Seasonal changes of scrotal circumference, blood plasma testosterone concentration and semen characteristics in Racka rams

The first objective of this study was to compare the seasonal reproductive pattern of Corriedale and Milchschaf rams. Because seasonal patterns were similar, a second objective was to compare the effectiveness of rams from both breeds to induce oestrus in seasonally anoestrous Corriedale ewes using the ram effect. In the first experiment, the seasonal changes of bodyweight, scrotal circumference, testosterone concentrations, sexual behaviour towards oestrous ewes (ano-genital sniffing, lateral approaches, flehmen, mount attempts, mounts, and copulation), and semen characteristics (total spermatozoa in the ejaculate, mass motility, and percentage of alive and normal spermatozoa) were recorded during 13 months in five Corriedale and seven Milchschaf rams. All recorded variables changed through the year, with maximum reproductive patterns occurring in summer and autumn. Milchschaf rams were heavier than Corriedale rams, but no difference was observed in their reproductive patterns. Experiment 2 was performed during the non-breeding season with 169 Corriedale and Polwarth mulitparous ewes. All ewes were isolated from the rams so that they could not see, hear or smell them (minimum distance: 1000 m) from Day –40. They were primed over 8 days with an intravaginal sponge impregnated with 50 mg of medroxiprogesterone. Four Corriedale rams were introduced to 83 ewes, and four Milchschaf rams to the remaining 86 ewes at sponge withdrawal, and oestrus was recorded for 5 days. On Day 5, no ewe of the group bred with Milchschaf rams was marked. By contrast, 46 out of 83 (55.4%) of the ewes bred with Corriedale rams were marked (P < 0.0001). It was concluded that reproductive seasonal pattern of Corriedale and Milchschaf rams, including scrotal circumference, testosterone concentrations, sexual behaviour and semen characteristics, was similar. However, Corriedale rams were more effective than Milchschaf rams in inducing oestrus in anoestrus ewes (the ram effect).

Download Full-text

Seasonal changes in plasma testosterone concentration and mating activity in Border Leicester, Poll Dorset, Romney and Suffolk rams

Australian Journal of Experimental Agriculture ◽

10.1071/ea9830248 ◽

1983 ◽

Vol 23 (122) ◽

pp. 248 ◽

Cited By ~ 18

Author(s):

MJ D'Occhio ◽

DE Brooks

Keyword(s):

Seasonal Changes ◽

Extended Period ◽

Field Conditions ◽

Plasma Testosterone ◽

Real Relationship ◽

Mating Activity ◽

Testosterone Concentration ◽

Testosterone Levels ◽

Seasonal Peak ◽

Precise Time

Seasonal changes in the plasma testosterone profile and mating activity were compared for Border Leicester, Poll Dorset, Romney and Suffolk rams (three of each breed) maintained under field conditions at latitude 35�S. Border Leicester, Romney and Suffolk showed maximum testosterone levels from February to May. Peak mating activity occurred from March to August, but the precise time and duration of the peak differed between the three breeds. A correlation (r = 0.65, P<0 .05) existed between seasonal changes in plasma testosterone and mating activity in Border Leicester but not in Romney or Suffolk. However, in all three breeds, peak testosterone levels preceded peak mating activity by 1-2 months. Poll Dorset rams showed an extended period of high testosterone levels from August to March but no seasonal peak in mating activity. There was no real relationship, in any breed, between plasma testosterone concentration and mating activity for individual rams within any month.

Download Full-text

The effect of hormonal treatment with kisspeptin, GnRH and hCG on semen characteristics in buck Cyprus goats during non-breeding season as compared with breeding season

Al-Anbar Journal of Veterinary Sciences ◽

10.37940/ajvs.2019.12.1.9 ◽

2019 ◽

Vol 12 (1) ◽

pp. 74-88

Author(s):

Maad AL-Ameri ◽

Talal Abdulkareem ◽

Ahmed Taha

Keyword(s):

Body Weight ◽

Breeding Season ◽

Normal Saline ◽

Hormonal Treatment ◽

Post Treatment ◽

Abu Ghraib ◽

Plasma Testosterone ◽

Control Group ◽

Testosterone Concentration ◽

Semen Characteristics

The current study aimed to determine the effect of hormonal treatment with kisspeptin, GnRH and hCG on plasma testosterone concentration and semen characteristics in buck Cyprus goats during non-breeding season as compared with breeding season. This study was executed at the Ruminant Researches Station pertaining to the Directorate of Agricultural Researches, Ministry of Agriculture, Abu-Ghraib, Baghdad (latitude 33˚20' N) for the period from November 15th, 2012 to December 〖31〗^st 2013. A total of 20 buck Cyprus goats 2 years old and averages 55 kg body weight. During non-breeding season bucks were randomly divided into five equal groups (4 bucks / group). The first group (A1) was regarded as a control group, i.m injected with normal saline, whereas, the second (A2) and third (A3) groups were i.v injected with 4 and 8 µg / kg body weight of Kisspeptin-10 respectively. The fourth (A4) and fifth (A5) groups were i.m injected with hCG (250 IU / buck) and GnRH (20 µg / buck) respectively. Plasma testosterone concentrations were significantly (P≤ 0.01 and P≤ 0.05) increased at 20, 30, 40 and 50 min post-treatment in A5, A2 and A3 groups as compared with control A1. Mass motility and individual motility were significantly (P≤ 0.01) in A5, A4, A2 and A3 as compared with control during non-breeding season. In conclusion, our results show that Kisspeptin-10, GnRH and hCG can stimulate the quiescent hypothalamic–pituitary–gonadal axis of bucks during non-breeding season by increasing plasma testosterone concentration post treatment that leads improving some semen characteristics during non-breeding season.

Download Full-text

144 Serum testosterone profile in Marwari stallions and its relationship with testicular parameters, semen characteristics, reaction time, stallion age, bodyweight, and height

Reproduction Fertility and Development ◽

10.1071/rdv32n2ab144 ◽

2020 ◽

Vol 32 (2) ◽

pp. 198

Author(s):

A. K. Chaudhary ◽

G. N. Purohit ◽

J. S. Mehta ◽

S. K. Ravi ◽

T. R. Talluri

Keyword(s):

Reaction Time ◽

Testosterone Level ◽

Sperm Concentration ◽

Serum Testosterone ◽

Testosterone Concentration ◽

Scrotal Circumference ◽

Semen Collection ◽

Semen Characteristics ◽

Before And After ◽

Relationship Of

The present study investigated the serum testosterone profile of Marwari stallions before and after exposure to a mare and the relationship of serum testosterone profile with scrotal circumference, semen characteristics, reaction time, stallion age, bodyweight, and height. Marwari stallions (n=9) of three age groups (2-4 years, n=3; 4-6 years, n=3; and 6+ years, n=3) were used in the study. Scrotal circumference, height, and bodyweight of each of the stallions were measured. Semen was collected from each stallion twice per week in the early-morning hours using an artificial vagina and a mare in oestrus. Six ejaculates were collected from each stallion for evaluation of various seminal parameters (semen volume, sperm concentration, and progressive sperm motility). Reaction time for each stallion was also recorded. At every alternate semen collection (first, third, and fifth collections), blood samples were taken 15min before exposure to the mare and just before the semen collection for serum testosterone hormone assay using a horse testosterone enzyme-linked immunosorbent assay kit. The data obtained were analysed statistically using SPSS ver. 20.0 (IBM Corp.). The results showed that mean testosterone concentration was significantly different (P ≤ 0.01) among the stallions and was significantly lower (P ≤ 0.01) in the stallions below 4 years of age. No significant difference in testosterone level was observed before and after exposure to a mare. A positive correlation was detected between testosterone and both scrotal circumference (P ≤ 0.05) and sperm concentration (P ≤ 0.05), whereas a negative correlation was observed with reaction time (P ≤ 0.01). It was concluded that exposure to a mare does not change the testosterone level in stallion blood and that there is a relationship of serum testosterone concentration with scrotal circumference, sperm concentration, reaction time, and age but not with height and bodyweight.

Download Full-text

Seasonal variation in the plasma testosterone concentration of reindeer and caribou

Canadian Journal of Zoology ◽

10.1139/z73-096 ◽

1973 ◽

Vol 51 (6) ◽

pp. 651-658 ◽

Cited By ~ 31

Author(s):

P. E. Whitehead ◽

E. H. McEwan

Keyword(s):

Seasonal Variation ◽

Growth Pattern ◽

Seasonal Changes ◽

Seasonal Pattern ◽

Plasma Testosterone ◽

Endocrine Glands ◽

Testosterone Concentration ◽

Testosterone Levels ◽

Rhythmic Growth ◽

Two Hybrid

Plasma testosterone levels of reindeer increased from 1 ng/cm3 in August to 30–60 ng/cm3 in mid-September. By late October, when rutting activity had almost ceased, the testosterone concentration had declined to barely detectable levels. The seasonal pattern exhibited by caribou was similar except the peak levels associated with rutting occurred about 1 month later than reindeer. The seasonal changes in plasma testosterone levels of two hybrid calves were studied. Peak testosterone levels of 5 and 3.8 ng/cm3 were attained in late October.The influence of the endocrine glands on antler renewal and casting, and the rhythmic growth pattern exhibited by caribou and reindeer are discussed.

Download Full-text