Effect of type of intravaginal progestagen on the outcome of fixed-time artificial insemination

1981 ◽  
Vol 96 (1) ◽  
pp. 243-245 ◽  
Author(s):  
P. A. Smith ◽  
M. P. Boland ◽  
I. Gordon
Keyword(s):  
Artificial Insemination ◽  
Present Experiment ◽  
Fixed Time ◽  
Field Trials ◽  
Oestrous Cycle ◽  
Conception Rates ◽  
Natural Service ◽  
Dose Levels ◽  
Pregnant Mare Serum Gonadotrophin

It is now possible to synchronize the cycle of ewes at all times of the year (Gordon, 1975). Conception rates approaching those obtained following natural service have been reported following double (Colas & Brice, 1970; Colas et al. 1973; Barlow, Pryce-Jones & Reed, 1974; Gordon, 1975) or single (Smith, Boland & Gordon, 1978) set-time inseminations. In France, synchronization of ewes' oestrous cycle is based on the use of a Cronolone pessary (Colas, 1975), while field trials conducted in Britain have used the 60 mg Medroxy progesterone acetate (MAP) sponge (Barlow et al. 1974). Robinson et al. (1967) in an evaluation of different progestagen treatments found MAP to be less predictable than Cronolone. The purpose of the present experiment therefore was to evaluate the use of a 30 mg Cronolone or a 60 mg MAP intravaginal treatment when used in conjunction with fixed-time inseminations. In addition, two dose levels of pregnant mare serum gonadotrophin (PMSG) were compared.

Effect of dose of Gronolone in intravaginal sponges on lambing outcome to fixed-time artificial insemination

1981 ◽  
Vol 96 (1) ◽  
pp. 253-254 ◽  
Author(s):  
P. A. Smith ◽  
M. P. Boland ◽  
I. Gordon
Keyword(s):  
Artificial Insemination ◽  
Ovarian Stimulation ◽  
Present Experiment ◽  
Intramuscular Injection ◽  
Relative Effectiveness ◽  
Fixed Time ◽  
Oestrous Cycle ◽  
High Concentration ◽  
High Degree ◽  
Pregnant Mare Serum Gonadotrophin

Research has shown that it is now possible to control the oestrous cycle of ewes with a high degree of precision (Robinson et al. 1967; Gordon, 1975; Boland, Kelleher & Gordon, 1978). There is general agreement that a high concentration of progestagen, followed by rapid withdrawal and adequate ovarian stimulation is necessary for acceptable fertility (Robinson et al. 1967; Gordon, 1975; Colas, 1975). Application of artificial insemination in France has involved the use of a 40–45 mg Cronolone sponge (Cognie, Mariana & Thimonier, 1970; Colas et al. 1973) while controlled breeding in sheep in Ireland has been used in conjunction with a 30 mg Cronolone pessary (Gordon, 1975; Smith, Boland & Gordon, 1978, 1981). The present experiment was designed to compare the relative effectiveness of two doses of Cronolone (30 or 45 mg) when administered in conjunction with two quantities(375 or 750 i.u.) of pregnant mare serum gonadotrophin (PMSG), given by intramuscular injection.

Field Trials in Fixed Time Sheep A.I. in Ireland

1984 ◽  
Vol 1984 ◽  
pp. 99-99
Author(s):  
T F Crosby ◽  
M P Boland ◽  
I Gordon
Keyword(s):  
Wave Motion ◽  
Day Treatment ◽  
Skim Milk ◽  
Fixed Time ◽  
Field Trials ◽  
Single Intramuscular Injection ◽  
Previously Treated ◽  
Breeding Seasons ◽  
Natural Service ◽  
Pregnant Mare Serum Gonadotrophin

Studies reported from this laboratory in the mid seventies showed that it was possible to achieve a conception rate of 73% to a single fixed-time insemination in the autumn breeding season in ewes previously treated with intravaginal progestagen and pregnant mare serum gonadotrophin (PMSG). The present work was aimed principally at an examination of the AI technique in commercial flocks when applied over a period of three years (1979–81) and when applied in sheep of different breeds (Galways and Suffolk-cross).In the course of three successive breeding seasons, a total of 2,704 cyclic ewes in 87 farm flocks were bred to Texel or Suffolk rams by A.I. using a sperm dose of 400 million in 0.2 ml volume of a skim milk diluent; only semen samples showing a wave motion rating of 3.5 or higher were used and accepted samples were pooled. A further 525 ewes in 20 farm flocks were bred by natural service (ratio of 1 ram: 10 ewes) in one area covered by the AI work. Control of oestrus and ovulation was achieved by a 12-day treatment using commercially available progestagen sponges (Chronogest, Intervet. Ltd.; Veramix, Upjohn Ltd.); at sponge withdrawal a single intramuscular injection of 500 i.u. PMSG (Intervet. Ltd.) was administered.

Breeding ewes using natural service or artificial insemination

1986 ◽  
Vol 1986 ◽  
pp. 67-67 ◽  
Author(s):  
Margaret E. King ◽  
Beverly J. Keeling
Keyword(s):  
Artificial Insemination ◽  
Fixed Time ◽  
Small Scale ◽  
Financial Investment ◽  
Commercial Scale ◽  
Frozen Semen ◽  
The Cost ◽  
Natural Service ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Fresh Semen

Artificial insemination of ewes has become commercially available in Britain on a small scale over the last few years. It allows the farmer to benefit from MLC recorded rams which have been selected for growth rate and more recently for carcass quality. However, proximity to an A.I. centre is an important consideration as A.I. of ewes requires the use of fresh semen. Frozen semen has not vet achieved the quality and reliability necessary on a commercial scale. Insemination is carried out at a fixed time after the removal of Intra-vaginal pessaries and an injection of Pregnant Mare Serum Gonadotrophin (PMSG). Synchronisation of oestrus using sponges and PMSG adds to the cost of using a commercial A.I. service. If A.I. is not used then one ram per ten ewes is necessary for a synchronised mating which either requires a ram sharing group or considerable financial investment if rams of equivalent quality to those used in A.I. centres are to be purchased.

scholarly journals 27 A retrospective analysis of bull:cow ratio effects on pregnancy rates of beef cows previously enrolled in fixed-time artificial insemination protocols

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 20-20
Author(s):  
Claire L Timlin ◽  
Laura Hungerford ◽  
Tracey Redifer ◽  
John F Currin ◽  
Vitor R G Mercadante
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Economic Feasibility ◽  
Average Ratio ◽  
Conception Rates ◽  
Virginia Department ◽  
Natural Service

Abstract This retrospective study analyzed the effect of bull:cow ratio on pregnancy rates of cows returning to estrus after enrollment in fixed-time artificial insemination (TAI). Data were compiled over the course of 6 breeding seasons between 2014 and 2017 from the Virginia Department of Corrections herd containing 15 farms and 141 groups of cows (average 44 cows/group). Multiparous cows aged 2 years and older (n = 6002) were exposed to estrus synchronization. Non-pregnant cows after TAI (n=3079, average 21 cows/group) were exposed to natural service with bulls diagnosed as fertile by a breeding soundness exam. Percent data were given an arcsine transformation. A one-way ANOVA evaluated TAI rates by season and a linear regression was performed to compare conception rates to the bull:cow ratio. Pregnancy rate to TAI among groups averaged 53% and ranged from 11% to 83%. First bull pregnancy rate of cows returning to estrus was 47% overall, with fall seasons having greater conception rates than spring (51.1% vs. 44.5%, P = 0.03). The ratio of bulls to total number of cows ranged from 1:8 to 1:68 with an average ratio of 1:28. The ratio of bulls to the number of open cows ranged from 1:2 to 1:39 with an average ratio of 1:14. There was no correlation between the bull:cow ratio and return to estrus pregnancy rate (r = -0.12), and there was no correlation between the number of open cows per bull and return to estrus conception rates (r = -0.17). Thus, higher bull:cow ratios (between 1:8 and 1:68) did not effect return to estrus pregnancy rate; producers may consider a lower number of bulls needed for natural service breeding post TAI, decreasing bull related costs and increasing the economic feasibility of adopting TAI protocols.

Conception rates following cervical and intrauterine insemination in the ewe

1986 ◽  
Vol 1986 ◽  
pp. 65-65
Author(s):  
W. Haresign ◽  
R.M. Curnock ◽  
H.C.B. Reed
Keyword(s):  
Artificial Insemination ◽  
Intrauterine Insemination ◽  
Fixed Time ◽  
Field Trials ◽  
Conception Rate ◽  
Major Barrier ◽  
Extensive Field ◽  
Conception Rates ◽  
Potential Benefits ◽  
The Uk

The current technique for artificial insemination (AI) of ewes during the breeding season necessitates the synchronisation of oestrus with progestagen sponges and PMSG, and involves depositing semen into the posterior cervix at a fixed time after sponge removal. Extensive field trials over a number of years in the UK have indicated that a single insemination using fresh diluted semen 56 h after sponge removal generally results in a conception rate of 70%, while conception rates following a single insemination of frozen-thawed semen 57 h after sponge removal have ranged from 19% to 34% (mean 28%). Giving two inseminations of frozen-thawed semen at 50 h and 60 h after sponge removal increased the overall mean conception rate, but only up to 48%. This inability to achieve acceptable conception rates with frozen-thawed semen nullifies many of the potential benefits of AI in sheep flocks.It is well established that the cervix presents a major barrier to sperm transport in the ewe, particularly when oestrus has been synchronised with progestagens and PMSG.

scholarly journals 58 A retrospective analysis of bull:cow ratio effects on pregnancy rates of beef cows previously enrolled in fixed-time artificial insemination protocols

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 1-1
Author(s):  
Claire L Timlin ◽  
Laura Hungerford ◽  
Tracey Redifer ◽  
John F Currin ◽  
Vitor R G Mercadante
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Economic Feasibility ◽  
Average Ratio ◽  
Conception Rates ◽  
Virginia Department ◽  
Natural Service

Abstract This retrospective study analyzed the effect of bull:cow ratio on pregnancy rates of cows returning to estrus after enrollment in fixed-time artificial insemination (TAI). Data were compiled over the course of 6 breeding seasons between 2014 and 2017 from the Virginia Department of Corrections herd containing 15 farms and 141 groups of cows (average 44 cows/group). Multiparous cows aged 2 years and older (n = 6002) were exposed to estrus synchronization. Non-pregnant cows after TAI (n = 3079, average 21 cows/group) were exposed to natural service with bulls diagnosed as fertile by a breeding soundness exam. Percent data were given an arcsine transformation. A one-way ANOVA evaluated TAI rates by season and a linear regression was performed to compare conception rates to the bull:cow ratio. Pregnancy rate to TAI among groups averaged 53% and ranged from 11% to 83%. First bull pregnancy rate of cows returning to estrus was 47% overall, with fall seasons having greater conception rates than spring (51.1% vs. 44.5%, P = 0.03). The ratio of bulls to total number of cows ranged from 1:8 to 1:68 with an average ratio of 1:28. The ratio of bulls to the number of open cows ranged from 1:2 to 1:39 with an average ratio of 1:14. There was no correlation between the bull:cow ratio and return to estrus pregnancy rate (r = -0.12), and there was no correlation between the number of open cows per bull and return to estrus conception rates (r = -0.17). Thus, higher bull:cow ratios (between 1:8 and 1:68) did not effect return to estrus pregnancy rate; producers may consider a lower number of bulls needed for natural service breeding post TAI, decreasing bull related costs and increasing the economic feasibility of adopting TAI protocols

Fertility following synchronization of oestrus in the sheep with intravaginal sponges. II. Effect of dose of progestagen and rate of absorption

1970 ◽  
Vol 21 (5) ◽  
pp. 783 ◽  
Author(s):  
TJ Robinson
Keyword(s):  
Linear Relationship ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Great Variability ◽  
Significant Linear Relationship ◽  
Rate Of Absorption ◽  
Time Basis ◽  
Dose Levels

The effect on fertility of the amount of Cronolone (Searle) absorbed from intravaginal sponges and the method of artificial insemination was studied. A significant linear relationship exists between fertility and the amount absorbed in 16 days, over the range 1-10 mg. No such relationship can be demonstrated above this amount, and great variability and sensitivity to failure of fertility is shown at all dose levels. Insemination on a fixed time basis is superior to that on teasing. Of ewes inseminated on a time basis on the second or third day after withdrawal of sponges, 117 lambed of 237 treated (49.4%). Of ewes inseminated on detection of oestrus, 97 lambed of 196 in oestrus (49.5 %) of 249 treated (39 .O %).

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