Captive breeding does not alter brain volume in a marsupial over a few generations.

Captive breeding followed by reintroduction to the wild is a common component of conservation management plans for various taxa. Although it is commonly used, captive breeding can result in morphological changes, including brain size decrease. Brain size reduction has been associated with behavioral changes in domestic animals, and such changes may negatively influence reintroduction success of captive-bred animals. Many marsupials are currently bred in captivity for reintroduction, yet the impacts of captive breeding on brain size have never been studied in this taxa. We investigated the impacts of a few generations (2-7) of captive breeding on brain volume in the stripe-faced dunnart (Sminthopsis macroura), and found that captive breeding in a relatively enriched environment did not cause any changes in brain volume. Nonetheless, we advocate that great care be taken to provide suitable husbandry conditions and to minimize the number of captive generations if marsupial reintroduction programs are to be successful.

The ecdysone-induced puffing cascade in Drosophila salivary glands: a Broad-Complex early gene regulates intermolt and late gene transcription.

The steroid hormone 20-OH ecdysone triggers a classic and well-defined program of chromosome puffing that is assumed to reflect changes in transcriptional activity in Drosophila salivary glands. Mutations in each of four Broad-Complex locus (BR-C) complementation groups were analyzed for their effects on the expression of other genes that reside in several major salivary gland puffs. RNA blot analysis showed that the rbp function of the BR-C is required for the transcription of six genes in the 71E late puff and is the first demonstration that an ecdysone-induced early gene controls the transcription of late genes within the puffing cascade. In addition, the rbp function is required for the transcription of four intermolt genes (Sgs-3, Sgs-4, Sgs-5 and 71E gene VII). Mutations in the broad, l(1)2Bc and l(1)2Bd functions of the BR-C had no effect on the expression of the genes examined. We propose that the BR-C functions to control transcription at many other salivary gland loci at the beginning of metamorphosis.

Superovulatory and endocrine responses in holstein heifers treated with either prostaglandin F(2alpha), cloprostenol or fenprostalene.

Fifty Holstein heifers were each superovulated three times with FSH-P. At 60 h after the first injection of FSH-P, the animals received either prostaglandin F(2alpha), cloprostenol or fenprostalene in random order. A significant decrease in serum progesterone and a significant increase in serum estradiol-17beta were observed within 24 h of prostaglandin injection, but there were no significant differences among the three treatments. Neither were there any significant differences among the treatments with respect to the frequency of nonresponse to FSH-P treatment, nor the total number of ova/embryos collected between Days 6 and 8 of gestation.

Estrus induction with prostaglandin F2alpha, cloprostenol or fenprostalene during the normal estrous cycle, superovulation and after embryo collection.

Holstein heifers used as embryo donors were treated with three luteolytic agents (PGF2alpha, cloprostenol, fenprostalene) during the normal estrous cycle, superovulation or after embryo collection to determine the interval from treatment to estrus. A similar return-to-estrus interval was observed for each luteolytic agent among the three groups of heifers. Nevertheless, after embryo collection, fenprostalene had a tendency to induce the longest delays (p = 0.08). This tendency is supported by a higher proportion of delayed luteolysis and more heifers showing estrus later than 11 d post treatment. Also, during normal estrous cycles, 5/10 and 0/8 fenprostalene- and cloprostenol-treated heifers, respectively, showed progesterone concentrations higher than 1 ng/mL 48 h after treatment. Regardless of the luteolytic agent used, estrus was induced earlier (P < 0.005) during superovulation than when heifers were treated between Days 9 to 16 of the normal estrous cycle or after embryo collection. However, the return-to-estrus interval was similar between heifers treated during superovulation and those treated between Days 6 to 8 of the normal estrous cycle. After embryo collection, intervals before the return to estrus increased with the number of Corpora lutea (CL) palpated except in the nonresponding group (0 to 1 CL), which returned to estrus later than the low responding group (2 to 4 CL).

Assessment of embryo potential by visual and metabolic evaluation.

Morphological evaluation of embryos is essential to the success of embryo transfer procedures and is presumed to reflect embryo metabolic activity. To investigate this assumption, correlations between morphological and metabolic parameters were determined for cultured murine morulae. After 18 h (n = 47) or 36 h (n = 48) of culture in M16, the developmental rate and quality (poor or good) of embryos were estimated, and, then, either their (14)C-glucose utilization or (35)s-methionine uptake and incorporation were measured. Retarded developing, or poor-quality embryos had lower mean glucose utilization, uptake and incorporation rates than normally developing or good-quality embryos (P < 0.05). After 18 h of culture, an association was found between developmental rate and metabolic activity, but this was not evident after 36 h of culture. Similarly, an association was found between embryo quality and metabolic activity. As expected, poor embryo quality was indicative of low metabolism throughout the culture period, but good quality did not necessarily indicate normal metabolic activity. Thus, morphological parameters do not always reflect metabolic competence, and some functional defects were not detectable by visual evaluation alone. Measuring metabolic parameters could complement visual evaluation for a better selection of embryos prior to transfer.

Seasonality and variability of the interestrous interval in the bitch.

Records from two breeding colonies (A and B) located near each other were analyzed for this experiment. Colony A consisted of 19 bitches (8 Maltese, 5 Yorkshire, 3 Lhasa Apso, and 3 Bouvier des Flandres), while Colony B consisted of 48 Beagle bitches. A total of 126 interestrous intervals (141 estrous cycles) from Colony A were reviewed to quantitate the variability of the interestrous interval. Analysis of variance showed that the degree of variation of the estrous cycle length within bitches (65%) was about twice the degree of variation of means of the estrous cycle length among bitches (35%). It was found that the estrous cycle length is extremely variable, and it cannot be used to predict the next estrus in a single bitch, although some bitches were very consistent. The seasonal and monthly distribution of estrous cycles throughout the year was also analyzed from bitches kept in Colonies A and B for a total of 210 estrous cycles. The data were collected over a four-year period. A seasonal pattern was observed when the cumulative distributions over years were analyzed. A higher frequency of estrous cycles was observed during winter and summer. This seasonality pattern was not observed when individual years were analyzed separately. However, the overall probability that an estrus would occur at any month of the year was the same for each month (1/12) when cumulative distribution over years were analyzed.

Effect of glycerol on motility, viability, extracellular aspartate aminotransferase release and fertility of stallion semen before and after freezing.

The effect of different glycerol concentrations (0 to 5.3 per cent) on motility, viability and aspartate aminotransferase (AST) release of stallion spermatozoa was studied before and after deep-freezing. Addition of glycerol to a TRIS-fructose-egg yolk diluent used to extend stallion semen had no effect on motility and viability of spermatozoa and it did not increase AST release. Inclusion of glycerol in the extender only partially preserved the motility and viability of stallion semen during deep-freezing. A fertility trial revealed that concentrating stallion semen by centrifugation, followed by addition of the extender containing 7.5 per cent glycerol, had little effect on fertility and a 70 per cent conception rate was obtained in 10 mares after inseminations during one service period. Freezing and thawing horse spermatozoa, even in the presence of 7.5 per cent glycerol, significantly decreased the fertilisation rate.

The effectiveness of gentamicin or polymyxin B for the control of bacterial growth in equine semen stored at 20 degrees C or 5 degrees C for up to forty-eight hours.

Semen from three stallions was used to evaluate the effectiveness of two antibiotics added to semen extender for samples stored at 20 degrees C or 5 degrees C for up to 48 hours. Each ejaculate was divided into six different treatments: semen+extender (SE); SE+gentamicin (100 micrograms/mL); SE+polymyxin B (1000 units/mL); and each of the above treatments inoculated with Pseudomonas aeruginosa ATCC 27853. Sampling of diluted semen for bacteriological analysis was performed after 2, 8, 24 and 48 hours of preservation at either temperatures. The presence of nonspecific bacteria was noted after two hours in all SE aliquots. The number of bacteria did not change in samples stored at 5 degrees C, while in samples preserved at 20 degrees C, it increased by three to four times after 48 hours. In semen aliquots treated with either of the antibiotics, the number of nonspecific bacteria was very low after two and eight hours at both temperatures. This number remained stable up to 48 hours at 5 degrees C, while an increase was noted at 24 and 48 hours at 20 degrees C. At 5 degrees C, the number of P. aeruginosa cells tended to decrease between 24 and 48 hours in SE aliquots. The presence of gentamicin or polymyxin B appeared to rapidly inhibit growth of P. aeruginosa. At 20 degrees C, growth of P. aeruginosa increased between 8 and 24 hours in SE, while the presence of antibiotics almost completely inhibited the growth of the bacterium.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro viability of cryopreserved equine embryos following different freezing protocols.

The main objective of this study was to evaluate two freezing protocols and the effect of agar embedding on survival of day 6.5 equine embryos. A total of 133 embryos were used, in one group (n = 51), embryos were first embedded in agar before the freezing protocol was started. A freezing protocol to -30 degrees C or -33 degrees C was used before plunging embryos into liquid nitrogen (LN2). The embryos were thawed in water at 37 degrees C, evaluated and placed in culture. After 24 h culture, the embryos were evaluated for their morphology and development. No differences were observed between embryos plunged at -30 degrees or at -33 degrees C in LN2. The analysis of the morphology and development after thawing showed that the diameter and developmental stage at freezing correlated with embryo survival. Morula and early blastocyst stages of development were associated with better quality after freezing and thawing and had a better potential to survive after in vitro culture (p < 0.05) compared to more advanced stages. The agar failed to protect embryos from zona pellucida damage, but a tendency to prevent rupture was observed in larger embedded embryos.

Growth and metabolism of murine and bovine embryos in bovine uterine flushing-supplemented culture media.

The aim of this study was to compare the development and metabolic activity of cultured murine and bovine embryos in 2 standard media (HAM F-10 and RPMI) in the presence or absence of bovine uterine flushings. Murine morulae (n = 653) and day 7 bovine embryos (n = 273) were cultured for 18 h or 36 h in either HAM F-10 or RPMI in the presence or absence of bovine uterine flushings. After culture, the development, quality, and metabolic activity (glucose utilization or methionine uptake and incorporation) of embryos was assessed. It was found that HAM F-10 (without uterine flushings) was a more suitable medium than RPMI for optimal development and metabolism of murine and bovine embryos. Poor quality and development, as well as decreased metabolism, were evident after culture of murine embryos in RPMI; in contrast, this medium had no adverse effects on bovine embryos in culture. Supplementation of HAM F-10 with bovine uterine flushings improved the growth of murine embryos and the protein synthesis (as measured by an increased methionine incorporation) for both murine and bovine embryos. However, supplementation with bovine uterine flushings could not overcome deficiencies of an inappropriate medium (RPMI) for murine embryos. Supplementation of a well-defined culture medium with uterine flushings increased metabolism of embryos in culture, and thus might help to increase pregnancy rates after transfer of such embryos to recipient cows.

Penicillin concentrations in serum, milk, and urine following intramuscular and subcutaneous administration of increasing doses of procaine penicillin G in lactating dairy cows.

Eight healthy, non-pregnant, crossbred Holstein dairy cows (557-682 kg) within their first 3 months of lactation (13-21.5 kg of milk/day) were used. Cows were kept in tie stalls for the whole experiment. The 8 cows were randomly assigned to 2 (IM and SC) 4 x 4 balanced Latin square design experiments. Doses of procaine penicillin G (PPG) (300000 IU/mL) in each square were 7000, 14000, 21000 and 28000 IU/kg and were injected IM or SC once daily for 5 consecutive days. Volumes of PPG per site of injection never exceeded 20 mL. Blood was collected to determine the Cmax, Tmax, and AUC; urine and milk were also taken to measure the persistence of PPG in these fluids. Results show that serum Cmax and Tmax were only slightly affected by increasing the doses or the route of administration, whereas the AUC was linearly increased in relation to the dose injected in both modes of injection. In the urine, Cmax varied from 160 to 388 IU/mL and Tmax from 72-120 h during 5 consecutive days of PPG injection. A dose effect in Cmax was observed only for the IM route of administration and no variation (P > 0.05) was found between the IM and SC routes. Milk Cmax concentrations were only increased by the dose regimen in the IM group. At doses of 21000 and 28000 IU/kg, the IM group had a higher (P > 0.05) Cmax when compared with the SC groups. Milk PPG residues were not detectable over 96 h following the last IM injection, independently of the dose injected. However milk PPG residues were detected for up to 132 h following the last SC injection. These results show that when PPG is injected IM once daily in volumes not exceeding 20 mL/site at doses as high as 28000 IU/kg, the withdrawal period should be at least 96 h. Therefore, in the present model, there was no advantage to inject PPG by SC route to improve PPG kinetic parameters as the AUC, Cmax, or Tmax.

Failure to maintain luteal function: a possible cause of early embryonic loss in a cow.

The effect of early pregnancy failure on the release of prostaglandin F2 alpha (PGF2 alpha) in response to oxytocin (Ot) was examined in an abnormal breeder (AB) heifer that was not able to maintain a pregnancy beyond 21 days. This animal was used in three experiments: 1) She received one intravenous injection of 100 IU Ot 17 days after the onset of oestrus (Day 0). Frequent blood samples were taken for the measurement of 15-keto-13,14-dihydro-PGF2 alpha (PGFM) by radioimmunoassay. Daily samples for progesterone (P4) determinations were taken to monitor luteal function. This was then repeated using the same animal at either day 17 or 18 or 19 (day 17-19) of pregnancy. 2) Embryos from superovulated normal breeder (NB) donors were transferred at day 7 to the AB heifer as well as to NB control animals. 3) Seven day old embryos from the superovulated AB heifer were transferred to NB recipient animals. At day 17-19 of pregnancy all the recipient heifers (experiments 2 and 3) were subjected to the same protocol as in experiment 1. The results showed that the ability of Ot to stimulate PGF2 alpha release was reduced in the NB recipients bearing viable embryos when compared to cyclic animals. However, for the AB heifer, Ot stimulated PGF2 alpha release to the same extent whether the animal was cyclic or pregnant. Furthermore, the AB animal did not have the extended luteal function associated with removal of viable embryos on day 17-19. The data suggest that the embryonic loss might have been caused by failure of the embryos to prevent the luteolytic release of PGF2 alpha.

Counterimmunoelectrophoresis for the diagnosis of bovine mycoplasmosis.

Counterimmunoelectrophoresis (CIE) procedure has been established for mycoplasma identification from cultures, and the specificity and the sensitivity of this technique were evaluated. Preparations of milk samples and clinical and necropsy specimens were used for the technique. From 171 milk samples, 80 (46.8%) were positive by CIE (73 samples with Mycoplasma bovis and 7 with Mycoplasma arginini) and 77 (45%) were positive by biochemical and growth inhibition tests (70 samples with Mycoplasma bovis and 7 with Mycoplasma arginini). From 36 mycoplasma culture-positive clinical and necropsy specimens, CIE identified 5 different mycoplasma species and from 3 mycoplasma culture-positive specimens, the technique identified coinfection by 2 mycoplasma species. The CIE is a reliable, specific, sensitive, and rapid technique for the diagnosis of mycoplasmosis in the bovine.

A study of the equivalence between rectal palpation, laparoscopy, laparotomy and ovarian dissection for evaluation of the ovarian response of PMSG-superovulated cows.

The PMSG-superovulatory response was determined by ovarian dissection in 20 cows and compared with estimates made by laparoscopy laparotomy and rectal palpation at day 7 of the induced estrus. The corpora lutea count made transrectally seriously underestimated real corpora lutea numbers when more than nine corpora lutea were present. Rectal palpation failed to correctly identify the number of follicles >/= 10 mm when more than four follicles were present. After ovarian dissection, laparotomy was the most constant and accurate method to obtain the number of ovulations, followed by laparoscopy. The excessive weight and the large size of the ovaries associated with the presence of large unovulated luteinized follicles were often responsible for the erroneous estimates of the ovulation rate by rectal palpation.

Metritis following parturition: serum progesterone and 17 beta-oestradiol levels. The significance of the corpus luteum and the advisability of using a luteolytic agent as a treatment.

A group of 22 postpartum Holstein Friesian cows showing abnormal uterus were divided into two groups and treated with a) PGF(2)alpha or b) diethylstilboestrol and oxytocin. Most blood P(4) values were under 0.5 ng/mL whereas E(2) blood level was higher than in normal cycling cows. The report emphasizes the need for a careful clinical examination in order to apply the proper therapy.

[Ecbolic and hormonal action of synthetic prostaglandin F2a in fetal mummification in two Holstein cows (author's transl)]. / Actions ecbolique et hormonale de la prostaglandine F2a synthétique lors de momification foetale chez deux vaches Holstein.

Ecbolic and Hormonal Action of Synthetic Prostaglandin F(2)a in Fetal Mummification in Two Holstein CowsThe effects of treatment with synthetic prostaglandin F(2)a (500mug i.m.) to correct cases of fetal mummification in two Holstein cows are described.

Waterbird movement across the Great Dividing Range and implications for arbovirus irruption into southern Victoria.

BACKGROUND: Waterbirds are the major hosts of various arboviruses. Murray Valley encephalitis virus (MVEV) is an arbovirus native to northern Australia, the major hosts of which are Phalacrocoraciformes (cormorants), Ciconiiformes (herons) and other waterbirds. MVEV is transmitted to humans by mosquitoes and can cause acute encephalomyelitis. In Victoria, MVEV is restricted to the northern side of the Great Dividing Range (GDR), suggesting that waterbirds cannot cross the high country. METHODS AND RESULTS: We tested this hypothesis by analysing data on waterbird banding and recovery and discovered that 12 species can cross the GDR. CONCLUSION: Waterbirds have the potential to carry arboviruses, including MVEV, into southern Victoria.