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PubMed2004

Prostaglandin F2alpha treatment associated with timed artificial insemination in ewes.

Traditional treatments of two prostaglandin F2 alpha (PGF2alpha) doses at 10-day intervals or more did not result in acceptable pregnancy rates in timed artificial insemination (TAI) programmes in ewes. An explanation might be the undefined time-period of the onset of oestrus and ovulation after the treatment. Recently a consistent interval to oestrus and ovulation was obtained by giving PGF2alpha at day 3 post-ovulation, i.e. when the largest follicle of the first follicular wave of the cycle was still growing. This can be achieved when a second dose of PGF2alpha is given 7 days after a first dose. In this work, we evaluated the synchronization of oestrus and determined which of three different moments of TAI was the most successful using a PGF2alpha (PG-7d) protocol in a large flock. A total of 436 nulliparous and multiparous ewes were treated with two doses of a PGF2alpha analogue (delprostenate 160 microg, i.m.) separated by 7 days. Onset of oestrus was recorded twice a day and a single cervical TAI with fresh undiluted semen was performed either at 42 h (n = 152), 48 h (n = 120), or 54 h (n = 164), after the second PGF2alpha dose without taking into account the oestrous response. Pregnancy rate was determined by transrectal ultrasonography 30 days after insemination. Onset of oestrus was detected in 308 of 328 and 89 of 108 multiparous and nulliparous ewes, respectively (p < 0.001), within 72 h after treatment. The distribution of the onset of oestrus did not differ between multiparous and nulliparous ewes and the highest proportion of ewes in oestrus was detected between 25 to 48 h (313/397) from the second PGF2alpha dose. The pregnancy rate in ewes inseminated at 42 h tended to be higher than those inseminated at 48 h (p = 0.09) and was higher than those inseminated at 54 h (p < 0.05) (56/152, 31/120, 37/164; respectively). Therefore, the use of the PG-7d protocol resulted in a very high synchronization of oestrus with the highest concentration (around 80%) between 25 to 48 h from the end of treatment. The best pregnancy rate (37%) was obtained after a single cervical TAI with fresh semen at 42 h.

Animals↗
PubMed1998

Effect of time of artificial insemination on pregnancy rates, calving rates, pregnancy loss, and gender ratio after synchronization of ovulation in lactating dairy cows.

In order to assess the optimal time of artificial insemination (AI) in relation to ovulation, lactating dairy cows (n = 732) from herds with rolling herd averages of 9980 to 11,800 kg from three milkings per day were randomly assigned to five groups by stage of lactation and parity. Ovulation was synchronized by administration of GnRH followed 7 d later with PGF2 alpha followed 2 d later with a second treatment with GnRH. Cows were inseminated at 0, 8, 16, 24, or 32 h after the second injection of GnRH (ovulation occurs between 24 and 32 h after GnRH). Pregnancy diagnoses were performed by ultrasound at 25 to 35 d post-AI. Pregnancy rates per AI were similar for the groups inseminated at 0, 8, 16, and 24 h and lower for the group inseminated at 32 h. A significant quadratic effect of treatment suggests that the middle time periods (8, 16, and 24 h) may produce the greatest pregnancy rate per AI. However, the group inseminated at 0 h had lowest pregnancy loss, and the group inseminated at 32 h tended to have the greatest pregnancy loss compared with that of the other groups. The calving rate was similar between the groups inseminated at 0, 8, 16, and 24 h and lower in the group inseminated at 32 h. The time of AI also appeared to affect gender of calf: cows bred at 0 and 32 h having a higher percentage of female offspring. In conclusion, there appears to be substantial flexibility in the time of AI after the second injection of GnRH, and lower reproductive rates were observed only when AI was after the time of ovulation.

Abortion, Veterinary↗
PubMed2005

Induction of estrus in suckled female yaks (Bos grunniens) and synchronization of ovulation in the non-sucklers for timed artificial insemination using progesterone treatments and Co-Synch regimens.

The objectives of the present study were to evaluate the induction of estrus and fertility in yak cows treated with Co-Synch regimens or progesterone (P(4)). In Experiment 1, postpartum suckled yaks were assigned to three treatments: (1) A (n=28), insertion of an intravaginal device containing P(4) (CIDR) on Day 0, PGF(2alpha) (i.m.) on Day 6 and PMSG (i.m.) at the time of CIDR removal on Day 7 (P(4)-PGF(2alpha)-PMSG); (2) B (n=21), PGF(2alpha) (i.m.) on Day 6 and PMSG on Day 7; (3) C (n=26), control group. Seven yak bulls were grazed with the cows for natural breeding. Rate of estrus within 96h of the end of treatment was greater (P<0.05) in A (100.0%) than in B (28.6%) or C (0.0%). First service conception rate (CR) determined by serum P(4) on Day 21 after breeding was greater (P<0.05) in A (78.6%) than in B (22.2%). Also, pregnancy rate (PR) during the breeding season was greater (P<0.05) in A (82.1%) than in B (19.0%) and C (7.7%). In Experiment 2, non-suckled yaks that calved in previous years but not in the current year were assigned to three treatments: (1) A (n=31), GnRH (i.m.) on Day 0, followed by PGF(2alpha) on Day 7 and timed artificial insemination (TAI) concurrently with GnRH treatment on Day 9 (Co-Synch regimen); (2) B (n=50), a CIDR device for 7 days plus PGF(2alpha) and PMSG at the time of CIDR withdrawal on Day 7 and TAI on Day 9 (P(4)-PGF(2alpha)-PMSG); (3) C (n=50), yak cows were artificially inseminated at spontaneous estrus. Frozen semen of Holstein and Jersey were used for insemination in Experiment 2. The CR assessed by rectal palpation 35 days after TAI was not different in A (22.6%), B (30.0%) and C (33.3%), but PR was greater in A and B than in C, when based on those cows presented for estrous synchronization programs. It is concluded that P(4)-PGF(2alpha)-PMSG protocol could efficiently induce estrus and result in an acceptable pregnancy rate in postpartum suckled yak cows. This technique and Co-Synch regimen can be applied successfully for TAI of non-suckled yak cows.

Animals↗
PubMed1997

CASA as an aid to selecting sperm suspensions for artificial insemination in Callithrix jacchus.

The ability to use sperm motility parameters, obtained by computer-assisted sperm motility analysis (CASA), as an aid to selecting sperm samples for artificial insemination (AI) would have considerable benefits for commercial organizations and for the captive breeding of endangered species. In this study the Hobson sperm tracker (HST) was validated for use with spermatozoa from Callithrix jacchus, the common marmoset, by comparing values for straight line velocity by CASA with those obtained by direct measurement of sperm tracks. Using the settings established during validation, ejaculated and epididymal spermatozoa were analysed with the HST. The range of values for velocity parameters were used to establish expected motility profiles for the two types of spermatozoa as follows: for epididymal spermatozoa (concentration 2.2 - 85.8 x 10(6) spermatozoa/mL) VCL 109.8-155.9, VSL 75.2-141.5, VAP 85.8-142.1, MAD 13.7-40.7, ALH 3.8-7.8, BCF 1.4-4.2, LIN 40.5-91.1% and STR 70.1-97.1%; for ejaculated spermatozoa (concentration 3.2-82.0 x 10(6) spermatozoa/mL) VCL 89.6-136.7, VSL 69.6-110.3, VAP 74.5-121.9, MAD 19.2-29.3, ALH 3.0-9.9, BCF 2.8-5.5., LIN 65.4-85.3% and STR 93.8-97.7%. Epididymal spermatozoa from males which were not sexually active had significantly lower values for VCL, VSL and VAP, while values for MAD were significantly higher than for spermatozoa from sexually active males (p < 0.031). Sperm concentration affected motility parameters significantly. Although motility parameters differed according to the batch of medium used, the differences were not statistically significant. Epididymal sperm samples had significantly higher VCL, VSL and VAP but lower BCF and LIN than ejaculated sperm samples of the same concentration diluted in the same batch of medium, while MAD, ALH and STR were not different. Urine contamination significantly reduced VCL, VSL and VAP (p < 0.008, < 0.016 and < 0.008, respectively, sample size = 7) whereas MAD, ALH, BCF, LIN and STR were not affected. Therefore CASA could be useful in screening ejaculates for use in Al to eliminate samples with unusual motility patterns.

Animals↗
PubMed2001

Factors affecting the reproductive efficiency of artificial insemination programmes in a seasonal breeding pasture-based dairy system with the aid of milk progesterone.

To determine the factors affecting reproductive efficiency in a seasonal breeding artificial insemination (AI) programme in dairy herds in Uruguay, a field trial was conducted on three dairy farms. Lactating cows (n=328) intended to be bred at the following breeding period were selected. The trial started 1 week before the beginning of the breeding period and lasted 80 days or until first service. Milk samples were obtained biweekly for 12 weeks, starting 1 week prior to the breeding season to determine progesterone concentrations. Data indicated that 12.5% of the cows were anoestrus at the beginning of the season remaining in this condition throughout the trial. Most of the anoestrous animals were first-calf heifers. A varying number of cycling cows (8.5%) at each farm were never reported in heat. Oestrous detection rate for cows cycling, as determined by progesterone patterns, was evaluated in three periods of 21 days and resulted in an overall efficiency of 46.9%. Main factors affecting oestrous detection were farm, with an effect of parity (67.8%, mature cows and 33.2%, first-calf heifers) and no effect of days postpartum. Mean interval from the beginning of the breeding season to first breeding was 27.4 days, which was also affected by farm. Neither parity nor days postpartum affected this parameter.

Anestrus↗
PubMed2006

Milk progesterone profile at and after artificial insemination in repeat-breeding cows: effects on conception rate and embryonic death.

The aim of this study was to investigate whether the skim milk progesterone concentrations at artificial insemination (AI) and day of rise of post-ovulatory progesterone concentration thereafter affect the conception and embryonic death rates in repeat-breeding cows. Milk samples were obtained from 96 repeat-breeding cows that failed to conceive to three or more AIs. The samples were taken from the cows at the day of AI and three times/week until day 45 post-AI. Skim milk was obtained after centrifugation and used for progesterone assay. The cows with a progesterone concentration more than 0.5 ng/ml at AI showed a significantly higher incidence of late embryonic death than those having a progesterone concentration<0.5 ng/ml at AI (p<0.01). As the progesterone level at insemination rose, conception rate declined. A negative correlation was shown between conception rate and skim milk progesterone level at AI. Of 56 cows showing a rise of progesterone to 1 ng/ml or more within 6 days after AI, 28 cows (50%) conceived. On the contrary, only eight of 39 cows (20.5%) conceived when the progesterone rose up to 1 ng/ml after day 6 post-AI. We concluded that increased progesterone concentration at the time of AI and delayed rise of progesterone post-AI might lead to decrease in fertility in repeat-breeding cows.

Animals↗
PubMed2005

Estrous cycle characterisation and artificial insemination using frozen-thawed spermatozoa in the bottlenose dolphin (Tursiops truncatus).

The reproductive endocrinology of the bottlenose dolphin, Tursiops truncatus, was characterized to facilitate the development of artificial insemination using cryopreserved spermatozoa. Specific objectives were: (i) to determine the excretory dynamics of urinary luteinizing hormone (LH) and ovarian steroid metabolites during the estrous cycle; (ii) to evaluate the effect of an exogenously administered synthetic progesterone analog (altrenogest) on reproductive hormone excretion; (iii) to correlate follicular growth and ovulation (as determined by transabdominal ultrasound) to urinary LH and ovarian steroid metabolites; (iv) examine the in vivo fertilisation capacity of cryopreserved semen, and (v) to develop an intrauterine insemination technique. Based on urinary endocrine monitoring of natural estrous cycles (2 consecutive cycles) and nine post altrenogest cycles in ten females, estrous cycles were found to be 36 days long and comprised of an 8 day and 19 day follicular and luteal phase, respectively. Peak estrogen conjugates (EC; 5.4+/-3.8 ng/mg creatinine (Cr)) occurred 8 h prior to the LH surge (70.9+/-115.7 ng/mg Cr). The time of ovulation, as determined by ultrasonography, occurred 32.1+/-8.9 h and 24.3+/-7.0 h after the onset of the LH surge and LH peak, respectively. Mean preovulatory follicular diameter and circumference were 2.1+/-0.5 cm and 6.5+/-1.5 cm, respectively. Of the 27 estrous synchronisation attempts, 13 resulted in an ovulatory cycle, with ovulation occurring 21 days post-altrenogest treatment. Intrauterine (4 of 5) and intracornual (1 of 3) inseminations conducted across eight estrous cycles resulted in five pregnancies (63%), one pregnancy resulted from the use of liquid stored semen, whereas four were achieved using cryopreserved semen. These data provide new information on female bottlenose dolphin reproductive physiology, and demonstrate that the combination of endocrine monitoring and serial ultrasonography contributed to successful AI using liquid-stored and cryopreserved semen.

Animals↗
PubMed1980

Conception rates of Holstein bulls for artificial insemination on a California dairy.

Data of milk production and reproduction were collected from a 2,500-cow dairy in California for measuring conception rates of bulls for artificial insemination. The bulls were placed into groups of low, medium, or high conception rates. Mean conception rates were 38.2%, 55.7%, and 66.1%, range 34% to 70%. To predict the conception-rate group of a bull required 30 services. There were no differences in average number of lactations and days to first service of the cows bred to the three groups of bulls. Cows bred to the bulls with high conception rate produced 667 kg more milk than cows bred to bulls with low conception rate. Cows bred to the low bulls were bred, on the average, in mid-July, whereas cows bred to the other two groups were bred in June and May. The cost to this dairy for using low conception rate bulls was $21,000.

Animals↗
PubMed1996

Reproductive and financial impact of a do-it-yourself artificial insemination programme compared with keeping a bull.

The fertility of five dairy herds was studied for three years while they initiated a programme of do-it-yourself artificial insemination (DIY AI) and kept a herd bull, and the financial impact of the new programme was assessed. The herds of approximately 100 cows were all Friesian pedigree, changing to Friesian/Holstein. The DIY inseminators each operated within one herd and were all trained at the same centre. Within a herd, each cow inseminated by a bull was paired with a cow inseminated by AI. The paired cows calved during the same week and were of the same lactation number and genetic type. Each year 20 matched pairs, that is 40 cows per herd, were used, giving a total of 600 cow records. During the first two years, in the majority of herds the calving interval decreased in both the cows inseminated by DIY AI and by the bull. There was a higher culling rate for all cows in the first year, resulting in an improved Fertex score and improved profitability in the second year compared with the first. However, in the five herds combined it was only by the third year that the calving interval for the DIY AI cows was shorter (by 17.9 days) than for cows inseminated by the bull (P < 0.05). The first year of the DIY AI programme was a financial strain for the farmers, but the second and third years showed enough improvement to recover the losses incurred in initiating DIY AI, that is, the capital investment and learning period.

Animal Husbandry↗
PubMed1993

Norgestomet implants synchronize estrus and enhance fertility in beef heifers subsequent to a timed artificial insemination.

Three trials involving 128 heifers were conducted to determine whether norgestomet implants administered during the mid- and late luteal phases after breeding could be used to synchronize a second estrus in nonpregnant, inseminated heifers without adversely affecting pregnancy in pregnant heifers. All heifers were initially synchronized with Syncro-Mate B and artificially inseminated 47 h after implant removal. On d 9 (Trial 1) or d 12 (Trial 2) after the timed AI, the heifers were randomly assigned to treated or control groups. Treated heifers received two silicone implants containing 10.0 mg of norgestomet each (Trial 1) or one silicone implant containing 3.6 mg of norgestomet (Trial 2). Silicone implants were removed on d 21 after the initial AI. In Trial 1, the calving rate to the initial AI of the control heifers was 35 vs 55% for the norgestomet-implanted heifers (P > .05). In Trial 2 the calving rate to the initial AI of the control heifers was 9 vs 45% in the treated heifers (P < .01). At the return estrus 52% of the control heifers returned to estrus within a 3-d period, whereas 93% of the norgestomet-treated heifers returned to estrus within a 3-d period (P < .01). Norgestomet treatment had no effect on serum progesterone concentrations of the pregnant heifers on d 21 after the initial AI. In Trial 3, both control and treated heifers were administered silicone implants containing 3.6 mg of norgestomet on d 12; additionally, the treated heifers received an injection containing 3.0 mg of norgestomet and 5.0 mg of estradiol valerate. Norgestomet implants were removed on d 21.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Socio-economic characteristics of artificial insemination donor (AID) couples compared with matched population controls.

Socio-economic characteristics like education, occupation and religion may play a role when choosing or refraining from treatment by artificial insemination by donor (AID). From a cohort of 189 AID-patients, the socio-economic characteristics were established from the notes and a questionnaire that was sent to all patients to complete the available data. The response rate to the questionnaire was 83.6% (158 women). Data were compared with population controls that were matched for age and region. AID patients in this study had significantly lower educational and/or occupational levels than matched population controls and were significantly more religious.

Adult↗
PubMed2004

Fixed-time artificial insemination of postpartum beef cows at 72 or 80 h after treatment with the MGA Select protocol.

The objective was to determine the appropriate timing of fixed-time artificial insemination (AI) following administration of the MGA Select protocol. Cows at two locations (Location 1, n=114; Location 2, n=97 ) were assigned to fixed-time AI at 72 or 80 h by age, body condition score (BCS), days postpartum (DPP), AI technician, and sire. All cows were synchronized with the MGA Select protocol, consisting of oral administration of melengestrol acetate (MGA; 0.5mg/hd per day) for 14 days, GnRH (Cysotrelin, 100 microg, i.m.; Day 26) 12 days after MGA withdrawal, followed in 7 days with PGF(2alpha) (PG; Lutalyse, 25mg i.m.; Day 33). Cows were inseminated at 72 h ( n=108 ) or 80 h ( n=103 ) after PG and GnRH (100 microg) was given at insemination. Location was not significant and, therefore, was removed from the model. Mean BCS ( 5.2+/-0.1, 72 h; 5.3+/-0.1, 80 h) and DPP ( 34+/-2, 72 h; 35+/-2, 80 h) did not differ ( P>0.1 ) between treatments. Serum progesterone concentrations 7 and 1 day prior to MGA were used to determine pre-treatment cyclicity: cows with at least one sample with progesterone > or =1 ng/ml were defined as cyclic (33/108, 31%, 72 h, versus 32/103, 31%, 80 h; P>0.1). Cows with serum progesterone concentrations > or =1 ng/ml on the day of PG were defined as responding to the synchronization protocol (74/108 (69%), 72 h versus 69/103 (67%), 80 h; P>0.1 ). Although pregnancy rates were higher ( P<0.05 ) for cows inseminated at 72 h (69/108, 64%) versus 80 h (52/103, 50%) after PG, pregnancy rates at the end of the breeding season did not differ ( P>0.1 ) between treatments (98/108 (91%), 72 h; 88/103 (85%), 80 h). In conclusion, pregnancy rates were higher when postpartum beef cows synchronized with the MGA Select protocol were inseminated at 72 h versus 80 h after PG.

Animals↗
PubMed2005

JSAR Innovative Technology Award. Development of ovulation synchronization and fixed time artificial insemination in dairy cows.

Recently, reproductive management has become more difficult as a result of increased herd size. Problems with missing estrous signs and decrease in conception rate by artificial insemination (AI) performed at wrong timing have caused low AI conception rates. In 1995, ovulation synchronization and fixed-time AI (Ovsynch/TAI) was developed in the USA as a new reproductive technology, which was accepted as an useful reproductive management tool in many countries. However, no information on the use of Ovsynch/TAI was available in Japan. It was, therefore, warranted to show the ovulation rate and conception rate after Ovsynch/TAI using gonadotropin releasing hormone analogue (GnRH-A, fertirelin acetate) and prostaglandin F2alpha (PGF2alpha)-THAM, both were commercially available in this country. The conception rate after Ovsynch/TAI has been known to vary among different herds and individuals. Investigation and analysis of factors affecting the conception rate was also warranted to improve the conception rate. A series of experiments were carried out to establish Ovsynch/TAI using domestically produced GnRH-A and PGF2alpha and to study factors affecting conception rate after Ovsynch protocol. Ovsynch using 100 microg GnRH-A and 25 mg PGF2alpha were observed using ultrasonography. As a result, a high synchronization rate of ovulation at 16 to 20 h after the second GnRH injection was confirmed. The conception rate after Ovsynch/TAI was compared in 87 cows with the conception rate after AI at estrus induced by PGF2alpha (139 cows). Conception rate after Ovsynch/TAI was higher than the figure after AI at induced estrus (59.1% vs 20.9%, P<0.05). The dose of GnRH-A was also studied and a practical dose of GnRH-A was found to be 50 microg per cow. To clarify some factors affecting the conception rate after Ovsynch/TAI, 1,558 cows were investigated for the state of their ovaries, days after calving, parity, season, ovarian cyclicity postpartum and nutritional state at the day of Ovsynch. The overall conception rate after Ovsynch/TAI was 51.5%. Fifty-six cows (3.6%) showed estrus at 6 to 7 d after the first injection of GnRH-A. The conception rate after Ovsynch/TAI was low in cows that were 40 to 60 d postpartum, those in their 5th lactation or more, those bred in July to August, and those recovering ovarian cyclicity later than 56 d postpartum. The conception rate after Ovsynch/TAI was high in cows in which body condition score (BCS) was 3.75 at dry period and 3.0 at the day of Ovsynch. In conclusion, Ovsynch/TAI is an effective tool for the reproductive management of dairy cows. A steady and sufficient conception rate after Ovsynch/TAI could be expected by taking the factors affecting the conception rate into the consideration.

Animals↗
PubMed2003

Effect of resynchronization with GnRH on day 21 after artificial insemination on pregnancy rate and pregnancy loss in lactating dairy cows.

The objectives of the present study were to determine the effects of resynchronization with GnRH on Day 21 after artificial insemination (AI) on pregnancy rate and losses of pregnancy in lactating dairy cows. Holstein cows (n=585) on two dairy farms were assigned to one of two treatments in a randomized complete block design. On Day 21 after a pre-enrollment AI, animals assigned to the resynchronization (RES) group received 100 microg of GnRH i.m., whereas animals in the control (CON) group received no treatment. All animals were examined ultrasonographically on Days 21 and 28 after AI, and blood samples were taken for progesterone measurement on Day 21. Pregnancy was diagnosed on Day 28 and reconfirmed 14 days later. Nonpregnant cows on Day 28 were inseminated using timed AI after the completion of the Ovsynch protocol 10 and 17 days after enrollment in the study for RES and CON groups, respectively. Progesterone concentration > or =2.35 ng/ml was used as an indicator of pregnancy on Day 21. For RES and CON cows, pregnancy rate at Days 21 (70.9% versus 73.0%, P<0.56), 28 (33.1% versus 33.6%; P<0.80) and 42 (27.0% versus 26.8%; P<0.98) after the pre-enrollment AI did not differ. Administration of GnRH on Day 21 after AI had no effect on pregnancy loss in RES and CON groups from days 21 to 28 (53.2% versus 53.5%; P<0.94) and days 28 to 42 (17.9%; P<0.74) after AI. Pregnancy rate after the resynchronization period was similar for both treatment groups. Resynchronization with GnRH given on Day 21 after AI for initiation of a timed AI protocol prior to pregnancy diagnosis does not affect pregnancy rate and pregnancy loss in lactating dairy cows.

Abortion, Veterinary↗
PubMed1999

Estrus synchronization and artificial insemination of hair sheep ewes in the tropics.

Hair sheep ewes (St. Croix White and Barbados Blackbelly) were used to evaluate 3 methods of estrus synchronization for use with transcervical artificial insemination (TAI). To synchronize estrus, ewes (n = 18) were treated with PGF2alpha (15 mg, im) 10 d apart, with controlled internal drug release (CIDR) devices containing 300 mg progesterone for 12 d (n = 18), or with intravaginal sponges containing 500 mg progesterone for 12 d (n = 18). On the day of the second PGF2alpha injection or at CIDR or sponge removal, sterile rams were placed with the ewes. Jugular blood samples were collected from the ewes at 6-h intervals until the time of ovulation, and daily for 16 d after estrus (Day 0). Plasma was harvested and stored at -20 degrees C until LH, and progesterone concentrations were determined by RIA. There was no difference (P>0.10) in time to estrus among the CIDR-, PGF2alpha- or sponge-treated ewes. All of the ewes in the CIDR group and 94.4% of the sponge treated ewes exhibited estrus by 36 h after ram introduction, while only 72.2% of PGF2alpha-treated ewes showed signs of estrus by this time (P<0.06). The time from ram introduction to ovulation was not different (P>0.10) among the CIDR-, PGF2alpha- or sponge-treated ewes. The time to the preovulatory LH surge was similar (P>0.10) among CIDR, PGF2alpha and sponge treated ewes. Progesterone levels through Day 16 after the synchronized estrus were not different (P>0.10) among treatment groups. Hair sheep ewes (n = 23) were synchronized using PGF2alpha and bred by TAI using frozen-thawed semen 48 h after the second injection. The conception rate to TAI was 2/23 (8.7%) and produced 3 ram lambs. In a subsequent trial, 17 ewes were synchronized with CIDR devices and bred by TAI using frozen-thawed semen 48 h after CIDR removal, resulting in a conception rate of 52.9% (9/17). It is possible to synchronize estrus in hair sheep using either CIDRs, sponges or PGF2alpha. Even though there were no significant differences in the timing of ovulation or the LH surge among the treatment groups, a higher conception rate was achieved in ewes synchronized with CIDR devices during the second trial. This may reflect an increase in the skill level of the TAI technician.

Administration, Intravaginal↗
PubMed2000

Short-term dietary effects on reproductive wastage after induced ovulation and artificial insemination in primiparous lactating Sarda ewes.

Short-term effects of nutrition on conception rate (CR), ovulation rate (OR), ova and embryo losses (OEL) during the first 50 days following insemination and total reproductive wastage after ovulation (TRW), were investigated in primiparous lactating Sarda ewes after oestrous synchronisation and cervical [corrected] artificial insemination (AI). Eighty ewes grazing a green high-quality pasture were offered one of three iso-energetic supplements from day 14 before to day 2 after AI: whole maize grain (M); soyabean meal (S); maize gluten meal (G); or served as controls (C). Supplements G and S were iso-nitrogenous but provided different amounts of rumen undegradable digestible protein. The intake of herbage and digestible dry matter, measured by the n560 mg/l was associated with lower CR. Ranking by ovulation groups of CR was single<double=triple; and of TRW was double<triple<single. In conclusion, OR in primiparous lactating Sarda ewes grazing on a good quality pasture is high, and CR after AI is reduced by ova as well as embryo loss, especially following single ovulations. Short-term supplementation with a soyabean-based concentrate may help alleviate these losses.

Alkanes↗