The pattern of LH secretion and the ovarian response to the ‘ram effect’ in the anoestrous ewe is influenced by body condition but not by short-term nutritional supplementation

2014 ◽  
Vol 26 (8) ◽  
pp. 1154 ◽  
Author(s):  
R. J. Scaramuzzi ◽  
L. Oujagir ◽  
J-B. Menassol ◽  
S. Freret ◽  
A. Piezel ◽  
...  
Keyword(s):  
Body Condition ◽  
Ovarian Response ◽  
Nutritional Supplementation ◽  
Short Term ◽  
Blood Concentrations ◽  
Lh Surge ◽  
Lh Pulsatility ◽  
Lower Glucose ◽  
Good Nutrition ◽  
Ram Effect

In sheep, the ‘ram effect’ induces out-of-season fertility and good nutrition increases prolificacy. This experiment determined if fatness or short-term nutritional supplementation modified the response to the ‘ram effect’. A group of 48 Île-de-France ewes were fed diets that produced groups with body-condition scores (BCS) of >3.0 and <2.0. Within each BCS group animals were supplemented daily with 500 g of lupins from Day –5 to Day 0 (ram introduction) resulting in four groups: low BCS, supplemented (n = 7) and non-supplemented (n = 8) and high BCS, supplemented (n = 12) and non-supplemented (n = 11). The blood concentrations of glucose and insulin and the LH response to gonadotrophin-releasing hormone (GnRH) were determined. After the ‘ram effect’ the pattern of LH pulsatility, the LH surge and ovarian responses were analysed. Low BCS ewes had lower glucose and insulin (P < 0.001) and supplementation increased both (P ≤ 0.001). The increase in LH induced by GnRH was reduced in low BCS ewes (P = 0.015) but it was not affected by supplementation. Similarly, LH pulsatility was reduced in low BCS ewes (P < 0.05). The LH surge and ovarian cyclicity were not affected but the follow-up cycle was delayed (P = 0.034) and progesterone was reduced (P = 0.029) in low BCS ewes. There was an effect of BCS on ovulation rate (P < 0.05). These results show that the BCS can modify the response to the ‘ram effect’ and that supplementation has little effect on this response.

Overview of the response of anoestrous ewes to the ram effect

2004 ◽  
Vol 16 (4) ◽  
pp. 479 ◽  
Author(s):  
R. Ungerfeld ◽  
M. Forsberg ◽  
E. Rubianes
Keyword(s):  
Post Partum ◽  
Ovarian Response ◽  
Short Length ◽  
Present Review ◽  
Response Patterns ◽  
Endocrine Response ◽  
Lh Pulsatility ◽  
Reproductive Response ◽  
Endocrine Parameters ◽  
Ram Effect

The present review summarises knowledge of the reproductive response of anoestrous ewes to the introduction of rams – in other words, the ram effect. The ovarian and endocrine response, the factors that determine whether ewes will respond or not (associated with both the stimulus and the receptivity of the ewes) and some aspects of practical management are discussed. Information on the use of the ram effect to stimulate post-partum, prepubertal and cyclic ewes is also given. New insights are provided on ovarian response patterns, including recently collected information on luteal responses. The existence of delayed ovulation (5–7 days after the introduction of the rams) followed by luteal phases of normal or short length, luteal cysts and luteinised follicles is reported after scanning the ovaries with ultrasound. Endocrine parameters for depth of anoestrus, such as LH pulsatility and FSH concentrations, and how the concentrations of these hormones should be considered are discussed. Particular attention is paid to the observation of spontaneous, higher LH pulsatility and higher FSH concentrations in anoestrous ewes that respond to rams with luteal phases than in those that fail to respond. The use of progestogen priming and single progestogen administration and the possible advantages for synchronisation of oestrus are also discussed. Other factors that should be considered before the ram effect is applied, such as the strength of the stimulus and some practical considerations, are also included.

scholarly journals Short-term nutritional supplementation of ewes in low body condition affects follicle development due to an increase in glucose and metabolic hormones

Reproduction ◽  
2005 ◽  
Vol 129 (3) ◽  
pp. 299-309 ◽  
Author(s):  
C Viñoles ◽  
M Forsberg ◽  
G B Martin ◽  
C Cajarville ◽  
J Repetto ◽  
...  
Keyword(s):  
Body Condition ◽  
Oestrous Cycle ◽  
Nutritional Supplementation ◽  
Ovulation Rate ◽  
Follicle Development ◽  
Short Term ◽  
Metabolic Hormones ◽  
The Third ◽  
Short Period ◽  
Igf I

This study tested whether the effects of a short period of nutritional supplementation given to ewes during the luteal phase on follicle development and ovulation rate is associated with an increase in circulating concentrations of FSH, glucose or metabolic hormones. Oestrus was synchronised with two prostaglandin injections given 9 days apart and the supplement consisted of corn grain and soybean meal. Corriedale ewes with low body condition were randomly assigned to 2 groups: the control group (C; n = 10) received a maintenance diet while the short-term supplemented group (STS; n = 10) received double the maintenance diet over days 9 to 14 of the oestrous cycle (day 0 = ovulation). Ovaries were examined daily by ultrasound and blood was sampled three times a day during the inter-ovulatory interval for measuring reproductive and metabolic hormones. On days 9, 11 and 14 of the oestrous cycle, half of the ewes from each group (n = 5) were bled intensively to determine the concentrations of glucose, insulin, IGF-I and leptin. Plasma FSH, progesterone, oestradiol and androstenedione concentrations were similar among groups. Dietary supplementation increased plasma insulin concentrations from the first to the sixth day of supplementation and increased glucose concentrations on the third day, compared with control ewes. Plasma leptin concentrations were higher in STS ewes from the second to the fifth day of supplementation. The pattern of IGF-I concentrations was similar among groups. In STS ewes, the nutritional treatment prolonged the lifespan of the last non-ovulatory follicle, so fewer follicular waves developed during the cycle. In STS ewes, increased concentrations of glucose, insulin and leptin one day before ovulatory wave emergence were associated with increased numbers of follicles growing from 2 to 3 mm and with stimulation of the dominant follicle to grow for a longer period. We suggest that the mechanism by which short-term nutritional supplementation affects follicle development does not involve an increase in FSH concentrations, but may involve responses to increased concentrations of glucose, insulin and leptin, acting directly at the ovarian level. This effect is acute, since concentrations of all three substances decrease after reaching peak values on the third day of supplementation. The status of follicle development at the time of maximum concentrations of glucose and metabolic hormones may be one of the factors that determines whether ovulation rate increases or not.

scholarly journals The use of a ‘first-wave’ model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep

Reproduction ◽  
2010 ◽  
Vol 140 (6) ◽  
pp. 865-874 ◽  
Author(s):  
C Viñoles ◽  
B Paganoni ◽  
K M M Glover ◽  
J T B Milton ◽  
D Blache ◽  
...  
Keyword(s):  
Body Condition ◽  
Wave Model ◽  
Ovulation Rate ◽  
Short Term ◽  
Metabolic Hormones ◽  
Follicular Waves ◽  
Follicular Wave ◽  
The Third ◽  
High Concentrations ◽  
Follicular Dynamics

We have developed an experimental model in which groups of ewes are simultaneously experiencing the first ovarian follicular wave of their oestrous cycle. We used this ‘first-wave model’ in a 2×2 factorial experiment (ten ewes per group) to study the effect of body condition (BC) and a short-term supplement on follicular dynamics and ovulation rate. The ‘first-wave’ was established by giving ewes three injections of prostaglandin (PG), 7 days apart. The 6-day supplement (lupin grain) began 2 days after the second PG injection and continued until the third. Follicles were studied by ultrasound, and blood was sampled to measure glucose and hormones. The supplement increased (P<0.01) the concentrations of glucose, insulin and leptin, decreased FSH concentrations (P<0.01) and tended to increase oestradiol concentrations (P=0.06). The supplement tended to increase the number of 3 mm follicles (P=0.06). Compared with low-BC ewes, high-BC ewes had more follicular waves (P<0.05), higher concentrations of insulin, leptin and IGF1 (P<0.05) and tended to have higher FSH concentrations (P=0.09). Leptin and insulin concentrations remained high until the end of supplementation in high-BC ewes, whereas they decreased after the third day of supplementation in low-BC ewes. In conclusion, high concentrations of metabolic hormones in fat ewes are associated with the development of more follicular waves. When a supplement is superimposed on this situation, changes in glucose and metabolic hormones allow more follicles to be selected to ovulate.

Do researchers impact their study populations? Assessing the effect of field procedures in a long term population monitoring of sea kraits

2012 ◽  
Vol 33 (3-4) ◽  
pp. 365-372 ◽  
Author(s):  
Thomas Fauvel ◽  
François Brischoux ◽  
Marine Jeanne Briand ◽  
Xavier Bonnet
Keyword(s):  
Body Condition ◽  
New Caledonia ◽  
Stress Hormones ◽  
Population Level ◽  
Population Monitoring ◽  
Long Term Effects ◽  
Negative Effects ◽  
Short Term ◽  
Head Morphology

Long term population monitoring is essential to ecological studies; however, field procedures may disturb individuals. Assessing this topic is important in worldwide declining taxa such as reptiles. Previous studies focussed on animal welfare issues and examined short-term effects (e.g. increase of stress hormones due to handling). Long-term effects with possible consequences at the population level remain poorly investigated. In the present study, we evaluated the effects of widely used field procedures (e.g. handling, marking, forced regurgitation) both on short-term (hormonal stress response) and on long-term (changes in body condition, survival) scales in two intensively monitored populations of sea kraits (Laticauda spp.) in New Caledonia. Focusing on the most intensively monitored sites, from 2002 to 2012, we gathered approximately 11 200 captures/recaptures on 4500 individuals. Each snake was individually marked (scale clipping + branding) and subjected to various measurements (e.g. body size, head morphology, palpation). In addition, a subsample of more than 500 snakes was forced to regurgitate their prey for dietary analyses. Handling caused a significant stress hormonal response, however we found no detrimental long-term effect on body condition. Forced regurgitation did not cause any significant effect on both body condition one year later and survival. These results suggest that the strong short-term stress provoked by field procedures did not translate into negative effects on the population. Although similar analyses are required to test the validity of our conclusions in other species, our results suggest distinguishing welfare and population issues to evaluate the potential impact of population surveys.

scholarly journals Use of GnRH for Synchronization of the Follicular Wave in Assisted Reproductive Technologies in Sheep: A Preliminary Study

Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1208
Author(s):  
Aina Año-Perello ◽  
Zurisaday Santos-Jimenez ◽  
Teresa Encinas ◽  
Paula Martinez-Ros ◽  
Antonio Gonzalez-Bulnes
Keyword(s):  
Luteinizing Hormone ◽  
Assisted Reproductive Technologies ◽  
Ovarian Response ◽  
Reproductive Technologies ◽  
Estrus Synchronization ◽  
Short Term ◽  
Follicular Wave ◽  
Preliminary Study ◽  
Cost Efficient ◽  
Set Up

The present study aimed to set up a short-term protocol for synchronization of follicular wave emergence in sheep, concomitant with estrus synchronization, which would improve ovarian response in assisted reproductive technologies. Administration of a single GnRH dose, concomitant with the insertion of a progesterone-loaded CIDR device, caused regression of gonadotrophin-dependent follicles ≥4 mm in all the GnRH-treated sheep and in around 80% of the controls treated only with CIDR (p < 0.05). Similar percentages of ewes lost all follicles (around 70%) or only the largest one (around 30%) in both groups. Hence, 54.1% and 70% of the sheep lost all large follicles and initiated a new follicular wave in the control and GnRH groups, respectively (p < 0.05). The remaining sheep showed follicles that were still not dependent of luteinizing hormone (LH). So, in fact, all the sheep had non-dominant follicles after treatment. In conclusion, a treatment including GnRH at CIDR insertion would offer a time- and cost-efficient protocol for inducing follicular turnover and synchronizing a new follicular wave at any stage of the estrous cycle.

scholarly journals Uropygial gland and bib colouration in the house sparrow

2016 ◽  
Author(s):  
Gregorio Moreno-Rueda
Keyword(s):  
Body Condition ◽  
Passer Domesticus ◽  
Uropygial Gland ◽  
Short Term ◽  
House Sparrows ◽  
Gland Size ◽  
Plumage Colouration ◽  
Preen Oil ◽  
Male House

Birds frequently signal different qualities by plumage colouration, mainly during mating. However, plumage colouration is determined during the moult, and therefore it would indicate the quality of individual birds during the moult, not its current quality. Recent studies, however, suggest that birds could modify plumage colouration by using cosmetic preen oil. In this study, I show that bib colouration is related to uropygial gland size and body condition in male house sparrows (Passer domesticus). Moreover, I conducted an experiment in which a group of sparrows were inoculated with an antigen, mimicking an illness. In control birds, short-term changes in bib colouration were related to both body condition and change in uropygial gland size. Therefore, birds that spent more preen oil (thus, reducing uropygial gland size), showed a greater colouration change. However, bib colouration did not change with use of preen oil in experimental birds inoculated with the antigen. That is, the simulated illness cancelled the effect of preen oil on bib colouration. Given that the experiment did not affect preen oil production, this finding suggests that the immune challenge provoked a change in the composition of preen oil, affecting its cosmetic properties. In short, the results of this study suggest that (1) male house sparrows produce cosmetic preen oil that alters the colouration of their bibs; (2) the more effort in preening, the more change in bib colouration; and (3) in this way, bib colouration has the potential to signal current health status, since less healthy birds showed less capacity to change bib colouration.

A comparison of the effects of body condition and short-term food restriction on the feeding behaviour of sheep

1996 ◽  
Vol 1996 ◽  
pp. 174-174
Author(s):  
A.M. Sibbald
Keyword(s):  
Food Intake ◽  
Body Condition ◽  
Feeding Behaviour ◽  
Food Restriction ◽  
Term Effect ◽  
Short Term ◽  
Daily Food ◽  
Long Term Effect ◽  
Single Meal

Voluntary food intake is generally inversely related to body condition or fatness in mature sheep (Foot, 1972). Since the intake of pelleted diets by housed sheep consists of a number of discrete feeding bouts or 'meals' (e.g. Bermudez et al., 1989), the relatively long-term effect of body condition on intake will be achieved through changes in feeding behaviour at the level of a single meal. The aim of this experiment was to compare the effects of body condition and short-term food restriction on meal patterns in sheep, to investigate the mechanism by which body condition influences daily food intake.

scholarly journals Costly parasite resistance: a genotype-dependent handicap in sand lizards?

2005 ◽  
Vol 1 (3) ◽  
pp. 375-377 ◽  
Author(s):  
Mats Olsson ◽  
Erik Wapstra ◽  
Thomas Madsen ◽  
Beata Ujvari ◽  
Carl Rugfelt
Keyword(s):  
Body Condition ◽  
Blood Stream ◽  
Encounter Rate ◽  
Short Term ◽  
Adaptive Immune ◽  
Reduced Body ◽  
Histocompatibility Complex ◽  
Secondary Infections ◽  
Specific Restriction ◽  
Lacerta Agilis

Male sand lizards ( Lacerta agilis ) with a specific restriction fragment length polymorphism fragment in their major histocompatibility complex (MHC) genotype (‘O-males’) are more resistant to ectoparasites (a tick, Ixodes ricinus ) than are males that lack this fragment (‘NO-males’). However, emerging evidence suggests that such adaptive immune responses are costly, here manifested by reduced body condition and a compromised defence against secondary infections by haemoprotid parasites that use the ticks as vectors. Subsequent to tick encounter, O-males suffer from a higher leucocyte–erythrocyte ratio, and higher haemoprotid parasitaemia, in particular in relation to vector encounter rate. Furthermore, O-males (i.e. successful tick defenders) with more haemoprotid parasites remaining in their blood stream were in better body condition, whereas this did not apply in NO-males, demonstrating that the adaptive immunoreaction can—in the short term—be energetically even more costly than being moderately parasitized. In agreement with Zahavian handicap theory, O-males had a (marginally) higher reproductive success than males that lacked this fragment.

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