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Abstract. This study investigated the relationship between follicle size (FS) and developmental competence of calf oocytes. Cumulus-oocyte-complexes (COCs) from follicles >8 (L-COCs; n=19), 4-8 (M-COCs; n=54), and 2-3 mm (S-COCs; n=155) were recovered from non-stimulated 1-4 months old dairy calves post mortem and ex vivo (laparoscopy), and in parallel from slaughtered adult cows from follicles of identical size categories [> 8 (n=91); 4-8 (n=138); 2-3 mm (n=193)]. Morphologically intact COCs were subjected to in vitro maturation, fertilization, and embryo culture. Cleavage rate (CR; 46 h post-insemination=p.i.), rate of morulae/blastocysts (M/Bl; day 7 p.i.), and blastocysts (Bl; day 9 p.i.) were recorded. FS had no effect on the CR in calves. However, calf L-COCs yielded the highest rates of M/Bl and Bl compared with the two other size categories (P<0.05). In contrast, calf S-and M-COCs gave similar rates of M/Bl, whereas the proportion of Bl was lowest for S-COCs (P<0.05). This was almost identical to findings in cows, except that the CR was highest for L-COCs and M/Bl yields were lowest for S-COCs (P<0.05). There were no differences between calf and cows with regard to CR for the respective FS categories. L-COCs from calves and cows yielded similar rates of M/Bl and Bl, whereas calf S-and M-COCs yielded lower rates of Bl than S-and M-COCs from cows and a lower rate of M/Bl when S-and M-COCs were analyzed as one group (P<0.05). Whereas the CR was similar in calves and cows, calf COCs yielded lower rates of M/Bl and Bl (P<0.05). In conclusion, the results show that the developmental competence of calf oocytes is higher in those derived from follicles larger than 8 mm, and thus are almost equally as competent as cow oocytes derived from follicles of identical size. This suggests that calf oocytes acquire developmental competence within the large follicle, potentially due to a process similar to prematuration of the oocyte in the adult cow. It is proposed that procedures that facilitate prematuration, such as "coasting" following a preceding superstimulation, might increase the developmental competence of calf oocytes.

The objective of this clinical control trial was to examine the effectiveness of the classical homeopathic treatment strategy in cases of mild and moderate bovine clinical mastitis in comparison with antibiotic and placebo treatments. Owing to characteristics of the selected herds, only cases of clinical mastitis caused by environmental pathogens and clinical cases with negative bacteriological result in the pre-treatment milk sample were included in the trial. A total of 136 lactating dairy cows with 147 affected quarters from four herds in Germany were randomly allocated to three treatment groups. The cows were examined on days 0, 1, 2 and on days 7, 14, 28 and 56 post initial infection to assess clinical signs. Simultaneously, with the exception of days 1 and 2, quarter milk samples for laboratory examinations (bacteriology, somatic cell count) were collected to assess bacteriological and cytological cure rates. On days 28 and 56, treatment strategies did not differ significantly with respect to the clinical outcomes and the total cure rate in cases of bacteriological negative mastitis (n=56). In cases of pathogen-positive mastitis (n=91), the cure rate after 4 and 8 weeks was similar between the two treatment strategies, homeopathy and antibiotic treatment, but the difference between the homeopathic and the placebo treatment at day 56 was significant (P<0·05). The results indicate a therapeutic effect of homeopathic treatment in cases of mild and moderate clinical mastitis. However, independent of treatment strategy and bacteriological status, the total cure rate was on a low level, revealing limitations in the effectiveness of both antibiotic and homeopathic treatment strategies.

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