiwal as well as in Hariana cows. Results of present study revealed that indigenous Sahiwal is more heat tolerant as compared to Hariana breed.     

Effect of addition of buserelin acetate to the extender on motility and viability of bovine spermatozoa

The present study was aimed to determine the effect of GnRH analog (buserelin acetate) on the quality of bovine spermatozoa stored at 16°?C for 24?h. Semen collected in the summer season from June to September from healthy Polish Holstein–Friesian bulls. Ejaculates were centrifuged, divided and diluted to the final concentration of 240?×?10⁶ spermatozoa/mL using animal protein–free commercial BIOXcell^® extender (IMV Technologies, L’aigle, France) (Control) or with BIOXcell^® extender supplemented with buserelin acetate and stored 0, 8 and 24?h. Sperm motility parameters analysis was performed using a computer-assisted sperm analysis (CASA) system. The viability of spermatozoa was performed using flow cytometer. The addition of buserelin acetate to BIOXcell^® extender did positively affect the total motility (was higher in the observed samples with the addition of 2?µg/mL and 4?µg/mL than in the control group), progressive motile (forward progressing sperm was significantly increased (p?<?0.05) over the control group at the 0?h and 8?h of incubation following the supplementation of 2, 4 and 8?μg/mL buserelin acetate) and viability of spermatozoa (the number of live spermatozoa was significantly higher (p?<?0.05) in 2?µg/mL and 4?µg/mL samples with buserelin acetate at 8th hour of incubation and in sample with 4?µg/mL at 24th hour of incubation compared to the control group). We recommend adding 4?µg/mL to the extender to improve the quality of bovine semen.     

Evaluation of adaptability to different seasons in goat breeds of semi-arid region in India through differential expression pattern of heat shock protein genes

The present study was conducted to examine differential expression pattern of HSP genes and adaptability in Indian goat breeds of semi-arid region. The study was conducted in five animals from each breed viz. Barbari, Sirohi, and Jhakrana during winter, thermo-neutral and summer seasons. The respiratory rate (RR) and rectal temperature (RT) of the goats were recorded at 09:00 h during the study period. The blood samples were collected for RNA isolation, cDNA synthesis, and quantitative analysis of HSP genes expression by quantitative RT-PCR. The RR increased significantly (p < 0.01) during summer as compared to winter and thermo-neutral season however, RT did not change (p > 0.05) during different seasons. The expression of HSP genes was significantly (p < 0.01) increased during summer (high THI) as compared to thermo-neutral season in all the goat breeds. Among HSPs, only HSP90 was upregulated (p < 0.01) in Jhakrana goats during winter as compared to thermo-neutral season. The deviation in expression of HSP genes during summer and winter with respect to thermo-neutral season was minimum in Barbari goats. Therefore, it can be concluded that Barbari goats possessed better adaptability during summer and winter as compared to Sirohi and Jhakrana goats in semi-arid climatic conditions of India.     

Subjective and objective sleep among air ambulance personnel

ABSTRACT

The present study aimed to investigate the effects of shift work on sleep among pilots and Helicopter Emergency Medical Service crew members (HCM) in the Norwegian Air Ambulance. Sleep was assessed by diaries and actigraphy during a workweek (24 h duty for 7 consecutive days) in the winter season and a workweek during the summer season in pilots and HCM (N = 50). Additionally, differences in sleep were studied between the week before work, the workweek, and the week after work in both seasons. Results indicated that bedtime was later (p <.001) and time spent in bed (p <.05) was shorter during the summer, compared to the winter, season. The workers delayed the sleep period in the workweek, compared to the week before (winter: p <.001, summer: p <.001) and the week after (winter: p <.05-.001, summer: p <.001). They spent more time in bed during the workweek, compared to the week before (winter: p <.001, summer: p <.01) and after (winter: p <.001, summer: p =.37). Further, the workers had longer wake after sleep onset during the workweek, compared to the week before (winter: p <.001, summer: p <.01) and the week after (winter: p <.01, summer: p <.01). Finally, the workers had lower sleep efficiency during the workweek recorded by actigraphy compared to the week before (winter: p <.01, summer: p <.001) and the week after (winter: p <.01, summer: p <.001). According to the sleep diaries the total sleep time was 7:17 h in the winter and 7:03 h in the summer season. Overall, the sleep was somewhat affected during the workweek, with delayed sleep period, longer wake after sleep onset, and lower sleep efficiency compared to when off work. However, the workers spent more time in bed during the workweek compared to the weeks off, and they obtained over 7 h of sleep in both workweeks. Our findings suggest that the pilots and the HCM sleep well during the workweek, although it affected their sleep to some extent.     

Seasonal variation in semen quality in Bos indicus and Bos taurus bulls raised under tropical conditions

In the present study, we tested the hypothesis that Bos taurus taurus bulls have greater reactive oxygen species (ROS) and lower activity of antioxidant enzymes in their semen than Bos taurus indicus bulls. Sixteen Simmental bulls (B. t. taurus) and 11 Nelore bulls (B. t. indicus) were managed extensively in a tropical environment. Semen was collected twice annually (summer and winter) for 2 consecutive years. Simmental bulls had significantly higher percentages of major sperm defects during the summer than the winter (20.3+/-3.1% versus 12.2+/-2.4%, respectively; mean+/-S.E.M.). There was an interaction of breed and season for minor sperm defects (P=0.037; highest in Nelore bulls in the summer) and an effect of season on total defects (P=0.066; higher in summer). To evaluate oxidative damage, malondialdehyde (lipid-peroxidation metabolite) concentrations were indirectly measured by semen concentrations of thiobarbituric acid reactive substances (TBARS); these were higher in summer than in winter (728.1+/-79.3ng/mL versus 423.8+/-72.6ng/mL, respectively; P=0.01). Glutathione peroxidase/redutase (GPx) activity in semen was higher in Simmental versus Nelore bulls (741.6+/-62.1 versus 510.2+/-62.8; P<0.01). However, superoxide dismutase (SOD), another antioxidant enzyme, was not significantly affected by breed or season. There were correlations between TBARS and sperm primary defects during the summer for both Simmental and Nelore bulls (r=0.59, P=0.021 and r=0.40, P=0.034, respectively), and between SOD and primary defects during summer for Simmental bulls only (r=-0.51, P=0.041). In conclusion, there was a higher level of lipid peroxidation (ROS) in semen of Simmental versus Nelore bulls; apparently the higher GPx activity in Simmental bulls was insufficient to avoid damage that occurred concurrent with increased ROS production during the summer.     

Offspring sex ratio in sheep,cattle, goats and pigs: influence of season and lunar phase at conception

This study assessed the relationship between season and lunar phase at conception on offspring sex ratio of four livestock species (sheep, cattle, goats and pigs). The sex of 66,830 lambs (1995–2015); 25,546 calves (2011–2015); 5671 kids (2002–2007) and 1916 piglets was recorded. Moon phases were categorized as either new moon, crescent moon, full moon or decrescent moon. Sex ratio, expressed as proportion of males (males/males + females), was tested against the expected value of 1:1. In sheep, offspring sex ratio and lunar phase were not correlated; season had a significant (p = 0.002) effect on offspring sex ratio. The proportion of males born of spring and winter matings was significantly higher than it was among offspring born of summer (p < 0.05) or autumn (p < 0.01) conceptions. Offspring sex ratios in spring (p < 0.05), autumn (p < 0.01) and winter (p < 0.05) differed significantly from the expected. In cattle, moon phase and season did not affect the offspring sex ratio; however, the interaction effect was highly significant (p = 0.001). The overall piglet sex ratio (0.522), and the sex ratios among piglets conceived during a crescent moon and those conceived in summer differed significantly (p < 0.05) from 1:1. Research including additional factors such as hormonal treatments prior to insemination, food availability, weather and maternal and paternal factors might provide the underlying reasons for the effects of season and moon phase on offspring sex ratio in some livestock species.