Prevalence of subclinical mastitis in Finnish dairy cows: changes during recent decades and impact of cow and herd factors

Abstract

BackgroundThe dairy industry has undergone substantial structural changes as intensive farming has developed during recent decades. Mastitis continues to be the most common production disease of dairy cows. Nationwide surveys of mastitis prevalence are useful in monitoring udder health of dairy herds and to study the impact of structural changes on the dairy industry. This survey on bovine subclinical mastitis was the first based on cow composite milk somatic cell count (SCC) data from the Finnish national health monitoring and milk recording database. A cow with composite milk SCC ≥200,000 cells/ml in at least one of the four test milkings during the year was considered to have subclinical mastitis and a cow with composite milk SCC ≥200,000 cells/ml in three or in all four test milkings during the year to have chronic subclinical mastitis. The aim of the study was to determine the prevalence of subclinical mastitis and chronic subclinical mastitis in Finland in 1991, 2001 and 2010 and to investigate cow and herd factors associated with elevated SCC.ResultsPrevalence of subclinical mastitis in Finland decreased over recent decades from 22.3% (1991) and 20.1% (2001) to 19.0% (2010). Prevalence of chronic subclinical mastitis was 20.4% in 1991, 15.5% in 2001 and 16.1% in 2010. The most significant cow and herd factors associated with subclinical mastitis or high milk SCC were increasing parity, Holstein breed, free-stalls with an automatic milking system and organic production. Milk SCC were highest from July to September. Main factors associated with chronic mastitis were increasing parity and Holstein breed.ConclusionsPrevalence of subclinical mastitis in Finland decreased over recent decades, the greatest change taking place during the first decade of the study. Prevalence of chronic subclinical mastitis significantly decreased from 1991. The most significant factors associated with both types of mastitis were increasing parity and Holstein breed, and for subclinical mastitis also free-stalls with automatic milking. National surveys on mastitis prevalence should be carried out at regular intervals to monitor udder health of dairy cows and to study the impact of the ongoing structural changes in the dairy industry to enable interventions related to udder health to be made when needed.Electronic supplementary materialThe online version of this article (doi:10.1186/s13028-017-0288-x) contains supplementary material, which is available to authorized users.

Relationship between the probability of veterinary-diagnosed bovine mastitis occurring and farm management risk factors on small dairy farms in Austria

“…For example, a study in the United States determined that cows kept in tiestalls had a 1.5 times greater risk than those housed in freestalls (Richert et al, 2013), confirming a previous Norwegian study (Valde et al, 1997). Nevertheless, this finding was not observed in the current study, although 34% of farms in this study population had tiestalls, which corresponds with findings on Finnish dairy farms, where cows kept in freestalls with automated milking systems or with milking parlors were reported to have a higher estimated SCC than cows kept in tiestalls (Hiitiö et al, 2017). Overall, herd size (median = 21 cows; mean = 26.9 cows in this study population) did not appear to have a substantial influence on the probability of mastitis occurring according to the statistical model applied here.…”

“…Similar findings have been reported in other studies of udder health in small dairy farms. For example, a Finnish study (largest herd size category: >60 cows) reported average herd size as having no effect on subclinical mastitis (OR = 1.003), whereas a Swiss study found that a herd size of >27 dairy cows and heifers increased the odds of subclinical mastitis occurring compared with smaller herds (<20 head; Doherr et al, 2007;Hiitiö et al, 2017). Dairy farms in other European countries often have much larger herds, with surveys from 2016 to 2017 reporting a mean of 61.9 cows per herd in Germany, 93.8 cows per herd in the Netherlands, and 146 cows per herd in the United Kingdom compared with just 21.3 cows per herd in Austria at that time (Barkema et al, 2015;AHDB Dairy, 2018;BMEL Statistik, 2018;CRV, 2018;ZAR, 2018).…”

Acute-phase inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) levels in serum and milk of cows with subclinical mastitis caused by Streptococcus species and coagulase-negative Staphylococcus species

“…Although the milk appears normal, cows with subclinical mastitis will produce less milk, and the quality of the milk will be reduced. In addition, infected cows can be a source of infection to other animals in the herd (Hiitiö et al, 2017).…”

S100 calcium‐binding protein A12 as a diagnostic index for subclinical mastitis in cows

“…Cows with a high SCC indicative of subclinical mastitis have an estimated loss in milk production of more than 1,500 pounds per cow (Kirkpatrick & Olson, ). Healthy milk (HM) has lower cell counts ranging from 50,000 to 200,000 cells/ml of milk (Hiitiö et al., ). However, the cell counts of milk from cows with SCM can reach a few million cells per millilitre and usually range from 200,000 to 500,000 cells/ml (Guan, Wu, Xu, Su, & Hu, ; Smith, ; Sun et al., ).…”

“…cow, diagnosis, S100A12, subclinical mastitis 50,000 to 200,000 cells/ml of milk (Hiitiö et al, 2017). However, the cell counts of milk from cows with SCM can reach a few million cells per millilitre and usually range from 200,000 to 500,000 cells/ml (Guan, Wu, Xu, Su, & Hu, 2017;Smith, 1996;Sun et al, 2017).…”