Morphometry,Morphology and Ultrastructure of Ring‐tailed Coati Sperm (Nasua nasua Linnaeus, 1766)

The ring‐tailed coati (Nasua nasua) is a procyonid whose population is in sharp decline. Therefore, studies are needed to better understand the reproduction of this animal. For this reason, this study aimed to evaluate the morphology, morphometry and sperm ultrastructure of ring‐tailed coati sperm. Four captive adult males were used for this study. Slides stained with Bengal Rose were used for the morphometric and morphologic analyses. The length and width of the head were measured, as well as the length of the midpiece and tail and the total length of the sperm. Scanning electron microscopy and transmission electron microscopy were used for the ultrastructural analyses. The most obvious morphological abnormalities observed were coiled tails (6.1 ± 8.7%) and the lack of acrosomes (5.4 ± 4.4%). Regarding the morphometry, the measurements of the head (length × width), midpiece (length) and tail (length) were (mean ± SD) 6.2 ± 0.4 × 8.1 ± 0.6 μm, 14.1 ± 0.5 and 63.9 ± 4.1 μm, respectively, and the total length of the sperm was 86.1 ± 4.3 μm. Through electron microscopy, the presence of electron‐lucent points in the nucleus and the presence of approximately 55 mitochondrial spirals in the midpiece were identified. The data obtained in this study provide detailed information on the sperm characteristics of coatis and may inform future research on germplasm conservation, both for this species and other threatened procyonids.     

Probing the Local Effects of Magnetic Impurities on Superconductivity

The local effects of isolated magnetic adatoms on the electronic properties of the surface of a superconductor were studied with a low-temperature scanning tunneling microscope. Tunneling spectra obtained near magnetic adsorbates reveal the presence of excitations within the superconductor's energy gap that can be detected over a few atomic diameters around the impurity at the surface. These excitations are locally asymmetric with respect to tunneling of electrons and holes. A model calculation based on the Bogoliubov-de Gennes equations can be used to understand the details of the local tunneling spectra.     

The effect of footrot on body weight and wool growth of sheep

Body weight and traits associated with production of wool were measured over a 2-year period between 1985 and 1987 in south-western New South Wales in a flock of Merino wethers experimentally infected with footrot. The disease was allowed to spread freely amongst 150 of the flock but kept at very low prevalence in the remaining 50 by preventive footbathing during transmission periods. Severe, underrunning footrot had a significant adverse effect on body weight, for each year of the trial. Body weight was most severely reduced at times of the year when footrot was spreading among animals and lesions were severe. The mean body weight of the infected group at the end of the 2 years of observation was 7.3 kg (11.6%) below that of the control group. Footrot also depressed wool growth, with the mean clean fleece weight of the infected group being 0.4 kg (8%) lighter than that of the controls at each of the 2 annual shearings. There were no consistent differences between the groups for the other wool characteristics measured.     

A survey of northern Victorian dairy farmers to investigate dairy calf management: colostrum feeding and management

Objectives

To describe colostrum management practices carried out in northern Victorian dairy herds and to identify weaknesses in these areas that may affect calf health and welfare by comparing the results with the current industry recommendations

Methods

A questionnaire to obtain information about colostrum management and calf‐rearing practices was sent to commercial dairy farming clients of Rochester Veterinary Practice between June and September 2013. The questionnaire consisted of a general herd overview and colostrum harvesting practices.

Results

The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) time of removal calf from the dam, (2) relying on calf suckling colostrum from the dam to achieve adequate passive transfer, (3) failing to supplement calves with colostrum, (4) feeding inadequate volumes of colostrum, (5) delayed colostrum harvesting, (6) pooling of colostrum, (7) failing to objectively assess colostrum quality or relying on visual assessment and (8) storing colostrum for a prolonged periods of time at ambient temperatures.

Conclusion

The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.

     

Scrotal circumference,bodyweight and semen characteristics in growing dairy-breed natural-service bulls in Tasmania,Australia

Aims: To provide herd managers with a set of decision rules allowing them to predict the likelihood that a juvenile bull is ready for Bull Breeding Soundness Evaluation (BBSE), or breeding, if bodyweight and scrotal circumference are known.

Methods: This was a longitudinal study following two groups of young pasture-fed Holstein and Jersey bulls from northwest Tasmania, Australia. Individual scrotal circumference, bodyweight and semen characteristics were recorded at 6–8 weekly intervals, from 6–18 months of age. Classification and regression tree analyses were used to predict the probability that a bull had ≥70% normal sperm morphology based on scrotal circumference and bodyweight measurements.

Results: Overall 1,661 scrotal circumference and bodyweight measurements were obtained, and 518 semen samples from 356 bulls were assessed for sperm morphology, from 16 examination sessions that took place between 29 May 2015 and 17 August 2016. Classification and regression tree analyses generated a decision tree for Holstein bulls with four node endpoints, and for Jersey bulls with three node endpoints. Diagnostic test performance showed that for Holstein bulls, using the node endpoints of scrotal circumference ≥27?cm and bodyweight ≥349?kg, 98% had ≥70% normal sperm (positive likelihood ratio 10.4; 95% CI?=?2.7–41), and using the node endpoints of scrotal circumference ≥27?cm and bodyweight between 282–349?kg, 89% had ≥70% normal sperm (positive likelihood ratio 1.6; 95% CI?=?0.9–2.6). For Jersey bulls, using the node endpoints of bodyweight ≥259?kg and scrotal circumference ≥29?cm, 88% had ≥70% normal sperm (positive likelihood ratio 3.4; 95% CI?=?1.6–7.0).

Conclusions: This study provides a set of relatively simple decision rules based on bodyweight and scrotal circumference measurements that allows herd managers to assess the likelihood that juvenile bulls are ready for BBSE or breeding.

Abbreviations: BBSE: Bull breeding soundness evaluation; BRT: Boosted regression tree     

Pathogenesis of reproductive failure induced by Trypanosoma vivax in experimentally infected pregnant ewes

The present study was aimed at investigating the effect of experimental infection by Trypanosoma vivax in different stages of pregnancy, determining the pathogenesis of reproductive failure, and confirming transplacental transmission. We used 12 pregnant ewes distributed into four experimental groups: G1, was formed by three ewes infected with T. vivax in the first third of pregnancy (30 days); G2 comprised three infected ewes in the final third of pregnancy (100 days); G3 and G4 were composed of three non-infected ewes with the same gestational period, respectively. Each ewe of G1 and G2 was inoculated with 1.25 × 10⁵ tripomastigotes. Clinical examination, determination of parasitemia, serum biochemistry (albumin, total protein, glucose, cholesterol, and urea), packed cell volume (PCV), serum progesterone, and pathological examination were performed. Placenta, amniotic fluid, blood and tissues from the fetuses and stillbirths were submitted to PCR. Two ewes of G1 (Ewe 1 and 3) presented severe infection and died in the 34^th and 35^th days post-infection (dpi), respectively; but both fetuses were recovered during necropsy. In G2, Ewe 5 aborted two fetuses on the 130^th day (30 dpi) of pregnancy; and Ewe 6 aborted one fetus in the 140^th day (40 dpi) of gestation. Ewes 2 and 4 delivered two weak lambs that died five days after birth. Factors possibly involved with the reproductive failure included high parasitemia, fever, low PCV, body score, serum glucose, total protein, cholesterol, and progesterone. Hepatitis, pericarditis, and encephalitis were observed in the aborted fetuses. The presence of T. vivax DNA in the placenta, amniotic fluid, blood, and tissues from the fetuses confirms the transplacental transmission of the parasite. Histological lesion in the fetuses and placenta also suggest the involvement of the parasite in the etiopathogenesis of reproductive failure in ewes.     

Anti‐Mullerian Hormone Concentration and Antral Ovarian Follicle Population in Murrah Heifers Compared to Holstein and Gyr Kept Under the Same Management

This study was performed to evaluate plasma concentrations of anti‐Mullerian hormone (AMH) and the ovarian antral follicle population (AFP) in different genetic groups. Cyclic heifers (13 Bubalus bubalis [Murrah]; 15 Bos taurus [Holstein] and 10 Bos indicus [Gyr]) were maintained under the same management and were synchronized with two doses of 150 μg IM d‐cloprostenol administered 14 days apart. After the second d‐cloprostenol treatment, heifers had their ovaries scanned daily by ultrasound to define the day of ovulation. On the same day, the AFP was determined and a plasma sample was collected to measure AMH. Murrah heifers had less AFP (25.6 ± 2.1 follicles; p = 0.01) and plasma AMH concentration (0.18 ± 0.03 ng/ml; p < 0.001) than Gyr (60.0 ± 12.2 follicles and 0.60 ± 0.12 ng/ml of AMH); however, data were similar when compared to Holstein (35.9 ± 6.8 follicles and 0.24 ± 0.06 ng/ml of AMH) heifers. Regardless of genetic background, there was a positive relationship between the AFP and plasmatic AMH concentration (Murrah [r = 0.62; p < 0.01], Holstein [r = 0.66; p < 0.001] and Gyr [r = 0.88; p < 0.001]). Also, when heifers were classified according to high‐ or low‐AMH concentration based on the average within each genetic group, high‐AMH heifers had greater (p < 0.0001) AFP than low‐AMH heifers. In conclusion, both Murrah and Holstein heifers presented lower plasma AMH concentration and AFP when compared to Gyr.     

Functional Activity of Frozen Thawed Chinchilla lanigera Spermatozoa Cryopreserved with Glycerol or Ethylene Glycol

The cryopreservation of spermatozoa constitutes a valuable tool for the captive breeding management of valuable and/or threatened species. Chinchilla lanigera is a species almost extinct in the wild, and the domestic counterpart has one of the most valuable pelts in the world. The objectives of this study were to: (i) compare the functional activity of post‐thawed chinchilla spermatozoa cryopreserved at ?196°C either with glycerol (G) or ethylene glycol (EG) as cryoprotectants (1 m final concentration) and (ii) investigate the effects of incubating the gametes for 4 h in the presence or in the absence of the cryoprotectants; evaluations were performed taking into account motility, viability, response to hypo‐osmotic shock and acrosome integrity of the cells. Parameters reflecting post‐thaw (0 h) sperm functional activity were significantly lower than those of freshly ejaculated gametes. When comparing the cryoprotectant efficiency of G vs EG, neither cryoprotectant agent offered appreciable advantages. After 4 h of incubation, in the presence or absence of the cryoprotectant agent, a rapid and significant decrease was found in all functional parameters and remained at ～ 20–30% motile, viable and viable acrosome intact cells. Viability was significantly lower when the cryoprotectant was removed from the media (possibly due to the centrifugation process). With respect to the maintenance of sperm membrane integrity, only ～ 10% of cells showed membrane resistance to hypo‐osmotic conditions after the 4 h incubation period. These results constitute new insights for cryopreservation protocols and the development of assisted reproductive techniques in this species.