Oestrus resynchronisation (RES, Resynch) programmes for non-pregnant cows allow shortening the period between an unsuccessful insemination and the next attempt on the same cow. The protocol of oestrus RES may be started after ruling out pregnancy by means of ultrasonography carried out 28 days after insemination or after performing a test for pregnancy-specific glycoproteins (PAG) in blood or milk. The Resynch protocol can be based on a double application of prostaglandins, the OvSynch protocol, or hormonal therapy with exogenous sources of progesterone (CIDR intravaginal devices). The efficiency of the method depends on the functional state of the ovaries, the diameter of the corpus luteum, external factors, and the health and maturity of the cows. The present paper constitutes a comparison of research findings concerning the effectiveness of RES programmes.

OBJECTIVE To evaluate lameness and morphological changes associated with an osteochondral fragment–groove procedure as a means of experimental induction of metacarpophalangeal (MCP) joint osteoarthritis within an 11-week period in horses. ANIMALS 6 nonlame adult warmbloods. PROCEDURES The right MCP joint of each horse underwent an osteochondral fragment–groove procedure (day 0). After 1 week of stall rest (ie, starting day 7), each horse was trained daily on a treadmill. Weekly, horses underwent visual and inertial sensor-based assessments of lameness. Both MCP joints were assessed radiographically on days 0 (before surgery), 1, 35, and 77. A synovial fluid sample was collected from the right MCP joint on days 0 (before surgery), 35, 36, 49, 63, and 77 for cytologic and biomarker analyses. On day 77, each horse was euthanized; both MCP joints were evaluated macroscopically and histologically. RESULTS Right forelimb lameness was detected visually and by the inertial sensor system when horses were moving on a straight line after distal forelimb flexion or circling left on days 14 to 77. Compared with presurgical values, synovial fluid interleukin-6, prostaglandin E2, hyaluronic acid, and interleukin-1 receptor antagonist protein concentrations were increased at 2 or 3 time points, whereas tumor necrosis factor-α and interleukin-10 concentrations were decreased at 1 time point. Gross examination of all right MCP joints revealed synovitis and wear lines; synovitis was confirmed histologically. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a combined osteochondral fragment–groove procedure can be used to induce clinically and grossly observable early MCP joint osteoarthritis during an 11-week period in horses.

OBJECTIVE To determine pharmacokinetics and pharmacodynamics after oral administration of a single dose of clopidogrel to horses. ANIMALS 6 healthy adult horses. PROCEDURES Blood samples were collected before and at various times up to 24 hours after oral administration of clopidogrel (2 mg/kg). Reactivity of platelets from each blood sample was determined by optical aggregometry and phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Concentrations of clopidogrel and the clopidogrel active metabolite derivative (CAMD) were measured in each blood sample by use of liquid chromatography–tandem mass spectrometry, and pharmacokinetic parameters were determined with a noncompartmental model. RESULTS Compared with results for preadministration samples, platelet aggregation in response to 12.5μM ADP decreased significantly within 4 hours after clopidogrel administration for 5 of 6 horses. After 24 hours, platelet aggregation was identical to that measured before administration. Platelet aggregation in response to 25μM ADP was identical between samples obtained before and after administration. Phosphorylation of VASP in response to ADP (20μM) and prostaglandin E1 (3.3μM) was also unchanged by administration of clopidogrel. Time to maximum concentration of clopidogrel and CAMD was 0.54 and 0.71 hours, respectively, and calculated terminal-phase half-life of clopidogrel and CAMD was 1.81 and 0.97 hours, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Clopidogrel or CAMD caused competitive inhibition of ADP-induced platelet aggregation during the first 24 hours after clopidogrel administration. Because CAMD was rapidly eliminated from horses, clopidogrel administration may be needed more frequently than in other species in which clopidogrel causes irreversible platelet inhibition.

The use of dietary supplements as an alternative treatment for joint-related pathologies such as osteoarthritis (OA) is increasing. However, there is little scientific evidence to support the intended use. The aim of this study was to evaluate the anti-inflammatory effects of creatine- and amino acid-based supplements in primary cultured canine chondrocytes (CnCs) as an in-vitro model of OA and compare the effects to more commonly used agents, such as the non-steroidal anti-inflammatory drug (NSAID), carprofen, and the joint supplement, glucosamine (GS). CnCs were stimulated with interleukin-1β (IL-1β) and the subsequent release of prostaglandin E2 (PGE2) and tumor necrosis factor alpha (TNFα) was measured using an enzyme-linked immunosorbent assay (ELISA). Changes in oxylipins were also assessed using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). All compounds examined were able to significantly reduce the release of PGE2 and TNFα and were associated with reductions in cyclooxygenase-2 (COX-2) expression and nuclear factor-kappaB (NF-κB) phosphorylation. The creatine- and amino acids-based supplements also altered the profile of oxylipins produced. All compounds examined were less effective at reducing the release of PGE2 than carprofen. Carprofen significantly increased release of TNFα from CnCs, however, while the other agents reduced TNFα release. This study suggests that creatine- and amino acid-based supplements may have a beneficial role in preventing inflammation within the joint and that further studies are warranted.