Influence of some factors on milk flow and udder health status in two different cattle breeds

Abstract

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. 1 Introduction Average daily milk flow is an important functional trait in dairy cattle for its impact on labor cost (Boettcher et al., 1998). Genetic differences in milk yield exist between breeds because of their ethiology. Many different milking systems are used for dairy cows. Switching from a milking parlour to an automated milking (AM) system may affect the milking performance of the cows, the teat tissues and quality of the milk (Neijenhuis and Hillerton, 2002) but on the other hand induced many disorders of udder (Twardon et al., 2001). The teat of farm animals used for milk production is an important part of the udder, onto which a milking cluster is attached and which serve the role of both a valve regulating the outflow of milk and of a natural barrier for exogenous infections (Hamann and Mein, 1988). Many authors established a connection between mastitis in cows, the characteristics of the teat, the stage of lactation and the visualization of the teat canal (Celik et al., 2008). Ultrasonography of the udder is among other things for designation of the internal teat structures. It allows for detailed measurements of the length and diameter of the teat canal, cistern, and the thickness of the teat wall (Stádník et al., 2010). The aim of this study was to study differences in average dairy milk flow and SCS between two cattle breed and analyze of effects on these milking and udder health characteristics. 2 Material and methods Dairy cows of Holstein (n = 100) and Slovak Spotted (n = 48) breed in the first, second or third and higher (multiparous) parity were included in the data set. The experiment was carried out on two different farms with another AM system. All the cows had clinically healthy udders. The cows were housed in a free stable with a straw bedding and milked two times a day. Average daily milk flow was defined as total daily milk yield divided by total daily milking duration. Somatic cell count (SCC) was measured during the entire observation as well. The sample of milk was taken from each cow for milk SCC. Evaluation of SCC was performed by NucleoCounter NC-100 machine. The SCC values were converted to a somatic cell score (SCS) by following equation: SCS = log2 (SCC/100) + 3. The scanning procedure was based on studies of Stádník et al. (2010). Ultrasound images of the longitudinal cross-section of teats from the Aloka Prosound 2 (Aloka Co., Ltd., Tokyo, Japan) scanner coupled with 7.5MHz linear probe (UST586-7.5MHZ) were made. Images were recorded in real time