Milk yield, milk ingredients, health and other, production-related parameters of subclinically infected, Mycobacterium avium ssp. paratuberculosis (MAP-) shedding (positive faecal PCR, n = 20) and non-shedding (negative faecal PCR, n = 10) dairy cows were compared in the period from 10 days prepartum to 120 days postpartum. Body condition, rumen fill and faeces scores were lower in the MAP-shedding cows. There was no significant difference in plasma or urine metabolic parameters between the groups. Milk yield and lactose content tended to be lower (P = 0.074 and 0.077, respectively), somatic cell count tended to be higher (P = 0.097), while milk fat content was significantly higher (P = 0.006) in MAP-shedding cows than in the controls. Milk protein content did not differ between the groups. All other health and production parameters [number of reproductive tract treatments, number of udder treatments, number of artificial inseminations (AIs), calving interval, and service period] were significantly better in the control group. It is concluded that MAP infection, even in a subclinical form, has a significant impact on some production and health parameters of dairy cows.

The profitability of cattle farming is largely determined by ensuring high-quality breeding animals for replacement and longevity in production. The provision of breeding animals requires adequate fertility of the cowherd and then intensive weight gain in the calf rearing period. For ensuring these demands, many management aspects must be considered. Continuous monitoring of the herd’s health status, including redox status, is essential. This review aims to provide a summary of relevant scientific data published in the last few decades regarding the role of oxidative stress (OS) in infertility of dairy cows and developmental diseases in calves, the major predisposing factors, and possible prevention.

The aim of this work was to determine the changes of redox indicators such as reactive oxygen metabolites (dROMs), plasma antioxidant test (PAT) and the oxidative stress index (OSI) in dairy cows at different stages of lactation using a diagnostic equipment which is suitable for in vivo oxidative stress (OS) monitoring procedures. In total, 628 dairy cows were examined in the pre-parturient period (days in milk [DIM]: -21 to -1 day; n = 117), in the calving and maternity period (DIM: 0 to 7; n = 137), in the early lactation period (DIM: 8 to 30; n = 139), and the in the peak lactation (DIM: 31 to 150; n = 235). The dROMs and OSI values were significantly different (P < 0.05) when comparing the 1st and 2nd+ lactation cows in each group. The highest mean value of dROMs was detected at the calving and maternity stage in 1st lactation cows (141 ± 25 U. Carr) and the lowest (103 ± 29 U. Carr) was found in peak lactation. The OSI developed similarly, with the highest value of 5.58 ± 0.94 in the calving and maternity period in the 1st lactation cows and the lowest value of 4.05 ± 1.21 in peak lactation and significant differences were found in many cases. Based on the results, the measurement of dROMs and OSI may be suitable for detecting oxidative stress in different lactation stages.