Fitness and adaptation are fundamental characteristics of plant and animal species, enabling them to survive in their environment and to adapt to the inevitable changes in this environment. This is true for both the genetic resources of natural ecosystems as well as those used in agricultural production. Extensive genetic variation exists between varieties/breeds in a species and amongst individuals within breeds. This variation has developed over very long periods of time. A major ongoing challenge is how to best utilize this variation to meet short-term demands whilst also conserving it for longer-term possible use. Many animal breeding programs have led to increased performance for production traits but this has often been accompanied by reduced fitness. In addition, the global use of genetic resources prompts the question whether introduced genotypes are adapted to local production systems. Understanding the genetic nature of fitness and adaptation will enable us to better manage genetic resources allowing us to make efficient and sustainable decisions for the improvement or breeding of these resources. This book had an ambitious goal in bringing together a sample of the world’s leading scientists in animal breeding and evolutionary genetics to exchange knowledge to advance our understanding of these vital issues.

Worldwide, mastitis is still one of the most important diseases in the dairy sector. Being a multifactorial disease, caused by multiple pathogens, control remains a difficult issue. Mastitis not only affects the health of milk-producing animals, having consequences for the profitability of dairy farms, it also affects the animal welfare. Moreover, mastitis negatively influences the milk quality having consequences for the dairy processing industry. In other words: mastitis affects a large part of the dairy production chain. Due to ongoing scientific effort, insight in mastitis in the context of increasingly complex farming systems, is improving. This insight leads to better methods to control mastitis, either by prevention or by adequate measures (e.g. therapy) when a cow (or goat or sheep) gets mastitis. This book reflects the current knowledge from all over the world on mastitis as it was presented during the 4th IDF International Mastitis Conference, held in June 2005 in Maastricht, the Netherlands. The papers of the 115 oral presentations and the 13 keynote presentations are reflecting not only the current knowledge of mastitis control but are also giving ideas for future solutions for control measures.

In 1939, when the Bureau of Dairy Industry began its crossbreeding experiment at Beltsville, the published information on the crossbreeding of dairy cattle was slight, unimpressive, and very little of it was based on experimental results. The crossbreeding investigations at Beltsville were undertaken to develop knowledge on the subject which would provide a sound basis for advising the operators of milk-producing farms what to expect if they used crossbreeding in hopes of producing better replacements for their milking herds. Final results on any dairy cattle breeding research project cannot be published until the last animal on the project has died, so this report covers the breeding performance and milk and butterfat production on all individuals used on the project which have had time to complete a normal first-lactation period.

Deals with feed evaluation systems, the nutrient requirements of ruminant livestock and the feeding value of a wide range of feedstuffs. This book lists about 800 typical forages, 65 crop residues and 120 concentrate and by-product feeds. It is suitable for teachers, specialist scientists and industrialists.