Normal Breeding Research Articles

IF1, a natural inhibitor of mitochondrial ATP synthase, is not essential for the normal growth and breeding of mice

IF1 is an endogenous inhibitor protein of mitochondrial ATP synthase. It is evolutionarily conserved throughout all eukaryotes and it has been proposed to play crucial roles in prevention of the wasteful reverse reaction of ATP synthase, in the metabolic shift from oxidative phosphorylation to glycolysis, in the suppression of ROS (reactive oxygen species) generation, in mitochondria morphology and in haem biosynthesis in mitochondria, which leads to anaemia. Here, we report the phenotype of a mouse strain in which IF1 gene was destroyed. Unexpectedly, individuals of this IF1-KO (knockout) mouse strain grew and bred without defect. The general behaviours, blood test results and responses to starvation of the IF1-KO mice were apparently normal. There were no abnormalities in the tissue anatomy or the autophagy. Mitochondria of the IF1-KO mice were normal in morphology, in the content of ATP synthase molecules and in ATP synthesis activity. Thus, IF1 is not an essential protein for mice despite its ubiquitous presence in eukaryotes.

Changes in bacterial glycolipids as an index of intestinal lactobacilli and epithelial glycolipids in the digestive tracts of mice after administration of penicillin and streptomycin

The major lipid constituent of symbiotic gram-positive bacteria in animals are phosphatidylglycerol, cardiolipin and dihexaosyl diglycerides (DH-DG), whose hydrophobic structures are characteristic of the environments, and the carbohydrate structures of DH-DGs are bacterial species-characteristic. Immunization of rabbits with intestinal lactobacilli generated antibodies against DH-DGs and their modified structures, among which Galα1-6-substituted DH-DG, i.e., Lactobacillus tetrahexaosyl diglyceride (LacTetH-DG), reacted with antibodies more intensely than DH-DG. Whereas, from the 16S-rRNA sequence, the intestinal lactobacilli in murine digestive tracts were revealed to be L. johnsonii, in which LacTetH-DG is present at the concentration of 2.2 ng per 1 × 10(6) cells. To obtain more accurate estimates of intestinal lactobacilli in several regions of the digestive tract of mice, LacTetH-DG was detected by TLC-immunostaining with anti-Lactobacillus antisera, being found in the stomach, cecum and colon of normal breeding mice, 1.0 × 10(9), 3.5 × 10(9) and 7.4 × 10(9) cells, respectively. Administration of penicillin and streptomycin for 6 days resulted in a reduction in the number of intestinal lactobacilli, the levels being 0 %, 30 % and 4 % of the control ones in the stomach, cecum and colon, respectively, which was associated with the accumulation of the contents in the tracts from the stomach to the cecum and with diarrhea. In addition, a reduced amount of fucosyl GA1 (FGA1) and a compensatory increase in GA1 due to the reduced activity of α1,2-fucosyltransferase in the small intestine and the enhanced discharge of FGA1 into the contents occurred in mice, probably due to the altered population of bacteria caused by administration of penicillin and streptomycin.

Effect of sera of normal cycling, pregnant and repeat breeding buffaloes (Bubalus bubalis) on in vitro maturation of buffalo, sheep and goat oocytes

To examine the oocytes maturation capacity of buffalo, sheep and goat using media containing sera of three different groups of buffaloes (regularly cycling, pregnant and repeat breeding). The buffalo, sheep and goat oocytes were matured under suitable conditions in medium containing sera of regularly cycling, pregnant and repeat breeding buffaloes. The oocytes maturation rate containing buffalo oocytes cultured in media containing sera of the control group and regularly cycling group were not significantly different. However when oocytes cultured in the media containing sera of pregnant buffaloes the maturation rate were significantly declined. Further significant declined in maturation rate were observed when oocytes cultured in media containing sera of repeat breeding buffaloes. When sheep and goat oocytes cultured in the media containing control, pregnant and regularly cycling animals sera the oocytes maturation rate were not significantly different. A significant decline in maturation rate of sheep and goat oocytes were observed, when oocytes cultured in media containing sera of repeat breeding buffaloes. We may conclude that serum collected from normal cycling buffaloes can be used for oocytes maturation in both homogeneous and heterogeneous species.

Photoperiod and melatonin treatments for controlling sperm parameters, testicular and accessory sex glands size in male Iberian ibex: A model for captive mountain ruminants

This study examines whether photoperiod and/or melatonin treatments can improve sperm variables outside the breeding season in the Iberian ibex–a model species for wild mountain ruminants–thus helping in the collection of high quality sperm beyond the normal breeding season for depositing in genetic resource banks. Adult Iberian ibex males (n=17) were divided into four treatment groups: (1) controls under the natural photoperiod (control group; n=4), (2) treatment with melatonin implants on December 22nd, February 22nd and April 22nd (group WS-M; n=5), (3) treatment with short photoperiod cycles, i.e., 2 months of long days followed by melatonin implants (to emulate 2 months of short days) throughout the year (group PHPld+M; n=4), and (4) treatment with melatonin implants on June 22nd and August 22nd (group SS-M; n=4). The interaction treatment x season had a strong influence on testis size (P<0.05), the size of the seminal vesicles (P<0.001), the percentage of abnormal sperms (P<0.05), and percentage non-progressive (P<0.05) and progressive (P<0.001) sperm motility. In groups WS-M and PHPld+M, the normal springtime physiological reductions in testis size, non-progressive sperm motility and acrosome integrity were prevented. The values for the studied sperm variables were, however, reduced in the natural breeding season at the end of the experimental period in group PHPld+M, although not in group WS-M. The pattern of melatonin administration in group SS-M conferred no advantages on reproductive functionality. These results suggest that lengthening the short day period after the winter solstice (the WS-M treatment) extends reproductive activity in this species, allowing good quality sperm to be recovered for conservation purposes during the non-breeding season.

Exogenous melatonin after a treatment of artificial long days is able to increase LH secretion during seasonal anoestrus in Payoya goats

One experiment was conducted to determine whether the treatment with artificial long days and exogenous melatonin can increase, by itself, luteinizing hormone (LH) secretion during spring (seasonal anoestrus) in Payoya goats and whether this treatment causes a variation in the reactivation of the LH secretion in the normal breeding season. The experiment started on 4 November and finished on 27 October. A total of 22 ovariectomised-oestradiol treated goats were used. Ten goats were exposed to long days (16 h of light/day) from 14 November to 20 February. On 20 February, they received one s.c. melatonin implant and were exposed to natural photoperiodic changes in an open shed. The control group was located in another open shed with any treatment during the whole experiment. For both groups, plasma samples were obtained twice a week for LH assay. The photoperiodic treatment induced an earlier fall of the LH secretion. However, after the melatonin treatment, a clear increase of LH secretion during the natural seasonal anoestrus in the treated group was observed, and no difference in the onset of the LH secretion at the normal breeding season was observed. We can conclude that, in Payoya goats, the photoperiodic–melatonin treatment is by itself able to induce a clear LH increase during the seasonal anoestrus and does not modify the reactivation of the LH secretion at the normal breeding season.

Trace minerals profile of blood serum and estrual mucus in repeat breeder Kankrej cows

Aim: The study was carried out with an idea to ascertain involvement of trace minerals in failure of conception in Knakrej cow. Materials and Methods: The animals under study were comprised of 10 normal (Group-I) and 20 repeat breeder (Group-II) Kankrej cows. Blood and estrual mucus of each repeat breeding and normally cycling cows were collected aseptically before breeding. The cervical mucus was diluted with triple glass distilled water at the rate of 1: 3 using vertex machine. Serum and diluted mucus was used for the trace minerals estimation. Results: The values observed for copper, iron, zinc and manganese in blood serum of normal and repeat breeding animals was 2.27 ± 0.05 vs 0.87 ± 0.02, 1.41 ± 0.02 vs 0.65 ± 0.01, 1.94 ± 0.01 vs 1.78 ± 0.02 and 0.43 ± 0.02 vs 0.18 ± 0.01 ppm, respectively and in estrual mucus it was 1.37 ± 0.10 vs 0.44 ± 0.06, 0.74 ± 0.07 vs 0.33 ± 0.05, 1.47 ± 0.10 vs 0.82 ± 0.06 and 0.29 ± 0.04 vs 0.23 ± 0.03 ppm, respectively. All the values in blood serum and estrual mucus were significantly (p<0.01) higher in normal than repeat breeder cows except manganese in estrual mucus, which was non significantly higher in normal as compared to repeat breeder Kankrej cows. Conclusion: All trace minerals was higher in blood serum of Group I animals as compared to Group II. In estrual mucus except manganese, all trace minerals was higher in normal cows than repeat breeder.

Rapid adaptation to mammalian sociality via sexually selected traits.

BackgroundLaboratory studies show that the components of sexual selection (e.g., mate choice and intrasexual competition) can profoundly affect the development and fitness of offspring. Less is known, however, about the total effects of sexual selection on offspring in normal social conditions. Complex social networks, such as dominance hierarchies, regulate the opportunity for mating success, and are often missing from laboratory studies. Social selection is an extended view of sexual selection that incorporates competition during sexual and nonsexual interactions, and predicts complex evolutionary dynamics. Whether social selection improves or constrains offspring fitness is controversial.ResultsTo identify fitness consequences of social selection, wild-derived mice that had bred under laboratory conditions for eight generations were re-introduced to naturalistic competition in enclosures for three consecutive generations (promiscuous line). In parallel, a control lineage bred in cages under random mate assignment (monogamous line). A direct competition experiment using second-generation animals revealed that promiscuous line males had greater reproductive success than monogamous line males (particularly during extra-territorial matings), in spite of higher mortality and equivalent success in social dominance and sperm competition. There were no major female fitness effects (though promiscuous line females had fewer litters than monogamous line females). This result suggested that selection primarily acted upon a sexually attractive male phenotype in the promiscuous line, a hypothesis we confirmed in female odor and mating preference trials.ConclusionsWe present novel evidence for the strength of sexual selection under normal social conditions, and show rapid male adaptation driven largely by sexual trait expression, with tradeoffs in survivorship and female fecundity. Re-introducing wild-derived mice to competition quickly uncovers sexually selected phenotypes otherwise lost in normal colony breeding.

168 A NONINVASIVE, TRANSDERMAL ABSORPTION APPROACH FOR EXOGENOUS HORMONE INDUCTION OF SPAWNING IN THE NORTHERN CRICKET FROG, ACRIS CREPITANS: A MODEL FOR SMALL ENDANGERED AMPHIBIANS

The World Conservation Union (IUCN) currently recognises Eleutherodactylus locustus from Puerto Rico and Plectrohyla acanthodes from Mexico and Guatemala as critically endangered, and they are recommended for ex situ breeding by several amphibian conservation organizations (e.g. AZA, ATAG, RCP, and AARK). Because of their very small and delicate bodies, conventional injectable methods developed for hormonally stimulating spawning in larger frogs and toads are undesirable, because this can result in trauma and injury. Recently, a protocol was developed for inducing spawning in frogs by co-injection of a gonadotropin-releasing hormone agonist (GnRHa) with metoclopramide-HCl (MET), a dopamine antagonist (Amphiplex; Trudeau et al. 2010 Rep. Biol. Endo. 8, 36). The goal of this study, therefore, was to determine the effectiveness of Amphiplex using 3 routes of exogenous treatments: (1) direct IP injection (0.4 µg of GnRHa + 10 µg of MET per gram of body weight), (2) injection into prey (1 µg of GnRHa + 25 µg of MET per insect) before feeding, and (3) a 60-min immersion in 10 mL of pond water containing 0.17 µg of GnRHa + 0.42 µg of MET per microliter. The northern cricket frog (Acris crepitans), a very common local species, was used as a model because it is also small, delicate, and difficult to handle. A total of 110 cricket frogs were caught locally either late or after their normal breeding season, sexed as males or females, and segregated into a control group that was housed similarly ex situ but not exposed to Amphiplex and the 3 Amphiplex experimental groups. The frogs were monitored daily for egg production and behavioural amplexus (potential spermiation). The results are summarised as follows (Table 1): of the frogs exposed to the Amphiplex-supplemented pond water, 84% of 38 females deposited eggs, and 6 pairs were observed in amplexus (indicating spermiation). Approximately 27% of more than 2242 eggs were found to develop cleavage divisions, and tadpoles were first observed in vitro after 4 days. In conclusion, to our knowledge this is the first report indicating that transdermal absorption of a reproductive hormone cocktail (e.g. Amphiplex) may serve in the application of assisted reproductive technology to increase the populations of critically endangered amphibians such as frogs and toads that may be too small or delicate for conventional methods of exogenous hormone treatments that require handling and injections. Table 1.Treated northern cricket frogs

RADIOGRAPHIC LIVER SIZE IN PEKINGESE DOGS VERSUS OTHER DOG BREEDS

Differential diagnoses for canine liver disease are commonly based on radiographic estimates of liver size, however little has been published on breed variations. Aims of this study were to describe normal radiographic liver size in Pekingese dogs and to compare normal measurements for this breed with other dog breeds and Pekingese dogs with liver disease. Liver measurements were compared for clinically normal Pekingese (n = 61), normal non-Pekingese brachycephalic (n = 45), normal nonbrachycephalic (n = 71), and Pekingese breed dogs with liver disease (n = 22). For each dog, body weight, liver length, T11 vertebral length, thoracic depth, and thoracic width were measured on right lateral and ventrodorsal abdominal radiographs. Liver volume was calculated using a formula and ratios of liver length/T11 vertebral length and liver volume/body weight ratio were determined. Normal Pekingese dogs had a significantly smaller liver volume/body weight ratio (16.73 ± 5.67, P < 0.05) than normal non-Pekingese brachycephalic breed dogs (19.54 ± 5.03) and normal nonbrachycephalic breed dogs (18.72 ± 6.52). The liver length/T11 vertebral length ratio in normal Pekingese (4.64 ± 0.65) was significantly smaller than normal non-Pekingese brachycephalic breed dogs (5.16 ± 0.74) and normal nonbrachycephalic breed dogs (5.40 ± 0.74). Ratios of liver volume/body weight and liver length/T11 vertebral length in normal Pekingese were significantly different from Pekingese with liver diseases (P < 0.05). Findings supported our hypothesis that Pekingese dogs have a smaller normal radiographic liver size than other breeds. We recommend using 4.64× the length of the T11 vertebra as a radiographic criterion for normal liver length in Pekingese dogs.

Periovulatory changes in the endoscopic appearance of the reproductive tract and teasing behavior in the bitch

A variety of diagnostic techniques have been applied to address the problem of determining optimal mating time in the bitch, although some have not been objectively investigated. Nine healthy bitches were examined daily using routine clinical methods as part of their normal breeding management with the aim of establishing which method was most useful. Accordingly, measurement of the degree of vulval swelling, endoscopic measurement of the vaginal mucosal color and appearance, and objective evaluation of behavior of the bitch were related to the time of ovulation (calculated when progesterone reached 5 ng/mL; Day 0) and the duration of the fertilization period (Day 2 to Day 5) determined by measurement of plasma progesterone concentration and assessment of vaginal cytology. There was a surprisingly large individual variation in measurements of vulval swelling, such that although trends were apparent this technique was not precise enough to establish the optimal mating time. However, measuring color saturation and vaginal mucosal fold width was successful. A consistent change in the mucosal color saturation was observed that related to the beginning (Day −5) and duration of the fertile period although there was no difference in measurement of color saturation between Day −5 and Day 2 (P = 0.31), and Day 2 and Day 5 (P = 0.43). The vaginal mucosal folds were smaller in width at the beginning of the fertilization period (Day 2) than at the beginning of the fertile period (Day −5) (P = 0.008), and all bitches had a consistent appearance of mucosal contours on Day 3. Assessment of sexual behavior was not considered precise enough to enable determination of the optimal time for mating because of the large amount of individual variation in behavioral scores. There was no difference in female behavior scores between Day −5 and Day 2 (P = 0.29), or between Day 2 and Day 5 (P = 0.06). Using objective techniques this study has quantified changes in the color and fold width of the vaginal mucosa that have previously only been subjectively reported. These changes can be used to identify the fertilization period and it is possible, with future refining of the technique, that endoscopic examination could replace vaginal cytology to be used in conjunction with plasma progesterone concentration when examining bitches to determine the optimal time to breed.

Impact of miniature geolocation loggers on a small petrel, the thin-billed prion Pachyptila belcheri

Effects of deployment of miniaturised transmitters and loggers have been studied mainly in diving seabirds such as penguins, and less so in flying seabirds. However, some studies of albatrosses and petrels recorded extended trip durations and elevated rates of nest desertion following device attachment, especially if transmitter loads exceeded 3 % of adult mass. Studies have usually compared performance parameters such as trip duration, meal mass, breeding success or rate of return in the next season between birds with devices and controls. We here examined the effects of geolocator loggers (Global Location Sensing, (GLS)) on thin-billed prions Pachyptila belcheri (130 g), by comparing performance parameters and additionally eco-physiological parameters. GLS weighed ca. 1 % of the body mass, and were fixed on leg rings, which may influence the flight efficiency by creating an asymmetric load. We found no differences in the performance parameters, either in the season of attachment or the season following recovery. Similar stable isotope ratios in adult blood and feather samples further indicated that the foraging ecology was not influenced. However, after 1 year of logger deployment, adults differed in their hormonal response to stress: while baseline corticosterone levels were not influenced, corticosterone levels in response to handling were elevated. Moreover, increased heterophil/lymphocyte ratios and a decreased tail growth in winter suggest that carrying the GLS was energetically costly, and adults adapted physiologically to the higher work load, while keeping up a normal breeding performance.

Comparison of Gene Expression and Genome-Wide DNA Methylation Profiling between Phenotypically Normal Cloned Pigs and Conventionally Bred Controls

Animal breeding via Somatic Cell Nuclear Transfer (SCNT) has enormous potential in agriculture and biomedicine. However, concerns about whether SCNT animals are as healthy or epigenetically normal as conventionally bred ones are raised as the efficiency of cloning by SCNT is much lower than natural breeding or In-vitro fertilization (IVF). Thus, we have conducted a genome-wide gene expression and DNA methylation profiling between phenotypically normal cloned pigs and control pigs in two tissues (muscle and liver), using Affymetrix Porcine expression array as well as modified methylation-specific digital karyotyping (MMSDK) and Solexa sequencing technology. Typical tissue-specific differences with respect to both gene expression and DNA methylation were observed in muscle and liver from cloned as well as control pigs. Gene expression profiles were highly similar between cloned pigs and controls, though a small set of genes showed altered expression. Cloned pigs presented a more different pattern of DNA methylation in unique sequences in both tissues. Especially a small set of genomic sites had different DNA methylation status with a trend towards slightly increased methylation levels in cloned pigs. Molecular network analysis of the genes that contained such differential methylation loci revealed a significant network related to tissue development. In conclusion, our study showed that phenotypically normal cloned pigs were highly similar with normal breeding pigs in their gene expression, but moderate alteration in DNA methylation aspects still exists, especially in certain unique genomic regions.

Artificial long days and daily contact with bucks induce ovarian but not oestrous activity during the non-breeding season in Mediterranean goat females

The aim of the present study was to determine whether a treatment of 3 mo of artificial long days and daily contact with bucks can stimulate reproductive activity during the normal seasonal anoestrous in female goats, and whether such treatment modifies the onset of the normal breeding season. Thirty-nine adult, open does were assigned to two treatments of similar mean body weight (BW) and body condition score (BCS). One treatment (LD; n = 18) was housed in a light-proof building and exposed to long days (16 h of light/d) from 17 November to 5 February, and then exposed to the natural photoperiod in an open shed. The remaining females were housed in an open shed under natural photoperiod conditions throughout the experiment (control [C]; n = 21). Plasma samples for progesterone, BW and BCS were recorded every wk. Oestrous activity was checked daily using aproned bucks. Bucks were housed close to females in a separate barn from the onset of the experiment. Ovulation rate was determined by laparoscopy 7 d after positive identification of oestrus. The interaction of treatment by time for temporal concentrations patterns of progesterone concentrations indicated that luteal activity in LD does were greater ( P < 0.001) than those of C does during the natural seasonal anoestrous season. None of the C does exhibited oestrous or luteal activity during the non-breeding season; whereas, 72% of LD does exhibited luteal activity only 33% of them showed oestrous activity and during this season ( P < 0.01). Differences in resumption of the oestrous or luteal activity were not observed ( P > 0.05) in the subsequent breeding season between treatments. In conclusion, 3 mo of exposing does to long days and daily contact with bucks during the breeding season appears to stimulate reproductive processes that normal would not occur during the anoestrous season. However, this treatment does not induce oestrus is adequate numbers of does to be of practical value. Finally, this treatment does not modify the onset of the subsequent natural breeding season.

Ultrasonographic Adrenal Gland Measurements in Clinically Normal Small Breed Dogs and Comparison with Pituitary-Dependent Hyperadrenocorticism

Ultrasonography is a sensitive and specific screening method for assessing the adrenal glands. The upper limit of the normal adrenal gland width is used as 7.5 mm. It is not known if adrenal gland width remains consistent with body weight. A reliable criterion of adrenal gland width in small breed dogs should be established. Small breed dogs with body weights of less than 10 kg were divided into two groups: 189 normal dogs and 22 dogs with pituitary-dependent hyperadrenocorticism (PDH). A retrospective study was conducted on dogs seen between January 1, 2006, and February 10, 2008. One hundred eighty-nine dogs of 14 different small breeds were enrolled in the normal adrenal gland group; the median gland width was 4.20 mm. Twenty-two dogs were in the PDH group; the median gland width was 6.30 mm. The cut-off value between normal adrenal glands and PDH was 6.0 mm. This figure gave a sensitivity and specificity of 75 and 94%, respectively, for detecting PDH. The adrenal gland appeared as a peanut shape with homogeneous hypoechoic parenchyma in normal dogs and in most dogs with PDH as well. This study was performed in a large population of small breed dogs and suggests that the normal adrenal gland size in small breed dogs is smaller than previously reported. We believe that a cut-off of 6.0 mm may be used as the criterion for differentiating a normal adrenal gland from adrenal hyperplasia.

Artificial long days in addition to exogenous melatonin and daily contact with bucks stimulate the ovarian and oestrous activity in Mediterranean goat females

One experiment was conducted to determine whether the treatment with artificial long days and exogenous melatonin can induce reproductive activity during spring (seasonal anoestrus) in Mediterranean goats that are in daily contact with bucks and whether this treatment causes a variation in the reactivation of the reproductive activity in the normal breeding season. The experiment started on 4 November 2005 and finished on 27 October 2006. Thirty-four adult and barren does were used, distributed into two groups balanced according to their live weight (LW) and body condition score (BCS). Seventeen females were exposed to long days (16 h of light/day) from 14 November 2005 to 20 February 2006. On 20 February, they received one s.c. melatonin implant (LD-M group) and were exposed to natural photoperiodic changes in an open shed. The other females during the experiment were placed in an open shed under natural photoperiod and remained as the control group (C group). The C and LD-M groups were keeping in contact with males during the whole experiment. During the experiment, the LW, BCS and plasma progesterone concentrations were measured weekly, oestrous activity was tested daily using entire aproned bucks, and ovulation rate was evaluated by laparoscopy 7 days after positive identification of the oestrus. A clear treatment–time interaction was observed for plasma progesterone concentrations (P < 0.001), with a period of high progesterone concentrations during the natural seasonal anoestrus in the LD-M group. Although 94.1% of females in the LD-M group presented ovarian activity during this period, no female in group C did. Resumption of ovarian activity in the subsequent natural breeding season was 2 weeks later in the LD-M group in comparison with group C (P < 0.05). We can conclude that in Mediterranean goat breeding systems, when females are in daily contact with bucks, the treatment with 3 months of long days and melatonin implant at the end of the light photoperiodic treatment can induce ovarian and oestrous activity during the seasonal anoestrus. Finally, this treatment causes a short delay in the subsequent reactivation of ovarian activity in the natural breeding season.

Immunocontraception in wild horses (Equus caballus) extends reproductive cycling beyond the normal breeding season.

BackgroundAlthough the physiological effects of immunocontraceptive treatment with porcine zona pellucida (PZP) have been well studied, little is known about PZP's effects on the scheduling of reproductive cycling. Recent behavioral research has suggested that recipients of PZP extend the receptive breeding period into what is normally the non-breeding season.Methodology/Principal FindingsTo determine if this is the case, we compiled foaling data from wild horses (Equus caballus) living on Shackleford Banks, North Carolina for 4 years pre- and 8 years post-contraception management with PZP (pre-contraception, n = 65 births from 45 mares; post-contraception, n = 97 births from 46 mares). Gestation lasts approximately 11–12 months in wild horses, placing conception at approximately 11.5 months prior to birth. Since the contraception program began in January 2000, foaling has occurred over a significantly broader range than it had before the contraception program. Foaling in PZP recipients (n = 45 births from 27 mares) has consistently occurred over a broader range than has foaling in non-recipients (n = 52 births from 19 mares). In addition, current recipients of PZP foaled later in the year than did prior recipient and non-recipient mares. Females receiving more consecutive PZP applications gave birth later in the season than did females receiving fewer applications. Finally, the efficacy of PZP declined with increasing consecutive applications before reaching 100% after five consecutive applications.Conclusions/SignificanceFor a gregarious species such as the horse, the extension of reproductive cycling into the fall months has important social consequences, including decreased group stability and the extension of male reproductive behavior. In addition, reproductive cycling into the fall months could have long-term effects on foal survivorship. Managers should consider these factors before enacting immunocontraceptive programs in new populations. We suggest minor alterations to management strategies to help alleviate such unintended effects in new populations.

High prevalence of porcine circovirus viremia in newborn piglets in five clinically normal swine breeding herds in North America

Porcine circovirus type 2 (PCV2) can be vertically transmitted resulting in fetal infection with or without clinical signs and lesions. The primary objective of this study was to assess the prevalence of intrauterine PCV2 infection in clinically normal newborn piglets in conventional pork production facilities. Five commercial breeding herds located in the U.S. and Mexico were included in the study. A total of 125 sows and 3–5 neonatal piglets per sow were arbitrarily selected. Blood and colostrum samples were collected from sows. Blood was collected from piglets prior to suckling. All samples were analyzed for the presence of anti-PCV2 IgG antibodies and presence and amount of PCV2 DNA. In addition, PCV2 DNA positive samples were further subtyped into PCV2a and PCV2b. All (125/125) sow colostrum samples and 96.8% (121/125) of the sow serum samples and 21.4% (107/499) of the piglet pre-suckle serum samples were positive for anti-PCV2 IgG antibody. The overall PCV2 DNA prevalence was 47.2% (59/125) in sow serum, 40.8% (51/125) in sow colostrum, and 39.9% (199/499) in pre-suckle piglet serum. In the PCV2 DNA positive samples, PCV2b was detected at a higher frequency (69.5% for sow serum, 84.3% for sow colostrum, and 74.4% for piglet serum) compared to PCV2a (18.6% for sow serum, 9.8% for sow colostrum, and 15.6% for piglet serum). Concurrent PCV2a and PCV2b infection was detected in 11.9% of the sow serum, in 5.9% of the colostrum samples, and in 10.0% of the piglet serum samples. In conclusion, an unexpectedly high prevalence of PCV2 viremia was detected in healthy sows (serum and colostrum) and their pre-suckle piglets in the five breeding herds investigated and PCV2b was more prevalent than PCV2a. This information adds to the knowledge of PCV2 infection in breeding herds.

Relative roles of density and rainfall on the short-term regulation of Mediterraneanwood mouse Apodemus sylvaticus populations

This study aims to quantify the relative effects of density-dependent (feedback structure) and density-independent climatic factors (rainfall) in regulating the short-term population dynamics of wood mice Apodemus sylvaticus Linnaeus, 1758 in three Mediterranean forest plots. Rainfall and density explained additively 62% of variation in population growth rates (38 and 24%, respectively), with no differences among study plots. Population growth rate was positive during autumn–winter and negative during spring–summer during a 2.5-year period. Population rate of change was negatively affected by wood mouse density during the normal breeding season of Mediterranean mice (autumn–winter) but not outside it. Growth rate was positively affected by the cumulative amount of rainfall three months before the normal breeding season, but not during it. Female breeding activity and recruitment did not differ among plots, and was not affected by density or rainfall. However, recruitment was positively affected by density and, marginally, by rainfall. Our results suggest that intraspecific competition (density-dependence) and food availability (rainfall) are equally important factors driving wood mouse population dynamics in Mediterranean forests. Mechanisms underlying density-dependence during the breeding season seemed to be based on food-mediated survival rather than on behaviourally-mediated reproduction. Taken together, these results indicate a high sensitivity of marginal Mediterranean wood mouse populations to the expected climate changes in the Mediterranean region.

Prescrotal Urethrotomy for the Treatment of Urethral Calculi in a Captive Szechuan Bharal (Pseudois nayaur szechuanensis)

A captive 10-month-old male Szechuan bharal (Pseudois nayaur szechuanensis) presented with stranguria and depression. Physical examination, serum biochemistry analyses and radiographic evaluation indicated a urethral obstruction that was successfully treated by prescrotal urethrotomy. Postoperative severe uremia was treated with intravenous fluid administration. Following surgery, the stranguria and depression were resolved. The calculi causing the urethral obstruction were composed of calcium carbonate. As a first-line treatment of this condition, urethrotomy may be preferable over urethrostomy because urethrotomy decreases the risk of urinary tract infection and allows the maintenance of normal physiologic behaviors, including urination and breeding. The bharal has continued to urinate normally for 2 years following surgery.

Cerebral Metabolism in Dogs Assessed by 18F-FDG PET: A Pilot Study to Understand Physiological Changes in Behavioral Disorders in Dogs

The positron emission tomography (PET) imaging technique, which is utilized in human behavior and psychiatric disorder research, was performed on the brains of clinically normal mixed breed dogs, 3 hound-type (long floppy ears) mixed breed dogs and 3 non-hound retriever-type mixed breed dogs. Glucose metabolism was obtained with F-18 fluorodeoxyglucose (FDG), and quantitative analysis was performed by standardized uptake value (SUV) measurement. Magnetic resonance (MR) images were obtained in each dog, and these images were superimposed on PET images to identify anatomical locations. The glucose metabolism in each region of interest was compared between the three hound-type dogs and 3 non-hound-type dogs. The two anatomically different types of dog were compared to assess whether breed-typical behavioral tendencies (e.g., sniffing behavior in hound-type dogs, staring and retrieving in Labrador-type dogs) are reflected in baseline brain metabolic activity. There were no significant differences between the hound-type dogs and non-hound-type dogs in cerebral SUV values. These data might serve as normal canine cerebral metabolism data for FDG PET studies in dogs and form the basis for investigations into behavioral disorders in dogs such as compulsive disorder, anxiety disorders and cognitive dysfunction.