Regression models are proposed for predicting conception rate in a dairy herd under South African and especially Natal conditions. Conception rate (CR%) was related to mean monthly temperature-humidity index (THI) by curvilinear regression equation model; CR% = 812.7 +/- 28.61 THI - 0.2322THI2 (P = 0.061), and by linear regression equation model; CR% = 188.0 - 1.906THI (P = 0.023). Conception r...

The objective of this study was to investigate the impact of paratuberculosis sero-status on milk yield, fat, protein, somatic cell count and calving interval in Irish dairy herds. Serum from all animals over 12 months of age (n = 2,602) in 34 dairy herds was tested for antibodies to Mycobacterium avium subsp. paratuberculosis using an ELISA. Herds were categorised by sero-status into positive,...

Delayed conception is defined as an interval of greater than 90 days postpartum before a cow becomes pregnant again. In this study, the risk factors for delayed conception in Korean dairy herds were determined by evaluating several reproductive factors in individual cows. The following data was recorded from 1,012 pregnancies in eight dairy herds (designated A-H) from July 2001 to June 2006: he...

An increase in on-farm mortality (euthanasia and death) in dairy herds has been reported in several countries in the last decade. This does not only imply possible problems with animal welfare, but it also causes economic losses to the farmer. The objective of this study was to evaluate time trends in on-farm dairy cow mortality in Sweden and identify potential herd-level risk factors. Data wer...

OBJECTIVE To evaluate associations among herd infection status, herd management practices, and familiarity of the herd manager with Mycobacterium paratuberculosis (Johne's disease) or prior disease diagnosis in that herd to support development of Johne's disease-control programs. DESIGN Population-based cross-sectional study. SAMPLE POPULATION 1,004 US dairies, each with > or = 30 cows, rep...

The objective of the present study was to determine factors affecting body condition score (BCS) and its association with productive and reproductive performances in Holstein cows. Mixed model analysis was performed on monthly records of BCS from April 2006 to July 2012 comprising 34666 records from 3134 dairy cows in a large commercial dairy herd under arid climatic conditions of Isfahan in Ir...

G-typing of rotavirus strains enables the study of molecular epidemiology and gathering of information to promote disease prevention and control. Rotavirus strains in fecal specimens from neonatal calves in Swedish cattle herds were therefore characterized by using G1 to -4-, G6-, G8-, and G10-specific primers in reverse transcription (RT)-PCR. Fecal samples were collected from one dairy herd (...

Two of the most important broad classifications of phenotypes for successful dairy production are milk yield and fertility. The nature of the relationship between milk production and reproductive performance of dairy cows is uncertain due to conflicting results reported in many studies. A common deficiency in many such studies is an underappreciation of the dual dimension of the production-repr...

The relationship of first score and length of life in the herd was measured in Holstein females two or three years of age at first classification. The regression of herd life (number of times classified) on the first over-all type score (nearly all values were between 65 and 90 points) was 1.7 months. Correlation between first classification score and herd life was approximately 0.2, indicating...