Effects of recent sexual experience and melatonin treatment of rams on plasma testosterone concentration, sexual behaviour and ability to induce ovulation in seasonally anoestrous ewes

Reproduction ◽  
2000 ◽  
pp. 169-176 ◽  
Author(s):  
HJ Rosa ◽  
DT Juniper ◽  
MJ Bryant
Keyword(s):  
Seasonal Changes ◽  
Body Condition Score ◽  
Sexual Experience ◽  
Plasma Testosterone ◽  
Melatonin Treatment ◽  
Plasma Progesterone ◽  
Plasma Melatonin ◽  
Live Body Weight ◽  
Condition Score ◽  
Subcutaneous Implant

The aim of this study was to determine whether advancing the seasonal changes associated with rams by treatment with exogenous melatonin and allowing the rams previous sexual experience would increase the proportion of anoestrous ewes ovulating in early July. North Country Mule ewes (n = 225) were grouped by live body weight and body condition score and allocated randomly to the following treatments: (i) isolated from rams (control; n = 25); (ii) introduced to rams (treatment 2); (iii) introduced to rams that had mated with ewes during the previous 2 days (treatment 3); (iv) introduced to rams implanted with melatonin (treatment 4); and (v) introduced to rams that were implanted with melatonin and had mated with ewes during the previous 2 days (treatment 5). Treatments 2-5 were replicated (2 x 25 ewes) and two rams were introduced to each replicate group. Introductions began on 4 July and were completed by 11 July. The rams were withdrawn from the ewes after 8 days. Melatonin was administered as a subcutaneous implant (Regulin((R))) on 22 May and again on 20 June. Blood samples were taken from all rams to determine plasma melatonin and testosterone concentrations (19 samples in 6 h). The behaviour of the sheep was videotaped continuously during the first 3 h after the ram was introduced. Ovulation was detected by an increase in plasma progesterone concentrations from < 0.5 ng ml(-1) to > 0.5 ng ml(-1). Mean +/- SE plasma melatonin concentrations were 649.7 +/- 281.4 and 18.3 +/- 2.4 pg ml(-1) in rams with and without melatonin implants, respectively (P < 0.001). Melatonin implants also increased plasma testosterone concentrations from 4.30 +/- 1.88 to 10.10 +/- 1.10 ng ml(-1) (P < 0.01), the libido of the rams and the proportion of ewes that ovulated in response to the rams (43 and 56% (treatments 4 and 5) versus 24% (treatments 2 and 3)). In conclusion, implanting rams with melatonin before introducing them to seasonally anoestrous ewes increases the proportion of ewes that ovulate in response to introduction of a ram, but previous sexual experience of rams appears to have little or no effect.

10 TIMED ARTIFICIAL INSEMINATION PROTOCOLS TO SYNCHRONIZATION OF OVULATION IN BOS TAURUS TAURUS SUCKLING BEEF COWS

2015 ◽  
Vol 27 (1) ◽  
pp. 97
Author(s):  
G. A. Pessoa ◽  
A. P. Martini ◽  
J. M. Trentin ◽  
D. R. Dotto ◽  
H. L. D. Neri ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Body Condition Score ◽  
Animal Health ◽  
Beef Cows ◽  
Treated Group ◽  
Conception Rate ◽  
Plasma Progesterone ◽  
Follicle Diameter ◽  
Condition Score ◽  
South Of Brazil

The aim of this study was to compare 3 methods for synchronization of ovulation in anestrous beef cows. The hypothesis of this study was to determine whether low doses of hCG has superior efficacy to cypionate to induce ovulation in anestrous cows and provide higher pregnancy rate in oestrus-synchronization programs. Synchronization of ovulation and conception rate to timed AI (TAI) were evaluated in anestrus Bos taurus taurus suckling beef cows 45 ± 15 days postpartum and with body condition score of 2.9 (1 to 5) maintained in a native pastured system in the south of Brazil. Females were evaluated with ultrasound on the Day 0 (D0) of the protocol (Day 0), day 8 (D8), immediately before TAI (D10), and 7 days after TAI (Day 17). All cows were synchronized with an intravaginal progesterone-releasing device (IPRD; 0.75 g of progesterone, Prociclar®, Hertape Calier Animal Health, Juatuba, Brazil) and 2 mg IM of oestradiol benzoate (EB; Benzoato HC®) on D0. On Day 8, the IPRD was removed and 150 μg of D (+) cloprostenol (Veteglan Luteolytic®), and 25 IU IM FSH/LH (Pluset®) were administered. Females of the EC (n = 84) group received 1 mg IM of oestradiol cypionate (EC; Cipionato HC®). Females on D8 of the hCG (n = 81) group received 500 IU IM of hCG (Vetecor®, Hertape Calier) at the time of TAI. The females of the EC + hCG group (n = 83) received both treatments. All cows were submitted to TAI 54 h after withdrawal of IPRD. A part of the cows (n = 102) had the ovulation evaluated every 12 h from the withdrawal of IPRD [EC (n = 34), hCG (n = 34), and hCG + EC (n = 33)]. Statistical analysis was performed using SAS PROC GLIMMIX. The dominant follicle diameter (FD) on Day 8 (8.7 ± 0.2, 8.8 ± 0.2, 8.6 ± 0.2) did not differ between treatments EC, EC + hCG, or hCG (P = 0.79). However, the FD on D10 was higher (P = 0.001) for cows treated with hCG (12.9 ± 0.3) compared with cows from the EC (11.3 ± 0.2) or EC + hCG group (11.8 ± 0.2). The interval (h) between the withdrawal of IPRD and ovulation was lower (P = 0.01) for the hCG group, (71.2 ± 1.7) compared with the groups treated with EC or EC + hCG (76.6 ± 2.18 and 74.2 ± 1.65), respectively. The ovulation rate did not differ (P = 0.61) among the EC (85.2%, 29/34), hCG (91.1%, 31/34), or EC + hCG groups (90.9%, 30/33). Corpus luteum diameter (mm) was higher (P = 0.04) on D17 for the hCG-treated group (21.4 ± 0.3) compared with others treatments (EC = 19.1 ± 0.8 or EC + hCG = 20.4 ± 0.8). However, the plasma progesterone levels on D17 were EC = 2.0 ± 0.1, hCG = 2.4 ± 0.1, and EC + hCG = 2.3 ± 0.1 ng mL–1 (P = 0.19), and the conception rate on the 28th day after TAI (EC = 43.0%; hCG = 47.0%, and EC + hCG = 48.8%; P = 0.76) was also similar. The hCG determined smallest ovulation interval, but similar rates of pregnancy were observed with both treatments.

scholarly journals Effect of Body Condition Score, Treatment Period and Month of the Previous Lambing on the Reproductive Resumption of Melatonin-Treated Sarda Breed Sheep during Spring

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1898
Author(s):  
Luisa Pulinas ◽  
Giovanni Cosso ◽  
Maria Consuelo Mura ◽  
Melissa Carvajal-Serna ◽  
Hatem Ouled Ahmed ◽  
...  
Keyword(s):  
Treatment Period ◽  
Body Condition ◽  
Body Condition Score ◽  
Reproductive Activity ◽  
Melatonin Treatment ◽  
The Third ◽  
Condition Score ◽  
Effect Of Treatment ◽  
Rearing Techniques ◽  
Breed Sheep

Stakeholders place great emphasis upon rationalizing the management and rearing techniques which are utilized within sheep farms. The present study aimed to investigate factors which may improve the reproductive performance of melatonin-treated Sardinian sheep via a series of three trials. The first trial (n = 100) investigated the effect of melatonin treatment alongside body condition score (BCS), the second trial (n = 150) investigated the effect of treatment alongside the date of treatment (treatment period) and the third trial (n = 150) investigated the effect of treatment alongside the previous lambing of the ewes. The findings indicated that melatonin is an effective tool for anticipating and improving the reproductive activity of in Sarda breed sheep during the springtime. Furthermore, to obtain optional results, melatonin implantation should be conducted in April, in ewes that have a BCS of >2.5 and that have passed their third month of lactation.

scholarly journals Plasma Melatonin and Progesterone Profiles of Suffolk and Romney Marsh Ewes Implanted with Melatonin during Anoestrus Season at Lower Latitudes in Southern Hemisphere

2018 ◽  
Vol 44 (1) ◽  
pp. 8
Author(s):  
Aya Sasa ◽  
Paula Almeida Rodrigues ◽  
Keico Okino Nonaka ◽  
Julio César de Carvalho Balieiro ◽  
Lia Alencar Coelho
Keyword(s):  
Individual Variation ◽  
Southeastern Brazil ◽  
Individual Response ◽  
Light Phase ◽  
Melatonin Treatment ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Mean Values ◽  
Positive Effects ◽  
Plasma Melatonin

Background: The subcutaneous implants of melatonin are stimulatory and mimic the positive effects of short photoperiod on reproduction in small ruminants. This study investigated the daily plasma melatonin profiles in ewes treated with melatonin implants and kept under natural photoperiod in Southeastern Brazil. The plasma progesterone concentrations were also investigated before and after melatonin implantation.Materials, Methods & Results: Romney Marsh (n = 11) and Suffolk (n = 10) ewes, which had been isolated from rams for at least 2 months prior to the beginning of the trial, were randomly allocated in two groups based on melatonin implant treatment (with or without melatonin implant). For plasma melatonin concentration, 43 days after melatonin implantation and 3 days before the ram introduction blood samples were collected every 2 hours during 24 hours. For plasma progesterone concentrations, blood samples were collected every once to twice a week for 2 different periods: prior to melatonin implantation and 46 days after the melatonin implantation and at the same day of the introduction of rams. The hormonal concentrations were determined by the radioimmunoassay method (RIA). The data were analyzed according to MIXED procedure (SAS) as repeated measurements for random animal effects. The effect of melatonin treatment on plasma melatonin 24-h period varied according to the breed. At the dark-phase, there were no plasma melatonin differences (P > 0.05) between implanted and no-implanted (228.02 ± 58.39 vs. 169.59 ± 48.39) Romney Marsh ewes whereas for Suffolk ewes the plasma melatonin levels were higher in implanted (305.61 ± 68.39 pg/mL) than no-implanted (151.26 ± 38.35 pg/mL) ones. At the light-phase, melatonin treatment effects could be evidenced and these differences (P < 0.01) consisted of higher melatonin values for implanted ewes and basal values for no-implanted ones in both breed groups. Before the melatonin implantation, the plasma progesterone levels were ˂ 1 ng/mL for Romney Marsh (0.41 ± 0.02 ng/mL) and Suffolk (0.47 ± 0.02 ng/mL) ewes. During the ram introduction period, no melatonin treatment effect was observed on plasma progesterone concentrations in both breed groups, but 2 days after ram introduction the plasma progesterone concentrations increased the mean values > than 1 ng/mL in implanted and no-implanted Suffolk ewes. In implanted Romney Marsh ewes the elevation of progesterone mean values was weak whereas in no-implanted Romney Marsh ewes the progesterone levels were maintained ˂ 1 ng/mL during all the blood sample collection times.Discussion: The melatonin treatment also produced a similar model of daily melatonin levels as reported previously by others, which is characterized by high plasma melatonin concentrations during the light phase of the day. The effect of melatonin implants on plasma melatonin profiles interacted with breed confirming an individual response to melatonin implantation which is proportional to genetic individual variation pattern of melatonin secretion. Before the melatonin implantation all Romney Marsh and Suffolk ewes were judged to be in non-ovulatory period (anoestrus) with plasma progesterone mean values lower than 1 ng/mL. The melatonin treatment helped to induce the ovulatory activity in most of the ewes that were in anestrous at the time of melatonin implantation and the efficacy of this treatment depends on the individual variation in ovulatory response to ram introduction. In Southeastern Brazil., melatonin implant altered the daily plasma melatonin profiles of Suffolk and Romney Marsh ewes by increasing the melatonin levels during the light-phase of the day. Melatonin implant also induced an ovulatory response in Suffolk and Romney Marsh after the introduction of the rams. For no-implanted Suffolk ewes, the male effect is sufficient to provoke an ovulatory response.

scholarly journals Effects of a synthetic gonadotrophin-releasing hormone agonist, leuprolide, on rut-associated events in male red deer

2009 ◽  
Vol 49 (12) ◽  
pp. 1120 ◽  
Author(s):  
G. K. Barrell ◽  
S. C. T. Schaafsma ◽  
M. J. Ridgway ◽  
M. Wellby ◽  
L. A. Miller
Keyword(s):  
Cervus Elaphus ◽  
Red Deer ◽  
Body Condition Score ◽  
Plasma Testosterone ◽  
High Dose ◽  
Release Formulation ◽  
Releasing Hormone ◽  
Condition Score ◽  
Gonadotrophin Releasing Hormone ◽  
Farming Industry

This study examined the effectiveness of leuprolide, a gonadotrophin-releasing hormone agonist, in suppressing rut-associated events in farmed male red deer. In mid-January (~6 weeks before the rut period in the southern hemisphere) adult red deer (Cervus elaphus scoticus) stags that had been allocated to three groups (n = 10 per group) received leuprolide, administered subcutaneously in a 90-day release formulation, at zero (control), low (22.5 mg) or high (45 mg) doses. Following treatment with leuprolide there was evidence of suppression of mean plasma luteinising hormone concentration that was significant (P < 0.05) at 9 weeks. Mean plasma testosterone concentration of all three groups rose following treatment, then declined prematurely in the low- and high-dose leuprolide-treated groups, so that it was significantly (P < 0.05) suppressed (0.66 ± 0.29 and 2.0 ± 0.88 ng mL–1, low and high dose respectively) in early April when the peak value (9.0 ± 1.94 ng mL–1) was recorded from control stags. A reduction in mean liveweight occurred in all three groups through February–April and this did not differ among treatments. However, a corresponding reduction in mean body condition score was greater in the control stags (P < 0.05). There was little effect of leuprolide treatment on aggressive behaviours, but it lowered roaring frequency in the latter period of the rut. The results indicate that this gonadotrophin-releasing hormone agonist has potential for application in the deer farming industry to suppress undesirable effects of the rut.

scholarly journals Reproductive seasonality in domestic sows kept outdoors without boars

Reproduction ◽  
2001 ◽  
pp. 613-629 ◽  
Author(s):  
JM Bassett ◽  
CJ Bray ◽  
CE Sharpe
Keyword(s):  
Seasonal Changes ◽  
Plasma Prolactin ◽  
Summer Solstice ◽  
Reproductive Seasonality ◽  
Plasma Progesterone ◽  
Plasma Melatonin ◽  
Melatonin Administration ◽  
Spring Equinox ◽  
Low Amplitude ◽  
Seasonal Infertility

Plasma progesterone, LH and prolactin concentrations were measured twice a week in mature sows kept outdoors without boars in two experiments to examine whether perception of daylength change underlies seasonal infertility in domestic pigs. In Expt 1, melatonin implants inserted on 12 April or 22 May to block perception of the increasing daylength did not affect the oestrous cycle significantly, since only two untreated control sows became seasonally anoestrous. In Expt 2, all control sows became anoestrous for 131 +/- 42.5 days (n = 11). Melatonin implants inserted at the spring equinox (n = 9) prevented seasonal anoestrus (P < 0.001), but timed daily oral melatonin administration was less effective (P < 0.05): 5 of 11 sows became anoestrous for 132 +/- 45.6 days. In both experiments, there were significant low-amplitude seasonal rhythms in mean plasma prolactin and LH concentrations. Prolactin reached maximum concentrations 2-4 weeks before the summer solstice, whereas LH reached a nadir 4-6 weeks after the summer solstice. Neither anoestrus nor melatonin administration altered these patterns consistently. Endogenous plasma melatonin was higher (P < 0.001) during darkness (12.5 ng l(-1)) than during daytime (8.9 ng l(-1)) in untreated sows, but only clearly so during spring and summer. Melatonin implants increased mean daily plasma melatonin to 146 ng l(-1), whereas melatonin fed at 15:00 h increased values to 40-60 ng l(-1) 2-4 h after administration, but daytime concentrations were unchanged. Melatonin administration, despite decreasing seasonal anoestrus, did not prevent the seasonal increase in plasma prolactin and had no significant effect on plasma LH; therefore, its role in regulating seasonal changes in the reproduction of domestic sows remains uncertain.

The effects of melatonin treatment and recent sexual experience on the ability of rams to induce ovulation in seasonally anoestrous ewes

1999 ◽  
Vol 1999 ◽  
pp. 69-69
Author(s):  
H.J.D. Rosa ◽  
M.J. Bryant
Keyword(s):  
Seasonal Changes ◽  
Sexual Experience ◽  
Significant Trend ◽  
Melatonin Treatment ◽  
Exogenous Melatonin

Rosa and Bryant (1997) have described how sexual experience increased the amount of time that rams spent in courtship of seasonally anoestrous ewes. There was a non-significant trend for a greater proportion of ewes to respond to increased ram stimulation in early July, indicating that efforts to enhance the cues provided by rams at this time may be effective in increasing the incidence of ovulation. The objective of this experiment was to establish if advancing the seasonal changes associated with the rams by treatment with exogenous melatonin and allowing the rams prior sexual experience would induce ovulation in anoestrous ewes in early July.

Impact of simulated heat stress on growth, physiological adaptability, blood metabolites and endocrine responses in Malpura ewes under semiarid tropical environment

2015 ◽  
Vol 55 (6) ◽  
pp. 766 ◽  
Author(s):  
S. Indu ◽  
V. Sejian ◽  
S. M. K. Naqvi
Keyword(s):  
Heat Stress ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Adaptive Behaviour ◽  
Blood Metabolites ◽  
Plasma Progesterone ◽  
Blood Biochemical ◽  
Condition Score ◽  
Endocrine Parameters ◽  
Plasma Oestradiol

The study was conducted to develop a simulated heat stress model for sheep depicting natural environmental conditions and to observe its impact on growth, reproductive performance, physiological adaptability, blood metabolites and endocrine responses in Malpura ewes. The experiment was conducted on 16 adult Malpura ewes for a period of 35 days. The animals were randomly divided into two groups of eight animals each (GI – control, GII – heat stress). The GII ewes were exposed to different temperature at different hours of the day i.e. 38°C at 1000–1100 hours; 40°C at 1100–1200 hours; 42°C at 1200–1300 hours; 43°C at 1300–1400 hours; 44°C at 1400–1500 hours and 42°C at 1500–1600 hours in a climatic chamber. Feed intake (P < 0.01), bodyweight (P < 0.05) and body condition score (P < 0.01) reduced significantly in GII as compared with GI ewes while water intake increased significantly (P < 0.01). All physiological responses also showed significant variation between the groups for treatment. In addition, all endocrine parameters showed highly significant (P < 0.01) variation for the treatment. Plasma cortisol increased significantly (P < 0.01) while T3 (P < 0.01) and T4 (P < 0.01) decreased significantly in GII as compared with GI ewes. Further, plasma oestradiol decreased significantly (P < 0.01) while plasma progesterone increased significantly (P < 0.01) in GII as compared with GI. Among the biochemical parameters, hemoglobin, packed cell volume, plasma glucose, total cholesterol, urea and blood urea nitrogen differed significantly between the groups. In addition, oestrus duration also significantly (P < 0.05) reduced in GII as compared with GI. Based on the results obtained from the study it can be concluded that simulated heat stress influenced the adaptive behaviour of sheep in terms of changes in physiological, blood biochemical and endocrine responses. Ultimately, their growth and reproductive performance are compromised during the process of adaptation to the simulated heat stress.

Prediction of body fat from body condition score and live body weight in adult churra ewes

1994 ◽  
Vol 1994 ◽  
pp. 209-209
Author(s):  
P. Frutos ◽  
A.R. Mantecón ◽  
P.R. Revesado ◽  
J.S. González
Keyword(s):  
Body Weight ◽  
Body Fat ◽  
Body Condition ◽  
Production Systems ◽  
Body Condition Score ◽  
Fat Depots ◽  
Live Body Weight ◽  
Condition Score ◽  
Sheep Production ◽  
Semiarid Conditions

Most sheep production systems under arid or semiarid conditions are dependent on the ability of animal to retain and movilize body fat.The sucess of body condition score (BCS) method (Russel et al., 1969) and live body weight (LBW) as mesures of body reserves is in function of body fat depots distribution, and the sheep genotype could determine this distribution (Taylor et al., 1989).The aim of this work is to predict body fat depots of adult Churra ewes, from BCS and/or LBW.A total of 36 adult Churra ewes, with a range of body condition score between 1.25 and 4.00 and live body weight between 30.3 and 52.6 kg were used.At slaugther, internal fat depots (IF; omental:OF, mesenteric:MF and perirenal:PF) were removed and weighed. Chemical fat of carcass (CF) and non-carcass (NCF) were also estimated.

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