Seasonal changes in reproductive parameters and seminal plasma constituents of rams in Afyon province of Turkey

The objective of the present study was to describe seasonal changes in semen quality, serum testosterone and seminal plasma constituents for 9 months in 10 rams from a mature local (Daglic) and imported breed (Chios) under Afyon province conditions typical for the internal Anatolian region. Sperm motility and sperm concentration and testosterone level were higher, percentage of abnormal spermatozoa was the lowest during autumn. The biochemical analyses of ram seminal plasma indicated that the highest values of total protein, albumin (A), globulin (G), total lipid and cholesterol were recorded in autumn while A/G ratio exhibited the lowest values. Aspartate amino transferase (AST) activity and AST/ALT ratio recorded the lowest values, while moderate values were recorded for alanine amino transferase (ALT) activity in autumn. The results suggest that the rams under Afyon province conditions show seasonal changes for some reproductive parameters and seminal plasma constituents.     

Dominance and mating behavior of rams under paddock conditions

Contents A total of 30 ewes in three-sire or four-sire breeding pens were observed continously during daylight for four consecutive days of a synchronised estrus period. A linear dominance hierarchy was observed between the rams which was consistent and stable for each observation period. The highest ranking ram had more mounting encounters and was more aggressive than the subordinate rams. This activity disturbed his ejaculatory mechanism and sometimes resulted in the absence of ejaculation or energetic ejaculation. In the four-sire breeding pens the dominant ram often found it impossible to completely curtail the sexual activity of the subordinate rams. He made 70.9% and 49.0% of the total number of mounts in the three-sire and our-sire breeding pens, respectively. At the beginning of each observation period the highest ranking ram claimed most estrous ewes for his “harem”. The subordinate rams only had an opportunity to mate when several ewes were simultaneously in estrus. The average number of mounts per first copulation per ram was 2.2 (range 1.3–3.1). The time spent from first contact with the ewes until completion of the copulatory act in first copulation varied from 0.2–16.2 min. with an average of 4.0 min., whereas this interval was increased during the second copulation (average = 5.8 min.). Furthermore, the mating behavior of single rams was also observed. Inhalt: Rangordnung und Paarungsverhalten von Schafbocken unter Stallhaltungsbedingungen Es wurden insgesamt 30 Mutterschafe in Zehnergruppen mit 3 bzw. 4 Böcken gleichzeitig in einer Buchte gehalten und wahrend einer Östrusperiode tagsüber beobachtet. Fur die Böcke konnte eine klare Rangordnung erkannt werden, die über alle Beobachtungsperioden unverändert blieb. Der an höchster Stelle stehende Bock vollzog mehr Aufsprungsversuche und war aggressiver als die untergeordneten Böcke. Diese Aktivitäten störten bei ihm wiederholt den Ejakulatonsmechanismus, so daß ein unvollständiger Deckakt bei fehlender Ejakulation die Folge war. Bei gleichzeitiger Anwesenheit von 4 Böcken in einer Gruppe way es für den dominanten Bock häufig unmöglich, die Sexualaktivität der untergeordneten Böcke vollständig zu unterbinden. Auf den dominanten Bock entfielen bei Anwesenheit von 3 Böcken 70,9% aller Auf sprünge, bei der Anwesenheit von 4 Böcken waren dies 49,0%. Zu Beginn einer jeden Beobachtungs-periode versuchte der an höchster Stelle rangierende Bock, die meisten östrischen Mutterschafe für seinen “Harem” zu beanspruchen. Die untergeordneten Böcke hatten nur dann Gelegenheit zu decken, wenn mehrere Mutterschafe gleichzeitig im Östrus waren. Im Durchschnitt betrug die Anzahl der Auf sprünge bei der ersten Belegung pro Bock 2,2 (Schwankungsbreite 1,3 -3, 1). Die erforderliche Zeit fur die erste Paarung uariierte bei einem Mittelwert uon 4,0 Alin. zwischen 0,2 und 16,2 Min.; diese Zeitspanne erhöhte sich allerdings für die zweite Belegung auf durchschnittlich 5,8 Min. Darüber hinaus wurde das Paarungsuerhalten einzelner Böcke ohne die Anwesenheit anderer beobachtet.     

Changes in serum thyroxine and thyroid-stimulating hormone concentrations in epileptic dogs receiving phenobarbital for one year

A multicentric prospective study was conducted to monitor the effect of phenobarbital on serum total thyroxine (T4) and thyroid-stimulating hormone (TSH) concentrations in epileptic dogs. Serum T4 concentrations were determined for 22 epileptic dogs prior to initiation of phenobarbital therapy (time 0), and 3 weeks, 6 months, and 12 months after the start of phenobarbital. Median T4 concentration was significantly lower at 3 weeks and 6 months compared to time 0. Thirty-two percent of dogs had T4 concentrations below the reference range at 6 and 12 months. Nineteen of the 22 dogs had serum TSH concentrations determined at all sampling times. A significant upward trend in median TSH concentration was found. No associations were found between T4 concentration, dose of phenobarbital, or serum phenobarbital concentration. No signs of overt hypothyroidism were evident in dogs with low T4, with one exception. TSH stimulation tests were performed on six of seven dogs with low T4 concentrations at 12 months, and all but one had normal responses. In conclusion, phenobarbital therapy decreased serum T4 concentration but did not appear to cause clinical signs of hypothyroidism. Serum TSH concentrations and TSH stimulation tests suggest that the hypothalamic-pituitary-thyroid axis is functioning appropriately.     

Influence of age and testosterone levels on masculine development in rams

Fifty wethers and 51 spring-born rams were divided into five groups and slaughtered at different seasons of the year at average ages of 271, 361, 459, 557 or 652 d to determine the age and season at which differences in secondary sex characteristics could be detected. Serum testosterone concentrations and testes weights were low in January when the rams were 271 d of age and again in April at 361 d of age. By July, at 459 d of age, testosterone concentrations and testes weights had peaked and then decreased the following November at 557 d and February at 652 d. In contrast with plasma testosterone concentrations and testes weights, buckiness scores, splenius to semimembranosus or semitendinosus muscle ratios, splenius muscle weights and neck and shoulder percentages were not seasonal. All of these measures increased significantly up to July and continued to increase slowly, but not significantly, thereafter. Muscle color and texture scores and rib eye color scores tended to increase in a linear manner for both rams and wethers as age increased. Subcutaneous fat from rams was yellower and softer than that from wethers over all age groups. Ram fat firmness did not change (P greater than .05) with age, and the only significant change in ram fat color was between the groups at 271 and 361 d of age. Overall, season of year coupled with higher levels of serum testosterone was related to initial development of secondary sex characteristics in ram lambs.     

Changes of fructose concentrations in seminal plasma and glucose and testosterone concentrations in blood plasma in rams over the course of a year

The present study was performed to examine seasonal changes in the fructose concentrations of seminal plasma and glucose and testosterone concentrations of blood plasma over the course of a year (from November 2004 to November 2005) using 5 Suffolk rams. Osmolality of the seminal plasma was also measured. The fructose concentrations in the seminal plasma increased as the breeding season approached, with the maximum in October (179.8 mg/dl) and the minimum in May (6.9 mg/dl), although there were no significant differences during the year. Osmolality of the seminal plasma in February (304 mOsm) was significantly (P<0.05) lower than in January (325 mOsm), July (327 mOsm), and August (325 mOsm). It was also significantly (P<0.05) lower in November (308 mOsm) than in January and August. The blood plasma glucose concentration in October (79.3 mg/dl) was significantly (P<0.05) higher than in January and February (43.2 and 43.7 mg/dl, respectively). The blood plasma testosterone (T) concentrations were significantly (P<0.05) higher in September (8.5 ng/ml) and October (10.2 ng/ml) than in other months. The fructose concentrations in the seminal plasma appeared to be related to the glucose and T concentrations in the blood plasma. These results show that fructose concentrations in the seminal plasma and blood plasma glucose and T concentrations tended to increase during the breeding season, with the highest concentrations in October.     

Immunoglobulins and immunoglobulin-containing cells in the reproductive tract of normal rams

The levels of the immunoglobulins IgA, IgG1, IgG2, and IgM were measured in serum and fluid from various locations in the reproductive tract of normal rams. These fluids included semen, preputial washings, and fluid from the accessory sex glands (ASG), vasa deferens, rete testes, and tissue fluid from the seminal vesicles, bulbourethral glands, epididymal tails and efferent ducts. In addition, the prevalence of specific Ig-containing cells (ICC) was measured in sections of formalin fixed tissues stained by an indirect peroxidase-antiperoxidase labelling technique. Mean IgA levels in semen (1.23 mg/ml) and ASG fluid (0.46 mg/ml), were higher than in serum (0.19 mg/ml) and were at levels higher than IgG1 or IgG2 levels in semen, ASG fluid, and preputial washings, thus confirming the existence of a local immune system primarily in the ASG of ram genitalia. Relatively low concentrations of IgA and IgG in other genital fluids and IgG levels in these fluids were consistent with diffusion from serum. The relatively high prevalence of IgA-containing cells in bulbourethral (56% of all ICC) and prostate (49%) glands confirmed these tissues as major sites of local Ig production. ICC were also found in large numbers beneath pelvic urethral and preputial epithelia, but these were predominantly IgG-containing (88 and 72% respectively).     

Effects of age and reproductive stage on certain serum biochemical parameters of chios sheep under greek rearing conditions

The aim of the present study was to determine the normal ranges of the most commonly used serum biochemical parameters of sheep reared under Greek breeding conditions, as well as to test for the effects of the age and reproductive status of the animals on the normal values of these parameters. In total, 200 clinically healthy Chios sheep from 10 farms were used in the experiment. For the determination of the effect of age 150 sheep were assigned in three groups. Group A consisting of 50 lambs aged 2-6 months (mean +/- SD: 4.15 +/- 1.08), group B of 50 non-pregnant ewes into lactation aged 1-3 years (mean +/- SD: 2.12 +/- 0.86) and group C of 50 non-pregnant ewes into lactation aged more than 3 years (mean +/- SD: 5.98 +/- 1.66). For evaluating the effect of reproductive status 50 pregnant ewes in dry period were used, 15-30 days before the expected day of lambing (group D), along with the 100 non-pregnant ewes into lactation of groups B and C (group E). Blood sampling was performed once, in dry ewes from December to January, and in lambs and lactating ewes from March to May. The results showed that of the 14 biochemical parameters determined in serum, six were significantly affected by the age and eight by the reproductive stage of the animals.     

Metabolic and endocrine profiles and reproductive parameters in dairy cows under grazing conditions: effect of polymorphisms in somatotropic axis genes

Background

The present study hypothesized that GH-AluI and IGF-I-SnabI polymorphisms do change the metabolic/endocrine profiles in Holstein cows during the transition period, which in turn are associated with productive and reproductive parameters.

Methods

Holstein cows (Farm 1, primiparous cows, n = 110, and Farm 2, multiparous cows, n = 76) under grazing conditions were selected and GH and IGF-I genotypes were determined. Blood samples for metabolic/endocrine determinations were taken during the transition period and early lactation in both farms. Data was analyzed by farm using a repeated measures analyses including GH and IGF-I genotypes, days and interactions as fixed effects, sire and cow as random effects and calving date as covariate.

Results and Discussion

Frequencies of GH and IGF-I alleles were L:0.84, V:0.16 and A:0.60, B:0.40, respectively. The GH genotype was not associated with productive or reproductive variables, but interaction with days affected FCM yield in multiparous (farm 2) cows (LL yielded more than LV cows) in early lactation. The GH genotype affected NEFA and IGF-I concentrations in farm 1 (LV had higher NEFA and lower IGF-I than LL cows) suggesting a better energy status of LL cows.There was no effect of IGF-I genotype on productive variables, but a trend was found for FCM in farm 2 (AB cows yielded more than AA cows). IGF-I genotype affected calving first service interval in farm 1, and the interaction with days tended to affect FCM yield (AB cows had a shorter interval and yielded more FCM than BB cows). IGF-I genotype affected BHB, NEFA, and insulin concentrations in farm 1: primiparous BB cows had lower NEFA and BHB and higher insulin concentrations. In farm 2, there was no effect of IGF-I genotype, but there was an interaction with days on IGF-I concentration, suggesting a greater uncoupling somatropic axis in AB and BB than AA cows, being in accordance with greater FCM yield in AB cows.

Conclusion

The GH and IGF-I genotypes had no substantial effect on productive parameters, although IGF-I genotype affected calving-first service interval in primiparous cows. Besides, these genotypes may modify the endocrine/metabolic profiles of the transition dairy cow under grazing conditions.     

Gene and protein expression in the reproductive tract of Brazilian Somalis rams

Brazilian Somalis is a locally‐adapted breed of rams raised in tropical climate and native pastures. The present study was conducted to evaluate gene expression and proteome of the reproductive tract of such rams. Samples were collected from testes, epididymides, seminal vesicles and bulbourethral glands of four rams. Expression of clusterin (CLU), osteopontin (OPN) and prostaglandin D2 synthase (PGDS) genes were evaluated in all samples by real‐time PCR. Shotgun proteomic analysis was performed using samples from the head, corpus and cauda epididymides and from all other structures as well. Gene ontology terms and protein interactions were obtained from UniProtKB databases and MetaCore v.6.8 platform. CLU trasncripts were detected in the testes, epididymides, seminal vesicles and bulbourethral glands of the Somalis rams. The initial region and body of the epididymis had the greatest CLU expression. OPN mRNA was localized in all tissues of the ram reproductive tract. PGDS mRNA was detected in the testes and epididymides. Lable‐free mass spectrometry allowed the identification of 137 proteins in all samples. Proteins of the epididymis head mainly participate in cellular processes and response to stimulus, participating in catalityc activity and binding. Proteins of epididymis body acted as regulatory proteins and in cellular processes, with binding and catalytic activity. Cauda epididymis molecules were associated with cellular processes and regulation, with binding function and catalytic activity as well. Testis proteins were mainly linked to cell processes and response to stimuli, and had catalytic function. Seminal vesicle proteins were involved in regulation and mainly with binding functions. Most bulbourethral gland proteins participated in cellular processes. The present study is the first to evaluate the proteome and gene expressions in the reproductive tract of Brazilian Somalis rams. Such pieces of information bring significant cointribution for the understanding of the reproductive physiology of locally‐adapted livestock.     

Effects of testosterone on lipid peroxidation, lipid profiles and some coagulation parameters in rabbits

The purpose of this study was to investigate the effects of testosterone on some risk factors of atherosclerosis. Twenty-four male New Zealand white rabbits were randomly divided into three groups of eight. The first group was used as control. Second group was injected with 10 mg of testosterone propionate. Third group was castrated bilaterally. At the end of 6 weeks, lipid peroxidation (LPO), lipid profile, fibrinogen (FBN) level and coagulation parameters were evaluated. Testosterone administration decreased the level of high-density lipoprotein cholesterol (HDL-C), while castration increased this level (P < 0.05). Triglyceride (TG) and total cholesterol (TC) levels in the castration group were significantly higher (P < 0.05) than those in the testosterone group. The ratio of HDL-C:low-density lipoprotein cholesterol (LDL-C) decreased, while TC:HDL-C ratio increased (P < 0.05) in the testosterone group. No significant differences were found in the LDL-C and FBN levels among groups. However, there was a tendency for higher FBN level in the testosterone group. Testosterone administration resulted in an increase in the level of LPO (P < 0.05). Clotting time and prothrombin time prolonged in the castration group compared with testosterone group (P < 0.05). As a result, testosterone has exacerbating effect on atherosclerosis risk factors including lipid profile, LPO, FBN and coagulation system.     

Seasonal changes in breeding activity, testicular size, testosterone concentration and seminal characteristics in rams with long or short breeding season

Breeding activity (libido), testicular size, testosterone levels and seminal characteristics of 10 DLS adult rams (a population of 1/2 Dorset, 1/4 Leicester and 1/4 Suffolk selected for extended breeding season) were compared with those of 10 adult Suffolk rams. The study lasted 18 mo during which the data were recorded over 30 collection periods. All characteristics varied significantly with the season of the year, being lowest during the summer and highest during the fall. Suffolk rams had higher libido but lower testosterone levels than the DLS rams throughout the study. Testosterone increased earlier and decreased later in the breeding season in DLS compared with Suffolk rams, the interaction breed X period being significant. Testosterone concentration was highly associated with testicular size and libido, accounting for 65 and 28% of the variation in the Suffolk and 37 and 18% in the DLS rams, respectively. Seminal output and quality (motility and percentage of live spermatozoa) were highest in October and November and lowest in April and May. Rams within breeds differed significantly in the seminal characteristics studied. Results of the study showed that selecting the DLS ewes for extended breeding season may have altered the reproductive performance of the rams of that breed.     

A retrospective study on some reproductive parameters of German shepherd bitches in Kenya

Data relating to reproductive parameters of German shepherd bitches were collected from registered German shepherd dog (GSD) breeders with information kept over a 15-year period (1982-1997). The information obtained was verified using the East African Kennel Club records. A total of 594 bitches from 280 breeders were recorded. From these, 798 heats were observed, 594 of which were used for breeding, resulting in 3592 puppies. The mean age at puberty was 519.0 +/- 41 days. Heats occurred throughout the year, although significantly (P < 0.05) higher and lower incidences were observed in October and April respectively Pregnancy significantly (P < 0.01) increased interoestrous interval, which was 247.8 +/- 99.6 and 183 +/- 52 days among bred/pregnant and non-bred bitches respectively. Most bitches in oestrus (73.7%) were bred, and breeding was carried out throughout the year, with a distribution closely related to that of heat incidence. Subsequently, whelping occurred throughout the year, and 95.5% of the bitches that were mated whelped. A mean gestation period of 60.6 +/- 5.1 days was observed. The mean litter size was 6.4 +/- 0.4 puppies, and did not differ significantly between months. The preweaning losses were low, with 2.3% stillbirths, 0.9% culls and 11.4% mortalities.     

Heat stress in dairy cattle and other livestock under southern African conditions. III. Monthly temperature-humidity index mean values and their significance in the performance of dairy cattle

Temperature-humidity index (THI) values applicable to South Africa and Namibia have been established during this investigation for each month of the year by means of computerized modelling and mapping techniques. The data indicate that each year heat stress risk areas (HSRA's) expand from August to January and retract from February to July. The THI values classified according to the Livestock Weather Safety Index (LWSI) for lactating dairy cattle (LDC), suggest that, especially during November to March there is the risk of moderate to advanced heat stress in most South African dairy cows. This has important implications for their general health, udder health, production and reproduction. Careful planning of facilities and highly adaptable herd management are required to protect dairy cattle from heat stress.     

Comparison of cortisol, luteinizing hormone, and testosterone responses to a defined stressor in sexually inactive rams and sexually active female-oriented and male-oriented rams

The objective of this study was to determine whether the effect of restraint stress on cortisol, LH, and testosterone varied among sexually inactive and sexually active female- and male-oriented rams, to allow differentiation among ram classes. Restraint stress or no stress was imposed on sexually inactive (n = 7) and sexually active female- (n = 17) and male-oriented (n = 6) rams in a 2 x 3 factorial arrangement. Rams were assigned to restraint or control within each classification. Rams were habituated to wearing halters and being tethered in separate pens, permitting visual, vocal, and olfactory contact with adjacent rams for 7 d before treatment. After 1 d of habituation, rams were fitted with jugular catheters that were checked twice daily for patency. For restraint stress, rams were laid on their side with their legs tied for 1 h. For no stress, rams were tethered with halters and leads, but their legs were not tied. On the treatment day, blood was collected at 30-min intervals for 3 h followed by 15-min intervals for 1 h before restraint, during 1-h restraint, and for 1 h after liberation from restraint. Then blood was collected at 30-min intervals for an additional 2 h. Blood was collected from controls at similar intervals. Control rams were isolated from stressed rams. Cortisol, LH, and testosterone were measured using RIA. Mixed model analyses with repeated measures were used on transformed data. Average prestress data were used as a covariate. Cortisol increased (P < 0.01) within 15 min after restraint and remained increased until 1.5 h after liberation from 1-h of restraint stress. In contrast, in controls cortisol remained unchanged at 5 ng/ mL. Cortisol did not differ over time among ram classes, and the treatment x ram class x time interaction was not significant. For LH and testosterone, the ram class x time interactions appeared to compromise the ability to identify differences in these hormones, indicating that they were not good endocrine candidates for methods of classifying rams. In conclusion, restraint stress increased cortisol in sexually inactive and sexually active female- and male-oriented rams alike, thus not providing a method to differentiate among ram classes.