The relationships between early lactation energy status indicators and endocrine fertility traits in dairy cows.

The relationships between dairy cow milk-based energy status (ES) indicators and fertility traits were studied during periods 8 to 21, 22 to 35, 36 to 49, and 50 to 63 d in milk. Commencement of luteal activity (C-LA) and interval from calving to the first heat (CFH), based on frequent measurements of progesterone by the management tool Herd Navigator (DeLaval), were used as fertility traits. Energy status indicator traits were milk β-hydroxybutyrate (BHB) concentration provided by Herd Navigator and milk fat:protein ratio, concentration of C18:1 cis-9, the ratio of fatty acids (FA) C18:1 cis-9 and C10:0 in test-day milk samples, and predicted plasma concentration of nonesterified fatty acids (NEFA) on test days.

Net benefits of smallholder dairy cattle farms in Senegal can be significantly increased through the use of better dairy cattle breeds and improved management practices.

Senegal, located in West Africa, is an example of a low- to middle-income country where the government has prioritized improving livestock production self-sufficiency, with a strong focus on dairy. Among other initiatives, the use of exotic dairy cattle has been promoted, despite no evidence for the potential livelihood benefits (or otherwise) to smallholder farmers on adopting the new genetics. The current work fills this evidence gap by performing a farm-level economic study comparing the keeping of different breed and cross-breed types of dairy cattle under different management levels.

Variation in the actual preferences for AI bull traits among Finnish dairy herds.

Changing production circumstances, a wide range of traits and the international bull market enable dairy farmers to make increasingly specific choices concerning artificial insemination (AI) bulls. Finland is part of the joint Nordic dairy cattle breeding programme where in addition to yield, high emphasis is given to health, fertility, conformation and longevity. The aims of our study were (a) to investigate whether Finnish dairy farmers differ in their selection preferences for AI bull traits and can be clustered into herd groups, (b) to determine whether AI bull selection in different herd groups is in line with the Nordic Total Merit index (NTM) and (c) to analyse how the herd groups are related to herd characteristics.

Genetic parameters for endocrine and traditional fertility traits, hyperketonemia and milk yield in dairy cattle.

High-yielding cows may suffer from negative energy balance during early lactation, which can lead to ketosis and delayed ability of returning to cyclicity after calving. Fast recovery after calving is essential when breeding for improved fertility. Traditionally used fertility traits, such as the interval from calving to first insemination (CFI), have low heritabilities and are highly influenced by management decisions.

Genetic co-variance functions for live weight, feed intake, and efficiency measures in growing pigs.

The objective of the present study was to estimate genetic co-variance parameters pertaining to live weight, feed intake, and 2 efficiency traits (i.e., residual feed intake and residual daily gain) in a population of pigs over a defined growing phase using Legendre polynomial equations.