Benefits and risks of antimicrobial drugs, used in food-producing animals, continue to be complex and controversial issues. This review comprehensively presents the benefits of antimicrobials drugs regarding control of animal diseases, protection of public health, enhancement of animal production, improvement of environment, and effects of the drugs on biogas production and public health associated with antimicrobial resistance. The positive and negative impact, due to ban issue of antimicrobial agents used in food-producing animals, is also included in discussion. As a double-edged sword, use of these drugs in food-animals persists as a great challenge.

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Benefits and risks of antimicrobial use in food-producing animals

The main objective was to determine the prevalence of intramammary infections (IMI) in dairy cows in Flanders, Belgium. Data were obtained from quarter milk samples of dairy herds subjected to a mandatory yearly screening of all lactating cows. A total of 178 668 quarter milk samples were collected at 1087 cross-sectional dairy herd screenings performed in three consecutive years. Of the dairy cows, 40% had at least one culture-positive quarter. More than 50% of all IMI were caused by non-aureus staphylococci. Streptococcus agalactiae is almost eradicated in Flanders, whereas Staphylococcus aureus was isolated from 18% of the culture-positive quarters. In addition, the distribution of mastitis pathogens in quarter milk samples from selected dairy cows with an elevated somatic cell count (SCC) is described. From 6390 cows with a geometric mean composite SCC ⩾250 000 cells/ml, nearly 65% had at least one culture-positive quarter. The majority of the IMI were caused by non-aureus staphylococci (41·1%), whereas Staph. aureus and aesculin-positive cocci were found in respectively 25% and 18% of the culture-positive milk samples. We conclude that more efforts are needed in the prevention and control of subclinical mastitis in Flanders. Non-aureus staphylococci are the predominant cause of IMI, warranting more research regarding the epidemiology and pathogenicity of those species.

Prevalence and distribution of mastitis pathogens in subclinically infected dairy cows in Flanders, Belgium.

https://jcp.bmj.com/content/jclinpath/30/11/1089.1.full.pdf

Theory and Practice of Histological Techniques

Sperm competition is now recognised as a potent selective force shaping many male reproductive traits. While the influence of sperm competition on sperm number is widely accepted, its effects upon sperm size remain controversial. It had been traditionally assumed that there is a trade-off between sperm number and sperm size, so that an increase in sperm number would result in a decrease in sperm size, under conditions of sperm competition. Contrary to this prediction, we proposed some time ago that sperm competition favours an increase in sperm size, because longer sperm swim faster and are more likely to win the race to fertilize ova. Comparative studies between species show that in many taxa such a relationship exists, but the consequences of an increase in sperm size may vary between taxa depending on the environment in which spermatozoa have to compete. We present new evidence showing that in mammals longer sperm swim at higher speeds. We also show that mean swimming speed is highly correlated with maximum swimming speed, so even if the fastest swimming sperm are more likely to fertilize, both measures are informative. When individuals of the same species are compared, ratios between the dimensions of different sperm components, as well as the shape of the head, seem better at explaining sperm swimming velocity. Finally, we show that mean and maximum sperm swimming speed determine male fertility. Other studies have shown that in competitive contexts, males with faster swimming sperm have higher fertilization success. We conclude that the available evidence supports our original hypothesis.

/pdf/implications-of-diversity-in-sperm-size-and-function-for-38og988qs0.pdf

Implications of diversity in sperm size and function for sperm competition and fertility

Predictors of success of semen cryopreservation in chickens.

Because of the elective use of Caesarean Section (CS), the Belgian Blue (BB) breed is being criticized by animal health organizations in Europe and it also has economical consequences. Within the selection for the reduction of CS, the increase of pelvic dimensions plays a crucial role. Correct information about the pelvic canal is a very important condition to perform this selection. Measurements of the pelvic canal in living animals can be performed by using a Rice pelvimeter. The present paper describes a study of the repeatability between two different technicians and within one technician of pelvic measurements in double muscled BB cows using a Rice pelvimeter. Additionally, changes within the pelvic dimensions at parturition were examined by measurements at three different points around calving (one month before, within 24 hours and two weeks after parturition). No significant differences were found for the pelvic height between the two technicians. The variation coefficient of the measurements of the second technician proved to be smaller but not significantly different from technician 1, for pelvic width as well as for pelvic height. Only the pelvic height measured at parturition significantly dif

https://biblio.ugent.be/publication/628000/file/667924.pdf

The agreement of pelvic measurements obtained in Belgian Blue cows with a Rice pelvimeter and the differences between these measurements around parturition

Geert Hoflack

Papers

The agreement of pelvic measurements obtained in Belgian Blue cows with a Rice pelvimeter and the differences between these measurements around parturition

Computer-assisted motility analysis of bull semen stored under different conditions

Endometritis bij het rund: een blijvend dilemma voor de practicus ?

Embryotransplantatie bij het varken.

Colostrum quality and quantity in Belgian Blue cows and the subsequent maternel immunty