Systematic effects on activity, milk yield, milk flow rate and electrical conductivity

Abstract

SummaryThe traits activity, milk yield, milk flow rate and electrical conductivity were analysed in preparation for automatic oestrus detection. Collection of data was performed on a commercial dairy farm and milking took place in a rotary milking parlour. Between February and December 1998 1,090,031 observations from 2,422 Holstein Friesian cows were accumulated. Around 30% of cows were milked thrice daily. For each trait and each cow a daily value was calculated. The fixed effects test day, parity, calving season, milking frequency, week of lactation and the random effect cow were considered in statistical analyses. With increasing number of parity, activity decreased and milk yield, milk flow rate and electrical conductivity increased. The milking frequency had significant influence on all analysed traits and for the effect calving season no consistent trend was found. All traits showed characteristic patterns during lactation. Between test days high variations were found for the trait activity. The remaining traits showed a steady level except for small fluctuations. Repeatability was 27.4% for activity and between 70 and 78.7% for the milk parameters. The repeatabilities verified the collected field data having a satisfying structure for application in automatic oestrus detection. The repeatability of the trait activity indicated high differences between and within cows. The right skewed distribution indicated the activity as a promising trait for further analyses. Introduction Income in milk production is directly influenced by reproductive performance. For example, increased calving intervals lead to a reduction of milk yield per cow and year, an increased number of replaced heifers, a reduced genetic impact on traits with economic importance and an increased amount of voluntary and involuntary culling (BRITT, 1985). MACK (1996) calculated costs between 0.59 and 1.17€ per day for prolonged calving interval. A decrease in conception rate of 1% results in costs of 1.52€ per cow and year (BOICHARD, 1990). An effective possibility to improve fertility performance is to intensify oestrus detection. Efficient oestrus detection by visual observation is time-consuming and requires diligent attention. As pointed out by ERADUS et al. (1992) visual oestrus detection is especially difficult to realise in large herds. Despite twice daily observation periods, 32% of oestrus are undetectable (WILLIAMS et al., 1981). Oestrus detection can be simplified and improved by application of technical equipment. Automatically measurable traits promise successful oestrus detection results. Several traits for univariate and multivariate oestrus detection are presented in a literature review of FIRK et al. (2001). In this investigation, the traits activity, milk yield, milk flow rate and electrical conductivity are analysed concerning the influence of the fixed effects test day, parity, calving season, milking frequency and week of lactation. Additionally, the random effect of the cow was considered. In preparation for further analy...

Effect of strain of Holstein–Friesian and feed system on udder health and milking characteristics

“…Correction for daily milk yield indicates differences in milking duration to be a consequence of the observed differences in milk flow. Increased AMF with parity corroborates previous reports (Firk et al, 2002), while Petersen et al (1986) also reported increasing PMF with increasing parity number. Higher PMF in older animals may be associated with the possible weakening of the teat end with age or as a result of damage of the teat sphincter as parity number increases due to harmful effects of machine milking (Maltz et al, 2000).…”

ALT pedometer - a new sensor-aided measurement system for improvement in oestrus detection

“…measuring of milk temperature shows a high interest of "false positive" animals and the results are not usable. These problems with other physiological animal parameter are also confirmed by other authors (Gartland et al 1976;Firk et al 2002). The measuring of progesterone is very expensive and problematic in its precision (moore & Spahr 1991;Eddy & Clark 1987;Nebel et al 1987).…”

Investigations on automatically measured feed intake amount in dairy cows during the oestrus period

“…The higher activity in primiparous cows might be directly related to the higher number of visits to the feeding trough observed in the current study. The statement of Ulbrich et al (2004) and the findings of Firk et al (2002) might explain the observed result of a higher feed intake amount in older cows, accompanied by fewer visits to the feeding trough and less time spent feeding per day.…”

“…However, according to Ulbrich et al (2004), older cows have a higher velocity of feed intake when compared to heifers. Furthermore, in the study of Firk et al (2002) it was found that activity, measured by pedometers, decreased significantly with increasing number of parity. The higher activity in primiparous cows might be directly related to the higher number of visits to the feeding trough observed in the current study.…”