There is an increased interest in using automatic milking systems (AMS) to indirectly assess the welfare of dairy cows, but knowledge on analyzing the association between lameness, milk yield characteristics, and reproductive performance in cows is still insufficient. The main aims of this study were to evaluate the influence of lameness on several AMS variables and reproduc- tive performance indicators during the early stage of lactation and estrus in Lithuanian Black and White dairy cows, as well as to assess the associations between lameness, productivity and repro- ductive efficiency. A total of 418 milking cows (50.3±1.2 d postpartum) without any apparent reproductive disorder were monitored for hoof health status. Cows were assigned to two groups on the basis of visual locomotion scoring: “non-lame“cows (group 1; 74.20%) and cows presen- ting “lameness“ (lame cows) (group 2; 25.80%).

Productive and milking performances of dairy cows were recorded from 50 to 100 days in milk (DIM) and 1 day after the first estrus. The lameness was predominantly localized on the hind feet (79.60%) and less frequently - on the front feet (20.40%; p<0.001). Furthermore, the lameness had a tendency to decrease milk production (4.24%; p<0.05) and increase the diffe- rence in milk yield between rear and front quarters of the udder (1.20%; p<0.05). The frequency of milking (5.19%) was lower in lame cows (p<0.05). The lame cows during estrus showed a more pronounced decrement in milk yield and milking frequency (p<0.05), and also higher milk progesterone concentration values (1.55-1.76 time’s; p<0.001), and an increasing number of inseminations (11.69%; p<0.05) were observed. The results highlighted that analysis of data from AMS programs can be a successful tool for reducing risk factors related to the effective management of reproductive performance and hoof health of dairy cows.

The work involved assessment of the Myzus persicae (Sulz.) capability to infect successively potato plants with PVY and PVM after a Sunspray 850 EC mineral oil application. The tests were carried out in the greenhouse, with 4-week-old, healthy potato plants possessing low ressistance to viruses, derived from in vitro (test plants). Any time, for each combination and each virus, 10 successive plants were inoculated in 6 repetitions. Virus sources were potato plants infected with PVY or PVM, kept in isolated rooms. As a result of oil application, feeding of the M. persicae specimens on plants previously treated with this oil was delayed. The highest reduction as regards PVY and PVM transmission by M. persicae was obtained in the treatment where both plants constituting virus sources and test plants were protected, because only two of ten plants were infected with PVY, and only one with PVM. Mineral oil application only on potato test plants (healthy ones) reduced to a small degree M. persicae capability to transmit PVY to six successive plants (to seven in control), whereas it was much higher for PVM – to three (to six in control). In the case when only plants constituting virus sources were oil-protected, aphid’s capability to transmit PVY was limited only to four plants, and PVM – to two. These results seem to confirm much more the hypothesis that mineral oil inactivates virus particles in the stylets of aphids while they attempt to acquire it from plants which have been previously protected with mineral oil.