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Pregnancy to artificial insemination and late gestation fetal programming of the next calf crop are central to genetic development, reproductive longevity, calf crop productivity, and efficiency of cow/calf ranching. The purposes of this research are to find methods to improve pregnancy rate to artificial insemination, the growth and reproductive health of pregnant heifers, and the productivity of their offspring. In the first of four studies we found that extending the period of progesterone administration in an estrus synchronization protocol did not significantly hasten estrus response or increase pregnancy rate to artificial insemination, but timing of estrus within the melengestrol acetate artificial insemination protocol demonstrated periodicity of estrus. In the second study we found that supplementation of late gestation heifers with monensin and/or a rumen-undegradable protein did not significantly improve reproductive health of the heifers or affect the productivity of their offspring. Monensin successfully decreased dry matter intake while increasing body weight during treatment and the rumen-undegradable protein successfully increased body weight during treatment. Neither appear to have had a definitive effect in the first two years of the study. In the third study we found that pregnancy to artificial insemination using a one-third sample of semen from three bulls inside a single straw is effective but did not significantly increase pregnancy rate compared to semen from a single bull. Although pregnancy rate by each single bull was very similar, the ratio of paternity within the mixed semen sample numerically disfavored one of the bulls, but Year One results are not significantly different. In a fourth study, that did not have a control treatment and was considered observational, we found that artificial insemination using mixed sex-sorted semen from multiple bulls within a single straw resulted in above average pregnancy rate to artificial insemination for each of three years. When semen quality is reduced by the sex-sorting process, this may be a viable method of artificial insemination and merits further study. Advisor: Rick N. Funston

Recent studies of wild felid populations in southern Texas have shown loss of genetic variability and inbreeding depression over time, increasing the risk of reduced reproductive and immune fitness leading to an overall decrease in reproductive success, increase in disease susceptibility, and further population demise. Assessment of general health, pathogen exposure, and reproductive health can provide documentation of the possible effects of inbreeding and inform the development of conservation strategies. Assisted reproductive technologies have been used in many other species and can address behavioral or physical incompatibilities among breeding pairs, connect distant populations by transporting frozen gametes, preserve genetic diversity within liquid nitrogen tanks and link wild and human-managed populations without the movement of individuals. The main goals of this study were to: (1) determine the general and reproductive health status and pathogen prevalence of free-ranging ocelot and bobcat populations in south Texas, given the concern for the impact of declining genetic diversity on population health, (2) compare the effectiveness of urethral catheterization (UC) and ultra-rapid freezing (URF) to traditional cryopreservation methods as a field-friendly semen collection and cryopreservation combination, and (3) assess the use of laparoscopic oviductal artificial insemination (LO-AI) in human-managed ocelot females with semen from wild Texas males to explore the feasibility of this approach to facilitate ocelot pregnancies. While our populations did not show declines in general health, reproductive health parameters of wild ocelots were inferior to human-managed ocelot populations and bobcats exhibited low overall semen quality similar to other Lynx species. We found that UC collected samples were consistently damaged by urine contamination for ocelots and that electroejaculation with straw freezing was superior. For bobcats, while UC and URF appeared adequate, electroejaculation would need to be further explored. No pregnancies (0/5) have been produced in ocelots by LO-AI using frozen-thawed semen thus far; however, eventual success with this technique will allow the use of minimal sperm numbers to promote gene flow among isolated populations and re-establish extirpated populations with genetically diverse individuals. Further assessment of bobcat sperm viability in vivo will be required to demonstrate the practicality of these methods for future conservation initiatives.

From the turn of the century, social attitudes have shifted away from secrecy and anonymity in donor conception in line with broader recognition that children have a right to accurate information about their identity and family. As such, some donor-conceived people are now growing up in families who disclose and discuss donor conception openly while others are unexpectedly learning of their donor-conceived status later in life. Yet, little empirical research has explored the array of actors, processes and technologies that shape experiences of belonging for donor-conceived people. This thesis reports on exploratory research of Australian donor-conceived adults’ experiences. The project adopted an innovative interdisciplinary approach, combining methods and analytic techniques from sociology, social semiotics and media studies to explore everyday social, linguistic and digital practices. Data comprise Hansard from a public hearing of a Senate Committee Inquiry into donor conception; a national online survey with sperm donor-conceived (n=90) and egg donor-conceived (n=1) respondents over 16 years of age; and semi-structured interviews with sperm donor-conceived adults (N=28). The research is also underpinned by vignettes of personal experience to reflexively foreground my own positionality as a donor-conceived person. Findings reveal the significant role that digital technologies play in donor-conceived people’s everyday lives. Donor-conceived peers used digital platforms to exchange experiential knowledge and negotiate meanings ascribed to their collective identity, to educate (prospective) recipient parents and the general public about their perspectives, to trace family members through direct-to-consumer DNA testing, and to strategise for increased recognition in legislation. In terms of family, participants navigated complex and dynamic familial (non) relationships and the lingering consequences of anonymity. However, donor-conceived people also found strategies to help them reckon with secrecy and silence, actively responding to social conditions and challenging the institutions of medicine and the law. Indeed, donor-conceived people drew on experiential and institutional knowledges to position themselves as an authority on donor conception as people with lived expertise. I argue that belonging, for donor-conceived people, is experienced across three planes: in relation to peers, family and the State. In doing so, this thesis underscores how everyday belonging is relational and processual, and achieved through a range of momentous events, everyday encounters and humorous artefacts.

Three studies were conducted to improve simple artificial insemination in sheep using chilled extended semen and evaluate methods to predict fertility in ewes. The first study evaluated the effect of semen extenders and storage temperature on motility parameters of ram semen stored for up to 72 h. Single semen collected from each ram was divided into four parts and extended using four extenders: milk, TRIS, TEST, and CJ-2, diluted to 600 million sperm/ml and loaded into 0.25 ml straws for storage at 4 and 15° C. Most of the CASA motility parameters were higher after extension and storage at 4 compared with 15° C (P < 0.05). Ram semen stored using milk or TRIS based extenders at 4° C maintained similar sperm motility parameters but both were higher compared with TEST or CJ-2 extenders after storage for up to 3 d (P < 0.05). The second study evaluated the effects of different combinations of extenders, ethylene glycol (EG), egg yolk and penicillamine, hypotaurine and epinephrine (PHE) on ram sperm motility parameters during storage. Semen electroejaculated from each ram was distributed across treatment combinations consisting of either TRIS or milk extenders supplemented with 5 or 20% (v/v) egg yolk, ± EG, and ± PHE. Milk extender supplemented with 1% EG, PHE and either 5 or 20% egg yolk can protect sperm cells better than other extender and supplement combination after storage at 4° C for up to 72 h. The third study was conducted to correlate serum AMH and lambs born with estimated breeding values determined through National Sheep Improvement Program for reproductive performance (NLB or number of lambs born; NLW or number of lambs weaned; MWWT or maternal weaning weight; and the Katahdin index) and WWT or weaning weight. Additionally, correlation between AMH quartiles and lambs born after fall versus summer breeding was determined. There was no correlation between serum AMH and EBVs for NLB, NLW, MWWT, WWT and the Katahdin index in Katahdin ewes (P > 0.05). Ewes in the lowest quartile (Q1) had lower number of offsprings born from summer breeding compared with ewes in other AMH quartiles.

Changes to sire selection, such as the utilization of genomic evaluations, have created a desire to collect semen from superior sires as early as possible. Therefore, a series of experiments was performed in order to determine whether a novel exogenous FSH treatment hastened puberty and positively impacted postpubertal semen production in bulls. In the first experiment, angus-cross bulls received either 30 mg NIH-FSH-P1 in a 2% hyaluronic acid solution (FSH-HA, n =11) or saline (control, n = 11) every 3.5 days from 59 to 167.5 days of age. Blood was collected every 7 days to determine testosterone concentrations and at 59, 84, 94, 130, and 169 days of age to determine activin A concentrations. FSH concentrations were determined from blood collected preceding treatment every 3.5 days, as well as during three intensive collections commencing at 66, 108, and 157 days of age. Castration was performed at 170 days of age to examine testis weight, volume, diameter of seminiferous tubules, and the number of Sertoli cells per tubule cross section. Concentrations of FSH did not differ from 59 to 91 days of age, but became greater (P < 0.05) in FSH-HA than control bulls from 94 to 167.5 days. For each intensive sampling, FSH concentration was elevated (P < 0.05) in FSH-HA bulls for at least 18 hours post-injection at all ages examined. Activin A concentrations were greater in FSH-HA than control bulls at 84 and 94 days. Testosterone concentrations, testis weight, testis volume, and seminiferous tubule diameter did not differ between treatments, but FSH-HA bulls had greater (P < 0.05) numbers of Sertoli cells per tubule cross section (45.2 ± 1.4 vs. 41.7 ± 0.9 cells).In a second experiment, Holstein bulls were utilized to determine the FSH-HA treatment's effect on puberty attainment and mature sperm production. Bulls received either the FSH-HA treatment (FSH-HA, n = 17) or saline (n = 12) every 3.5 days from 62 to 170.5 days of age. Concentrations of FSH did not differ between treatments from 62 to 93.5 days of age, but became greater (P < 0.05) in FSH-HA bulls from 97 to 170.5 days of age. Activin A concentrations measured at 62, 86.5, 107.5, 139, and 170.5 days were greater (P < 0.05) in FSH-HA than control bulls at 86.5 and 107.5 days. FSH-HA bulls reached puberty (ability to produce 50 x 106 cells, 10% motility) sooner (P < 0.05) than control bulls (278 ± 7.7 vs. 303 ± 9.1 days), but there was no differences in mature sperm production measured from 571 to 627 days of age.Together, these experiments highlight the efficacy of a novel FSH-HA treatment to hasten puberty. We propose that FSH-HA treatment positively effects the hypothalamo-pituitary-gonadal axis of bulls by stimulating the feedback loop involving activin A and FSH production as evidence by increased Sertoli cells. Impacts of this research are important not only to AI organizations, but also for cattle producers who AI their cows, and for consumers who rely on efficient food production.

Three studies were conducted to improve and incorporate reproductive management practices into beef cow-calf production. First study evaluated serial use of Estrotect estrous detection patches as a simple, cost-effective reproductive management tool to identify cyclic animals before breeding, distinguish between females conceiving to AI versus natural service, and determine seasonal pregnancy rate after bull removal. Also determined, was effectiveness of altered timing of GnRH treatment (1 d ± CIDR removal) in a modified 14-d CIDR-Select Synch protocol. When evaluated over a 4-wk period, estrous detection patches correctly (P < 0.01) identified 79% of cyclic and 86% of non-cyclic heifers. Patches were 96 and 98% accurate in identifying heifers and cows pregnant by AI, respectively, and were 76 and 87% accurate in identifying pregnant heifers and cows at the end of the breeding season (P < 0.01). Treatment with GnRH at CIDR removal reduced labor costs and animal handling without compromising estrous response (both ~63.0%) and AI pregnancy rates (~76 and 77%; P > 0.1). Second study determined if addition of PGF2alpha treatment on d 7 of a modified 14-d progesterone protocol improved estrous response in beef cows and effect of insemination timing on conception rate when using X-sorted semen. Cows were inseminated with X-sorted semen either 9 to 15, or 16 to 24 h after detected estrus. Percentage of cows exhibiting estrus was similar (76.5 and 71.2%; P = 0.33) regardless of treatment. Pregnancy rates after AI were similar (P = 0.64) at 63.3 and 66.7% for cows inseminated 9 to 15, or 16 to 24 h after estrus, respectively. Third study compared estrous response and synchrony resulting from administration of PGF2alpha on D 6 of CIDR protocol, with CIDR removal occurring concurrently (D 6) or 1 d later (D 7). Percentage of cows detected in estrus after synchronization was similar between treatments (74.0 and 71.4%, respectively; P = 0.83). However, 7 d CIDR treatment resulted in 100% of cows exhibiting estrus within a 12-h period versus 75% of 6 d treatment cows. Similar AI pregnancy rates were also observed regardless of treatment (65.0 and 60.0%, respectively; P = 0.74).

Three experiments were conducted to determine the impact of development systems, maternal protein supplementation, and estrus synchronization systems on beef cattle. Experiment 1 evaluated the effects of winter supplementation on cow performance and the effects of post-weaning management on progeny. Late spring calving cows grazed dormant range or meadow over winter and received either supplementation or no supplementation. Steer and heifer progeny were weaned and placed on dormant meadow or fed hay ad libitum. One half of the steers were placed in the feedlot at the end of treatment and the other half grazed range over summer. Cow winter treatment did not affect cow performance. Steers and heifers fed hay had increased ADG during winter trt compared to calves on meadow. Feedlot system did not have a significant effect on carcass data. In experiment 2, cows were synchronized for fixed-time AI (TAI) utilizing the CO-Synch and the CO-Synch + CIDR protocols. Cows synchronized with the CO-Synch + CIDR protocol had increased AI pregnancy rates compared to CO-Synch synchronized cows. In experiment 3, heifers were synchronized for TAI using the MGA + PGF2α protocol or CO-Synch + CIDR protocol. Half of the CO-Synch + CIDR heifers received PGF2α at the time of CIDR insertion. Heifers were time stamped at the time of final PGF2α administration and at the TAI. Pregnancy rates were not affected due to PGF2α administration at the time of CIDR insertion or time interval between final PGF2α administration and TAI. In summary, these experiments provide evidence to support the following findings: (1) there are minimal effects of winter supplementation on late spring calving cows and progeny performance; (2) post-weaning treatment had minimal effects on heifer and steer productivity; (3) cows utilizing CO-Synch + CIDR AI protocol have higher pregnancy rates; (4) fluctuations in time interval from time of PG administration to breeding had no effects on pregnancy rates. Advisors: Richard N. Funston and Brett R. White

The black-footed ferret (Mustela nigripes) is an endangered mustelid native to the grasslands of the North American western Great Plains. Recovery efforts for the species warranted the capture of the last remaining 18 black-footed ferrets for ex situ propagation. Despite vigorous attempts to equalize genetic representation, reproductive inefficiency has been documented. Black-footed ferret spermatozoa suffer significant cryodamage and a decline in percentages of normal sperm in fresh ejaculates has been observed. The decline in reproductive fitness has been attributed to the low number of founders (n = 7) that comprise the current population.The first aim of this project was to improve genetic diversity in the black-footed ferret population by using cryopreserved spermatozoa from a genome resource bank. Black-footed ferret females (n = 4) chosen for laparoscopic artificial insemination were evaluated for estrus. Ovulation was induced with luteinizing hormone. Sires from the genome resource bank were selected based on genetic representation. Two of four (50%) females inseminated became pregnant and produced kits (mean litter size, 1.0). The second aim of this project was to investigate three commercially available density gradient products (PureSperm, ISolate, Enhance-S Plus) to develop a technique to improve the quality of black-footed ferret frozen-thawed sperm fractions for artificial insemination. Domestic ferret ejaculates (used as a model for this study) were collected via electroejaculation and frozen according to standard procedures. Frozen- thawed spermatozoa were divided into 4 groups and either received a simple washing (control) or were subjected to one of three gradient treatments. Results indicated that PureSperm filtration produced the best sperm fractions with the highest percentages of structurally normal and motile sperm. The third aim of this project was to investigate cholesterol-loaded cyclodextrin (CLC) technology as a means to develop a pre-freeze treatment to improve sperm cryosurvival. Domestic ferret ejaculates (chosen as the model for this study) were collected via electroejaculation, evaluated, and were divided among three groups: 1) control, 2) low dose CLC (1.5 mg CLC/ 120 x106 sperm/ml), and 3) high dose CLC (3.0 mg CLC/ 120 x106 sperm/ml). After receiving treatment, ejaculates were subjected to standard cryopreservation methods. Results indicated significant improvement in acrosomal integrity due to treatment, but there was no significant difference in this regard between low and high doses. CLC treatment appeared to have no significant effect on sperm motility or forward progression. Offspring that resulted from this study (n = 2) are currently considered the most genetically valuable animals in the black-footed ferret population. However, further studies are warranted in these individuals and subsequent generations to determine whether increased genetic fitness improves sperm viability in this species. Moreover, future artificial inseminations using cryopreserved sperm from the black-footed ferret genome resource bank may benefit from PureSperm density gradient processing since application of this product enhanced cryopreserved sperm fractions in the domestic ferret. Although use of CLC as a pre-freeze treatment did not appear to affect sperm longevity, further investigations are warranted to confirm the degree of membrane manipulation that occurs with CLC application prior to cryopreservation, which is shown to improve acrosomal integrity in domestic ferret frozen-thawed sperm.

The objectives were to: 1) determine if im treatments of Lutalyse expedited the training of sexually inexperienced boars for semen collection and increased spermatozoal output, and 2) determine the effects of dietary L-carnitine supplementation on boar libido, semen quality, sperm production, and maintenance of sperm motility during liquid storage. Experiment 1 utilized lean-type, terminal-line boars (National Pig Development, Roanoke Rapids, NC) (n = 40; 177.4 ± 2.4 d of age and 112.8 ± 2.0 kg body weight) that had not previously experienced natural mating. Boars were individually moved twice weekly for 6 weeks (total of 12 training sessions) to a semen collection room equipped with an artificial sow. Upon entering the semen collection room, boars received in treatments of either deionized water (4 mL, n = 10) or Lutalyse at doses of 5 mg (n = 10), 10 mg (n = 10), or 20 mg (n = 10), and subsequently received a libido score of 1 to 5 (1 = no interest in the artificial sow; 5 = mounting the artificial sow and allowing semen collection). The percentages of boars successfully trained for semen collection during the experimental period were similar (P > 0.05) for controls (20%) and boars receiving 5 mg (30%), 10 mg (20%), or 20 mg (10%) of Lutalyse. Average libido score for boars receiving 10 mg Lutalyse (2.35 ± 0.08) was greater (P < 0.05) than for controls (2.14 ± 0.06). Libido score for the 20 mg treatment group were (1.78 ± 0.06) lower (P < 0.05) compared to the other treatment groups. Characteristics of ejaculates (volume, gel weight, sperm concentration, total spermatozoa) from control boars and boars treated with Lutalyse at doses of 5, 10, or 20 mg were similar (P > 0.05). For Exp. 2, the same group of boars was utilized in two similar trials (Trial 1, 1a, 1b: n = 9 for control and L-carnitine-treated boars; Trial 2, 2a, 2b: n = 10 for control and L-carnitine-treated boars). Boars were fed a fortified, corn and soybean meal-based diet at a rate of 2 kg/d. Boars that were randomly selected for L-carnitine treatment received the same diet mixed with L-carnitine to achieve supplementation of 500 mg/d. For 16 wk, semen was collected weekly via the gloved hand method and was analyzed for gel-free volume, gel weight, sperm concentration, sperm per ejaculate, and characteristics of sperm motility. Time to ejaculation (reaction time), duration of ejaculation, and number of false mounts were also recorded for each collection. Trials 1a and 2a were conducted during weeks 16 and 17 for each respective trial. Boars were collected once on 4 consecutive days, allowed 4 d of rest, and then collected again, to estimate daily spermatozoal production. At the end of 16 wk, a semen sample was also processed and extended in Beltsville Thawing Solution (BTS) to achieve a dilution of 3 x 109 spermatozoa/100 mL-dose for Trials 1b and 2b. The extended semen was stored in plastic bottles at 18°C and motility was evaluated daily for 7 d post collection. L-carnitine supplementation for 16 wk had no effects on semen volume, gel weight, total number of sperm cells per ejaculate, reaction time, or sperm motility (P > 0.1). Boars receiving the L-carnitine-supplemented diet displayed an increase in the number of false mounts before ejaculating and an increase in sperm concentration (P < 0.05) in Trial 2. A treatment by week interaction was detected for sperm concentration in Trial 2 (P < 0.005). Increased sperm concentrations in L-carnitine-treated boars were demonstrated after only one week of feeding the respective diets. Given that the production of a mature sperm cell requires 7 to 8 wk in boars, it is therefore difficult to conclude that differences in sperm concentration were due solely to treatment. Daily spermatozoal production was similar between control boars and boars supplemented with L-carnitine (P > 0.1) for both Trials 1a and 2a. L-carnitine supplementation did not affect percent motility in Trials 1b and 2b or sperm progressive motility in Trial 2b during 7 d storage (P > 0.1). A treatment by day interaction was determined for sperm velocity (P < 0.05) in Trial 2b. L-carnitine supplementation decreased mean sperm velocity significantly after 2 d of storage. Overall, L-carnitine had no beneficial effects on boar libido, semen quality, sperm production, or maintenance of sperm motility during liquid storage. However, Lutalyse increased libido scores, but did not affect the number of boars trained for semen collection or number of spermatozoa ejaculated.

To identify factors important to the efficiency of artificial insemination in cattle, four studies were conducted. In the first study, the addition of cream to the inseminate was used in an attempt to increase accessory sperm number. On d 6 after insemination, 60 embryos were evaluated. The addition of cream to the inseminate had no effect on accessory sperm number. In the second study, cryopreserved semen of a marked bull (spermatozoa exhibiting a semi-flattened anterior head) was matched with semen from an unmarked bull (conventional sperm head shape) to determine competitively the effect of a deep uterine insemination on accessory sperm number. Forty embryos were recovered 6 d after insemination and the ratio of accessory sperm observed was different: 62:38 for unmarked semen in the uterine body and marked semen in the uterine horn, and 72:28 for unmarked semen in the uterine horn and marked semen in the uterine body (P < .05). In the third study, superovulated cows were utilized to determine the effect of artificial insemination time on fertilization status and accessory sperm number. Cows were inseminated once at 0 h (n=10), 12 h (n=10), or 24 h (n=10) after the first standing event. On d 6 after insemination, 529 embryos(ova) were recovered. Fertilization rates were 29% (0 h); 60% (12 h); and 81% (24 h)(P < .01). Percentages of embryos with accessory sperm were: 5 (0 h); 8 (12 h); and 41(24 h) (P < .01). In the fourth study, three experiments utilizing superovulated cows were conducted to provide a basis for distinguishing unfertilized ova from very early embryonic death. In Exp. 1, recovered d 6 unfertilized ova were classified morphologically as either: 1) typical, 2) satellite, or 3) fragmented. In Exp. 2, recovered d 6 unfertilized ova from the third study were classified morphologically, and typical ova were fixed. In Exp. 3, ultrastructural features of preovulatory, tubal-stage, and typical d 6 unfertilized ova were investigated. Preovulatory ova revealed normal ultrastructure; tubal-stage ova exhibited evidence of degeneration; typical d 6 ova were degenerated and contained no discernable organelles. The first three studies support the use of accessory sperm evaluation as an alternative measure of fertility. The final study provides a basis from which future embryologists may distinguish fertilization failure from very early embryonic death.

Estrus detection programs practiced on most U.S. dairy farms are not intense enough to provide the information needed to accurately time insemination, thus preventing AI from obtaining its full conception rate potential. Herds (n = 17) participated in a trial designed to evaluate percent pregnant relative to various characteristics of estrus. Herds utilized HeatWatch® electronic estrus detection system to detect and record mounting activity for cows in estrus. Inseminations were performed daily during a three hour interval for all cows identified in estrus the previous 24 h. Model characterizing percent pregnant for cows (services = 2661) included effects of interval from first mount to AI (P < 0.01), mounts per estrus (P < 0.01), DIM at insemination (P < 0.01), herd (P 4 to 16 h following onset of estrus. Model for heifers (n = 306) included linear effects of interval (P < 0.01), season (P < 0.05), and herd (P < 0.01). In dairy heifers, as interval from first mount to AI increased, percent pregnant decreased. Timing of insemination in dairy cows can now be performed relative to first mount of estrus, with highest probability of pregnancy occurring between >4 to 16 h after onset. If onset of estrus is not known, insemination should be performed at the next most convenient time within 3 h.

Studies presented in this thesis investigated alterative extender-cryoprotectant combinations for semen preservation in red deer (Cervus elaphus) and fallow deer (Dama dama). Semen was collected by electroejaculation under anaesthesia and pooled from four red deer stags and four fallow deer bucks. The ejaculated semen was diluted to a final concentration of 100x10⁶ sperm/ml in sodium citrate, tris citrate, skim milk, lactose and ram synthetic based extenders, with glycerol, propan-1, 2-diol (PROH) and dimethyl sulphoxide (DMSO) cryoprotectants at two concentrations, undiluted (U) and half dilution (0.5D). Semen was frozen in 0.25 ml straws in an automated chamber freezer and stored immersed in liquid nitrogen. In vitro laboratory evaluation of frozen-thawed semen involved the recording of motility and progressive motility of sperm by phase contrast microscopy over a 4 hour incubation period at the equivalent rectal body temperature of female red and fallow deer. Post-thaw (t=0) acrosomal status and sperm morphology were determined by histology using phase contrast optics. Red deer semen gave the highest post-thaw motility (56.7±8,4%) and incubation performance with tris citrate-glycerol (0.5D) extender. Glycerol was the overall optimum cryoprotectant at the undiluted concentration for both deer species, the above being the only exception. Lactose glycerol (U) was the superior extender buffer (p0.10), with a genotype effect (P

Results are reported from a fresh semen cervical artificial insemination trial in April 1989 at the Lincoln College Research Farm. One hundred and ninety Coopworth ewes were inseminated over 5 days. Semen was collected twice daily from four Dorset Down rams using an artifical vagina (A.V.). Fixed-time insemination versus on-oestrus insemination and 'synchronised on-oestrus' versus 'natural on-oestrus' were compared. 'On-time' ewes (TI) were inseminated at 50-51 hours after CIDR withdrawl. On-oestrus treatments (T2 and T3) were drafted twice daily and inseminated on average 15-22 hours after the onset of oestrus. Oestrus was detected by two vasectomised rams and five testosterone treated wethers, harnessed with crayons. Fifty-seven (97%) T1 ewes were marked within 50 hours after CIDR withdrawal. Submission rates were 100% for T2 and T3 (not including 5 (3%) ewes that lost CIDR's). Sixty-four (97%) T3 ewes were inseminated over three days on their second cycle after synchronisation using CIDR's. Two (1%) ewes lambed to A.I with no significant difference between treatments or across insemination days. The low lambing percentage appears to be due to an error in semen handling post collection/dilution, but results may have been compounded by low dose rates (96-232 x 10⁶ spermatozoa/inseminate) and marginal semen quality (motility) prior to insemination. Seventy-seven (41%) ewes were inseminated intrauterine via the cervix (including the two ewes that lambed to A.I). Ejaculate volume and motility varied significantly between collections and between rams - average ejaculate volume was 0.6 ml (0.2 - 2.0 ml), and average motility was 3+ (range 1-4).