Hereford cows were randomly bred to Hereford, Angus, Simmental X Hereford and Simmental sires. Each sire breed group was represented by nine or 10 sires. These matings produced approximately 100 calves in each sire breed group over 4 yr. The objective of this study was to determine the effect of calf breed on characteristics of the cow such as milk production, reproduction, measures of conditio...

This experiment consisted of the following treatment-breed groups: 1) White crossbred gilts, 2) White crossbred gilts treated with progesterone (200 mg/d in corn oil given on d 2 and 3 after estrus), and 3) Chinese Meishan gilts. Pregnant and nonpregnant gilts (n=3 to 6) from each treatment-breed combination were assigned to be slaughtered on d 10, 11, 12, 13, and 15. At slaughter each uterine ...

The Genetic Basis For Increased Productivity Considerable research by various State Agricultural Experiment Stations and the USDA has clearly demonstrated the potential for increasing beef cattle productivity through crossbreeding. Consequently, the use of crossbreeding for the commercial production of beef is rapidly increasing. Crossbreeding (the mating of animals from different breeds) is si...

Effects of heterosis on reproduction were evaluated in a comprehensive experiment comparing straightbred Hereford (H), Angus (A) and Shorthorn (S) females to reciprocal cross females among these breeds when mated to produce crossbred calves with equal additive and non-additive genetic composition. This phase of the experiment involved 570 matings (cow-years) of straightbred cows and 687 matings...

Studies on the trypanotolerance of Orma Boran X Maasai Zebu (Orma Zebu) crossbred cattle (F1 progeny) and pure-bred Maasai Zebu contemporaries were carried out in Nguruman, south western Kenya. The two groups were monitored from birth for a period of 2 years. The incidence of trypanosomosis, parasitaemia, packed cell volume (PCV), body mass and average daily mass gain were monitored. During the...

Two separate animal trials were conducted to evaluate the coincidence of dry matter intake (DMI) and average daily gain (ADG) predicted by the Cornell Net Carbohydrate and Protein System (CNCPS) and observed actually in crossbred growing bulls kept in a traditionally confined feeding system in China. In Trial 1, 45 growing Simmental×Mongolia crossbred F1 bulls were assigned to three treatments ...

A study was undertaken to compare the longevity and lifetime lamb output of purebred Scottish Blackface (BF) ewes with a range of crossbred genotypes from Scottish BF dams. For up to five successive breeding seasons, 1143 Scottish BF, Swaledale × BF (SW × BF), North Country Cheviot × BF (CH × BF), Lleyn × BF (LL × BF) and Texel × BF (T × BF) ewes were mated to a range of sire breeds on six hill...

In livestock, genomic selection (GS) has primarily been investigated by simulation of purebred populations. Traits of interest are, however, often measured in crossbred or mixed populations with uncertain breed composition. If such data are used as the training data for GS without accounting for breed composition, estimates of marker effects may be biased due to population stratification and ad...