REPRODUCTIVE PERFORMANCE OF HORMONALLY TREATED SHEEP MAINTAINED YEAR-ROUND IN A CONTROLLED-LIGHT ENVIRONMENT

1982 ◽  
Vol 62 (4) ◽  
pp. 1109-1117 ◽  
Author(s):  
A. J. HACKETT ◽  
H. A. ROBERTSON ◽  
H. A. ROBERTSON ◽  
R. J. DWYER ◽  
M. S. WOLYNETZ
Keyword(s):  
Key Words ◽  
Reproductive Performance ◽  
Similar Pattern ◽  
Treatment Effects ◽  
Hormone Treatment ◽  
Breeding Program ◽  
Light Environment ◽  
Day Length ◽  
Ovarian Activity ◽  
Prostaglandin F

Six experiments were conducted on hormonally treated ewes maintained year-round in a controlled-light environment in a breeding program designed to produce three lamb crops in 2 yr. Various combinations of fluorogestone acetate (FGA), prostaglandin F2α (PGF2α) and pregnant mares' serum gonadotrophin (PMSG) were used to synchronize estrus in the ewes. There were no significant differences (P > 0.05) in fertility between FGA- and PGF2α-treated ewes when the ewes were having cyclic ovarian activity (cycling) at the time of treatment, i.e. in January and May in our system. Among ewes in the constant day-length lighting regime, fertility was lower in September than in January or May. Prolificacy ranged from 1.7 to 2.0 in the six experiments. Fecundity, a measure of the overall productivity, followed a similar pattern to fertility and was not significantly (P > 0.05) affected by the various treatments. These findings demonstrated the feasibility of maintaining a controlled 8-mo breeding program for sheep maintained year-round in a controlled-light environment. Key words: Reproduction in sheep, controlled light, hormone treatment effects.

A protocol for initiating oestrus and ovulation earlypost partumin dairy cows

2001 ◽  
Vol 72 (3) ◽  
pp. 539-546 ◽  
Author(s):  
A. O. Darwash ◽  
G. E. Lamming ◽  
M. D. Royal
Keyword(s):  
Reproductive Performance ◽  
Post Partum ◽  
Treatment Protocol ◽  
Ovarian Activity ◽  
Milk Samples ◽  
Management Regime ◽  
Holstein Friesian ◽  
Prostaglandin F ◽  
The Mean ◽  
Friesian Cows

AbstractThe objective of the present study was to evaluate the efficacy of a prostaglandin F2α(PGF2α) and progesterone (P4) treatment in initiating oestrus and ovulation post partum (PP) in Holstein-Friesian cows. Using four herds, the treatment protocol consisted of a single intra-muscular injection of PGF2α(Estrumate) between days 12 to 14 PP followed 48 h later by progesterone treatment via intra-vaginal CIDR insertion for a period of 7 days. Milk samples for progesterone determination were collected three times weekly from 7 to 65 days PP. The ovarian activity and reproductive performance of treated (T, no. = 153) animals and untreated control cows (C, no. = 315) were compared. Treatment was effective (P< 0·001) in reducing the mean interval to PP commencement of luteal activity from 29·62 (s.e. 0·82) days to 22·09 (s.e. 0·70) days. The mean interval to first PP oestrus in the T animals was significantly reduced (P< 0·001) from 55·62 (s.e. 1·58) days to 44·91 (s.e. 1·44) days and the incidence of silent ovulation in cycles between days 21 to 65 PP was reduced (P< 0·001) from 56·28% to 42·27%. In two herds under one management regime and with a similar block-calving pattern (no. = 280 animals), the treatment protocol was beneficial to the overall reproductive performance as there was a significant shortening in the mean interval to first PP service (75·82 (s.e. 1·93) v. 80·86 (s.e. 1·32) days) and in the interval to PP conception (83·07 (s.e. 2·49) v. 88·90 (s.e. 1·95) days), bothP< 0·05.

EFFECT OF PROGESTERONE AND TEMPORARY WEANING ON CYCLIC ACTIVITY AND FERTILITY OF BEEF COWS AT A PROSTAGLANDIN- SYNCHRONIZED ESTRUS

1983 ◽  
Vol 63 (2) ◽  
pp. 325-330 ◽  
Author(s):  
J. G. MANNS ◽  
W. D. HUMPHREY ◽  
J. R. NKUUHE
Keyword(s):  
Key Words ◽  
Beef Cows ◽  
Ovarian Activity ◽  
Moderate Increase ◽  
Short Term ◽  
Cyclic Activity ◽  
Estrous Cycles ◽  
Prostaglandin F ◽  
Calf Removal

Three experiments were conducted to assess the effect of short-term calf removal (CR) or treatment with progesterone (P4) on onset of cyclic ovarian activity and fertility in beef cows suckled by a single calf. Estrous cycles of all cows were synchronized by two injections of a prostaglandin F (PGF) analogue 11 days apart. The cows were inseminated at 68 and 92 h after the second PGF injection. In exp. 1, calf removal for 48 h after the second injection of PGF did not alter fertility compared to controls. In exp. 2, cows were treated with 100 mg P4 at the time of the first PGF injection. P4 increased the number of cycling animals by 7% and fertility by 13%, but the differences were not significant. In exp. 3, combinations of CR and P4 were used. When these latter data were summarized and pooled with similar groups from previous experiments, P4 increased cyclic ovarian activity by 9% (P < 0.07) and fertility by 14% (P < 0.04). The results indicate that treatment with P4 caused a moderate increase in onset of cyclic ovarian activity and significantly increased fertility. Key words: Beef cows, postpartum anestrus, progesterone

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

Reproductive performance of Shorthorn and Brahman crossbred cows in the dry tropics of north Queensland

1979 ◽  
Vol 19 (98) ◽  
pp. 276 ◽  
Author(s):  
RG Holroyd ◽  
PK O'Rourke ◽  
PJ Allan
Keyword(s):  
Reproductive Performance ◽  
Experimental Period ◽  
Ovarian Activity ◽  
Gestation Length ◽  
Variable Effect ◽  
Crossbred Cows ◽  
Lactating Cows ◽  
Dry Tropics ◽  
Significant Difference ◽  
Conception Rates

A study was made (1 970 to 1973) of the reproductive performance of Shorthorn and Brahman crossbred cows grazing pasture in the dry tropics of north Queensland. Breed had a variable effect on the conception rates of lactating cows, with Brahman crossbreds having significantly higher (P < 0.05) conception rates in the first year. The two breeds had similar conception rates in the following year. In the third year, overall conception rates of both breeds were reduced due to a prolonged dry season, with Shorthorn cows having significantly higher (P < 0.01) conception rates than Brahman cows. However, during this dry period, twice as many Shorthorn cows required survival feeding as did Brahman cows. Calving rates followed conception rates closely, prenatal loss in each breed being low. In all years, Shorthorns had significantly earlier (P < 0.05) calving dates than Brahmans. The interval from calving to first recorded ovarian activity was significantly longer (P < 0.05) in Brahman cross than in Shorthorn cows in only one of the three years. There was no significant difference between breeds for the interval from first recorded ovarian activity to conception, but this interval decreased with increasing age of the cow. Breed had a variable effect on gestation length. Brahman cows were generally heavier each year in April and in better condition throughout the experimental period than Shorthorn cows.

COMPARISON OF ARTIFICIAL INSEMINATION AND NATURAL MATING ON REPRODUCTIVE PERFORMANCE OF FIVE STRAINS OF SHEEP DURING THE ANESTROUS SEASON IN AN INTENSIVE SYSTEM

1979 ◽  
Vol 59 (4) ◽  
pp. 675-683 ◽  
Author(s):  
A. J. HACKETT ◽  
H. A. ROBERTSON ◽  
E. K. INSKEEP ◽  
J. N. B. SHRESTHA ◽  
M. S. WOLYNETZ
Keyword(s):  
Reproductive Performance ◽  
Artificial Insemination ◽  
Hormone Treatment ◽  
Corpora Lutea ◽  
Blood Samples ◽  
Natural Mating ◽  
Main Effects ◽  
Mating Method ◽  
Intensive System

Synchronized estrus and ovulation were induced during the anestrous season (April–May 1974) in 373 ewes of three synthetic (one sire and two dam) strains and two unselected (Suffolk and Finnish Landrace) purebred strains by treatment with 30 mg fluorogestone acetate (FGA) impregnated in polyurethane intravaginal sponges for 12 days. Following sponge removal each ewe received 500 IU pregnant mares’ serum gonadotrophin (PMSG) IM. Of these, 167 were bred by artificial insemination (AI) at 48 and 60 h post sponge removal with 0.2 ml raw unextended semen collected by electroejaculation (EE). Five days after AI, ewes were exposed to a follow up ram for 16 days for subsequent mating if a second estrus occurred. The remaining 206 were exposed to rams for a period of 22 days for natural mating. Blood samples were collected from 69 ewes, 9, 19 and 27 days post sponge removal and analyzed for progesterone to ascertain if corpora lutea were formed and whether the ewes recycled. The age of ram by mating method interaction significantly affected both fertility and fecundity mainly because some of the younger rams lacked libido and experience for natural mating. There were no significant differences in prolificacy due to any of the main effects tested. Among the 69 ewes examined for progesterone levels, 93% had formed corpora lutea after hormone treatment and 16% recycled. Only 16 of the 255 ewes that did not conceive to the synchronized estrus lambed to the subsequent estrus.

scholarly journals Effects of Photoperiodism and Other Factors on the Improvement of Pigeonpea Varieties

1969 ◽  
Vol 48 (3) ◽  
pp. 232-235
Author(s):  
Arturo Riollano
Keyword(s):  
Day Treatment ◽  
Breeding Program ◽  
Flower Induction ◽  
Day Length ◽  
Flower Formation ◽  
Length Of Day ◽  
Short Day ◽  
Late Variety ◽  
Polyethylene Bags

Studies on the effects of photoperiodism and other factors were conducted to obtain information which might be useful in a breeding program with pigeonpeas. The information was sought for accelerating this work in a region where extremes of day-length vary by only 2 hours because of its location in latitude 18°. By shortening the length of day to 8 hours through the use of a darkroom, and planting during the month of February, it was possible to induce flower formation 4 months earlier in two early varieties and 7 weeks earlier in a late variety. However, this short-day treatment did not appreciably affect the time of flower induction in an all-season, or "Totiempo" variety. One-gallon tin-can containers and 10-inch polyethylene bags were found satisfactory for growing pigeonpea plants of different varieties.

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

scholarly journals Endogenous circannual rhythm in luteinizing hormone secretion: insight from signal analysis coupled with mathematical modelling

2009 ◽  
Vol 367 (1908) ◽  
pp. 4759-4777 ◽  
Author(s):  
Alexandre Vidal ◽  
Claire Médigue ◽  
Benoît Malpaux ◽  
Frédérique Clément
Keyword(s):  
Luteinizing Hormone ◽  
Day Length ◽  
Ovarian Activity ◽  
Circannual Rhythm ◽  
Time Frequency ◽  
Gnrh Secretion ◽  
Plasmatic Level ◽  
Lh Secretion ◽  
Experimental Sampling ◽  
Sampling Times

In sheep, as in many vertebrates, the seasonal pattern of reproduction is timed by the annual photoperiodic cycle, characterized by seasonal changes in the day length. The photoperiodic information is translated into a circadian profile of melatonin secretion. After multiple neuronal relays (within the hypothalamus), melatonin affects gonadotrophin-releasing hormone (GnRH) secretion, which in turn controls ovarian cyclicity. The pattern of GnRH secretion is mirrored by that of luteinizing hormone (LH) secretion, whose plasmatic level can be easily measured. We addressed the question of whether there exists an endogenous circannual rhythm in a tropical sheep (Blackbelly) population that exhibits clear seasonal ovarian activity when ewes are subject to temperate latitudes. We based our analysis on LH time series collected in the course of 3 years from ewes subject to a constant photoperiodic regime. Owing to intra- and interanimal variability and unequal sampling times, the existence of an endogenous rhythm is not straightforward. We have used time–frequency signal processing methods, and especially the smooth pseudo-Wigner–Ville distribution, to extract possible hidden rhythms from the data. To further investigate the low-frequency (LF) and high-frequency (HF) components of the signals, we have designed a simple mathematical model of the LH plasmatic level accounting for the effect of experimental sampling times. The model enables us to (i) confirm the existence of an endogenous circannual rhythm as detected by the LF signal component, (ii) investigate the action mechanism of the photoperiod on the pulsatile pattern of LH secretion (control of the interpulse interval), and (iii) conclude that the HF component is mainly due to the experimental sampling protocol.

scholarly journals Effects of Separation of Cows and Calves on Reproductive Performance and Animal Welfare in Tropical Beef Cattle

Animals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 223 ◽  
Author(s):  
Agustín Orihuela ◽  
Carlos S. Galina
Keyword(s):  
Beef Cattle ◽  
Animal Welfare ◽  
Reproductive Performance ◽  
Ovarian Activity ◽  
Early Weaning ◽  
Established Method ◽  
Common Procedure ◽  
Traditional System ◽  
Welfare Implications ◽  
The Tropics

Nursing a calf suppresses postpartum ovarian activity prolonging the period of anestrus. Diverse methods are used to reduce the effect of suckling; the most popular, restricted suckling, reduces the number of encounters mother-calf. Temporal weaning of the calf for periods of 24 h, 48 h, or even 72 h also suppress the effect of suckling and is commonly applied to cow-calf operations in the tropics. Early weaning of the calf, usually three to five months after birth, is a practice gaining popularity over the traditional system of weaning at seven months. Furthermore, the use of nose-flaps in the calf to avoid suckling is a common procedure in South America. Finally, weaning during the first week after calving is an established method to reduce postpartum anestrus. The objective of the present review is to discuss the effects of these methods on the reproductive performance of beef cattle and their animal welfare implications.

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