The aim of this thesis was to explore conditions for selection and genetic improvement of fertility and longevity in dairy cattle. The background is that single-trait selection for milk production is known to lead to impaired fertility and consequently to shorter lifespan. This in turn results in financial losses and ethical concerns. Since many years, the Swedish dairy farmers have recorded mi...

In German Holstein population a very signifi cant QTL with effects on milk yield trait (MY) was mapped on chromosome 6 and 20 to the interval BM143–ILSTS97 and AGLA29–ILSTS72, respectively. Where, three markers BM143, FBN13 and ILSTS97 on chromosome 6 and two markers AGLA29 and ILSTS72 on chromosome 20 were associated with highly signifi cant effects (P<0.01) for milk yield. Findings from this ...

The objective of this study was to apply factor analysis to describe lactation curves in dairy buffaloes in order to estimate the phenotypic and genetic association between common latent factors and cumulative milk yield. A total of 31 257 monthly test-day milk yield records from buffaloes belonging to herds located in the state of São Paulo were used to estimate two common latent factors, whic...

Female fertility is one of the most economically important traits for the dairy cattle industry. Because of a few decades of selection mainly for higher milk production, many dairy farms around the world suffer from the consequences of female fertility loss. The aims of this thesis were to study the international genetic evaluation of female fertility traits, to quantify the bias of analyzing m...

Test-day records of somatic cell count (SCC), milk yield, fat and protein content and six linearly scored type traits (fore udder attachment, udder depth, central ligament, rear udder height, front teat placement, teat length) of 22 613 first lactation cows from 117 herds were included in this study. SCC was log-transformed into somatic cell score (SCS). Milk yield was standardized as follows: ...

Social and psychological stressors are both a part of daily life and are increasingly recognized as contributors to individual susceptibility to develop diseases and metabolic disorders. The present study investigated how snacks differing in sensory properties and presentation can influence ratings of affect in consumers with different levels of dispositional anxiety. This study examines the re...

Longevity is a highly desirable trait that considerably affects overall profitability. With increased longevity the mean production of the herd increases because a greater proportion of the culling decisions are based on production and the proportion of mature cows, which produce more milk than young, cows is increased. An increased longevity enables higher selection intensity of females and th...

Streptococcus thermophilus is a dairy species commonly used in the manufacture of cheese and yogurt. Here, we report the complete sequence of S. thermophilus strain JIM8232, isolated from milk and which produces a yellow pigment, an atypical trait for this bacterium.

Rate of genetic improvement for milk yield has been increasing in recent years. Cows born in 1986 were about 135 kg superior in breeding value for milk yield to those born in 1985. Over 2.2 million cows contribute new data to genetic evaluations for production traits annually. These evaluations are computed with an animal model that provides best linear unbiased predictions of transmitting abil...

The objective of this study was to estimate genetic parameters of antibody response to Mycobacterium avium ssp. paratuberculosis using routinely collected Minnesota Dairy Herd Improvement milk ELISA tests. After all edits, 25,809 tests from 21,514 Holstein cows in 282 Johne's positive herds were available for analysis. The Johne's test results were analyzed both as a binary trait (positive or n...