Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin c...

the main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (bw), gestation length (gl) and calving difficulty (cd) in first-parity iranian holstein dairy cattle. the data included 29,950 calving records collected during 1995 to 2014 by the animal breeding and improvement center of iran. a threshold-linear sire-maternal grandsire model was ...

Lameness of dairy cattle is an economic and welfare issue. It is the third most important health related economic loss facing the dairy industry, following fertility and mastitis. Most economic loss due to lameness results from costs of premature culling, veterinary treatment, increased labor, discarded milk, prolonged calving interval, and reduced milk production (Kossaibati and Esslemont, 199...

Fikre Lobago, 2007. Reproductive and Lactation Performance of Dairy Cattle in the Oromia Central Highlands of Ethiopia with Special Emphasis on the Pregnancy Period. Doctoral thesis. ISSN 1652-6880, ISBN 978-91-85913-20-6 This thesis presents studies of the reproductive and lactation performance of dairy cattle in the Oromia Central Highlands of Ethiopia, with particular emphasis on diagnosing ...

Twinning costs the dairy industry an estimated $96 million each year. Twin pregnancy occurrence in high-producing cows is primarily a result of multiple ovulations associated with low circulating concentrations progesterone due to high milk production. The present retrospective observational study aimed identify associations between (1) previous parity yield and subsequent twin birth prevalence...

Historically, genetic improvement programs for dairy cattle focused on within-breed selection strategies due to the strong role of breed associations in developing selection policies and a milk pricing system that rewarded volume rather than cheese yield. As a result, Holsteins became the predominant breed in the US and most other major milk producing nations. However, farmers have become incre...

Male calves and culled cows of dairy cattle are used for beef production. However, unlike beef breeds, the genetics of growth performance traits in dairy breeds have not been extensively studied. Here, we performed a genome-wide association study (GWAS) on Holsteins ( = 5,519), Jerseys ( = 1,231), and Red Dairy Cattle ( = 4,410) to identify QTL for growth traits. First, a GWAS was performed wit...

Genetic improvement in beef and dairy cattle reproductive traits has historically been hampered by the availability and accuracy of applicable genetic predictions. Reproductive trait phenotypes are generally time-consuming to measure, categorical and/or threshold in nature, often are not collected in the context of inventory-based performance recording systems, and typically of lower relative h...

The aim of this study was to attempt at providing a complete picture of dynamics of selected biochemical blood parameters (parathyroid hormone, Calcium, Phosphorus, Sodium, Potassium, Chlorine and ionized calcium) around calving period in high producing dairy cattle (Holstein breed), giving new and useful information about the guidelines for the management strategies during different physiologi...

Mortality in dairy cattle is not only relevant with regard to economic losses but also to animal health and welfare. Thus, the aim of this investigation was to explore the genetic background of postnatal mortality in calves and replacement heifers in different age groups until first calving in Danish Holsteins. Records of Danish Holstein heifer calves born in the years 1998 to 2007 were extract...