The relationship between milk oestradiol concentrations and oestrus activity in lactating Holstein–Friesian cows

Context Detecting oestrus to facilitate the optimal timing of artificial insemination is key reproductive performance in dairy cows. Aims The aims present study were investigate relationship between activity and milk oestradiol concentrations during oestrus. Methods Accelerometers (IceQubes, IceRobotics Ltd, UK) used monitor (the number steps per day) 37 lactating Holstein–Friesian cows peri-oestrus period. Daily samples analysed for progesterone concentrations. Key results An increase sufficient generate an alert (behavioural oestrus) from sensor (GEA Rescounter II) was detected 29 (78%) Milk increased 2.0 ± 0.5 pg/mL 4 days before 8.3 1.1 on day behavioural oestrus, then fell 2.6 0.6 by 3 afterwards. Similarly, also peaked However, 8 (22%) cows, although following fall progesterone, there no significant (silent oestrus). positively correlated (r = 0.37; P 0.03) with Cows that subsequently became pregnant took a similar (2806 282.3 vs 2850 372.5 PD+ PD− respectively) but had higher (11.2 2.06 5.1 0.51 than did not become pregnant. Conclusions Increases above threshold approximately 10 are associated activity, oestral rate pregnancy insemination. Implications This has demonstrated significance concentration fertility Thus, strategies enhance secretion may fertility. Further, measures be developed as aid detection further studies required determine whether on-farm assessment can add repertoire biomarkers cattle.