Efficacy of a mephentermine‐based product as a vasopressor and a cardiac performance enhancer when given intramuscularly to cattle

The goal of this study was to confirm the vasopressor and cardiac effects of POTENAY^® INJETÁVEL (POT), a mephentermine‐based product, given to cattle with induced vascular/cardiac depression. Ten healthy Holstein cattle (206 ± 13 kg) followed a randomized‐complete‐block design (RCBD) utilizing crossover study design. Each animal randomly received (1 ml/25 kg, IM) of either POT (n = 10) or volume‐matched placebo control (0.9%NaCl, CP, n = 10). A subset of animals (n = 5) received POT first (day 0) while the remaining (n = 5) received CP; after a six‐day washout period, cattle received the opposite compound. Animals were anesthetized and catheterized for systemic/left ventricular hemodynamic monitoring. Myocardial dysfunction/hypotension was induced by increasing the end‐tidal isoflurane concentration until arterial blood pressure was 20% lower than at baseline and remained stable. Once the animal was determined to be hypotensive and hemodynamically stable, steady‐state hypotensive baseline data (BL2) were acquired, and treatment with either POT or CP was given. Data were acquired post‐treatment at every 15 min for 90 min. POT improved cardiac output (+68 L/min, ±14%, p < 0.05), MAP (+14 mmHg, ±4%, p < 0.05), HR (+22 bpm, ±8%, p < 0.05), and peak rates of ventricular pressure change during both systole (dP/dt_max: +37 mmHg/s ±13%, p < 0.05) and diastole (dP/dt_min: +31 mmHg/s, ±7%, p < 0.05). No improvements were noted following placebo‐control administration. Results indicate that POT improves cardiac performance and systemic hemodynamics in cattle with induced cardiovascular depression when given as single intramuscular injection.     

A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators

Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle.     

Contagious bovine pleuropneumonia within the 19th century miasmatic landscape

When contagious bovine pleuropneumonia (CBPP) was first detected on a farm north of Melbourne, at Bundoora, in 1858, the predominant theory of miasma was being challenged by contagionist theories of disease transmission. This well‐documented case was recorded during a period of change in the scientific assessment of disease and therefore affords an exploration of what aspects of the landscape were considered important for livestock health at the time. Although the introduction, vaccination programs and eventual eradication of CBPP on mainland Australia has been well explored, scholars have neglected this aspect of the disease's history. By comparing 19th century records of farmland with how the site appears today, it is also possible to highlight the limited information provided by contemporary texts, while at the same time developing an appreciation of the ways in which the perception of the rural landscape has changed. This differing perception has implications for the utilisation of these sources for veterinary and environmental historians seeking to understand the mid‐19th century agricultural landscape and how it relates to animal health.     

CD117‐ and vimentin‐positive telocytes in the bovine teat sphincter

Mastitis is a common economically relevant problem in dairy farming. As the major entry for pathogens is the papillary duct, one of the first defence mechanisms is the teat sphincter. This sphincter shows a rhythmic contractility of yet unknown origin. Searching for possible modulatory pacemaker cells, teat sphincters of eight cows were stained immunohistochemically with antibodies against CD117 and vimentin and evaluated microscopically for the presence of telocytes. CD117‐ and vimentin‐positive telocytes with telopodes were found in close contact with smooth muscle cells. Our findings present a first evidence of telocytes in the teat of bovines.     

Effect of bovine seminal plasma on bovine endometrial epithelial cells in culture

The purpose of this study was to investigate the effect of seminal plasma (SP) from bulls of known fertility on bovine endometrial epithelial cells (bEEC) in culture. The bEEC from passage 5, approximately 5.0–13 × 10⁵ cells per flask, were challenged with SP from bulls of high or low fertility (n = 3 and 2, respectively) or PBS (control), at 1% (75 μl) or 4% (300 μl) and were incubated for 72 hr (n = 13 per challenge). Total cell number and viability of bEEC after challenge with 1% SP from either high‐ or low‐fertility bulls (75H or 75L, respectively) did not differ from controls. In contrast, challenge with 4% of SP from high‐ or low‐fertility bulls (300H or 300L) negatively affected bEEC cell number and viability. Challenge with 300 L had a greater adverse effect than 300H. These results suggest that the negative effect of bovine SP on bEEC is both dose‐dependent and fertility‐dependent.     

Bovine foetal sex determination—Different DNA extraction and amplification approaches for efficient livestock production

Foetal sex determination using polymerase chain reaction (PCR) in mammals is based on the amplification of gender‐specific foetal DNA sequences circulating in maternal blood. The bovine synepitheliochorial placenta does not allow a direct contact between the trophoblast and the maternal blood, resulting in difficult passage of foetal DNA and, consequently, its very small amounts in maternal bloodstream. Circulating cell‐free foetal DNA (ccffDNA) encompasses short nucleotide fragments (300–600 bp) in maternal circulation. The aim of this study was to assess this non‐invasive method in accurate prenatal sexing in early and late gestational periods in comparison with ultrasound diagnostics. As various DNA isolation and amplification methods were tested, their success in obtaining reliable results was evaluated. Two groups were tested, each consisting of 20 pregnant cows. Blood of a bull and a non‐pregnant heifer was the controls. Extraction of foetal DNA was accomplished by three different methods: using tubes with silicone membranes, a single‐tube extraction without silicone membranes and phenol–chloroform extraction. Following each extraction method, foetal DNA was amplified using PCR and real‐time PCR with both bAML and TSPY primers in a separate reaction. Positive results were obtained only after amplification of foetal DNA extracted with a single‐tube extraction kit. In comparison with ultrasound examination results and foetal gender recorded at birth, the sensitivity of the PCR test was 90% in Group I, but the technique failed to detect male foetuses in Group II. The real‐time PCR test sensitivity in Group I was 90% and in Group II 91.6%.     

In vitro studies of Norwegian Red bovine semen immobilized and cryopreserved in alginate solid gel network

Development of new semen cryopreservation techniques improving sperm survival and ensuring availability of viable spermatozoa for a prolonged time‐period after AI is promising tools to reduce sensitivity of timing of AI and enhance overall fertility. The SpermVital^® technology utilizes immobilization of bull spermatozoa in a solid network of alginate gel prior to freezing, which will provide a gradual release of spermatozoa after AI. The objective of this study was to compare post‐thaw sperm quality and in vitro sperm survival over time of Norwegian Red bull semen processed by the SpermVital^® (SV) technology, the first commercialized production line of SpermVital^® (C) and by conventional procedure applying Biladyl^® extender (B). Post‐thaw sperm motility was not significantly different between SV, C and B semen (p > .05). However, sperm viability and acrosome intactness were higher for SV than C and B semen (p < .05). Small differences in DNA quality were observed (p < .05). Sperm viability after storage in uterus ex vivo was higher for SV than for C semen (p < .05). Furthermore, sperm survival in vitro over time at physiological temperature was significantly higher for SV semen than C semen as well as B semen during the incubation period of 48 hr (p < .05). In conclusion, the SpermVital^® technology is improved and is more efficient in conserving post‐thaw sperm quality and results in higher sperm viability over time in vitro for SV than for C and B semen.     

Histological and immunohistochemical evaluation of granulosa cells during different stages of folliculogenesis in bovine ovaries

Bovine granulosa cells (GC) vary in their morphological aspect during different stages of folliculogenesis. In this study, 10 morphologically normal bovine ovaries were collected to study the structural aspects of different stages of GC using intermediate filament protein antibodies including cytokeratin AE1/AE3 (AE1/AE3), vimentin, nectin‐4 and desmin. Hormonal immunolocalization was assessed using the immunomarkers anti‐Müllerian hormone (AMH) and inhibin alpha. In addition, tumour markers and proliferation markers using c‐erbB‐2 oncoprotein and proliferating cell nuclear antigen, respectively, were investigated. The immunolabelling of AE1/AE3 in GC was strongest in the early follicle stage and gradually decreased when reaching the Graafian follicle stage. Its immunolabelling increased again as the stage progressed from stage I to stage III. The immunolabelling of inhibin alpha was inversely proportional to that of AE1/AE3 in the developing ovarian follicles as their immunolabelling is opposite to each other during folliculogenesis. AMH was immunopositive in almost all GC stages in different intensities and percentages, except for some negative staining in the atretic IV follicles. The atretic IV follicle is a unique type of atretic follicle that shows Call‐Exner body formation, which was mainly found in older cows in this study. The distinct patterns of immunoreactivity for various types of immunomarkers in the different GC stages will play an important role in diagnostic assistance of various follicle conditions, including cystic ovaries and GC tumours.     

Effects of five cryoprotectants on proliferation and differentiation‐related gene expression of frozen‐thawed bovine calf testicular tissue

The cryopreservation of testicular tissue is a potential method for preserving male fertility. However, the effect of cryopreservation on bovine calf testicular tissue is scarce. This study investigated the effect of different cryoprotectants on bovine calf testicular tissue at the molecular level. Testicular tissue from ten immature bovine calves (6 months) was collected after slaughter and cryopreserved in an extender containing different concentrations of the following five cryopreservation solutions (CP): bovine serum albumin (BSA) with 5% dimethyl sulfoxide (DMSO), trehalose with 5% DMSO, DMSO and glycerol and ethylene glycol (EG). After 7‐day cryopreservation, the expression levels of three spermatogonial stem cell (SSC)‐related genes, octamer‐4 (OCT4), KIT ligand (MGF/SCF) and kit oncogene (C‐KIT), were investigated by quantitative PCR (qPCR). The cell viability was highest for the tissues preserved with 30 mg/ml BSA (77.82% ± 1.22) and 40 mg/ml trehalose (74.23% ± 1.16) compared with other groups (p < 0.05), and the level of expression of the three genes was highest with 30 mg/ml BSA (p < 0.05). Compared with other CPs, the 30 mg/ml BSA and 40 mg/ml trehalose have the better cryopreserve protection. The 30 mg/ml BSA is the most viable media for the cryopreservation of testicular tissue from cattle.