Cervix-rectum temperature differential at the time of insemination is correlated with the potential for pregnancy in dairy cows.

This study sought to establish whether temperature gradients between the cervix, vagina, and rectum at and 7 days post-artificial insemination (AI) were associated with the incidence of pregnancy in lactating dairy cows (Experiment I; n = 90 ovulating cows) and to evaluate temperature gradient dynamics from the time of insemination to 7 days post-AI under heat stress conditions (Experiment II; n = 16 ovulating and 4 non-ovulating cows). In Experiment I, 39 cows (43.3%) became pregnant. The odds ratio for pregnancy was 2.5 for each one-tenth of a degree drop in cervical temperature with reference to the control rectal temperature at the time of AI (P = 0.01), whereas the same decrease in the cervix-rectum temperature differential 7 days post-AI resulted in an odds ratio of 0.44 (P = 0.02). In Experiment II, 5 of the ovulating cows (31.3%) became pregnant. The mean values of the vagina-rectum, vagina-cervix, and cervix-rectum temperature differentials at AI (day 0), 8 h, 24 h, and 7 days post-AI changed significantly from day 0 to day 7 (within-subject effect; P < 0.02) in ovulating cows but not in non-ovulating cows. Temperature differentials on days 0 and 7 were similar between ovulating cows and cows of Experiment I. Overall, our findings support the notion that a temperature differential between the caudal cervical canal and rectum at AI may be an indicator of the likelihood of pregnancy. Possible prospects of confirming estrus at the herd-level are also suggested.

Protocolo com nove dias de progesterona para inseminação artificial em tempo fixo em vacas taurinas adaptadas ao clima tropical / Protocol with nine days of progesterone for fixed-time artificial insemination in Bos taurus cows adapted to the tropical weather

Três experimentos foram realizados para adaptar um protocolo de sincronização de estro e da ovulação para ser utilizado em programas de inseminação artificial em tempo fixo (IATF) em vacas taurinas tropicalmente adaptadas. No Exp. 1 (crossover), vacas pluríparas Curraleiro Pé-Duro (n= 12) receberam um dispositivo intravaginal contendo 1g de P4 por oito dias e 2mg de BE intramuscular (IM) no momento da inserção do dispositivo (dia 0). No dia da remoção do dispositivo (dia 8), as fêmeas receberam 150µg de D-cloprostenol sódico e 300UI de gonadotrofina coriônica equina (eCG) IM, sendo, então, divididas aleatoriamente para receber 1mg de BE no dia 8 (BE8) ou 1mg de BE no dia 9 (BE9). A aplicação de BE no D9 atrasou a ovulação em aproximadamente 15 horas (P<0,05). No Experimento 2, foram avaliados protocolos com oito (P4D8) e nove dias (P4D9) de exposição à progesterona, resultando em parâmetros de desenvolvimento folicular e luteal semelhantes entre os tratamentos (P>0,05). No Experimento 3, os protocolos hormonais de IATF BE8 e P4D9 foram testados para a taxa de prenhez, alcançando 23% (10/43) e 20% (9/45), respectivamente (P>0,05). Embora o grupo P4D9 tenha mostrado avanço na proporção de animais que responderam ao protocolo quando comparado ao protocolo BE8, este não se refletiu em melhora na taxa de prenhez.(AU)

Three experiments were performed to adapt a synchronization protocol of estrus synchronization and ovulation to be used in fixed time artificial insemination programs (FTAI) in tropically adapted Bos taurus cows. In Exp. 1 (crossover) multiparous Curraleiro Pé-Duro cows (n= 12) received an intravaginal device containing 1g of P4 for 8 days and 2mg of EB at the time of device insertion (Day 0). On the P4 device removal (Day 8) females received 150g of D-cloprostenol Sodic and 300IU of equine chorionic gonadotropin (eCG). Then, they were randomly divided to receive 1mg of EB on Day 8 (EB8) or on Day 9 (EB9). EB9 delayed ovulation approximately 15 hours (P<0.05). In Exp. 2, protocols using progesterone for eight (P4D8) or nine days (P4D9) were evaluated, resulting in similar parameters of folicular and luteal development (P>0.05). In Exp. 3, EB8 and P4D9 protocols were used to evaluate the pregnancy rate, reaching 23% (10/43) and 20% (9/45), respectively (P>0.05). Although P4D9 protocol has shown improvement in proportion of animals that responded to the protocol when compared to EB8 protocol, it was not able to improve pregnancy rate.(AU)

Artificial insemination of Holstein heifers with sex-sorted semen during the hot season in a subtropical region.

Our aim was to investigate insemination techniques in order to improve pregnancy rates of artificial insemination (AI) using sex-sorted semen (sexed AI) in cattle in tropical and subtropical (T/ST) regions. In T/ST regions, the pregnancy rates by sexed AI are reportedly the lowest in the hottest months of the year, with less than 15% in cows and 35-40% in heifers (PMID 24048822). We compared sexed AI by depositing the semen into the uterine body (UB-AI, n = 12) versus the unilateral uterine horn (UUH-AI, n = 14) of pre-ovulation heifers. The ovary and follicle were assessed by rectal ultrasound before AI. After insemination, pregnancy was determined by ultrasound at approximately 40 days and approximately 70 days. In the present study, we demonstrated that high pregnancy rates (>70%) by sexed AI in the hottest season in a subtropical region such as Taiwan can be achieved when heifers with pre-ovulation follicles are used. The overall pregnancy rates were 54% higher in the UUH-AI (71%) group than in the UB-AI (42%) group (P = 0.06), examined on approximately 40 days post-sexed AI. Surprisingly, however, the pregnancy outcome appeared to be higher in the hot season (62%) than in the cool season (46%) although this difference was not statistically significant. Based on the present study, we recommend that cattle breeders perform UUH-AI using sex-sorted semen for heifers with pre-ovulation follicles in order to achieve satisfactory pregnancy outcome in the hot seasons in T/ST regions.

Alternative programs for synchronizing and resynchronizing ovulation in beef cattle.

Fixed-time artificial insemination (FTAI) has been regarded as the most useful method to increase the number of cows inseminated in a given herd. The main treatments for FTAI in beef cattle are based on the use of progesterone-releasing devices and GnRH or estradiol to synchronize follicle wave emergence, with a mean pregnancy per AI (P/AI) around 50%. However, more recent protocols based on GnRH (named 5-day Co-Synch) or estradiol (named J-Synch) that reduce the period of progesterone device insertion and extend the period from device removal to FTAI have been reported to improve P/AI in beef cattle. Furthermore, treatments to resynchronize ovulation for a second FTAI in nonpregnant cows have provided the opportunity to do sequential inseminations and achieve high P/AI in a breeding season, reducing or even eliminating the need for clean-up bulls. In summary, FTAI protocols have facilitated the widespread application of AI in beef cattle, primarily by eliminating the necessity of estrus detection in beef herds.

Ovarian responses of dairy buffalo cows to timed artificial insemination protocol, using new or used progesterone devices, during the breeding season (autumn-winter).

This study evaluated the effect of new or used P4 devices on the ovarian responses of dairy buffalo that were administered an estradiol (E2) plus progesterone (P4)-based timed artificial insemination (TAI) protocol during the breeding season. On the first day of the TAI protocol, 142 cows were randomly assigned to receive one of the following: a new device (New; 1.0 g of P4; n = 48); a device that had previously been used for 9 days (Used1x, n = 47); or a device that had previously been used for 18 days (Used2x, n = 47). Ultrasound was used to evaluate the following: the presence of a corpus luteum (CL); the diameter of the dominant follicle (ØDF) during protocol; ovulatory response; and pregnancies per AI (P/AI). Despite similar responses among the treatments, there was a significant positive association of the ØDF during TAI protocol with ovulatory responses and number of pregnancies. In conclusion, satisfactory ovarian responses and a satisfactory pregnancy rate were achieved when grazing dairy buffalo were subjected to the TAI protocol in breeding season, independent of whether a new or used P4 device was used. Furthermore, the presence of the larger follicle was associated with a higher ovulation rate and higher P/AI following TAI.

Reproductive and Metabolic Responses of Early-lactating Dairy Cows Fed Different Dietary Protein Sources.

Optimal reproduction is very closely tied with optimal nutrition, and early-lactation diets in cows are critical to successful reproduction and monitoring is important. To evaluate the effects of different dietary protein sources on metabolic parameters and reproductive activity, a total of 36 Italian Friesian early-lactating dairy cows were assigned for 16 weeks to three dietary treatments as follow: the control diet contained soya bean meal (SBM) as the main protein source, whereas the experimental diets contained faba bean (FB) or pea seeds (PS) as alternative protein sources. Diets were formulated to be isocaloric and isonitrogenous. Cow blood samples were collected, and plasma were analysed for metabolites, biological enzymes, ß-hydroxybutyrate (BHBA) and non-esterified fatty acids (NEFA). Feeding alternative protein sources had no effects on most metabolic blood profile, except for blood cholesterol, triglycerides and urea. Results from reproductive parameters indicated that cows fed FB diet had a lower insemination index, but a shorter calving to conception period and an improved conception rate and artificial insemination outcome, when compared to cows fed SBM or PS diets. It can be concluded that replacing conventional dietary SBM with alternative protein sources, especially FB, resulted in improved reproductive performances and metabolic parameters in early-lactating dairy cows.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study.

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures (Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR (P < 0.01) and summer inseminations under lower SR values (P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T (P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum (P < 0.05) and minimum Ts (P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Efficiency of ciprofloxacin for bacterial control, post-thaw quality, and in vivo fertility of buffalo spermatozoa.

Ciprofloxacin (CP) was evaluated for bacterial control, post-thaw quality, and fertility of buffalo semen. Pseudomonas aeruginosa, Escherichia coli, Proteus sp., Corynebacterium sp., Micrococcus sp., and Staphylococcus sp. were isolated from buffalo semen. Pseudomonas aeruginosa, Corynebacterium sp., and Micrococcus sp. were resistant to streptomycin, whereas P. aeruginosa and Proteus sp. were resistant to penicillin. All bacteria were susceptible to CP. In vitro dose toxicity was assessed in sodium citrate buffer containing 0, 200 to 2000 µg/mL of CP. CP up to 1000 µg/mL was found nontoxic to motility and viability of buffalo sperm. For post-thaw quality, buffalo semen was frozen in Tris-citric acid extender containing streptomycin-penicillin (SP; 1000 µg/mL-1000 IU/mL) or CP 600 µg/mL and was assessed for total aerobic bacterial count (post-thaw), motility, plasma membrane integrity, viability at 0, 2, and 4 hours post-thaw. At 4 hours post-thaw, plasma membrane integrity (%) was higher (P < 0.05) in extender containing CP than SP. Total aerobic bacterial count was 0.00 in extender containing CP compared with 0.07 × 10(4) cfu/mL with SP. To assess the in vivo fertility rate, semen (two bulls) frozen in Tris-citric acid extender containing SP or CP was used to inseminate, and 400 inseminations (200/group) were recorded. Higher (P ≤ 0.05) fertility rate was recorded with CP (55%) compared with SP (41%). In conclusion, use of CP in extender was efficient to control the bacterial contamination without compromising the post-thaw quality and fertility of cryopreserved water buffalo bull semen.

Adição de plasma seminal ao sêmen descongelado e taxa de prenhez de ovelhas inseminadas em tempo fixo / Addition of seminal plasma to frozen-thawed semen and pregnancy rate of fixed time inseminated ewes

Avaliou-se o efeito da adição de plasma seminal ovino ao sêmen descongelado sobre a taxa de prenhez de ovelhas em rebanho comercial. Cento e setenta e quatro ovelhas cruza Texel foram distribuídas em quatro tratamentos: T1) inseminação artificial cervical (IAC) com sêmen descongelado (SD) diluído em solução tampão fosfato salino (PBS); T2) IAC com SD e adição de plasma seminal ovino; T3) grupo-controle I: IAC com sêmen fresco diluído em PBS; T4) grupo-controle II: inseminação artificial por laparoscopia com SD diluído em PBS. Para indução de cio, utilizaram-se esponjas impregnadas com acetato de medroxiprogesterona (MAP) por 12 dias, com aplicação intramuscular de 400 UI de eCG (Novormon®) e de 37,5µg de cloprostenol sódico (Sincrocio®), no dia da retirada das esponjas. O aparecimento de cio foi monitorado com rufiões vasectomizados a partir da retirada das esponjas até a inseminação artificial em tempo fixo - 54 a 60 horas. A taxa de prenhez do tratamento com adição de plasma seminal ao sêmen descongelado (7,0%) não diferiu (P>0,05) do tratamento sem adição de plasma (4,3%), entretanto foi menor (P<0,05) se comparada à taxa de prenhez dos grupos-controle I inseminação via cervical superficial com sêmen fresco diluído (50,0%) e II inseminação via laparoscopia com sêmen descongelado (39,4%). A inseminação artificial por via cervical superficial com adição de plasma seminal ao sêmen descongelado não elevou o percentual de prenhez em valores que justifiquem a indicação desta biotecnologia em rebanhos comerciais de ovinos.

The effect of seminal plasma addition to thawed-frozen ram semen on the pregnancy rate of commercial herd ewes was evaluated. One hundred and seventy-four crossbred Texel sheep were allocated to four treatments: T1) cervical artificial insemination (CAI) using frozen-thawed semen (FTS) diluted in phosphate buffered saline solution (PBS); T2) CAI using FTS diluted in ovine seminal plasma; T3) control group I: CAI using fresh semen diluted in PBS; T4) control group II: laparoscopic insemination using FTS diluted in PBS. Estrus induction was performed with medroxiprogesterone acetate (MAP) impregnated sponges for 12 days, followed by intramuscular injection of 400 IU of eCG (Novormon®) and 37.5µg of sodium cloprostenol (Sincrocio®) on the day of sponge removal. Estrus was monitorated with vasectomized rams, beginning at the time of the sponge removal until the fixed time artificial insemination - 54 to 60 hours. The pregnancy rate of FTS diluted in seminal plasma treatment (7.0%) did not differ (P>0.05) for the treatment without addition of seminal plasma (4.3%), however it was lower (P<0.05) when compared to the pregnancy rate of the cervical inseminated control I group with PBS diluted fresh semen (50.0%) and laparoscopic inseminated control group II with PBS diluted FTS (39.4%). The cervical artificial insemination with the addition of seminal plasma to frozen-thawed semen did not increase the pregnancy rate at acceptable values to make this biotechnology useful on commercial herds.

Effects of caffeine on sperm characteristics after thawing and inflammatory response in the uterus after artificial insemination with frozen-thawed boar semen.

We previously reported that AI with frozen-thawed boar semen supplemented with caffeine increased the number of uterine sperm by inhibiting migration of polymorphonuclear leukocytes (PMNs) into the uterine lumen, and also improved fertility of gilts and sows. The objective of the present study was to determine the effects of the addition of caffeine to a thawing solution on postthaw sperm quality and uterine inflammatory response after AI with frozen-thawed boar semen. Incubation of frozen-thawed sperm in Modena solution supplemented with 10 mM caffeine for 90 minutes improved (P < 0.05) percentages of progressive motility, straightness, and linearity of sperm movement compared with no caffeine, without causing damage to plasma or acrosomal membranes. Gilts inseminated once with 2 × 10(9) frozen-thawed sperm suspended in Modena solution with or without caffeine, and gilts that did not receive AI, were slaughtered 4 hours later. Uteri were recovered for analysis of number of uterine PMNs and mRNA expression (quantitative reverse transcription polymerase chain reaction) of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, IL-8, monocyte chemoattractant protein-1, and cyclooxygenase 2 in the endometrium. Caffeine decreased (P < 0.05) both the number of total uterine PMNs and expression of IL-8 mRNA in the endometrium after AI. The amount of IL-8 and cyclooxygenase 2 mRNA after AI in the absence of caffeine were higher than samples from gilts that did not receive AI (P < 0.05), whereas there were no significant differences between treatments in expression levels of tumor necrosis factor-α, IL-1ß, IL-6, or monocyte chemoattractant protein-1 mRNA. Pregnancy rate in sows inseminated with sperm supplemented with caffeine (16 of 23; 70%) tended (P < 0.1) to exceed that without caffeine (12 of 26; 46%), but litter size was not affected. In conclusion, the addition of caffeine to the thawing solution inhibited migration of uterine PMNs, probably by downregulating IL-8 mRNA expression in the endometrium.

Presynchronization with Double-Ovsynch improves fertility at first postpartum artificial insemination in lactating dairy cows.

The objective of this study was to compare circulating progesterone (P4) profiles and pregnancies per AI (P/AI) in lactating dairy cows bred by timed artificial insemination (TAI) following Ovsynch-56 after 2 different presynchronization protocols: Double-Ovsynch (DO) or Presynch-Ovsynch (PS). Our main hypothesis was that DO would increase fertility in primiparous cows, but not in multiparous cows. Within each herd (n=3), lactating dairy cows (n=1,687; 778 primiparous, 909 multiparous) were randomly assigned to DO [n=837; GnRH-7d-PGF(2α)-3d-GnRH-7d-Ovsynch-56 (GnRH-7d-PGF(2α)-56h-GnRH-16hTAI)] or PS (n=850; PGF(2α)-14d-PGF(2α)-12d-Ovsynch-56). In 1 herd, concentrations of P4 were determined at the first GnRH (GnRH1) of Ovsynch-56 and at d 11 after TAI (n=739). In all herds, pregnancy was diagnosed by palpation per rectum at 39 d. In 1 herd, the incidence of late embryo loss was determined at 74d, and data were available on P/AI at the subsequent second service. Presynchronization with DO reduced the percentage of animals with low P4 concentrations (<0.50 ng/mL) at GnRH1 of Ovsynch-56 (5.4 vs. 25.3%, DO vs. PS). A lesser percentage of both primiparous and multiparous cows treated with DO had low P4 concentrations at GnRH1 of Ovsynch-56 (3.3 vs. 19.7%, DO vs. PS primiparous; and 8.8 vs. 31.9%, DO vs. PS multiparous). Presynchronization with DO improved P/AI at the first postpartum service (46.3 vs. 38.2%, DO vs. PS). Statistically, a fertility improvement could be detected for primiparous cows treated with DO (52.5 vs. 42.3%, DO vs. PS, primiparous), but only a tendency could be detected in multiparous cows (40.3 vs. 34.3%, DO vs. PS, multiparous), consistent with our original hypothesis. Presynchronization treatment had no effect on the incidence of late embryo loss after first service (8.5 vs. 5.5%, DO vs. PS). A lower body condition score increased the percentage of cows with low P4 at GnRH1 of Ovsynch-56 and reduced fertility to the TAI. In addition, P4 concentration at d 11 after TAI was reduced by DO. The method of presynchronization at first service had no effect on P/AI at the subsequent second service (34.7 vs. 36.5%, DO vs. PS). Thus, presynchronization with DO induced cyclicity in most anovular cows and improved fertility compared with PS, suggesting that DO could be a useful reproductive management protocol for synchronizing first service in commercial dairy herds.

Effects of calcium salts of polyunsaturated fatty acids on productive and reproductive parameters of lactating Holstein cows.

Two experiments evaluated milk production, serum progesterone and insulin, and reproductive performance of lactating Holstein cows receiving or not receiving Ca salts of polyunsaturated fatty acids (PUFA), or receiving Ca salts of PUFA at different daily frequencies. In experiment 1, 1,125 cows randomly distributed in 10 freestall barns were enrolled. Barns were assigned randomly to receive a high-concentrate diet containing (PF) or not containing (control, CON) 1.1% (dry matter basis) Ca salts of PUFA. Diets were offered 6 times daily, whereas the Ca salts of PUFA were included in the PF treatment in the first feeding of the day. In experiment 2, 1,572 cows were randomly distributed in 10 freestall barns, which were assigned randomly to receive a diet similar to PF, but with Ca salts of PUFA included only in the first feeding of the day (PF1X), or equally distributed across all 6 feedings (PF6X). During both experiments, cows were artificially inseminated 12 h after the onset of estrus. Once per month, cows that did not conceive to artificial insemination were assigned to a fixed-time embryo transfer protocol. Pregnancy was determined via transrectal ultrasonography 28 and 60 d after expected ovulation. Pregnancy loss was considered in cows that were pregnant on d 28 but nonpregnant on d 60. During both experiments, feed intake, milk yield, and milk protein and fat content were recorded weekly. Blood samples were collected concurrently with embryo transfer. During experiment 1, feed intake was similar between treatments. Compared with CON, PF cows had greater milk yield (37.8 vs. 35.3 kg/d), and reduced milk fat content (3.41 vs. 3.55%). However, PF cows had reduced pregnancy losses per service compared with CON (12.6 vs. 18.3%). Serum progesterone was greater and serum insulin tended to be greater in primiparous cows receiving PF compared with CON cohorts (4.50 vs. 3.67 ng of progesterone/mL, and 10.4 vs. 7.5 µUI of insulin/mL). During experiment 2, no treatment effects were detected for feed intake, milk yield, or milk fat, whereas PF1X cows tended to have reduced pregnancy losses per service compared with PF6X (14.4 vs. 18.4%). In summary, feeding Ca salts of PUFA to dairy cows increased milk production, did not alter feed intake, and reduced pregnancy losses per service. Further, the total daily amount of Ca salts of PUFA should be fed during the first feeding of the day to optimize its benefits on pregnancy maintenance of dairy cows.

Factors influencing pregnancy per artificial insemination in repeat-breeder cows induced to ovulate with a CIDR-based protocol.

The aim of this study was to determine, using multiple logistic models, factors affecting pregnancy per AI (P/AI) following fixed-time artificial insemination (FTAI) in repeat breeders cows (RBC) treated with rbST throughout lactation. 498 RBC received a CIDR device and 100µg of GnRH on day 0. CIDR removal and PGF(2α) (25mg) treatment were done concurrently on day 7. Estradiol benzoate (EB, 1mg) was injected on day 8 and GnRH on day 9; cows were inseminated 16-20h later. Cows with an average milk protein <3% were 43% more likely (P<0.05) to become pregnant at FTAI than cows with milk protein ≥3%. Cows with <6 services had significantly increased chances of becoming pregnant than cows with ≥6 services at FTAI (P/AI 36 vs. 27%; P<0.05). CIDR-treated cows with less than three lactations were 1.7 times more likely (P/AI 35 vs. 21%; P<0.05) to become pregnant than cows in third or greater lactation. Cows with peak milk yields lower than 55kg were 1.5 times more likely to get pregnant than cows with peak milk yields greater than 55kg (P/AI 37 vs. 28%; P<0.05). P/AI was lower (30 vs. 35%; P<0.01) for cows with dry periods <62 days than cows with dry periods ≥62 days. Cows subjected to FTAI with a temperature-humidity index (THI) <76 were 45% more likely (P<0.05) to become pregnant than cows inseminated at a THI≥76. It was concluded that an acceptable proportion (32%) of RBC can become pregnant with the protocol used in the present study. Also, subfertility in CIDR-treated cows was associated with high peak yields, high milk protein, increased service, increased lactation, high THI at AI and short dry periods.

Reproduction in the endangered African wild dog: basic physiology, reproductive suppression and possible benefits of artificial insemination.

The African wild dog (Lycaon pictus) is an endangered exotic canid with less than 5500 animals remaining in the wild. Despite numerous strategies to conserve this species, numbers of free-living animals are in decline. It is a highly social species with a complex pack structure: separate male and female dominant hierarchies with, typically, participation of subdominant adults in the rearing of the dominant breeding pairs' pups. Basic reproductive knowledge is largely missing in this species, with only limited information available on the profile of reproductive hormones, based on non-invasive endocrine monitoring. The dominant or alpha male and female are reproductively active and the subdominants are generally reproductively suppressed. However, the occasional production of litters by subdominant females and evidence of multiple paternity within litters suggests that fertility of subordinates is not completely inhibited. In this respect, there are still considerable gaps in our knowledge about the mechanisms governing reproduction and reproductive suppression in African wild dogs, particularly the influence of dominance and pack structure on both male and female fertility. Given concerns over the long-term survival of this species, further research in this area is essential to provide valuable information for their captive breeding and conservation. Reproductive information can also be applied to the development of Assisted Reproductive Techniques for this species; the utility of which in African wild dog conservation is also discussed.

Relationship between pregnancy per artificial insemination and early luteal concentrations of progesterone and establishment of repeatability estimates for these traits in Holstein-Friesian heifers.

Pregnancy per insemination is a major determinant of reproductive efficiency in cattle and is affected by concentrations of progesterone (P4) during early pregnancy. The relationship between pregnancy per artificial insemination (P/AI) and early luteal concentrations of P4, and repeatability of concentrations of P4 was examined on d 4, 5, 6, and 7 (day of standing estrus=d 0) in 118 Holstein Friesian heifers following 2 rounds of AI to 1 high-fertility sire. Repeatability estimates (R(e)) for P/AI were established following 4 rounds of AI. We found a linear and quadratic relationship between P/AI and concentrations of P4 on d 4 to 7 after estrus, as well as a linear and quadratic relationship between P/AI and the change in concentration of P4 from d 4 to 7 and from d 5 to 7. Optimum concentrations of P4 to maximize probability of P/AI were 2.5, 4.0, 5.0, 5.2, and 3.5 ng/mL for d 4, 5, 6, and 7, and the change from d 4 to 7, respectively. Repeatability of P/AI following 4 rounds of AI was low (R(e)=0.07). Repeatability estimates for concentrations of P4 from cycle to cycle indicated low repeatability between d 4 (R(e)=0.05) and 7 (R(e)=0.20). These data indicated the importance of P4 in the early luteal phase for pregnancy survival, but also demonstrated that high concentrations of P4 on these days have a deleterious effect on embryo viability. Early luteal (d 4 to 5) concentrations of P4 were a reasonable predictor of concentrations on d 7 and could be used as a diagnostic tool to identify animals at risk of subsequent embryo loss.

Improved knowledge about conception rates influences the decision to stop insemination in dairy cows.

The conception rate in dairy cows is dependent on a number of cow factors such as days in milk and insemination number. Unfortunately, some of these factors were not accounted for in optimal insemination and replacement decision models. By using wrong estimates of the conception rate, the calculated optimal insemination and replacement policy might differ from the real optimal insemination and replacement policy. The objective of this study was to evaluate different sets of conception rates with an increasing level of accuracy to determine the insemination policy. An existing dynamic program for optimal insemination and replacement was used to compare three different scenarios in the estimation of conception rates, based on the reproductive performance of Dutch dairy cattle: (i) constant conception rate throughout lactation, (ii) conception rate dependent on parity and months in milk, and (iii) conception rate dependent on parity, months in milk and insemination number. The time step of the model was 30.4 days (1 month). The discounted future cash flow of culling a cow at each time step (replace a heifer immediately) was compared with keeping that cow under optimal future decisions. The difference between immediate culling and optimal decisions is defined as the retention pay-off. The insemination value was calculated as the difference between the future cash flow between immediate insemination of a cow and waiting one time-step. The results show that the difference in the insemination values and the optimal time to stop insemination depend on parity, lactation stage and the relative milk yield. In older cows with equal milk yields and at the same months in milk, the insemination value was lower than in younger cows. Within a parity, the insemination value was higher for cows with a higher milk yield. On individual cow level, using more accurate conception rate as input in the optimal insemination and replacement model might reduce miscalculation of the economic consequences for at least of €20-€38 per cow per year. Basing insemination decisions on less accurate input of the probabilities of conception, however, did not have an economic consequence at the herd level. In conclusion, using the appropriate conception rate as input in the optimal insemination and replacement model would increase the precise decision for the optimal time to stop insemination and hence improve the reproductive management efficacy.

Effect of time from estrus to AI on pregnancy rates in estrous synchronized beef heifers.

For the last 65 years, the industry standard for time of artificial insemination (AI) relative to onset of estrus has been established as 12 h after observed estrus. More recent experiments indicated the optimum time for AI was 4-12 h after onset of estrus in dairy cattle, but little recent information is available on the effect of time of AI relative to the onset of estrus in beef cattle. Therefore, we conducted a retrospective study on the impact of time from onset of estrus to artificial insemination using records from estrous synchronized crossbred Angus heifers (n=1205). Data were compiled from experiments on estrous synchronization systems and AI where estrous detection was performed electronically with HeatWatch(®). Only data from heifers detected in estrus was used. Heifers averaged 440 days of age, and weighed 368 kg at insemination. Heifers were assigned to one of the following 4h blocks of time based on time from onset of estrus (hour 0) to insemination: 0-4 (n=79), 4-8 (n=163), 8-12 (n=211), 12-16 (n=163), 16-20 (n=193), 20-24 (n=149), >24 h (n=247). Pregnancy rates to AI were not affected by AI technician or season of breeding (P>0.80). However, time of insemination relative to onset of estrus affected (P<0.01) pregnancy rates to AI. Heifers inseminated between 4 and 24h after onset of estrus had greater AI pregnancy rates (P<0.05; 63.7%) compared to the 0-4h (48.1%) and >24h (55.9%) groups. The time period for achieving acceptable pregnancy rates to AI in beef heifers appears to be approximately 20 h in length. Estrous synchronization programs resulting in a majority of heifers in estrus between 4 and 24 h before AI should yield the greatest pregnancy rates.

Cardiorespiratory and blood gas alterations during laparoscopic surgery for intra-uterine artificial insemination in dogs.

Cardiorespiratory and blood gas alterations were evaluated in 6 healthy dogs that underwent a laparoscopic procedure using isoflurane anesthesia and carbon dioxide (CO(2)) pneumoperitoneum for 30 min. Heart rate, respiratory rate, body temperature, venous blood pH, partial pressure of CO(2) and oxygen, oxygen saturation, total carbon dioxide (TCO(2)) and bicarbonate were monitored. Significant alterations were hypercapnia, hypoventilation, and respiratory acidosis.

Periovulatory follicular volume and vascularization determined by 3D and power Doppler sonography as pregnancy predictors in intrauterine insemination cycles.

PURPOSE: To evaluate the relationship between volume and vascularization of the periovulatory follicle and subfollicular area measured by three-dimensional power Doppler ultrasound (US), and ovulation and pregnancy in patients undergoing intrauterine insemination (IUI). METHODS: We studied 79 consecutive cycles of IUI on hCG administration day. We measured the periovulatory follicle and subfollicular area by means of three-dimensional power Doppler US. The stored volumes were processed with the VOCAL image processing software to calculate the volume of the follicle and the following vascular indices: vascularization index (VI), flow index (FI), and vascularization flow index (VFI). RESULTS: The follicular volume was higher in anovulatory cycles (7.7 ± 3.7 cubic centimeters (CC) versus 4.1 ± 2.0 CC; p < 0.001). There was no difference between the follicular volumes in cycles with or without subsequent pregnancy. The vascular indices of the follicle did not differ significantly between ovulatory and anovulatory cycles, and between cycles that did and did not achieve pregnancy. Periovulatory subfollicular VI and VFI were lower in women who became pregnant (VI: 2.9 ± 2.3% versus 5.6 ± 4.6%; p < 0.05, and VFI: 1.1 ± 0.8 versus 2.2 ± 2.2; p < 0.01). CONCLUSIONS: High values of follicular volume were associated with anovulatory cycles. Subfollicular VI and VFI might be used as markers of follicular quality and pregnancy predictors.

Influence of seminal plasma, spermatozoa and semen extender on cytokine expression in the porcine endometrium after insemination.

The effects of semen components or extender alone on the expression of selected cytokines [interleukine (IL)-1ß, IL-6, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-10 and transforming growth factor (TGF)-ß1] on the porcine endometrium were studied, as well as the presence of polymorphonuclear neutrophilic granulocytes (PMNs). In experiment (Exp) I, groups of gilts were sampled at 5-6h after insemination with fresh semen in extender (Beltsville thawing solution, BTS), spermatozoa in extender (Spz), seminal plasma (SP), or only BTS (control). In Exp II, gilts were sampled 35-40h after insemination with Spz, SP, BTS or only catheter inserted (as control). Immunohistochemical (IHC) labelling of IL-6, IL-10 and TGF-ß1 was evident, especially in surface and glandular epithelia of the porcine endometrium. There were no consistent differences in IHC-labelling of the cytokines in relation to different treatments. However, the scores for IL-6 and IL-10 in surface epithelium and sub-epithelial connective tissue compartments were higher at 35-40h than shortly (5-6h) after treatment. Cytoplasmic labelling in the sub-epithelial connective tissue was observed in scattered individual cells but not in PMNs. Shortly (5-6h) after insemination, there were no differences between animals inseminated with BTS (control) and the semen components for any of the cytokine mRNAs. Later however, at 35-40h, lower endometrial expression of TGF-ß1 mRNA was observed in the Spz and BTS groups compared with the control (catheter only). The same pattern was found for IL-10 (NS). The mRNA expression of IL-6 in the BTS inseminated group was higher compared to the control group. Insemination with SP resulted in significantly lower PMN cell infiltration in the sub-epithelial connective tissue compared with Spz or BTS groups shortly (5-6h) after insemination. Later (35-40h), a significant difference was found between SP (lower) and the control group (only catheter). To conclude, our results show that insemination and/or inseminated components modulated cytokine expression in the gilt endometrium. The semen extender BTS stimulated immune reactivity, as shown by down-regulation of the suppressive cytokine TGF-ß1. Insemination with solely SP clearly decreased PMN cell infiltration of the gilt endometrium. However, no clear relation between the cytokines studied and PMN cell presence was found.