Cortisol levels in skimmed milk during the first 22?weeks of lactation and response to short-term metabolic stress and lameness in dairy cows

Background

Cortisol is secreted into blood in reaction to acute stress, but also in phases of diminished feed intake and changed animal behavior. As cows do not always show clear signs of discomfort, reliable diagnostic markers could be used to provide information regarding individual cows’ distress. The objective of this study was to establish an ether free immunoassay for the detection of cortisol and to determine values during the first 22 weeks of lactation. Furthermore, the response in milk cortisol levels was assessed during times of metabolic stress and pain associated symptoms of lameness.

Methods

Milk yield and composition, blood serum glucose, NEFA and BHBA as well as milk cortisol were determined in 24 multiparous Holstein-Friesian cows over the course of the first 22 weeks of lactation. Animals were further checked for signs of clinical diseases on a daily basis. Two feed restrictions over three days (FR; 70 % of precious ad libitum intake) were performed during the 4^th wk and the 21^st wk, respectively. An ELISA for cortisol measurement in easily accessible bovine skimmed milk was established and applied.

Results

On the last day of FR in early lactation, a reduction in milk yield and changes in serum metabolites compared to respective previous values were detected. The FR in mid-lactation resulted in no changes in milk production and serum metabolites. Milk cortisol was highest during first wk of lactation and remained on comparable levels thereafter. Milk yield and composition were not influenced by FR. Lameness resulted in enhanced milk cortisol levels.

Conclusion

Milk cortisol could be used as an indicator of painful symptoms such as lameness. Higher values of milk cortisol levels during first wk of lactation should be taken into account for interpretation.     

Is there a benefit from an early booster vaccination in the control of equine influenza?

Conventional equine influenza vaccination schedules consist of a primary course of two vaccinations given 4-6 weeks apart followed by a third vaccination (booster) given approximately 5 months later. In between the primary course and the third vaccination, horses are generally considered not to be adequately protected against influenza. This study aimed to investigate whether Thoroughbred foals would benefit from a vaccination schedule in which the third vaccination was given earlier than in conventional vaccination schedules. The vaccines used were an inactivated whole virus equine influenza vaccine and an inactivated whole virus combination vaccine containing equine influenza and equine herpesvirus antigens. Four groups of foals were vaccinated with the two vaccines according to a conventional and an accelerated vaccination schedule in which the third vaccination was given 14 weeks after the first administration. In both groups, the fourth vaccination was given at the normally recommended interval of 26 weeks after the third vaccination for the combination vaccine and 52 weeks after the third vaccination with the influenza only vaccine. The horses were 4-11 months of age and seronegative for influenza. Immunological responses after vaccination were monitored for several months using the single radial haemolysis test. The results indicated that 28 weeks after the first vaccination, antibody levels in horses vaccinated according to the accelerated schedule were not significantly higher than in horses vaccinated according to the conventional schedule. In addition, the total level of antibody production (area under the curve) was not significantly different at that point although antibody titres were slightly higher (but not significantly so) between 16-30 weeks in the accelerated schedule. Between the third and fourth doses, horses vaccinated according to the accelerated schedule had antibodies against influenza below the level required for clinical protection for 39 and 18 weeks for the influenza only and the combination vaccine, respectively, whereas those vaccinated according to the conventional schedule had antibody titres below the level for clinical protection for 9-15 weeks in the corresponding period for both vaccines. Horses vaccinated according to the accelerated schedule with the combination vaccine had lower antibody titres after the fourth vaccination than those vaccinated according to the conventional schedule after the third vaccination, although antibody titres prior to vaccination were similar. For the influenza only vaccine, titres after the accelerated fourth administration were not different to those after the conventional third vaccination. There was no benefit from early booster vaccinations with the vaccines used in this study, so for these vaccines the conventional schedule provided better protection than the selected accelerated alternative. This may contrast with some other vaccine formulations, although a direct comparison using similar protocols has not been made.     

Is there a predictable correlation between time of birth, birth and the puerperal period and clinical and hormonal findings in horses?

The investigations were done on 108 mares (78 warm-blooded horses, 25 cold-blooded horses and 5 trotters). To pursue the question in the title, progesterone and estradiol values in jugular vein-blood were examined starting from 30 days before the calculated date of parturition until 30 days after that event. In parallel to that Ca/Mg ratio was measured by means of a semiquantitative test-strip in the milk. Clinical signs of the birth, parturition itself and the post partum period were recorded. In respect to the P4 and E2 values it was that the P4:E2 ratio changed towards parturition in favour to E2 which was interpreted as a sign for the beginning of labour contractions as well as a signal to the ovarian hormonal activity and feed-back regulation. The "predict of the foal-test" by measuring Ca/Mg ratio is helpful only in combination with clinical findings. This test can be used for the decision to induce parturition. Concerning the colour and viscosity of the milk, it was observed to change from grey-aqueous 48 h a.p. through grey-brownish 24 h a.p. to white-yellow and viscous 12 h a.p. The results show that heavy mares more often retain the fetal membranes. They often bear lighter offspring with equally lighter fetal membranes, and the surfaces of the microvilli of the microcotyledonas seem to be smaller. Beside this it is concluded that during pregnancy disturbances in the fetomaternal relations probably exist as a result of a deficiency in placental development that finally results in retention secundinarum.     

Is there a relationship between clinical presentation,diagnostic and radiographic findings and outcome in horses with osteoarthritis of the small tarsal joints?

Reasons for performing study: Despite the possibility that sound horses may have radiographic signs consistent with osteoarthritis of the small tarsal joints (OA‐STJ), a diagnosis of ‘bone spavin’ as a cause of lameness is often made based only on radiographic examination. Objectives: To determine whether severity of radiographic change and response to treatment are correlated with the duration and degree of lameness and the response to intra‐articular anaesthesia in horses with OA‐STJ. Methods: A retrospective study of all horses that showed a positive response to intra‐articular anaesthesia of the STJ was performed. Details of history, clinical presentation and diagnostic findings were recorded. Radiographs of affected tarsi were evaluated and scored independently by 2 observers. Follow‐up was via a telephone questionnaire with the owner. Statistical analysis was used to assess the association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings. Response to treatment was compared with the findings from the diagnostic work‐up. Results: Ninety‐one horses were included (61 unilateral and 30 bilateral lameness). Fifty‐nine percent of horses had been lame for over 2 months. There was no association between the duration and degree of lameness, or between duration or degree of lameness, intra‐articular anaesthesia and radiographic findings. Response to treatment showed a significant positive association with less severe radiographic changes within the tarsometatarsal (TMT) joint. Follow‐up was available for 48% of cases, with 52% horses returning to the same level of exercise. Conclusions: There is no association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings in horses with OA‐STJ. However, horses that improved following treatment tended to have less marked TMT joint pathology. Potential relevance: Response to intra‐articular anaesthesia should remain the gold standard for diagnosis of OA‐STJ. Predicting which cases are likely to improve following treatment remains difficult.     

Effect of a single intrauterine administration of recombinant bovine interferon-τ on day 7 of the estrous cycle on the luteal phase length and blood profile in dairy cows

This study tested the effect of recombinant bovine interferon-tau (rboIFN-τ) on the length of estrous cycle, luteal lifespan and side effects of rboIFN-τ in the cow. A normal estrous cycle in six non-lactating cycling Holstein cows was observed (non-treated cycle), and either 2.0 mg of liposomalized rboIFN-τ (treated cycle) or bovine serum albumin (BSA; placebo cycle) was infused in the uterus on day 7 of the estrous cycle (day 0=day of ovulation). Rectal temperature, heart rate and respiratory rate were recorded and blood samples were collected before and after the treatments. The length of the estrous cycle and corpus luteum lifespan in rboIFN-τ treated cycles were not significantly different from those of the non-treated and placebo cycles. In contrast, the rboIFN-τ treatment caused a transient increase in rectal temperature and a decrease in the number of peripheral lymphocytes and neutrophils after the treatment.     

Morphological changes in the small intestinal smooth muscle layers of horses suffering from small intestinal strangulation. Is there a basis for predisposition for reduced contractility?

Reasons for performing study: Intestinal strangulation often leads to enterectomy after which ileus can develop. This has prompted research to look into possible pathophysiological processes triggering equine ileus. However, morphological changes of the small intestinal smooth muscle in relation to equine colic have not yet been studied. Objectives: The presence of some smooth muscle proteins was morphologically assessed and quantified in control and colic horses. In addition, the up‐ or down‐regulation of heat shock proteins (HSP20 and HSP27) influencing the contractility of smooth muscles was studied. Methods: Cranial resection margins of 18 strangulated small intestinal samples were collected. Small intestinal control samples were collected from 11 horses subjected to euthanasia for other than gastrointestinal‐related reasons. Formaldehyde‐fixed tissue was paraffin‐embedded and processed for conventional staining and immunohistochemistry. Snap‐frozen full‐thickness biopsies were collected for western blot analyses. Results: Evaluating the muscle layer microscopically, colic samples showed significantly more signs of degradation than controls (P = 0.026) of which vacuolar degeneration was most prominent (P = 0.009). In colic samples, myosin protein levels were decreased (P = 0.022) whereas desmin (P = 0.049) and HSP20 protein levels (P = 0.005) were elevated. Conclusions: In colic samples, microscopic lesions at the level of the muscle layer indicate a stress response. In addition, modified amounts of structural proteins such as myosin and desmin together with increased HSP20 levels could perhaps provide a basis for explaining the malfunctioning of the intestinal muscle layer. Potential relevance: Post operative ileus, following small intestinal strangulation and resection, could be related in part to a dysfunctional muscle layer. In addition to microscopic signs of degeneration, myosin and HSP20 were affected. Pharmacological interventions might alter HSP20 expressions and thus serve a protective effect.     

Research and implementation of novel approaches for the control of nematode parasites in Latin America and the Caribbean: is there sufficient incentive for a greater extension effort?

The widespread presence of anthelmintic resistant gastrointestinal parasitic nematodes in outdoor ruminant production systems has driven the need to identify and develop novel approaches for the control of helminths with the intention to reduce the dependence on commercial anthelmintic drugs. This paper identifies what has been done in Latin America (LA) in terms of estimating the prevalence of anthelmintic resistance (AR) in ruminant production systems and the application of different novel approaches for the control of helminths in those systems, including research and extension activities. Firstly, the paucity of knowledge of AR is discussed in the context of different countries, as well as, the available economic resources for research, the technical infrastructure available and the practical difficulties of the production systems. It is then proposed that the search for novel approaches is not only driven by AR but also by the need for techniques that are feasible for application by resource-poor farmers in non-commercial subsistence farming systems. However, the commercial benefits of these approaches are often limited and so are funding inputs in most countries. The workers participating in the research into different novel approaches are identified as well as the different methods being studied in the different areas of LA according to their published results. In addition, the difficulties experienced during extension efforts to reach farmers and help them to adopt novel approaches for the control of parasitic nematodes in LA are discussed. The role of regulatory authorities in these countries is discussed as some methods of control might need an official confirmation of their efficacy as well as authorization prior to application as they may affect animal products (i.e. residues) and/or impose a hazard for animal welfare. The role of the pharmaceutical companies is also discussed.     

A Review of Current Treatment Options in the Treatment of Ocular and/or Periocular Squamous Cell Carcinoma in Horses: Is There a Definitive “Best” Practice?

This review examines the most commonly reported treatment options for ocular squamous cell carcinoma (OSCC) and periocular squamous cell carcinoma (POSCC) in horses and proposes to conclude on the most viable method based on available published studies in terms of treatment outcome, known side effects, advantages, disadvantages, and reliability of available evidence. After a literature search for peer-reviewed published articles, seven most commonly reported on treatments for OSCC and/or POSCC were identified: surgery, photodynamic therapy, carbon dioxide (CO₂) laser ablation, radiofrequency hyperthermia, cryotherapy, chemotherapy, and radiation therapy. Combination therapies were supported as a most successful recommendation; however, when considering site-specific outcomes, the following conclusions may be drawn: limbal squamous cell carcinoma (SCC) was most effectively treated with surgery and adjunctive therapy including CO₂ laser ablation, mitomycin C, and brachytherapy; third eyelid SCC reported good outcomes when treated with surgery alone (clear margins) and in combination with brachytherapy for unclear margins; eyelid SCC, surgical resection was usually limited and most reports supported the use of adjunctive brachytherapy, although photodynamic therapy appeared to be a promising new treatment. It was deemed unreasonable to conclude on the best treatment for cornea, conjunctivae (palpebral and bulbar), and medial canthi in isolation because of lack of evidence. A consistently favored treatment for OSCC and/or POSCC in horses does not currently exist. The presentation of data in the literature and its lack of consistency make it impossible to statistically analyze and make comparative conclusions on treatment outcomes. This review provides a basis for further research to establish a best-practice protocol.