Evaluating somatic cell scores with a Bayesian Gaussian linear state-space model.

Because accurate characterization of health state is important for managing dairy herds, we propose to validate the use of a linear state-space model (LSSM) for evaluating monthly somatic cell scores (SCSs). To do so, we retrieved SCS from a dairy database and collected reports on clinical mastitis collected in 20 farms, during the period from January 2008 to December 2011 in the Walloon region of Belgium. The dependent variable was the SCS, and the independent variables were the number of days from calving, year of calving and parity. The LSSM also incorporated an error-free underlying variable that described the trend across time as a function of previous clinical and subclinical status. We computed the mean sum of squared differences between observed SCS and median values of the posterior SCS distribution and constructed the receiver operating characteristic (ROC) curve for SCS thresholds going from 0 to 6. Our results show SCS estimates are close to observed SCS and area under the ROC curve is higher than 90%. We discuss the meaning of the parameters in light of our current knowledge of the disease and propose methods to incorporate, in LSSM, this knowledge often expressed in the form of ordinary differential equations

<em>Antemortem</em> and <em>postmortem</em> examination of the genital tract of dairy cows in South Vietnam

A total of 507 culled crossbred Holstein x Lai Sind dairy cows aged 8.5 years on average were examined antemortem (age determination by teeth, body condition scoring, vaginal examination via speculum) and postmortem (ultrasound examination of ovaries,  examination  of  uterine  content).  Nearly  half of them (44.4%) had a body condition score lower than 2.5. The prevalences of pneumovagina and urovagina were 33.1 and 14.7%, respectively. The age and body condition score had a significant effect on the prevalence of these diseases. The prevalences of abnormal vaginal discharges and uterine content were 12.1 and 5.4%, respectively.  Among the 507 cows examined, 226 (44.6%) were in anestrus. The prevalence of anestrus associated with pregnancy was 4.9%. The prevalences of functional pathological anestrus (types 0, I and II), of anestrus associated with cyst, and with pyometra were 37.3, 2, and 0.4%, respectively. Anestrus types 0 and I have been more often observed in cows with low body condition scores and in those under six years old

Analysis of heat detection practices in dairy cattle farms in Algeria

A survey on heat detection practices was performed in 222 cattle farms spread over five regions (wilayas) of Central Algeria (Tizi Ouzou, Blida, Medea and Tipaza Bouira). The questionnaire contained general information on livestock (number of females, stabling, specialization) as well as heat detection practices (observation periods, signs observed) and complementary means as needed. The majority of farmers (57%) faced a problem of heat detection. In 49% of the cases, they inseminated their cows for the first time from 50 to 90 days after calving. One farmer out of two (53%) detected heats twice a day and 40% of them observed them three times a day, this activity being carried out at random. They primarily based their finding of estrus on the presence of a vulvar discharge (19%) or on mounting acceptance (16%). Herd size and specialization had no impact on the frequency of the signs considered. Cows that did not shown heat signs during the first 60 days after calving were clinically examined by a veterinarian in 76% of the farms. Additional means of detection such as rotating schedules or pencil marks were used only by 34% of the farmers. The factors responsible for heat manifestation, moments and numbers of observations, examination of post-partum anestrous, and use of additional means were influenced by the farm specialization and herd size, unlike heat signs, the waiting period and the difficulty of detection