The objectives of this experiment were to determine interrelationships among mastitis indicators and evaluate the subclinical mastitis detection ability of infrared thermography (IRT) in comparison with the California Mastitis Test (CMT). Somatic cell count (SCC), CMT, and udder skin surface temperature (USST) data were compiled from 62 Brown Swiss dairy cows (days in milk=117+/-51, milk yield=14.7+/-5.2 kg; mean +/- SD). The CORR, REG, and NLIN procedures of Statistical Analysis System (SAS Institute Inc., Cary, NC) were employed to attain interrelationships among mastitis indicators. The diagnostic merit of IRT as an indirect measure of subclinical mastitis was compared with CMT using the receiver operating characteristics curves. The udder skin surface temperature was positively correlated with the CMT score (r=0.86) and SCC (r=0.73). There was an exponential increase in SCC (SCC, x10(3) cells/mL=22.35 x e(1.31 x CMT score); R(2)=0.98) and a linear increase in USST (USST, degrees C=33.45+1.08 x CMT score; R(2)=0.75) as the CMT score increased. As SCC increased, USST increased logarithmically [USST, degrees C=28.72+0.49 x ln(SCC, x10(3) cells/mL); R(2)=0.72]. The USST for healthy quarters (SCC 400,000 cells/mL; n=135) (mean +/- SE; 33.45+/-0.09 vs. 35.80+/-0.08 degrees C). The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value were 95.6, 93.6, 14.97, 0.05, 95.0, and 93.6, respectively, for IRT and 88.9, 98.9, 83.56, 0.11, 99.2, and 86.1, respectively, for CMT. The area under the receiver operating characteristics curve for IRT and CMT was not different. In conclusion, as a noninvasive and quick tool, IRT can be employed for screening subclinical mastitis via measuring USST, with a high predictive diagnostic ability similar to CMT when microbiological culturing is unavailable. However, the reliability of IRT among cows with different characteristics and those living under various environmental conditions remains to be determined.

No abstract

Studies to determine the physiological effects and functions of progesterone started in the twentieth century. Progesterone is a steroid-structured hormone with 21 carbon atoms originating from cholesterol. The corpus luteum, formed after ovulation in ruminants, secretes progesterone, which plays a role in the continuity of the pregnancy. Progestagens can be used for estrus synchronization in cows and heifers. Similarly, they are used for estrus synchronization during the breeding season or outside the breeding season by taking advantage of the negative feedback effect of progesterone in small ruminants. It is applied for the treatment of embryonic deaths due to luteal insufficiency in cows with high milk yield. In anovulatory anestrus, exogenous progesterone applications can be very useful. Progesterone treatment contributes to the resolution of the anestrus by rearranging hypothalamic functions in cattle with follicular cysts. The oxidative stress index in the luteal phase, when progesterone is high in ruminants, is higher than in the follicular phase. In the critical period of pregnancy, a high index of oxidative stress-induced progesterone causes embryonic death. Factors that cause stress in high milk-yielding cows can affect the amount of progesterone synthesis by inhibiting luteal cell function due to excessive free radical production.

No abstract

The aim of this study was to determine gestational age in Abaza and Gurcu goats by measuring certain embryonic and foetal indices with ultrasonography. A 5–7.5 MHz linear probe was used to obtain ultrasound measurements from 30 pregnant goats (10 Abaza and 20 Gurcu). Heart diameter (HD), biparietal diameter (BPD), crown-rump length (CRL), trunk diameter (TD) and placentome diameter (PD) were measured to determine gestational age. The mean of embryonic and foetal indices were calculated and linear regression was performed. Heart diameter measurements for Abaza and Gurcu goats were significantly different on days 45 (P= 0.048) and 60 (P= 0.019). Biparietal diameter values were significantly different on day 45 (P= 0.035). Crown-rump length measurements were significantly different at days 30 (P= 0.003) and 60 (P= 0.002). We determined that HD and TD were the best predictors of gestational age for Abaza goats (R2= 0.952, R2= 0.949, respectively), whereas HD and CRL were the best predictors of gestational age for Gurcu goats (R2= 0.933, R2= 0.942, respectively). Based upon our study results, these specific indices could be applied during ultrasonographic examinations of Abaza and Gurcu goats to confirm gestational age when the day of mating is unknown.