Studies in controlled artificial insemination of Merino sheep

1958 ◽  
Vol 9 (5) ◽  
pp. 693 ◽  
Author(s):  
TJ Robinson
Keyword(s):  
Artificial Insemination ◽  
Treatment Effects ◽  
Factorial Experiment ◽  
Merino Sheep ◽  
High Incidence ◽  
Lambing Rate

A total number of 507 ewes were inseminated at the rate of approximately 100 per day for 5 days, in a factorial experiment with variables: rams (5), treatments (5), days of insemination (5), volume of semen (2). Treatments were: (1) control; (2) progesterone daily for 16 days, PMS on 17th, inseminated on teasing; (3) progesterone every 2 days, PMS on 17th, inseminated on teasing; (4) as for (2), but inseminated 2 days after PMS; (5) as for (3), but inseminated 2 days after PMS. The overall lambing rate was low (31-6 per cent.). There were significant differences between rams, treatments, and day of insemination. Relative infertility of one ram was related to high incidence of sperm with curled tails. Treatment effects were: (1) 40.8 per cent. of ewes lambed; (2) 33.7 per cent.; (3) 32.9 per cent.; (4) 30.2 per cent.; (5) 15.0 per cent. Insemination was less efficient on the first day. Volume of undiluted semen used (0.05 or 0.1 ml) had no effect.

Studies on the artificial insemination of Merino sheep. III. The effect of frequent ejaculation on semen characteristics and fertilizing capacity

1962 ◽  
Vol 13 (6) ◽  
pp. 1137 ◽  
Author(s):  
S Salamon
Keyword(s):  
Linear Relationship ◽  
Artificial Insemination ◽  
Volume Density ◽  
Merino Sheep ◽  
Significant Linear Relationship ◽  
Normal Sperm ◽  
Abnormal Sperm ◽  
Semen Characteristics ◽  
Linear Decline ◽  
Lambing Rate

(1) Fifty-five ejaculates were collected from each of two Merino rams over a period of 5 days (11 per day per ram at intervals of 20 min). Ejaculates were examined for semen characteristics and for fertilizing capacity following artificial insemination, a total of 300 ewes being used. (2) Volume, density, and number of sperm declined on successive days, and in successive ejaculates within days (P <0.001). Motility and percentage of abnormal sperm were not affected by frequent collection. (3) Fertility following insemination with a standard volume of diluted semen showed a significant linear decline with successive ejaculates, both within and between days of collection ( P <0.01, <0.001). (4) The decline in fertility could be accounted for entirely on the basis of sperm numbers. There was no evidence of a decline in the fertilizing capacity of spermatozoa with frequent ejaculation. (5) There was a highly significant linear relationship between sperm numbers and lambing percentage, over the range of 28 to 128 X 106 sperm (27–118 x 106 normal; b = 0.27; r = 0.69; P <0.01). (6) It is concluded that a dose of approximately 120–125 x l06 normal sperm is necessary for maximum fertility to artificial insemination; and that each 25 x 106 reduction down to a dose of 25 x 106 may be associated with a drop in lambing rate of about 13%.

The artificial insemination of the Merino sheep following the synchronization of oestrus and ovulation by progesterone injected alone and with Pregnant Mare Serum Gonadotrophin (PMS)

1956 ◽  
Vol 7 (3) ◽  
pp. 194 ◽  
Author(s):  
TJ Robinson
Keyword(s):  
Breeding Season ◽  
Artificial Insemination ◽  
Merino Sheep ◽  
The Third ◽  
Final Injection ◽  
Group 3 ◽  
Group 2 ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Group 1 ◽  
Lambing Rate

Two groups (2 and 3), each of 112 stud Merino ewes, which were experiencing regular oestrous cycles, received daily injections of 10 mg progesterone for 16 days, in an attempt to synchronize oestrus and ovulation for artificial insemination. One group (3) received an additional injection of 500 i.u. pregnant mare serum gonadotrophin (PMS) the day after the final progesterone injection. Injections were staggered so as to bring between 15 and 20 ewes of each group into oestrus on each of six days, on which days approximately equal numbers of untreated oestrous ewes were inseminated (group 1). In group 2 (progesterone alone), 104 ewes were teased and inseminated within 4 days of the final injection, including 74 (71 per cent.) on the third day. Corresponding numbers of ewes for group 3 (progesterone-PMS) were 107, 96 (90 per cent.). Injection of PMS significantly advanced and improved the precision of time of onset of oestrus, and presumably of ovulation. Of 315 ewes inseminated in all groups, 265 received 0.10 ml undiluted semen; 33, 0.05 ml; and 17, 0.20 ml. There were no apparent differences in lambing rate. Ewes inseminated, ewes lambing, and lambs born were: group 1, 104, 58 (55 per cent.), 74 (71 per cent.); group 2, 104, 53 (51 per cent.), 64 (62 per cent.); group 3, 107, 61 (57 per cent.), 85 (79 per cent.); overall, 315, 172 (55 per cent.), 223 (71 per cent.). There were no significant differences between groups in the proportion of ewes which lambed, or in the twinning rate. Ewes in oestrus and inseminated 72 hr after the final injection of progesterone had a significantly higher lambing rate than did ewes inseminated a day later. It is concluded that progesterone, particularly if used in conjunction with PMS, is of value in synchronizing oestrus in the breeding season for precisely planned artificial insemination.

Differences among Merino strains in resistance to fleece-rot

1958 ◽  
Vol 9 (2) ◽  
pp. 260 ◽  
Author(s):  
AA Dunlop ◽  
RH Hayman
Keyword(s):  
Field Conditions ◽  
Merino Sheep ◽  
High Incidence

The incidence of fleece-rot was observed in a number of strains of Merino sheep distributed variously over fire sets of field conditions. In three locations rainfall was sufficiently high to cause moderate to high incidence of fleece-rot among susceptible sheep. In two other locations conditions were such that its occurrence in susceptible sheep was either negligible or absent. In two of the former localities South Australian strong-wool Merinos proved to be highly susceptible, while in two medium-wool Peppin strains the susceptibility varied from moderate to high. In a medium-wool non-Peppin strain the incidence was less than in the Peppin and South Australian strains; in a fine non-Peppin strain the incidence was moderate to low; while in a flock of Camden Park fine-wools the incidence was low.

Further investigations on artificial insemination of sheep

1941 ◽  
Vol 31 (3) ◽  
pp. 354-369 ◽  
Author(s):  
J. Anderson
Keyword(s):  
Artificial Insemination ◽  
High Grade ◽  
Merino Sheep

The results obtained from artificial insemination of high grade Merino sheep in Kenya are given and discussed in relation to the season of the year, time of insemination during oestrus, the number of inseminations in each oestrous period and the degree of dilution of sperm.

scholarly journals OESTRUS SYNCHRONIZATION, ARTIFICIAL INSEMINATION AND EARLY REBREEDING IN YANKASA SHEEP

2021 ◽  
Vol 9 (2) ◽  
pp. 107-111
Author(s):  
O. A, OSINOWO
Keyword(s):  
Artificial Insemination ◽  
Production System ◽  
Post Treatment ◽  
Natural Mating ◽  
Sheep Production ◽  
Lambing Rate

COMPONENTS of an intensive sheep production system including oestrus synchronization, artificial insemination and early rebreeding were investigated in two trials with Yankasa sheep. Treatment of ewes with progrestagen pessaries for 12 days resulted in good synchronization of first and second post-treatment oestrus. In Trial I, (January–February, 1982) 33 ewes were treated, of which 81.8% showed oestrus within 4 days after the end of progrestagen treatment while 72.7% showed a second oestrus within 21 days. In Trial II, (August – September, 1982), 48 eyes were treated, of which 87.5 and 77.1% showed first and second oestrus respectively over the same periods as in Trial I. Mean interval (± s.e.m) between first and second induced oestrus in both trials was 16.4 ±0.1 days (n = 61). About 90% of ewes exhibiting oestrus were detected 2 to 4 and 17 to 20 days after progrestagen treatment for first and second oestrus respectively.  Lambing reates of ewes to artificial insemination or natural mating at the second induced oestrus in Trial I were 50.0 and 91.7% respectively, Corresponding lambing rates in Trial II were 65.0 and 86.70%.  Rebreeding interval in ewes which lambed in Trial I was 59.1 ±0.8 days following commencement of progestagen treatment approximately one month after lambing. Lambing rate in this group was 78.6%.

INTERPRETATION OF INTERACTION IN THE ANALYSIS OF VARIANCE OF A FACTORIAL EXPERIMENT

1958 ◽  
Vol 38 (2) ◽  
pp. 181-186
Author(s):  
G. C. Ashton ◽  
J. C. Rennie ◽  
E. Etter
Keyword(s):  
Analysis Of Variance ◽  
Treatment Effects ◽  
Study Data ◽  
Factorial Experiment ◽  
Biological Research ◽  
Feeding Experiment ◽  
Experimental Treatments

Frequently imposed experimental treatments in biological research produce results which require evaluation in terms of interdependence between the factors under study. Data from a 2-factor calf-feeding experiment have been used to illustrate the inadequacy of over-all means in describing the treatment effects where factor interdependence existed. It was shown that, to make accurate appraisal of the treatment effects under these conditions, it is necessary to restrict consideration to the subtreatment means.

The effect on conception rates of semen diluents containing citrate or phosphate buffer, with all combinations of sulphanilamide, streptomycin and penicillin

1955 ◽  
Vol 46 (1) ◽  
pp. 44-55 ◽  
Author(s):  
R. C. Campbell ◽  
J. Edwards
Keyword(s):  
Artificial Insemination ◽  
Phosphate Buffer ◽  
Conception Rate ◽  
Factorial Experiment ◽  
Citrate Buffer ◽  
Conception Rates

1. A 24 factorial experiment involving 68,713 first inseminations was carried out at four artificial insemination centres, to compare semen diluents containing citrate or phosphate buffers and all combinations of sulphanilamide, streptomycin and penicillin.2. The analysis of the results was carried out on punched card machines and on an automatic calculator (EDSAC), as well as on bench machines.3. The main results obtained were:(i) Unsupplemented phosphate buffer gave a conception rate 5·5% above that obtained with unsupplemented citrate buffer.(ii) Citrate buffer with sulphanilamide, streptomycin and penicillin gave a conception rate 6·8% above that obtained with unsupplemented citrate buffer; and(iii) Phosphate buffer with penicillin gave a conception rate 9·3% above that obtained with unsupplemented citrate buffer. This effect was not, however, significantly greater than that referred to in (ii).4. Phosphate buffer depressed conception rate when used with sulphanilamide or streptomycin.

Studies on the artificial insemination of Merino sheep. I. The effects of frequency and season of insemination, age of the ewe, rams, and milk diluents on lambing performance

1962 ◽  
Vol 13 (1) ◽  
pp. 52 ◽  
Author(s):  
S Salamon ◽  
TJ Robinson
Keyword(s):  
Central Europe ◽  
Artificial Insemination ◽  
Large Scale ◽  
Cow Milk ◽  
Field Methods ◽  
Merino Sheep ◽  
Standard Field ◽  
Period 2 ◽  
The One

(1) Results of large-scale artificial insemination of Merino sheep (2346 ewes) on a private stud are presented, together with data for seven factorial tests designed to determine effects on fertility, following insemination at one or two successive oestrous periods, of season of insemination, milk diluents, age of ewe, individual ram, and frequency of insemination within a single oestrous period. (2) Insemination in the autumn is more effective than in the spring (79.7 v. 54.7 % of inseminated ewes lambed to insemination over two cycles; P < 0.001). (3) Results for maiden ewes in autumn or spring are 15–20% less than those for older ewes (P < 0.05 to < 0.001). (4) Ewes inseminated with semen of rams producing semen of indistinguishable quality, as gauged by standard field methods, may differ in fertility at a single insemination (P <0.01), but this difference disappears if ewes which return are inseminated by semen of the same rams at the next oestrous period. (5) Dilution of semen to 1.4 with heated cow milk – skim or whole – does not depress fertility. (6) Ewe-milk diluent depresses fertility following a single insemination (68.6 v. 47.3%; P< 0.01). (7) Insemination twice in the one oestrous period may increase fertility by 8–9% (70.3 v. 60.9%; P, N.S.). Such an increase is not worth the additional effort. (8) Fertility with diluted semen is comparable with that reported from eastern and central Europe, provided that ewes are inseminated during the autumn.

Artificial insemination of sheep: I. Preliminary investigation on its application to sheep in Kenya

1937 ◽  
Vol 27 (1) ◽  
pp. 143-150 ◽  
Author(s):  
James Anderson
Keyword(s):  
Artificial Insemination ◽  
Preliminary Investigation ◽  
Practical Application ◽  
Sheep Breeding ◽  
Merino Sheep

An account is given of a preliminary experiment on artificial insemination of cross-bred Merino sheep in Kenya. 202 ewes were inseminated and 74·3 per cent conceived. The practical application of artificial insemination to sheep breeding in Kenya is discussed.

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