Factors influencing the abundance of wintering western snowy plovers at Crown Memorial State Beach

Survival during the nonbreeding season, when mortality from food shortages and raptor predation is highest, influences shorebird population growth. These selection pressures, as well as anthropogenic influences, can shape wintering shorebird habitat use patterns. The western snowy plover (Charadrius alexandrinus nivosus) is a small shorebird that uses sand-spits, dune-backed beaches, open areas around estuaries for foraging and roosting. The Pacific Coast population of western snowy plovers is listed as a federally threatened species and a California Species of Special Concern. Previous studies suggest humans, dogs and corvids are sources of disturbance to plovers on public beaches. During 2014 to 2019, these disturbance factors were examined at Robert W. Crown Memorial State Beach in Alameda, California. In decreasing order of impact, the beach using public, corvids, and dogs were found to be the major stressors to over wintering plovers. Both the public and corvids respectively, resulted in disturbance and avoidance behaviors by plovers nearly 40% of the time. In 2015, the District created the Plover Protection Zone (PPZ) by installing symbolic fencing, signage, and establishing a volunteer team to monitor plovers and educate the public. In 2016, the potential prey abundance within the plover protection zone and areas directly north and south were examined using core samples and sticky traps. Statistical analysis showed a significant difference in the amount of macro-invertebrate prey available in the area used by the plovers as compared to other locations. Habitat choice and prey availability are vital to wintering shorebird. During this study, the wintering population of western snowy plovers increased from six to over 54 individuals.

Spatially different annual cycles but similar haemosporidian infections in distant populations of collared sand martins

Background Populations of long-distance migratory birds experience different environments and are consequently exposed to different parasites throughout their annual cycles. Though, specific whereabouts and accompanied host-parasite interactions remain unknown for most migratory passerines. Collared sand martins (Riparia riparia) breeding in the western Palaearctic spend the nonbreeding period in Africa, but it is not yet clear whether specific populations differ in overwintering locations and whether these also result in varying infections with vector-transmitted endoparasites. Results Geolocator tracking revealed that collared sand martins from northern-central and central-eastern Europe migrate to distant nonbreeding sites in West Africa and the Lake Chad basin in central Africa, respectively. While the ranges of these populations were clearly separated throughout the year, they consistently spent up to 60% of the annual cycle in Africa. Ambient light recorded by geolocators further indicated unsheltered roosting during the nonbreeding season in Africa compared to the breeding season in Europe. We found 5–26% prevalence of haemosporidian parasites in three breeding populations and one migratory passage population that was only sampled but not tracked. In total, we identified seven Plasmodium and nine Haemoproteus lineages (incl. two and seven new lineages, respectively), the latter presumably typical for swallows (Hirundinae) hosts. 99.5% of infections had a low intensity, typical for chronic infection stages, whereas three individuals (0.5%) showed high parasitaemia typical for acute infections during spring migration and breeding. Conclusions Our study shows that blood parasite infections are common in several western Palaearctic breeding populations of collared sand martins who spent the nonbreeding season in West Africa and the lake Chad region. Due to long residency at the nonbreeding grounds blood parasite transmissions may mainly occur at host population-specific residences sites in Europe and Africa; the latter being likely facilitated by unsheltered roosting and thus high vulnerability to hematophagous insects. The rare cases of high parasitaemia during spring migration and breeding further indicates either relapses of chronic infection or primary infections which occurred shortly before migration and during breeding.

Assessment of Testicular Lhcgr mRNA Expression Correlated with Testis and Seminal Vesicle Activities in the Libyan jird (Meriones libycus, Rodentia: Muridae) during Breeding Season Compared with Nonbreeding Season

The Libyan jird (Meriones libycus, 1823) is a wild desert rodent that is a seasonal breeder species adapted to breed when the environmental conditions can satisfy the energy and hydrous requirements of pregnant and nursing females to ensure that births occur at the most favorable time of the year. We assessed gene expression of testicular luteinizing hormone receptor (Lhcgr) correlated to testis activity. The expression of Lhcgr was evaluated using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR and the testis activity by a histological method in adult male Libyan jirds during the nonbreeding and breeding seasons. Our results showed that Lhcgr mRNA expression increased in autumn during the nonbreeding season and decreased in spring during the breeding season. This expression varied in contrast to testicular structure or function and plasma testosterone levels. These results help to elucidate this desert rodent’s seasonal sexual activity, which is correlated with central regulation.

116 Differences between 5- and 6-day progestogen-based oestrus induction protocol in Saanen and Toggenburg goats

Hormonal oestrus induction treatment is an important tool for the success of reproductive biotechniques in anoestrus goats. In the nonbreeding season, oestrus induction can be performed by the use of several protocols, including those varying in their duration. This study aimed to compare short-term (for either 5 or 6 days) progestogen-based oestrus synchronization protocols in dairy [Toggenburg (n=12) and Saanen (n=12)] goats during the nonbreeding season. This study was performed in Minas Gerais State, Brazil (21°35′S and 43°15′W), with 12 nulliparous (12–14 months old) and 12 pluriparous (2–4 years old in final third of lactation) goats, all with body condition scores (BCS) of 3.0 to 3.5. They were equally assigned to both treatments according to their order of parturition, BCS, and breed. On a random day (Day 0), 24 goats received an intravaginal device of 60mg of medroxyprogesterone acetate (Progespon®, Zoetis) which remained for 5 (G5; n=12) or 6 (G6; n=12) days. On Day 5, goats from both groups received 30µg of cloprostenol intramuscularly (IM) (Prolise®, ARSA S.R.L.) and 200IU of equine chorionic gonadotrophin (eCG) IM (Novormon®, Schering Plough Animal Health). Both groups received cloprostenol and eCG on the same day (regardless of device removal) to ensure they were administered at the same follicular wave. Both device insertion and removal were performed in the morning. Ultrasound evaluations were performed every 12h from device removal to ovulation detection. Ovulations were considered as the average interval between the last observation of follicles and the first exam in which it was no longer seen. The normal distribution of variables was determined by Shapiro-Wilk test and homocedasticity by Levene’s test. All variables were not normally distributed and thus analysed by Mann–Whitney U test, with P<0.05 considered significantly different. Values are presented in median±interquartile range. There was no difference between G5 and G6, respectively, in the interval to oestrus (48.0±0.0 vs. 48.0±12.0h), interval from oestrus onset to ovulation (18.0±9.0 vs. 18.0±12.0h), interval from device removal to ovulation (66.0±18.0 vs. 66.0±24.0h), number of ovulated follicles (2.0±2.0 vs. 2.5±2.0), or mean diameter of ovulated follicles (6.6±1.6 vs. 6.6±1.4mm). All ovulations were detected in the morning. In conclusion, our data demonstrate that short-term hormonal treatment for 5 or 6 days is similarly efficient to induce synchronous oestrus in Saanen and Toggenburg goats. This research was supported by EMBRAPA (Project 20.19.01.004.00.03.001) and CNPq (314952/2018-7).

76 Effect of season on the superstimulation response, embryo quality, and pregnancy establishment in dromedary camel (Camelus dromedarius)

The present study was conducted to study the effect of season on the superstimulation response, embryo quality and pregnancy establishment in the dromedary camels. Two donors each were superstimulated in the month of June 2019 (non-breeding season) and January 2019 (breeding season) by a combination of 2500IU of equine chorionic gonadotrophin (eCG, Folligon; Intervet), given as a single intramuscular injection on Day 1 of the treatment protocol, and 400mg of pFSH (Folltropin; Bioniche) injected twice daily in declining doses of 2×80mg, 2×60mg, 2×40mg, and 2×20mg over 4 days, also beginning on Day 1. They were scanned by rectal ultrasonography and follicles counted before mating with a fertile bull on Day 11 after the start of treatment. An injection of 20µg of gonadotrophhin-releasing hormone (Receptal, Intervet) was given immediately after mating to induce ovulation. The number of corpora lutea (CL) were counted, and the embryos collected by the non-surgical method on Day 7 after ovulation. All embryos were washed and graded before they were transferred individually into the left uterine horn of recipient animals, synchronized to be on Day 6 after ovulation. All recipients were screened by ultrasonography on Day 22, Day 60, and Day 90 for pregnancies. The data were analysed using a two-sample t-test (Minitab statistical software, Minitab Ltd.). No difference was observed in the mean number of follicles developed (20.5 vs. 18.5) between the donors in breeding and non-breeding season, respectively. The percent mean±s.e.m. of ovulations as observed by counting the CL in nonbreeding season (80.7±3.4) were not different from those in breeding season (85.4±3.7). A total number of 16 embryos collected during non-breeding season and 20 embryos in breeding season were transferred to recipients. The percent mean±s.e.m. of pregnancies established on Day 22 (56.6±3.4 vs. 67.5±7.5) and on Day 90 (47.2±2.8 vs. 60±0.0) were similar in both groups. These observations indicate that embryo transfer technology can be applied to camels during the summer months, which is considered the non-breeding season, and pregnancies can be established at par with breeding season. In conclusion, to the best of our knowledge, this is the first study in camels wherein we have demonstrated that donor camels can be superstimulated, embryos can be collected, recipient animals can be synchronized, and pregnancies can be established in the summer (non-breeding) months. The embryos collected from elite donors can be transferred to synchronized recipients to establish pregnancies or preserved for future use. Some owners do not want calves to be born in summer months, so protocols need to be established for storing these embryos for a few months before their transfer to recipients, to have the calves delivered in the desired winter months.