Fawning Rate Research Articles

Effects of Vaccination against GDF9 and BMP15 on Fertility and Ovarian Function in the White-tailed Deer

The physiological mechanisms controlling ovarian follicular growth and ovulation involve a complex exchange of systemic signals and a localized exchange of molecules between the oocyte and surrounding somatic cells. It has been demonstrated that the oocyte itself plays an essential role in regulating these processes by secreting two key regulatory proteins: bone morphogenetic protein-15 (BMP15) and growth and differentiation factor-9 (GDF9). Natural mutations in their expression and vaccination against these growth factors have been shown to cause sterility in sheep. The aim of this 3-year study was to determine the effect of vaccination against GDF9 and BMP15 on fertility in female white-tailed deer. Does were randomly assigned to two groups (n = 10/group). Each doe received a primary vaccination followed by a booster 47 days later. After the first year, a subset of animals (n = 4-5/group) received an additional booster vaccination. Blood samples were collected at regular intervals to determine antibody titers and progesterone concentrations. Early pregnancy was assessed by ultrasound, and fawning was subsequently monitored. For the BMP15 group, over the 3 years 80%, 100%, and 75% of does fawned with fawning rates of 2.4, 3.5, and 3.3 fawns/doe, respectively. For the GDF9 group, 80%, 25%, and 25% of does fawned with fawning rates of 2.6, 1, and 2 fawns/doe, respectively. The fawning rate of untreated animals in the herd was 1.8 fawns/doe. Although all animals in the BMP15 group had high antibody titers, they were not made infertile, and they became more fecund. Most animals in the GDF9 group had high antibody titers, but fecundity was not affected the first year; however, they were made infertile in Years 2 and 3. Results from this study demonstrate that vaccination against GDF9 has potential to control fertility in deer. Further research will be required to determine the appropriate timing for administering the vaccine and the longevity of effect.

SINGLE-TREATMENT PORCINE ZONA PELLUCIDA IMMUNOCONTRACEPTION ASSOCIATED WITH REDUCTION OF A POPULATION OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS)

Previous reports have demonstrated gradual reductions of white-tailed deer (Odocoileus virginianus) populations through immunocontraception, with stabilization occurring after 2-4 yr of treatment, and subsequent reductions of 6-10% annually. These studies employed porcine zona pellucida (PZP) vaccines that required two initial treatments and annual retreatments. From 2005 to 2010, 258 adult and yearling female deer on Fripp Island, South Carolina, were treated with one of several PZP preparations designed to produce 2+ yr of effective contraception with a single treatment. These included several preparations of SpayVac and of native PZP-adjuvant emulsion plus PZP and QA-21 in timed-release pellets. Deer were chemically immobilized, ear-tagged, and administered initial treatments by hand in February-March. Some treated deer were boosted remotely with PZP-adjuvant emulsion 1.5 - 4.5 yr after initial treatments. Ground-based distance sampling was used to estimate deer population density at Fripp Island, a resort community, and at a relatively undeveloped neighboring control site, Hunting Island. Most vaccine preparations tested reduced fawning rates by 75% to 95% for at least 1 yr. From 2005 to 2011, deer density on Fripp Island declined by 50%, from 72 deer/km(2) to 36 deer/km(2), an average annual reduction of 11%. In contrast, population density on the Hunting Island control site fluctuated between 2005 and 2011, averaging 23 deer/km(2) (range, 19-28 deer/km(2)). Population declines on Fripp Island were associated with an increase in the proportion of treated females and with a progressive decrease in winter fawn:doe ratios, from 1.21 fawns/doe in 2005 to 0.19 fawns/doe in 2010. Winter fawn:doe ratios averaged 1.36 fawns/doe (range, 0.84 - 1.62 fawns/doe) at the Hunting Island control site. Annual survivorship averaged approximately 79% among ear-tagged females. The rate at which deer populations diminished in association with PZP treatments on Fripp Island was higher than that seen at other study sites, although the reasons for the more rapid decline on Fripp Island are not well understood.

Factors affecting reproductive performance of white-tailed deer subjected to fixed-time artificial insemination or natural mating

The objectives of this study were to examine the effects of several factors affecting fawning rate, litter size, litter weight and neonatal fawn mortality in white-tailed deer inseminated either transcervically or by means of laparoscopy. Oestrus synchronisation with a controlled internal drug release (CIDR)-based protocol and fixed-time artificial insemination (FTAI) was conducted in 130 white-tailed deer (Odocoileus virginianus texanus) during three reproductive seasons (2007-2009; 271 services) in a game-hunting ranch in a hot-arid environment (26°4' N, 101°25' W). Ninety additional non-treated does were exposed to bucks for natural mating. Fawning rate did not differ between AI methods (40.0 vs 45.0% for transcervical and laparoscopic AI, respectively). Overall fawning rate (proportion of all does fawning after FTAI and a subsequent period of buck exposure) did not differ between transcervical (89.5%), laparoscopic (80.3%) or natural (88.9%) insemination. Litter size per fawning doe was higher (P<0.05) in naturally-served does (1.65±0.48) than in transcervically-inseminated does (1.40±0.51) or in laparoscopically-inseminated does (1.48±0.50). The main conclusion was that no enhancement of fawning rate or litter size occurred as a result of intrauterine deposition of semen by laparoscopy compared with the transcervical insemination technique.

The reproductive performance of female Forest musk deer (Moschus berezovskii) in captivity

Reproductive performance of 750 adult female Forest musk deer (FMD, Moschus berezovskii) was monitored (from 2005 to 2009) on two Forest musk deer farms in Sichuan province, China. The mean (± SEM) lengths of the estrous cycle, pregnancy, and consecutive fawning intervals were 17.5 ± 0.8 d (n = 64), 182.9 ± 0.8 d (n =190), and 363.2 ± 2.4 d (n = 120), respectively. Copulation occurred from the end of October to early March, with the majority (84.1 ± 1.9%) during November and December (P < 0.05). The fawning rate was 68.7 ± 2.2% in yearling hinds and 73.3 ± 1.3% in adult hinds. Fawning occurred from the end of April to early September, with the majority (88. 9 ± 2.2%) during May and June (P < 0.005), including a peak in May (52.0 ± 1.0%). Yearling hinds fawned later (7.3 ± 1.8 d) than adult hinds. Rates of premature delivery and dystocia were 2.7 ± 0.4 and 2.0 ± 0.3%, respectively. There was a 1.07:1 female-to-male ratio at birth (P > 0.05), with 67.7% twins, but only two cases of triplets and one set of quadruplets among 537 fawns. Birth weight averaged 518.7 ± 10.3 g, ranging from 304 to 775 g (n = 240), with male fawns slightly heavier than females (521.1 ± 14.8 vs 516.9 ± 14.3 g). Postnatal and pre-weaning mortality rates were 25.0 ± 1.2 and 17.9 ± 3.1%, respectively. Postnatal mortality and urinary calculus were much more common in male fawns (P < 0.01). The mortality rate due to suppuration and dyspepsia were different (P < 0.001) between postnatal and pre-weaning periods. Due to higher mortality of male fawns, the adult sex ratio was significantly female-biased. In conclusion, captive FMD had similar seasonal patterns of copulation and fawning as wild FMD and other musk deer species.

Effectiveness of Spayvac® for Reducing White-tailed Deer Fertility

Overabundant white-tailed deer (Odocoileus virginianus) populations have been reported in many urban and suburban communities across the United States. Large populations of deer can potentially increase the risk of human-wildlife conflicts, such as deer-vehicle collisions, transmission of disease to humans, and vegetation damage. In 2003, efforts to control white-tailed deer numbers were initiated at the National Aeronautical and Space Agency's (NASA) Lyndon B. Johnson Space Center (JSC) in Houston, Texas, using the long-lasting, single-dose contraceptive SpayVac. Our objectives were to evaluate the effectiveness of SpayVac for reducing white-tailed deer fertility and determine the partial cost for treatment. Between 2003 and 2004, we monitored 45 adult female deer (34 treated with SpayVac, 11 controls treated with a placebo). Fawning rate over 2 yr for deer treated with SpayVac >30 days prior to the rut was 0% (n=31), whereas the fawning rate for control deer was 78% (n=11). Inoculation 1 mo prior to the breeding season was sufficient time to achieve fertility control. We conclude that SpayVac can effectively reduce the fertility of urban white-tailed deer.

Immunocontraception of captive exotic species. III. Contraception and population management of fallow deer (Cervus dama)

AbstractImmunocontraception has become an increasingly valuable tool in the population management of captive exotic ungulates. Although porcine zona pellucida vaccine (PZP) was used successfully in other cervids, a previous study with fallow deer (Cervus dama) suggested that the vaccine did not work in this species. In the current study, PZP was tested in two captive herds of fallow deer. Antibody titers were monitored over a 3‐year period to evaluate three different adjuvant protocols, and the vaccine was applied to an entire herd to determine the impact on fawning rates. In a semi‐free‐ranging herd, antibody titers rose from preimmunization levels of 2.6% of positive control serum to 56.5% 4 weeks after initial inoculations, to 65.1% at 1 year, and to 81.3% at 2 years, after a single annual booster was applied. Fawn production in this herd was reduced significantly over 3 years. The adjuvant protocol of Freund's Modified Adjuvant® (FMA) for the initial inoculation followed by a booster with Freund's Incomplete Adjuvant® (FIA), and the protocol of FMA for the initial inoculation followed in 3 weeks by a booster with FMA both produced significantly higher antibody titers than the 3× FIA (3 weeks apart) protocol after year 1. The FMA+FMA protocol produced significantly higher titers than the 3× FIA protocol at year 2, but was not different from the titers produced by the FMA+FIA protocol at year 2. Zoo Biol 22:261–268, 2003. © 2003 Wiley‐Liss, Inc.

Immunocontraception of white-tailed deer with GnRH vaccine.

Reduction of excess numbers of white-tailed deer (Odocoileus virginianus) is an example of a potential use for immunocontraception as a means of wildlife population management. A 4 year multifaceted study was conducted to determine the long term effects of gonadotropin releasing hormone (GnRH) contraceptive vaccine on the fertility and behavior of female and male white-tailed deer. Deer were monitored for breeding behavior, hormone levels, pregnancy, fawning and GnRH specific antibody levels. Treatment lead to reduced fawning rates, altered estrus behavior, reduced concentrations of progesterone, contraception and failure to maintain pregnancy following conception. GnRH immunized does bred to untreated bucks had an 88% reduction in fawning caused by either immunocontraception or immunocontragestion. The vaccine effect is reversible, directly related to the antibody titer. Infertility lasted up to two years without boosting. GnRH immunized bucks demonstrated no interest in sexual activity when paired with control females. Depending on the immunization schedule, antlers either dropped early or remained in velvet. The results of this study demonstrate that GnRH vaccine is effective in inducing a reversible infertility in white-tailed deer, the infertility lasting up to two years without boosting.

Immunocontraception of white-tailed deer using native and recombinant zona pellucida vaccines

We conducted a 2-year feasibility study with native porcine zona pellucida (PZP) vaccine and three recombinant rabbit zona pellucida vaccines (RC55, RC75a and a combination of RC55, RC75a and RC75b) as an initial phase of developing a recombinant immunocontraceptive vaccine to control reproduction in overpopulated herds of white-tailed deer ( Odocoileus virginianus). Forty captive white-tailed does were divided into five groups (one sham and four treated), of eight each and injected with a 500 μg prime dose of vaccine. Each prime dose was followed by a 300 μg booster dose at 3–7 weeks post prime. The frequency and number of months of observed breeding were higher in PZP immunized does than in sham controls. Although the antibody titers of the three recombinant groups were 1000 or less, as compared with the PZP group with titers often over 128,000, the fawning rates of the two recombinants were significantly lower than that of the control group. The combined antigen group did not have a significantly lower fawning rate.

The effect of ivermectin on reindeer offspring's weight gain and survival: preliminary findings

F a w n survival is a central issue for Scandinavia's reindeer industry. Nonetheless, there has been m i n i m a l research conducted on parasitism's effect on reproductive success of female reindeer and their abi l i ty to foster viable offspring to weaning. Investigation of the ecological relationship between parasitism and host fitness, as w e l l as the economic and veterinary medical importance of anthelmintic treatment, is faciliated by conducting field trials i n w h i c h animals treated w i t h anthelmintic are compared to nontreated controls. W e are presently conducting a randomized field tr ial to explore the effects of ivermectin treatment on pre-reproduc¬ tive and mature female reindeer. O u r p r imary response variables include age at first reproduct ion , and offspring survival and weight. F i n dings w i l l provide fundamental informat ion required for the development of an opt imal parasite treatment strategy w h i c h aims at m i n i m i z i n g parasite transmission and maximizing meat product ion. The possible long-term negative side effects of ivermectin are also being explored. O n a theoretical level, project result could elucidate the effects of the general parasite c o m m u n i t y on herd populat ion dynamics and provide data for the study of various quantitative genetic relationships in reindeer. N i e m i n e n (1989) found that offspring of ivermectin-treated females at Kaamanen Reindeer Research Station, F i n l a n d , had a significant 0.5 kg increase (p S 0.05) in average live b i r th weight and a non-significant 2.1 kg increase (p > 0.05) in average autumn live weight . 1 H o w e v e r , our pre l iminary findings indicate that ivermectin treatment of females induces no significant or consistent increase i n m i d to latesummer fawn live weight in coastal N o r t h e r n N o r w a y . This discrepancy f rom the F i n n i s h results may be explained by several factors, among w h i c h sample size or differences in parasite abundance are l i k e l y candidates. The response variable that showed the strongest treatment effect in our pre l iminary results was fawning percent. 2 Ivermectin treated females had a 9 % higher fawning rate (64 % vs. 55 %) than control females, although the difference was not statistically significant (Fisher's Exact Test, p = 0.15; n = 180). We calculated the statistical significance from the means and S.E. published in Poromies-Lehti. 3/1989. Fawning percent is defined as the proportion of research females that was accompanied by a fawn during the time of summer sampling. Rangif er, Special Issue N o . 5, 1990 15

The reproductive performance of farmed fallow deer (Dama dama) in New South Wales

Observations on the reproductive performance of fallow deer on 47 farms in New South Wales were made over 6 consecutive years. The minimum fawning rate for does varied significantly (p less than 0.001) between years, the corresponding fawning percentages varying from 75.0% to 96.4%, with an overall mean of 88.8%. The weaning rate also varied significantly (p less than 0.001) between years, the corresponding percentages varying from 65.0% to 89.1% with a mean over 6 years of 81.4%. Weaning rates were low given the known high fertility of fallow deer. The ratio of male to female fawns at weaning varied significantly (p less than 0.05) between years, although the ratio was exactly 1:1 for all births recorded over the 6-year period. The mean birthweights for female and male fawns were 4.01 kg +/- 0.61 (n = 330) and 4.23 kg +/- 0.72 (n = 348) respectively. Mean birthweights varied significantly (p less than 0.001) between the sexes and between years. There was a greater difference between birthweights of male and female fawns in years with higher mean fawn birthweight. Fawn birthweights generally approximated 10% of the pre-rut weight of their mother. Handling of newborn fawns for tagging and weighting did not increase the chance of mismothering and rejection. The mean weaning weight for doe fawns and buck fawns over 6 years was 18.7 kg (n = 227) and 21.2 kg (n = 231) respectively, with a mean birth to weaning interval of 108.4 +/- 4.89 (n = 458). Growth rates of male fawns from birth to weaning were significantly higher (p less than 0.01) than for female fawns, and the growth rates of fawns were significantly different (p less than 0.01) between years.(ABSTRACT TRUNCATED AT 250 WORDS)

Artificial insemination of farmed fallow deer (Dama dama): fixed-time insemination at a synchronized oestrus

ABSTRACTTwo trials were conducted in 1986 on artificial insemination of female fallow deer at fixed intervals from the cessation of oestrous synchronization treatment. Semen had been collected previously from mature bucks by electroejaculation and extended in sodium citrate/egg yolk diluent.In the first trial involving a comparison of the fertilization rates of fresh and frozen-thawed semen delivered intravaginally, 57 does each received a single intravaginal progesterone-releasing device (CIDRtype S, Carter Holt Harvey Plastic Products Group Ltd, Hamilton, NZ) for a 14-day period early in the 1986 breeding season. All does were inseminated intravaginally with either fresh (no. = 26) or frozenthawed (no. = 31) semen (85 × 106 motile spermatozoa per inseminate) at 48 h after CIDR removal. The apparent conception rates for the two types of semen were 65·4% and 64·5% respectively (P &gt; 0·1) and the actual fawning rates were 500% and 48·4% respectively (P &gt; 0·1).In the second trial involving an investigation of the feasibility of laparoscopic intrauterine insemination, 55 does were synchronized as for the first trial. At 56 to 58 h from CIDR removal, the does were anaesthetized and laparoscopically inseminated with frozen-thawed semen (85 × 106 motile spermatozoa per animal) by direct injection into both uterine horns. Anaesthesia was reversed immediately following artificial insemination. The apparent conception rate was 47·3% and the actual fawning rate was 41·8%.Data from both trials indicate that reasonable fawning rates can be obtained for artificially inseminated fallow deer. Between 11 and 25% of does expected to fawn did not and this may represent embryonic mortality attributable to the method of oestrus/ovulation synchronization.