Sven Konig

1 Introduction As outlined by, e.g., Gernand and König (2017), female fertility in dairy cattle can be defined as the ability to show heat or maturity, to conceive, and to recycle. In consequence, female fertility is a very complex trait, and accordingly, new breeding indexes have been developed to cover both major fertility components, i.e., the start of a new cycle after calving and the success of an insemination (e.g., Gonzalez-Recio and Alenda 2005; Jorjani 2006).

1 Introduction Domestic sheep naturally possess short tails that have developed into longer woollen appendages through selective breeding. With the waning economic importance of wool, tail docking has become a global norm in sheep husbandry (Hümmelchen et al. 2022). This practice primarily aims to prevent maggot infestation in the tail region caused by faecal contamination (Wall 2012). In some countries, tail docking of sheep is severely restricted or prohibited (Hannemann et al. 2017).

1 Introduction Diarrhoea (DIAR) and pneumonia (PNEU) are economically important diseases contributing to calf mortality up to an age of six months (e.g., Svensson, Linder, and Olsson 2006; Johnson, Burn, and Wathes 2011). Medrano-Galarza et al. (2018) and Dachrodt et al. (2021) reported a prevalence for DIAR and for PNEU larger than 20%. The aetiology of DIAR and PNEU is multi-factorial including the farm management (Svensson et al.