Changes in accessory sex glands of stallions after sexual preparation and ejaculation

Ultrasonographic images of the accessory sex glands of 8 stallions were recorded immediately prior to sexual preparation, immediately after sexual preparation, and immediately after ejaculation. Relative size changes, determined by measurements of ultrasonograms of accessory sex gland, were contrasted. Length and width of the bulbourethral glands increased significantly (P less than 0.05) after sexual preparation and decreased significantly (P less than 0.05) after ejaculation. The increase in bulbourethral gland volume following sexual preparation was correlated significantly (P less than 0.01) with the number of false mounts attempted by stallions during sexual preparation. Diameter of the pelvic portion of the urethra did not change significantly (P greater than 0.05) after sexual preparation or after ejaculation. Prostate gland lobular and isthmic thickness increased significantly (P less than 0.05) after sexual preparation and decreased significantly (P less than 0.05) after ejaculation. Total and lumenal diameter of the ampullae increased significantly (P less than 0.05) after sexual preparation and decreased significantly (P less than 0.05) after ejaculation. Diameter of the ampulla wall did not change significantly (P greater than 0.05) after sexual preparation or ejaculation. Reduction of the lumenal area of the ampullae after ejaculation was not correlated (P greater than 0.05) to concentration of spermatozoa or total spermatozoa per ejaculate. Total and lumenal diameters of the vesicular glands increased significantly (P less than 0.05) after sexual preparation and decreased significantly (P less than 0.05) after ejaculation. Diameter of the vesicular gland wall did not change significantly (P greater than 0.05) after sexual preparation or ejaculation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of breed of cattle on innate resistance to infection with <i>Babesia bovis, B bigemina and Anaplasma marginale

Objective To assess the innate resistance of naive Bos taurus, Bos taurus cross Bos indicus and Bos indicus cattle to virulent Babesia bovis, B bigemina and Anaplasma marginale parasites. Design Groups of 10, pure B indicus, fi B indicus cross,/B indicus cross and pure B taurus steers were infected with virulent B bovis, B bigemina and A marginale parasites. Procedure Sequential infections were carried out by intravenous inoculation of infected blood containing 1 times 10⁸ parasites of B bovis, followed by B bigemina and then A marginale. To assess resistance, measurements were made of parasitaemia, rectal temperature, packed cell volume and the number within a group requiring chemotherapy to control infection. There was a recovery period between each infection. Results Infection with B bovis showed that pure B indicus steers were significantly more resistant to B bovis infection than the other groups, with none of this group requiring treatment. There was no significant difference between fi B indicus cross and/B indicus cross with 30% and 20%, respectively, of steers in these groups requiring treatment. The pure B taurus steers were significantly more affected then those in the other three groups with 80% requiring treatment. Infections of B bigemina produced a mild response in comparison to that of B bovis and none of the steers required treatment. However, the pure B taurus group was significantly more affected than the other three groups for all other measurements. After the A marginale infection, B indicus steers were moderately affected with 50% requiring treatment, whereas 70% of the fi B indicus group, 80% of the /B indicus cross group and 100% of the pure B taurus group required treatment. Conclusions All breeds of cattle, ranging from pure B indicus to pure B taurus may be at risk of severe disease if exposed to virulent A marginale. The results confirm that pure B indicus cattle are relatively resistant to B bovis, but there could be a significant risk of severe mortalities if cross-bred herds are exposed to virulent infection.     

Does Fusarium‐caused seed mortality contribute to Bromus tectorum stand failure in the Great Basin?

Bromus tectorum (cheatgrass, downy brome) is an important invader in western North America, dominating millions of hectares of former semi‐arid shrubland. Stand failure or ‘die‐off’ is relatively common in monocultures of this annual grass. The study reported here investigated whether soil‐borne pathogens could be causal agents in die‐offs. Soils from two die‐off areas and adjacent B. tectorum stands were used in a glasshouse experiment with sterilised and non‐sterilised treatments. Soil sterilisation did not increase emergence, which averaged 80% in both die‐off and non‐die‐off soils. Seedling biomass was higher in die‐off soils, probably due to increased nitrogen availability. Fusarium was isolated from 80% of killed seeds in non‐sterilised soil treatments. In pathogenicity tests with 16 Fusarium isolates, host seeds incubated under water stress (?1.5MPa for 1 week prior to transfer to free water) suffered over twice the mortality of seeds incubated directly in free water (25–83% with water stress vs. 5–43% without water stress). These results suggest that soil‐borne Fusarium could play a role in B. tectorum stand failure in the field, but that low water stress conditions in the glasshouse experiment were not conducive to high levels of disease. Pathogenic Fusarium isolates were obtained from seeds planted in both die‐off and non‐die‐off soils, suggesting that microenvironmental factors that affect levels of water stress might be as important as relative abundance of soil‐borne pathogens in mediating spatial patterns of disease incidence in the field.     

Effects of restricted feeding of beef heifers during the postweaning period on growth, efficiency, and ultrasound carcass characteristics

Traits used for identification of replacement beef heifers and feeding levels provided during postweaning development may have major financial implications due to effects on maintenance requirements and level of lifetime production. The current study evaluated the effects of 2 levels of feeding during the postweaning period on growth, G:F, and ultrasound carcass measurements of heifers, and the associations among these traits. Heifers (1/2 Red Angus, 1/4 Charolais, and 1/4 Tarentaise) born in 3 yr were randomly assigned to a control (fed to appetite; n = 205) or restricted (fed at 80% of that consumed by controls adjusted to a common BW basis; n = 192) feeding during a 140-d postweaning period. Heifers were individually fed a diet of 68% corn silage, 18% alfalfa, and protein-mineral supplement (DM basis) in pens equipped with Calan gates. Ultrasound measurements of LM area, intramuscular fat, and subcutaneous fat thickness over the LM were made on d 140 (382 +/- 0.8 d of age). Average daily DMI was 4.1 and 5.6 kg/d for restricted and control heifers, respectively (P < 0.001). Feed restriction decreased (P < 0.001) BW (292 vs. 314 kg), ADG (0.52 vs. 0.65 kg/d), LM area (55 vs. 59 cm2), intramuscular fat (3.2 vs. 3.5%), and subcutaneous fat thickness over the LM (3.2 vs. 3.9 mm), but increased G:F (0.12 vs. 0.11) when compared with control at the end of the 140-d study. The magnitude of the associations of DMI with ADG (r = 0.32 vs. 0.21), 140-d BW (r = 0.78 vs. 0.36), hip height (r = 0.57 vs. 0.17), LMA (r = 0.30 vs. 0.18), and BCS (r = 0.17 vs. 0.11) was greater in restricted- than control-fed heifers. Variance of residual feed intake, calculated within each treatment, was greater (P < 0.01) in control (0.088) than restricted (0.004) heifers, and magnitude of association between residual feed intake and average DMI was greater in control (r = 0.88) than restricted (r = 0.41) heifers. Pregnancy rate tended (P = 0.11) to be reduced in heifers that had been developed on restricted feeding (86.3 +/- 2.3 vs. 91.5 +/- 2.3%). However, ADG was greater (P < 0.001) in restricted than control heifers (0.51 vs. 0.46 kg/d) while grazing native range in the 7 mo after restriction. In summary, restricted heifers consumed 22% less feed on a per-pregnant-heifer basis during the development period and had a greater magnitude of association between DMI and several growth-related traits at the end of the 140-d postweaning feeding period, which is indicative of improved efficiency.     

Synchronization of ovulation using GnRH or hCG with the CO-Synch protocol in suckled beef cows.

The objectives of this study were to evaluate replacing GnRH with hCG and the effects of 48-h calf removal (CR) on pregnancy rates of cows synchronized with the CO-Synch protocol. Suckled beef cows (n = 467) at two locations were assigned to treatment by breed, age, and calving date. Treatment included either GnRH with (n = 121) or without CR (n = 117) or hCG with (n = 115) or without CR (n = 114) using the CO-Synch protocol. On d 0 and 9, cows received either hCG (2,500 IU, i.m.) or GnRH (100 microg, i.m.), and on d 7 all cows received PGF2alpha (25 mg). At one location, blood samples were collected from all cows (n = 203) on d -14, -7, 0, 7, 9, and 16. Calves were removed on d 7 and returned on d 9 (48 h) from approximately half of the cows that received GnRH or hCG. Cows that were detected in estrus between d 6 and 9 were bred approximately 12 h later and received no further injections. Cows not observed in estrus by d 9 received a second injection of either GnRH or hCG and were timed-inseminated. The AI pregnancy rates for GnRH-treated cows with or without CR and hCG-treated cows with or without CR were 46, 49, 35, and 34%, respectively (P = 0.44). Pregnancy rates of cows differed by treatment x age interaction (P = 0.07), hormone (P = 0.09), and hormone x age (P = 0.01) but not by CR (P = 0.66) or CR x age (P = 0.33). Among 2-yr-olds, pregnancy rates were higher for cows treated with hCG without CR than for cows that received GnRH with calf removal, whereas cows treated with hCG with CR and GnRH without CR were intermediate. In addition hCG-treated 2-yr-olds had higher pregnancy rates than GnRH-treated 2-yr-olds regardless of calf presence, but the reverse was true for older cows. Overall, GnRH-treated cows (48%) had a higher (P = 0.09) pregnancy rate than hCG-treated cows (34%). Among anestrous cows, GnRH and hCG were similar (P = 0.40) in their ability to induce ovulation and corpus luteum formation after the first and second injections of GnRH (31 and 76%, respectively) or hCG (39 and 61%, respectively). More (P = 0.001) hCG-treated cows exhibited short estrous cycles following timed AI. We conclude that hCG is not a suitable replacement for GnRH to synchronize ovulation with the CO-Synch protocol in multiparous cows, although further evaluation among primiparous cows is warranted using hCG with the CO-Synch protocol.     

Atlanto Axial Subluxation in the Canine

Abstract— A slowly progressive subluxation of the atlanto-axial articulation has been seen in ten dogs of various small breeds. Lateral radiographs show the obvious vertebral displacement and clearly confirm the diagnosis. Surgical repair has been accomplished by wiring the atlas to the axis in the last three dogs.
Résumé— Une subluxation progressive, lente de l'articulation atlantoaxiale a été trouvée dans 10 chiens de races variées, tous de type "petit-chien". Des radiographies latérales montrent un déplace-ment vertébral évident et confirment clairement le diagnostique. L'intervention chirurgicale a été accomplice par fixation par fils métalliques de l'atlas à l'axis, chez les 3 derniers chiens.
Zusanunenfassnng—Eine langsam fortschreitende Subluxation des Atlas-Epistropheus- Gelenkes wurde bei 10 kleinrassigen Hunden beobachtet. Seitliche Röntgenaufnahmen zeigen die offen-sichtliche vertebrale Verlagerung und bestätigen einwandfrei die Diagnosis. Chirurgische Behand-lung bei den letzten drei Hunden war erfolgreich, indem der Atlas mit Draht in der richtigen Stellung an den Epistropheus befestigt wurde.     

Relative importance of vision and olfaction for detection of estrus by bulls.

The objective of this experiment was to determine the relative importance of olfaction and visual observation of heifer mounting behavior to the detection of estrus by bulls. An observation pen was designed to allow the evaluation of the preference of five sexually experienced bulls under three sets of stimuli. The observation pen was 4 m x 17 m with a smaller enclosure (2 m x 4 m) at each end that housed either a pair of heifers in diestrus (D), a pair of heifers in estrus that were allowed to mount one another (EM), or a pair of heifers in estrus that were separated by an aluminum panel to prevent mounting behavior (E). The preference of bulls was determined between EM heifers compared to D heifers, EM heifers compared to E heifers, and E heifers compared to D heifers. Each bull was individually allowed 5 min inside the observation pen to demonstrate its preference. Preference was defined as the total time that bulls spent within 2.5 m of either pair of heifers. Each bull was subjected to 10 observation periods of each set of stimuli during a 4-mo period. Bulls preferred to be near EM heifers compared with either E or D heifers (P less than .05). However, the bulls demonstrated no preference (P greater than .05) for E heifers compared with D heifers. These data indicate that when physical contact is denied, bulls use visual observation of female homosexual behavior as the primary indicator of estrus and that olfaction alone provides insufficient stimuli for bulls to indicate preference toward heifers in estrus compared with heifers in diestrus.     

Kepler-36: a pair of planets with neighboring orbits and dissimilar densities

In the solar system, the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal and that planets' orbits can change substantially after their formation. Here, we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10% and densities differing by a factor of 8. One planet is likely a rocky "super-Earth," whereas the other is more akin to Neptune. These planets are 20 times more closely spaced and have a larger density contrast than any adjacent pair of planets in the solar system.     

The effect of Psoroptes ovis infestation on ovine epidermal barrier function

Sheep scab is an intensively pruritic, exudative and allergic dermatitis of sheep caused by the ectoparasitic mite Psoroptes ovis. The purpose of the present study was to investigate the effect of P. ovis infestation on different components of the ovine epidermal barrier within the first 24 hours post-infestation (hpi). To achieve this, the expression of epidermal differentiation complex (EDC) genes and epidermal barrier proteins, the nature and severity of epidermal pathology and transepidermal water loss (TEWL) were evaluated.By 1 hpi a significant dermal polymorphonuclear infiltrate and a significant increase in TEWL with maximal mean TEWL (598.67 g/m²h) were observed. Epidermal pathology involving intra-epidermal pustulation, loss of epidermal architecture and damage to the basement membrane was seen by 3 hpi. Filaggrin and loricrin protein levels in the stratum corneum declined significantly in the first 24 hpi and qPCR validation confirmed the decrease in expression of the key EDC genes involucrin, filaggrin and loricrin observed by microarray analysis, with 5.8-fold, 4.5-fold and 80-fold decreases, respectively by 24 hpi.The present study has demonstrated that early P. ovis infestation disrupts the ovine epidermal barrier causing significant alterations in the expression of critical barrier components, epidermal pathology, and TEWL. Many of these features have also been documented in human and canine atopic dermatitis suggesting that sheep scab may provide a model for the elucidation of events occurring in the early phases of atopic sensitisation.     

Evidence for macrocyclic lactone anthelmintic resistance in Dirofilaria immitis

Reports of loss-of-efficacy (LOE) events in dogs infected with Dirofilaria immitis despite adherence to accepted prophylaxis regimens with a macrocyclic lactone anthelmintic are attracting considerable attention. It is crucially important to distinguish among several possible causes for these LOE reports, one of which is the evolution of resistance to these drugs in heartworms. We review here recent evidence at the molecular level that supports the hypothesis that parasites derived from LOE cases have experienced a strong selection event and that these populations are characterized by very high frequencies of single-nucleotide polymorphisms in a D. immitis gene encoding a P-glycoprotein transporter, comprised of homozygous guanosine residues at 2 locations ("GG-GG" genotype). Furthermore, an infected dog adopted to Canada from the southern United States harbored a microfilarial population that was insensitive to very high doses of macrocyclic lactones and was characterized by a high frequency of the GG-GG genotype associated with LOE cases. We propose that this case be defined as a drug-resistant heartworm infection and suggest that a simple assay for the existence of resistant parasites is a 7-day microfilariae suppression test, which can be performed in a veterinary clinic as part of an effort to document the geographic distribution of this phenotype.