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

Background: Oversupply of dietary copper (Cu) is common among UK dairy herds, but studies on the long‐term outcomes of this oversupply are scarce. Methods: A longitudinal study was undertaken to determine the long‐term implications when 80 Holstein‒Friesian heifers with a mean (±standard error) age of 4.1 ± 0.1 months and a mean liveweight of 137 ± 2.4 kg were fed a recommended (R; 16 mg/kg dry matter [DM]) or high (H; 32 mg/kg DM) dietary Cu concentration until 6 weeks prior to calving. Results: Hepatic Cu concentrations in both treatment groups were elevated into the ranges used to diagnose chronic Cu toxicity in cattle at 6.9 months of age (798 ± 46.4 mg/kg DM for H vs. 643 ± 35.4 mg/kg DM for R), with associated evidence of liver damage. Hepatic Cu concentrations then returned to normality but remained higher (p < 0.001) for heifers fed H than for those fed R and were associated with a reduced (p = 0.044) conception rate to first and second services (73.7 ± 8.05% for H vs. 91.2 ± 7.68% for R). Limitation: This retrospective analysis identified pre‐study liver damage, which may have affected results. Conclusions: Supplying Cu in excess of requirements resulted in liver damage and reduced conception rates. [ABSTRACT FROM AUTHOR]

Paratuberculosis or Johne's disease (JD) is a fatal chronic enteritis that causes detrimental effects on production and health and significantly reduces the welfare of cattle. Control of JD is highly desirable, but single milk ELISA testing may not be sensitive enough to identify all affected animals, particularly in the early stages of the disease. The objective of this study was to compare the activity of JD-positive (JD5) to JD-negative (JD0) cows from calving until wk 20 of lactation. The study was conducted at Harper Adams University, United Kingdom, using 42 multiparous [3.1 ± 0.22 (mean ± standard error of the mean); range: 2-7 lactations] Holstein Friesian cows, fitted with an IceQube accelerometer (IceRobotics Ltd., Edinburgh, UK) on the back left leg. The sensors recorded data on lying and standing time, steps, and motion index with a granularity of 15 min. In addition, start and stop times for lying bouts, and exact lying bout durations were recorded, which permits calculation of the number of lying bouts. Every 3 mo the cows were milk sampled and subsequently tested for JD using an ELISA. Cows in the infection group JD0 were classed as JD negative and cows in the infection group JD5 were classed as JD positive. Johne's-positive cows [JD5; n = 21 (repeat ELISA positive)] were matched to negative cows [JD0; n = 21 (repeat ELISA negative)] based on lactation number and age. Around peak lactation we found differences in lying behavior. The JD5 cows spend less time lying/d during wk 7 to 11 of lactation. The largest difference observed was around wk 8 of lactation, with JD5 cows spending, on average, 2 h/d less time lying down than JD0 cows (9.3 ± 0.33 vs. 11.3 ± 0.61 h/d, respectively). The JD5 cows also had fewer lying bouts per day from wk 7 to 15 of lactation (excluding wk 13), and during wk 11 and 12 average lying bout duration was longer for JD5 cows compared with JD0 cows. No differences were observed in steps per day, milk yield, BCS, and mobility score between JD5 and JD0 cows from calving to wk 20 of lactation. As far as we are aware, this is the first study to show changes in activity of JD-positive cows. The results show that activity data from leg-mounted accelerometers has the potential to help identify JD-positive cows, although more research is required., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Large percentages of dairy cows do not express behavioural signs of oestrus. Faecal and urine fatty acid concentrations increase during oestrus. The objective of the present study was to determine the milk FA profile of dairy cows during the oestrous and dioestrous periods and the relationship with behavioural signs on the day of oestrus. The activity of 32 Holstein Friesian cows was measured continuously using GEA Rescounter ll pedometers (GEA Farm Technologies, Düsseldorf, Germany) and IceQubes (IceRobotics Ltd., Edinburgh, UK). Milk samples were collected on the day of oestrus and on day 14 of the subsequent oestrous cycle and analysed for FA concentration using gas chromatography (GC) and milk composition was also determined. All cows were artificially inseminated within 12 h of the onset of oestrus. On the day of oestrus, the concentration of acetic acid (P < 0.001), valeric acid (P = 0.016), caproic acid (P < 0.001) and myristoleic (P = 0.035) were greater in milk compared to day 14. On day 14 milk arachidonic acid concentration, however, was greater (P = 0.004) compared to the day of oestrus. Also, on day 14 arachidonic acid concentration was greater (P = 0.002) in non-pregnant compared to pregnant cows. In conclusion, the results of this study indicate there are changes in the concentrations of some milk FA during oestrus and dioestrus in lactating dairy cows., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)