Results and Evaluation of Thirty Years of Health Recordings in the Norwegian Dairy Cattle Population

Abstract

The results are based on the Norwegian Cattle Health Recording System, which has been in place for the entire country since 1975. The dairy breeds in Norway consist of 94% Norwegian Red and 4% crossbreeds with Norwegian Red. No other breed consists of more than 0.5% of the total population. During the past 30 yr, there have been 11,563,692 dairy cows within the recording system, corresponding to 8,633,532 cow-years and 8,632,516 calvings. This population consisted of 3,038,675 first-calving cows. Altogether, 8,435,704 different diagnoses were recorded from 4,444,485 different cows each year. The general trend for all recordings was an increase in the incidence rate of all cases from 0.74 per 365 d at risk (cow-year) in 1976 to 1.36 in 1990, and then a decrease to 0.62 in 2002. The corresponding figures for cows treated per cow-year were 0.44 up to a maximum of 0.82, and then a decrease to 0.46 per cow-year in 2002. The most common diseases were acute (severe to moderate) clinical mastitis, chronic (mild) clinical mastitis, ketosis, milk fever, teat injuries, retained placenta, silent heat or anestrous, indigestion, cystic ovaries, and metritis. Clinical mastitis increased from 0.15 cows treated per cow-year in 1975 to 0.44 in 1994, and then decreased to 0.23 in 2002. Ketosis began at 0.10 in 1975, increased to 0.24 in 1985, and then decreased to 0.05 in 2005. For several of the most common diseases, there was a reduction of more than 50% from the 1990s to the years after 2000. Validation processes confirmed that this fluctuation reflected the general trend in the population. The disease recording system also reflected the known outbreaks of bovine respiratory syncytial virus during 1976, 1989 to 1990, and 1995. A marked increase in malformation diagnoses could be seen in 1986 and in 1989 and 1990. These could be related to the Chernobyl nuclear power plant accident in April 1986. The diagnosis that showed the most stability throughout these 30 yr was retained placenta. The 3 main reasons for the large fluctuation for many of the diseases could be the following: a breeding effect, an effect of preventive work, and an effect of changing the therapeutic attitude. Many of the actions taken to bring about improvements would not have been possible without a functioning and practical recording system. Our experience is that an organ-related diagnosis system with up to 60 or 70 different diagnoses will meet the needs of the dairy industry.

Genetic parameters for producer-recorded health data in Canadian Holstein cattle

“…The health data recording system is very new in Canada. A look at Norwegian data shows that during the first few years of data recording, reporting and incidences were low (Osteras et al, 2007). Producers need time to become familiar with the new management tools.…”

“…LAME The incidence for LAME was slightly lower than the value of 7.0% reported by Kelton et al (1998) as the median from 39 studies. A more recent study showed a higher incidence (Zwald et al, 2004a), but the incidence rate in the large Norwegian dataset was much lower (Osteras et al, 2007). The comparison with the latter must be taken with caution as it deals with another breed of cattle and a population that has had a health-recording programme for many years with genetic evaluations and selection of animals for disease resistance.…”

“…Zwald et al, 2004a); however, this aspect has not been given much attention in the dairy industry. Apart from the use of somatic cell score as an indicator trait to improve resistance to mastitis (MAST), direct selection for health has been limited to Nordic countries (Osteras et al, 2007;Steine et al, 2008). The reason for the absence of direct selection for health traits is often the result of a lack of information suitable for genetic evaluation.…”

“…Given the low heritability, results of selection are not as readily observable as results of improved a Present address: Linear SA, 1725 Posieux, Switzerland -E-mail: jjamrozi@uoguelph.ca management practices. Despite these limitations, genetic progress with respect to resistance to diseases is possible (Heringstad et al, 2000;Osteras et al, 2007).…”

Evaluating somatic cell scores with a Bayesian Gaussian linear state-space model

“…In five Holstein herds in the Czech Republic, the overall incidence was 0.68 clinical cases per cow per year, varying from 0.35 to 1.45 cases between farms (Wolfova et al, 2006). Other estimates were nearer to ours with 14.4 cases per 100 cow-years at risk in Uruguay (Gianneechini et al, 2002) and 14.8 in Norway (Osteras et al, 2007). Such differences between countries may be associated with factors such as climate, detection and reporting methods, breed, level of production and management.…”