Pituitary and ovarian response to transient doe-litter separation in nursing rabbits

Reproduction ◽  
2000 ◽  
pp. 361-366 ◽  
Author(s):  
E Ubilla ◽  
PG Rebollar ◽  
D Pazo ◽  
AI Esquifino ◽  
JM Alvarino
Keyword(s):  
Pituitary Gland ◽  
Litter Size ◽  
Artificial Insemination ◽  
Ovarian Response ◽  
Major Effect ◽  
Free Access ◽  
Plasma Prolactin ◽  
Follicular Waves ◽  
Higher Sensitivity

The effects of a transient doe-litter separation on plasma prolactin, FSH and oestradiol concentrations, as well as the effect on LH response to exogenous GnRH administered at the time of artificial insemination, were determined in nursing rabbits. The effects on fertility, and litter size after parturition, as well as litter survival after doe-litter separation, were also studied. Control does (n = 12) had free access to nursing, whereas biostimulated does (n = 12) were separated from their litters for 48 h before artificial insemination. Plasma prolactin concentrations were decreased 24 h after the doe-litter separation (P < 0.05). The response of prolactin to suckling reached 10 times the basal values measured on day 10 after parturition (P < 0.0001). Increased oestradiol concentrations were found during the 48 h after the doe-litter separation: at 0 h, before artificial insemination (P< 0. 0001), 1.0-2.0 h after artificial insemination (P < 0.001), at 2.5 h (P < 0.05), 3.0 h (P < 0.01), and at 3.5 h (P < 0.05) after artificial insemination. Exogenous GnRH administered at the time of artificial insemination caused a greater LH response in does previously separated from their litters during 48 h (P < 0.01). The transient doe-litter separation did not affect plasma FSH concentrations, fertility, litter size or litter survival. These results suggest that a transient separation of nursing does from their litters before artificial insemination results in a decrease in plasma prolactin concentrations that could promote growth of follicular waves, and high steroidogenesis activity, leading to increased oestradiol concentrations and inducing higher sensitivity of the pituitary gland to exogenous GnRH. These findings associated to the absence of suckling episodes would lead to higher LH response and, therefore, exert a major effect on fertility.

THYROTROPHIN RELEASING HORMONE-INDUCED GROWTH HORMONE AND PROLACTIN RELEASE: PHYSIOLOGICAL STUDIES IN INTACT RATS AND IN HYPOPHYSECTOMIZED RATS BEARING AN ECTOPIC PITUITARY GLAND

1977 ◽  
Vol 72 (3) ◽  
pp. 301-311 ◽  
Author(s):  
A. E. PANERAI ◽  
IRIT GIL-AD ◽  
DANIELA COCCHI ◽  
V. LOCATELLI ◽  
G. L. ROSSI ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Time Lapse ◽  
Anterior Pituitary Gland ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Clear Cut ◽  
Urethane Anaesthesia ◽  
Releasing Effect

SUMMARY To determine how the sensitivity of the ectopic anterior pituitary gland to the GH-releasing effect of thyrotrophin releasing hormone (TRH) might be affected by the time lapse from transplantation, TRH (0·15 and 0·6 μg) was injected i.v. into hypophysectomized (hypox)-transplanted rats under urethane anaesthesia 1,3, 8,15, 30 and 60 days after transplantation, and plasma samples were taken 5 and 10 min later. Baseline GH values gradually decreased with time from about 16·0 ng/ml (1 day) to about 3·0 ng/ml (30 and 60 days). The TRH-induced GH release was absent 1 day after transplantation, present only with the higher TRH dose 3 and 8 days after transplantation, and clearly elicitable, also with the lower TRH dose (0·15 μg), from 15 up to 60 days. Determination of plasma prolactin concentrations showed a decline from about 85·0 ng/ml (1 day) to about 32·0 ng/ml (8 days); subsequently (15–60 days) prolactin values stabilized. Plasma prolactin levels increased 15 and 60 days after transplantation only when a dose of 0·6 μg TRH was given. In intact weight-matched rats, TRH induced a GH response only at the dose of 1·2 μg while a short-lived but clear-cut prolactin response could be obtained even with the 0·3 μg dose. The present results indicate that: (1) disconnexion between the central nervous system and the anterior pituitary gland greatly enhances GH responsiveness while blunting prolactin responsiveness to TRH; (2) the sensitivity of the anterior pituitary gland to the GH-releasing effect of TRH increases with time from transplantation; (3) TRH is a more effective prolactin-than GH-releaser on the pituitary gland in situ.

Semen Viability Properties of Sexually Stimulated Boars on the Fertilization Capacity of Artificially Inseminated Large White Sows

2021 ◽  
Author(s):  
Tshepo Teele
Keyword(s):  
Litter Size ◽  
Artificial Insemination ◽  
Practical Method ◽  
Return Rate ◽  
Practical Significance ◽  
Large White ◽  
Sexual Stimulation ◽  
Semen Collection ◽  
Fertilization Capacity ◽  
Farrowing Rate

Background: This study aimed to investigate the influences of sexual preparation on the effects of boars’ semen viability on the fertilization capacity of artificially inseminated sows. After all, boar sires more pigs than farrowed by a sow which the boar has been mated to improve reproductive parameters in response to AI. Methods: The semen viability of boars were studied during various sexual stimulations and analyzed during the study period. Sperm rich fractions were collected and separated at every level of sexual stimulation during the morning (08:30) and the afternoon (14:30) hours, respectively. Artificial insemination was performed following three levels of sexual preparations of boars (0 minutes of sexual restraint (MSR), 5 MSR and 10 MSR) before semen collection. Receptive sows were inseminated and evaluated for fertility traits using non-return rate, farrowing rate and litter size. Result: The non-return rate was recorded as a percentage of sows conceived after insemination over the total number of sows inseminated. The farrowing rate was recorded as a percentage of sows that farrows over the number of sows conceived and litter size as several live piglets per sow. Sexual desire was influenced by sexual preparations and significantly influenced the fertility of the artificially inseminated sows. This study is of practical significance to the animal breeder mainly because boars have greater influence than sows on the average litter size and live piglets. The study concludes that the use of at least 5 to 10 minutes of sexual restraint during the afternoon periods prior to semen collection and artificial insemination is found to be a practical method for optimizing sperm viability and fertility of sows in the intensive system.

Obestatin acts in brain to inhibit thirst

2007 ◽  
Vol 292 (1) ◽  
pp. R637-R643 ◽  
Author(s):  
Willis K. Samson ◽  
Meghan M. White ◽  
Christopher Price ◽  
Alastair V. Ferguson
Keyword(s):  
Food Intake ◽  
Pituitary Gland ◽  
Behavioral Activity ◽  
Free Access ◽  
Gene Encoding ◽  
Gh Secretion ◽  
Water Drinking ◽  
Access To Water

Derived from the same prohormone, obestatin has been reported to exert effects on food intake that oppose those of ghrelin. The obestatin receptor GPR39 is present in brain and pituitary gland. Since the gene encoding those two peptides is expressed also in those tissues, we examined further the possible actions of obestatin in vivo and in vitro. Intracerebroventricular administration of obestatin inhibited water drinking in ad libitum-fed and -watered rats, and in food-and water-deprived animals. The effects on water drinking preceded and were more pronounced than any effect on food intake, and did not appear to be the result of altered locomotor/behavioral activity. In addition, obestatin inhibited ANG II-induced water drinking in animals provided free access to water and food. Current-clamp recordings from cultured, subfornical organ neurons revealed significant effects of the peptide on membrane potential, suggesting this as a potential site of action. In pituitary cell cultures, log molar concentrations of obestatin ranging from 1.0 pM to 100 nM failed to alter basal growth hormone (GH) secretion. In addition, 100 nM obestatin failed to interfere with the stimulation of GH secretion by GH-releasing hormone or ghrelin and did not alter the inhibition by somatostatin in vitro. We conclude that obestatin does not act in pituitary gland to regulate GH secretion but may act in brain to alter thirst mechanisms. Importantly, in rats the effects of obestatin on food intake may be secondary to an action of the peptide to inhibit water drinking.

scholarly journals The influence of adding estradiol to semen on reproductive performance of sows

1991 ◽  
Vol 71 (2) ◽  
pp. 589-591 ◽  
Author(s):  
R. N. Kirkwood ◽  
P. A. Thacker
Keyword(s):  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
And Control ◽  
Estradiol 17Β

One hundred gilts and one hundred mixed-parity sows of Yorkshire and Landrace breeding were inseminated with semen with or without an additional 10 μg estradiol-17β. Pregnancy rates of gilts receiving estradiol-supplemented and control semen were 90 and 79%, respectively (P < 0.09). The estradiol supplementation of semen did not improve the pregnancy rates or litter size in sows. Key words: Swine, artificial insemination, estradiol

The influence of purified porcine relaxin on the reproductive performance of sows following artificial insemination with fresh or frozen semen

1991 ◽  
Vol 71 (1) ◽  
pp. 237-239 ◽  
Author(s):  
P. A. Thacker ◽  
A. D. Gooneratne ◽  
R. N. Kirkwood
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Frozen Semen

Pregnancy rates and litter sizes following insemination of sows with fresh-extended and frozen-thawed semen averaged 71 vs. 53% and 10.6 vs. 4.4, respectively, and was not affected by the addition of 12.5 μg relaxin to semen. These results indicate no relaxin mediated effect on either pregnancy rate or litter size when sows are artificially inseminated with relaxin-supplemented semen. Key words: Artificial insemination, relaxin, sows

INDUCTION OF OVULATION IN SHEEP BY INTRA-ADENOHYPOPHYSIAL INFUSION OF HYPOTHALAMIC EXTRACTS

1968 ◽  
Vol 42 (3) ◽  
pp. 383-389 ◽  
Author(s):  
E. DOMÁNSKI ◽  
K. KOCHMAN
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Median Eminence ◽  
Strong Evidence ◽  
Late Phase ◽  
Follicle Stimulating Hormone ◽  
Ovarian Response ◽  
Corpora Lutea ◽  
Seasonal Differences ◽  
Releasing Factors

SUMMARY The follicle-stimulating hormone releasing factor (FSH-RF) and luteinizing hormone-releasing factor (LH-RF) activity in sheep hypothalamic extracts and their action on the release of gonadotrophins from the pituitary gland has been studied by the infusion of extracts of the stalk and median eminence (SME) directly into the adenohypophysis of ewes in various phases of their non-cycling quiescent sexual period. The intra-adenohypophysial infusion of hypothalamic extracts during mid-anoestrus elicited no ovarian response, while similar infusion of the same extracts in the late phase of anoestrus, e.g. in the last 2–4 weeks before the onset of the breeding season, induced the growth and rupture of ovarian follicles as well as development of corpora lutea. This ovulatory response provides indirect but strong evidence for the ability of hypothalamic extracts to release gonadotrophins (FSH as well as LH) from the pituitary gland. The seasonal differences in the response of ewes to intra-adenohypophysial infusions of hypothalamic extracts suggest that the sensitivity of the adenohypophysis to the hypothalamic releasing factors varies during the year.

350 EFFECT OF DIFFERENT SUB-DOSES OF EQUINE CHORIONIC GONADOTROPIN ON PREGNANCY AND TWINNING RATES OF CYCLIC ZEBU COWS SUBMITTED TO FIXED-TIME ARTIFICIAL INSEMINATION

2015 ◽  
Vol 27 (1) ◽  
pp. 263 ◽  
Author(s):  
R. H. Alvarez ◽  
F. L. N. Natal ◽  
R. M. L. Pires ◽  
K. M. R. Duarte ◽  
C. A. Oliveira
Keyword(s):  
Artificial Insemination ◽  
Ovarian Response ◽  
Fixed Time ◽  
Sao Paulo ◽  
São Paulo ◽  
Chi Square ◽  
Group 3 ◽  
Group 2 ◽  
Twin Pregnancies ◽  
Group 1

The injection of a low dose of eCG has the potential to induce multiple ovulation and pregnancies in cattle. The present study aimed to evaluate the ovarian response, conception rate and incidence of twin pregnancies of cyclic cows receiving 1 of 2 low doses of eCG. Multiparous Nellore (Bos t. indicus) cows with plasma progesterone levels >1 ng∙mL–1 on at least one of 2 blood samples collected at 10-day intervals (Day –10 and Day 0) received an intramuscular (IM) injection of 2 mg of oestradiol benzoate (EB; Estrogin®, AUSA, São Paulo, Brazil) and a vaginal device (DIP) containing 1 g of progesterone (Primer®, Tecnopec, São Paulo, SP, Brazil) on Day 0. On Day 8, the DIP was removed and cows received an IM injection of 150 μg of cloprostenol (Veteglan®, Hertape Calier, Juatuba, MG, Brazil). At this time, the animals were randomly distributed into 3 groups. Group 1 (n = 30) received an IM injection of 2 mL of saline, whereas groups 2 (n = 41) and 3 (n = 23) received 600 IU and 900 IU of eCG (Novormon® MSD Saude Animal, São Paulo, Brazil), respectively. Twenty-four hours later (Day 9), all groups received 1 mg of EB and were submitted to fixed-time artificial insemination (FTAI) 30 h later (i.e. 54 h after DIP removal). Oestrus observation was performed daily from the time of the withdrawal of the DIP until the day of FTAI. Ovaries were examined ultrasonically at the time of FTAI, the following day and 7 days after FTAI. Pregnancy diagnosis was done by ultrasonography 30 days after FTAI and the incidence of twin or single calves was recorded at birth. Data were analysed by chi-square test. The rate of expression of oestrus was 70.0% (group 1), 82.9% (group 2), and 78.2% (group 3; P = 0.25). Cows that had 2 or more large follicles at the time of FTAI was 0% (group 1), 14.6% (group 2), and 34.8% (group 3; P < 0.05). The ovulation rate of cows in group 1 (80.0%) was higher than cows in groups 2 (48.8%) and 3 (52.2%; P < 0.05). The conception rates for groups 1, 2, and 3 were 50.0, 26.8, and 39.1%, respectively (P < 0.05). Two animals in group 3, one in group 2, and none of group 1 had twin pregnancies on Day 30 after FTAI. Only one of these cows (group 3) had a twin calving. It was concluded that the injection of 600 or 900 IU eCG, in an oestradiol/progestogen FTAI protocol does not result in an increase in the rate of twin calvings, but may negatively affect pregnancy rates of cyclic Nellore cows.Financial support was provided by FAPESP (proc. 2011/13096–0).

122 OVARIAN FOLLICULAR DYNAMICS IN CROSS-BRED EWES DURING THE RAINY SEASON UNDER TROPICAL CONDITIONS

2017 ◽  
Vol 29 (1) ◽  
pp. 169
Author(s):  
E. A. Reyes ◽  
D. R. Bergfelt ◽  
V. F. Ratto ◽  
X. P. Valderrama ◽  
E. Arcelay ◽  
...  
Keyword(s):  
Body Condition Score ◽  
Salt Water ◽  
Small Ruminants ◽  
Pennisetum Purpureum ◽  
Caribbean Region ◽  
Free Access ◽  
Antral Follicles ◽  
Follicular Waves ◽  
Tropical Conditions ◽  
Ovulatory Follicles

Small ruminants are an important livestock species on many island nations of the Eastern Caribbean region and serve as a vital source of food and income. This study was designed to characterise follicular development during the inter-ovulatory interval (interval between 2 consecutive ovulations) under tropical conditions. Non-lactating, 2- to 4-year-old crossbred Barbados-Black Belly × White Virgin Island ewes weighing a mean 30.4 kg with mean body condition score 2.9 (score 1–5) were used during September–November for the study. Ewes were maintained in a paddock of 100 m2 at the research farm in St. Kitts and Nevis (17.3°N, 62.7°W). Animals were fed daily with 100 g of concentrate (17% crude protein) and had free access to elephant grass (Pennisetum purpureum), mineral salt, water, and shade. Ovaries of 19 females were examined daily for 46 days by transrectal B-mode ultrasonography using a 7.5-MHz lineal array transducer (Honda HS-2200UV, MA, USA) to detect ovulations and growth and regression of antral follicles. Data were analysed using chi-square, Student t-test, or one-way ANOVA. Proportion of females with 2, 3, and 4 follicular waves was 2/19 (10.5%), 10/19 (52.6%), and 7/19 (36.8%), respectively. Mean (± SEM) length of the inter-ovulatory intervals did not differ (P = 0.9) among females with 2 (16.5 ± 0.5 days), 3 (16.3 ± 0.4 days), and 4 (16.6 ± 0.2 days) follicular waves, respectively. Mean diameter of ovulatory follicles was 4.4 ± 0.1 mm, proportion of multiple ovulations was 11/19 (57.9%), and mean number of follicular waves was 3.3 ± 0.1. Wave emergence was normalized to the first ovulation of the inter-ovulatory interval (ovulation = Day 0). Mean days of wave emergence for 2 follicular waves were Days 1.0 ± 0 and 10.0 ± 0.0; for 3 follicular waves were Days 0.7 ± 0.1, 5.6 ± 0.5, and 10.4 ± 0.3; and 4 follicular waves were Days 0.8 ± 0.3, 4.7 ± 0.6, 8.4 ± 0.5, and 11.7 ± 0.3, respectively. The inter-wave intervals were 9.0 ± 0.0 days for 2 waves; 5.1 ± 0.5 and 4.8 ± 0.3 days for 3 waves; and 3.8 ± 0.5, 3.7 ± 0.3, and 3.3 ± 0.4 days for 4 waves. Growth rate (mm/day) of the largest follicle/wave did not differ (P = 07) among animals with 2 follicular waves (1.2 ± 0.7 v. 1.1 ± 0.0) or 3 follicular waves (0.9 ± 0.1 v. 0.9 ± 0.1 v. 1.2 ± 0.2). However, in animals with 4 follicular waves, the largest follicle grew faster (P < 0.05) for wave 1 (1.3 ± 0.2) than that of waves 2 (0.5 ± 0.2), 3 (0.6 ± 0.1), and 4 (0.6 ± 0.1). In conclusion, length of inter-ovulatory intervals, emergence of antral follicles, growth, and regression follicles in a wave-like pattern, inter-wave intervals, and diameter of ovulatory follicles in cross-bred ewes under tropical conditions are comparable to that described in sheep from temperate climates.

A COMPARISON OF FRESH AND FROZEN SEMEN IN THE INSEMINATION OF CONFINED SHEEP

1979 ◽  
Vol 59 (4) ◽  
pp. 685-691 ◽  
Author(s):  
G. A. LANGFORD ◽  
G. J. MARCUS ◽  
A. J. HACKETT ◽  
L. AINSWORTH ◽  
H. F. PETERS ◽  
...  
Keyword(s):  
Litter Size ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Embryonic Mortality ◽  
Frozen Semen ◽  
Serum Gonadotropin ◽  
Early Embryonic Mortality ◽  
The Difference ◽  
Natural Service ◽  
Fresh Semen

The reproductive performance of crossbred sheep maintained in total confinement was compared after artificial insemination with fresh or frozen semen. Estrus was synchronized with progestagen-impregnated vaginal sponges and pregnant mares’ serum gonadotropin. Inseminations were performed 54 and 60 h after sponge removal. The fertility of ewes inseminated with fresh semen was significantly higher than of ewes inseminated with frozen semen. Conception rates, lambing rates and litter size were 83%, 78% and 2.2 using fresh semen and 65%, 43% and 1.8 using frozen semen. In a group of similar ewes bred by natural service, the lambing performance was comparable to that obtained with fresh semen. The difference between conception and lambing rates suggests an increase in early embryonic mortality when breeding with frozen semen and confirms the need for improved frozen semen technology.

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