The aim of this study is to call attention to the possibility of using ultrasonography as a useful tool for the evaluation of morphological characteristics of the udder and teats in dairy cows in relation to milking characteristics and udder health. A total of 26 dairy cows of the Holstein breed in the first (n = 13) and second lactation (n = 13) were investigated with a linear array ultrasound probe. Recovery of the teat internal parameters after milking was determined by ultrasonographic scanning. Teat canal length, teat canal diameter and teat wall thickness of 103 teats were evaluated from 622 measurements before and directly after milking and every 15 minutes until 1 hour after milking (6 measurements). The most significant differences in internal proportions were determined within those values measured before and immediately after milking. The dynamics of changes in the length of the teat canal demonstrated the extension by 27%. A sudden restoration of the initial length by 11% was detected one hour after milking. Differences in teat canal diameter were significant at P<0.01 between the 1st and 4th measurement. The initial extension was 17% immediately after milking and the restoration about 9% one hour after milking. The wall thickness was strengthened during the 2nd measurement immediately after milking in comparison with the 1st measurement before milking (P<0.01). Significant differences in the wall thickness were detected between the 1st and 2nd measurement (+26%; P<0.01) and between the 2nd and 3rd measurement. The ultrasonographic scanning of the teat parameters was a useful tool to study teat changes caused by milking.

The oestrus is defined as a complex of physiological signs and changes of behavior occurring immediately before the ovulation. It is the period of sexual receptivity of the cow and this period characterized by, typical cow behaviour which is standing when mounted by a bull or companion cow. Cow indicates this willingness by a slight arching of the back and immobility when approached. The bovine estrus cycle averages 20 days in heifers and 21 days in cows, but the fluctuations in the cycle length is laying between 18 and 25 days. As a result of this progress often only 50 % of the estrus cycles are recognized, and it is extremely hard to find all cows on heat. We state a few methods for estrus detection such as visual observation, locomotion activity and rumination time measurement and other.

Strapák P., Strapáková E., Rušinová M., Szencziová I. (2017): The influence of milking on the teat canal of dairy cows determined by ultrasonographic measurements. Czech J. Anim. Sci., 62, 75-81.The effect of milking on the length and diameter of the teat canal during teat regeneration immediately after milking was evaluated. The practical measurements of the teat canal were performed on 70 Holstein cows using ultrasound Aloka Prosound device 2. A special "bath method" of the teat ultrasonographic scanning was used at set time intervals -before milking, immediately after milking, and 30, 60, 90, and 120 min after milking. Before milking, the average length of the teat canal was 10.67 mm and 9.3 mm and the teat canal diameter was 1.11 mm and 1.09 mm for front and rear teats, respectively. The average length of the front and rear teat canal significantly increased by about 20.5 and 32.9% and the front and rear teat canal diameter increased by 9.0 and 9.1% on average immediately after milking compared to values detected before milking. After 120 min of regeneration the teat canal was by 3.56 and 14.95% longer than before milking for front and rear teats, respectively. Prolongation of the teat canal was significantly affected by teat position. Based on the present results, the time period of 120 min is not sufficient for the complete regeneration of the teat canal length to the pre-milking values. On the other hand, we recorded total regeneration of the teat diameter within 120 min after milking. The initial values of the front and rear teat diameter were equal to those measurd 120 min after milking.

Milkability evaluation of Holstein dairy cows by LactocorderThe aim of this work was to evaluate chosen milk flow characteristics of Holstein dairy cows, using mobile electronic milk flow meters - Lactocorders. A total of 181 Holstein dairy cows were evaluated and divided according to parity, lactation stage and bimodality in order to carry out a detailed comparison of measured milkability traits. The average total milk yield was 11.98±3.41 kg per milking with an average milk flow rate of 2.52±0.75 kg min-1 and a maximum milk flow rate of 3.94±1.30 kg min-1. The total milk yield showed positive correlations with the average milk flow rate (r = 0.48; P<0.001) and also with the maximum milk flow rate (r = 0.32; P<0.001). More than 47% of milk flow curves were classified as bimodal. Bimodality was positively correlated with the duration of the incline phase (r = 0.73; P<0.001) and negatively correlated with the quantity of milk obtained during the first minute of milking (r = -0.34; P<0.001). In relation to the lactation stage - the highest average milk flow rate was reached by Holstein dairy cows at the beginning of the lactation (up to 100 days in milk), and in relation to parity - the highest milk flow rates were measured in second-lactation dairy cows.

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In this study were analyzed average daily milk flow and udder health status (by somatic cell score) in dairy cows. A total of 100 Holstein (H) and 48 Slovak Simmental (SS) cows were investigated. The Holstein cows had average daily milk flow significantly higher by 1.24 kg/min and somatic cell score (SCS) by 0.5 higher than Simmental cows. The factors like breed, parity, rear teat canal length and front teat canal diameter had a significant effect on milk flow but no significant effect on SCS. Thus, these results indicate differences between breeds and parity in milk traits and health status.

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