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This study was designed to evaluate the plasma profiles of oxidative stress biomarkers, progesterone and ovarian follicle diameter in ovulatory versus an-ovulatory cows. Twenty cows were synchronised using controlled internal drug release (CIDR) and prostaglandinF2α (PGF2α) protocol. Plasma samples were analysed for progesterone (P4), oxidative stress (OS) biomarkers; reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), oxidative stress index (OSI = ROMs/BAP × 100), advanced oxidation protein products, ceruloplasmin and glutathione (GSH). Plasma P4 concentration was greater in ovulated cows 24 hours (h) after PGF2α treatment but lower 48 h after PGF2α treatment compared with that of an-ovulated cows at those sampling sessions (P < 0.05). Ovulated cows were diagnosed with greater ovarian follicle diameter compared with that of their herd mates not diagnosed for ovulation. Significant interaction of time of PGF2α treatment and ovulation status (ovulatory versus an-ovulatory) with the plasma concentrations of OSI, BAP and GSH were observed. Ovulated cows had significantly lower BAP compared with that of an-ovulated cows (P < 0.05) 9 h, 48 h, 60 h and 128 h after PGF2α treatment. Plasma concentrations of GSH were lower (P < 0.05) in ovulated cows than that of an-ovulated cows 60 h and 96 h after PGF2α treatment. However, OSI was greater (P < 0.05) in ovulated cows than that of an-ovulated cows 9 h, 48 h, 60 h and 128 h after PGF2α treatment. Significant associations were observed between OS status and sampling time. Oxidative stress status may have important physiological role in facilitating the ovulation process in oestrus synchronised dairy cows.

AimsThe objective of this study was to investigate farmers' perception of lameness in comparison to the estimated prevalence of lameness in NSW pasture‐based dairies to evaluate farmers' perceptions and approaches to detection, treatment and prevention of lameness.MethodsAcross‐sectional study was conducted on 62 pasture‐based dairy farms across NSW, Australia. The prevalence of lameness in these farms was estimated using locomotion scoring (1–4 scale). A survey was also conducted, using a questionnaire and face‐to‐face interview, to explore farmers' perceived prevalence of lameness and approaches to treatment and prevention.ResultsThe prevalence of lameness estimated by farmers was 3.7 times less (mean: 5%; range 0% to 26%) than that determined by locomotion scoring (mean: 19.1%; range 5.0%–44.5%). Approaches to treatment included antimicrobial therapy, hoof inspection with or without application of wooden blocks. In 28% of the farms, the lame cows were managed by farmers or farm staff with no official training in treatment of lame cows. The mean interval from detection of lameness to examination of the affected hoof was almost 55 hours (range 2–720 hours). A very low percentage of farms kept lameness records or implemented lameness preventive strategies such as footbaths and prophylactic foot trimming.ConclusionsFarmers and farm managers were found to underestimate the prevalence of lameness which could be due to the low level of awareness and can contribute to subsequent lack of implementation of prophylactic procedures and preventive management strategies for lameness. These findings accentuate the need to improve farmers' ability to detect lame cows and to emphasise the importance of recording in order to facilitate the management of lameness in dairy herds.

Presence of luteal tissue at Ovsynch enrolment and recent disease events affected pregnancy per FTAI in cows inseminated after Ovsynch.