Stefan Aerts

University of Leuven, Louvain, Flanders, Belgium

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Publications (12)9.55 Total impact

  • I Kolkman · G Hoflack · S Aerts · H Laevens · D Lips · G Opsomer ·
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    ABSTRACT: Some anatomical characteristics of 507 Belgian Blue (BB) cattle, withers height (WH), heart girth (HG), the distance between the two tubera coxae (TcTc) and the distance between the two tubera ischiadica (TiTi), were compared with the internal pelvic measurements of width, height and area. Mean values were 58.9 ± 6.2 cm for TcTc, 14.6 ± 2.3 cm for TiTi, 15.2 ± 2.1 cm for pelvic width (PW), 18.8 ± 1.9 cm for pelvic height (PH) and 288.5 ± 60.9 cm(2) for pelvic area (PA). Cows that calved per vaginam had larger WH (p < 0.05), TcTc (p < 0.05) and TiTi (p < 0.001) and internal pelvic measurements [PH and PA (p < 0.001)] compared with those whose parturition was managed by caesarean section (CS): Correlations between internal pelvic measurements and TcTc were higher (r = 0.58-0.63) than TiTi (r = 0.22-0.28). Correlations between other external body measures such as HG and WH with the internal pelvic measurements were even higher for HG (r = 0.69-0.74) and for WH (r = 0.67-0.74). HG and WH, together with internal pelvic measures, may be added to estimated breeding values (EBV's) that should assist breeders in selecting cows that can calve per vaginam, thereby reducing the breed's dependence on elective CS for maintaining its unique characteristics.
    Reproduction in Domestic Animals 09/2011; 47(3):365-71. DOI:10.1111/j.1439-0531.2011.01881.x · 1.52 Impact Factor
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    I Kolkman · G Opsomer · S Aerts · G Hoflack · H Laevens · D Lips ·
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    ABSTRACT: At calving, purebred animals of the Belgian Blue (BB) breed are compromised by the incompatibility in size and shape of the dam and her calf, resulting in a very high incidence of dystocia problems. To clarify which body parts of the calf are of decisive importance to allow natural delivery and to investigate both the mean value as well as the variation among these body sizes within this breed (variation being an important condition for selection), measurements of nine body parts (body weight at birth (BW), body length (BL), length of the head (LH), shoulder width (SW), hip width (HW), heart girth (HG), withers height (WH) and the circumference of the fetlock of both the front (CFF) and the hind leg (CFH)) were assessed in 147 newborn purebred BB calves on 17 farms. Simple and partial correlations were assessed and we examined whether environmental factors (gender of the calf, parity of the cow, type of calving, season of birth and time of measurement after birth) were significantly associated with these specific calf measurements. The mean BW was 49.2 ± 7.1 kg. The average BL was 56.4 ± 4.5 cm and the mean LH was 24.4 ± 2.3 cm. Measurements obtained for SW and HW were 22.4 ± 2.2 and 22.9 ± 2.1 cm, respectively, whereas the mean WH was 71.1 ± 4.7 cm. Measurements of circumferences revealed a CFF of 17.9 ± 1.1 cm, a CFH of 18.0 ± 1.0 cm and a mean HG of 78.0 ± 5.4 cm. Partial correlations of the BW with eight body measurements were significant (P < 0.01) and ranged between 0.17 and 0.85; 0.42 and 0.88; and 0.24 and 0.88 when corrected for gender, parity and type of calving, respectively. BL (P < 0.01) and the CFF and CFH (P < 0.001) are larger in bull calves than in heifer calves. Calves born through caesarean section had broader SW (P < 0.01) and HW (P < 0.01) when compared with calves born after natural calving (defined as born per vaginam without assistance or with slight traction). Sizes of calves born out of multiparous cows were generally larger than of calves born out of heifers (SW: P < 0.001; HW: P < 0.05). As SW and HW are the broadest points of a BB calf, they are both candidates for being the limiting measures for calving ease, but the difference between HW and SW for the total data set was not different from zero (P > 0.05). In contrast to male calves in which no significant difference (between HW and SW) could be found, female calves show the difference between HW and SW that was significantly different from zero (P < 0.001); thus, in female calves, the HW is the most limiting factor of the calf's body. The significant variation in some body measures between the calves and the strong correlation within these sizes raises the possibility of selection towards smaller calves aiming to limit the dystocia problem in the BB breed. Furthermore, on the basis of our results, we were able to build equations for the farmer to use at the moment of calving containing the LH, the CF and the calf's gender to estimate SW and HW, the limiting body parts of the calf to be born naturally. Together with the knowledge of the pelvic size of the dam, this information gives the obstetrician or the farmer a more accurate prediction of the probability of natural calving at parturition.
    animal 05/2010; 4(5):661-71. DOI:10.1017/S1751731109991558 · 1.84 Impact Factor
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    ABSTRACT: This article describes a study of the behaviour of double muscled Belgian Blue (BB) cows during the peri partum period to assess the differences in pain perception in cows calving per vaginam vs cows delivering by caesarean section (CS). In one herd, a total of 30 multiparous cows, of which 17 delivered by CS and 13 calved per vaginam, were closely observed at approximately 1 month before calving and at days 1, 3 and 14 after parturition. The main behavioural indicators of pain were alertness, transition in posture from standing to lying and vice versa, aggressive behaviour, vocalization, rumination quality, reaction on wound and vulva pressure and the percentage of visible eye-white. The main significant differences were lower overall activity and more transition in posture in animals that delivered by CS than in cows that calved naturally. Less time was spent on eating and ruminating in the CS group, their total resting time was longer and their total standing time was shorter. These significant differences were only observed on the first day after calving. Cows of the CS group reacted significantly more when pressure was put on the left flank on the first, third and fourteenth day after calving, whereas animals that calved per vaginam showed more reaction when pressure was put on the area around the vulva, but only on the first day. Based on the results of the present study, we can conclude that there are some significant short-term behavioural differences between BB cows that calve naturally and those that deliver by CS, but in general, the differences are subtle and of short duration.
    Reproduction in Domestic Animals 02/2010; 45(1):160-7. DOI:10.1111/j.1439-0531.2008.01295.x · 1.52 Impact Factor
  • I. Kolkman · G. Hoflack · S. Aerts · R.D. Murray · G. Opsomer · D. Lips ·
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    ABSTRACT: The accuracy of the Rice pelvimeter for measuring pelvic area of double muscled Belgian Blue (BB) cattle was investigated by comparing measurements in the live animal with these obtained from the same animal after slaughter. Pelvic measurements from 466 BB-cows aged 2–10 years old and of an excellent carcass qualification (S and E in the SEUROP classification) were measured with the pelvimeter approximately 12 h prior to, and by graded ruler within 2 h after, slaughter. The mean difference of measurements between living and dead cattle were −0.2 cm for pelvic width (95% limits of agreement −2.5–2.1 cm), and 1.2 cm for pelvic height (95% limits of agreement −1.8–4.1 cm). The correlation coefficient between all pelvic measurements was between 0.46 and 0.59 (p
    Livestock Science 04/2009; 121(2):259-266. DOI:10.1016/j.livsci.2008.06.022 · 1.17 Impact Factor
  • Johan Evers · Stefan Aerts · Johan De Tavernier ·
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    ABSTRACT: Livestock production has been confronted with several epidemics over the last decades. The morality of common animal disease strategies—stamping out and vaccination—is being debated and provokes controversies among farmers, authorities and the broader public. Given the complexity and controversy of choosing an appropriate control strategy, this article explores the potential of nano-enabled diagnostics in future livestock production. At first glance, these applications offer promising opportunities for better animal disease surveillance. By significantly shortening the reaction time from diagnosis to appropriate control, they could complement the current disease management strategies. Although nano-enabled diagnostics will not make livestock disease eradication strategies redundant or completely free of the culling of infected animals, these diagnostics could significantly reduce the number of culled animals and animal suffering. This article aims to demonstrate that the ethical assessment of advanced diagnostics can build on the experiences with decision making in biomedical ethics where nonmaleficence, beneficence, autonomy and justice serve as important benchmarks. Nano-enabled diagnostics may be an ethically sound solution if it can resolve the dilemma between stamping out and vaccination in favor of the latter and if it can balance the autonomy–paternalism dilemma between farmers and authorities. The technology should allow to be switched on and off by farmers, whilst simultaneously allowing for a weak paternalism on behalf of authorities in order to benefit the farmer and broader society and to protect them from harm.
    NanoEthics 01/2008; 2(2):163-178. DOI:10.1007/s11569-008-0034-y · 0.70 Impact Factor
  • Look · van de · I Kolkman · H. Vervaecke · J Vicca · D Lips · S Aerts ·
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    ABSTRACT: De vraag is in hoeverre het welzijn van het dier door een keizersnede aangetast wordt. Onderzoek aan de Katholieke Hogeschool van Sint-Niklaas vergeleek de pijnindicatoren bij natuurlijk bevallen met het kalven via keizersnede bij Belgisch witblauwe runderen
  • Johan De Tavernier · Stefan Aerts ·

    Journal of Agricultural and Environmental Ethics 02/2006; 19(1). DOI:10.1007/s10806-005-4526-2 · 0.94 Impact Factor
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    ABSTRACT: When making an assessment of animal welfare, it is important to take environmental (housing) or animal-based parameters into account. An alternative approach is to focus on the behavior and appearance of the animal, without making actual measurements or quantifying this. None of these tell the whole story. In this paper, we suggest that it is possible to find common ground between these (seemingly) diametrically opposed positions and argue that this may be the way to deal with the complexity of animal welfare. The model will have to be acceptable for the different parties that will be affected by it and real benefits for the animal should result from it. This will be the basis of a practical ethical approach. All this can be condensed into a model that essentially is made up out of three basic elements: the classical welfare analysis with an existing welfare assessment tool, an assessment of the stockholder, and an implementation of the Free Choice Profiling technique. This new framework does not pretend to be a different or better animal welfare matrix; it is intended to integrate existing knowledge and to provide a practical tool to improve animal welfare. It identifies whether there are welfare problems on a farm, if present whether these problems are caused by the housing system or the stockholder, and what can be done to improve the situation.
    Journal of Agricultural and Environmental Ethics 01/2006; 19(1):67-76. DOI:10.1007/s10806-005-4376-y · 0.94 Impact Factor
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    ABSTRACT: Perhaps the commonest reasons for the keeping of pets are companionship and as a conduit for affection. Pets are, therefore, being “used” for human ends in much the same way as laboratory or farm animals. So shouldn’t the same arguments apply to the use of pets as to those used in other ways? In accepting the “rights” of farm animals to fully express their natural behavior, one must also accept the “right” of pets to express their intrinsic natural behavior. Dogs kept in houses for most of the day are being kept in an unnatural environment. So are rabbits kept in hutches, and guinea-pigs or birds in cages. These conditions infringe the animals’ telos. Dogs are naturally pack animals, so is a dog in isolation being denied its telos? Other actions more deliberately infringe telos and autonomy. Enforced shampooing – or even exercise; hair-cutting of poodles; putting animals in clothes; and tail-docking. If de-beaking of chickens is considered wrong, then the same must be true for tail-docking of dogs. One should also question the ethics of specialist breeding – especially when that results in physiological disadvantages (boxers with breathing troubles). There would appear to be no advantage to the animals in having such health problems and when these are the direct result of the breeders’ desire for specific cosmetic traits, we should question the ethics of the practice at least as much as when animals are bred for specific agricultural traits.
    Journal of Agricultural and Environmental Ethics 01/2006; 19(1):17-25. DOI:10.1007/s10806-005-4379-8 · 0.94 Impact Factor

  • Ethische Perspectieven 12/2004; 14(4):406-412. DOI:10.2143/EPN.14.4.516916
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    Stefan Aerts · Ruben Boonen · Johan De Tavernier · Dirk Lips ·
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    ABSTRACT: A dramatic gain in efficiency is an absolute necessity if we are to overcome the agricultural challenges of the third millennium. One of the ways that could lead to such a gain in efficiency is a renewed and augmented use of by-products. In an agricultural context the food industry is a major source of potentially valuable by-products. For other Western European countries VALORBIN (2003a) mentions 5 million tons in Denmark, 11 million in The Netherlands, and 14 million tons in Germany. 70 to 80 % of food industry by-products are reused in feed manufacturing. In all applications, two important ethical aspects seem to overarch all others, being (the care for) public health, and the need for recycling. Both aspects will be important with all by-products and all applications, but their relative importance will differ. This does not mean that zero-risk or maximum recycling need to be the goal. In both aspects environmental considerations are included. It is important to keep an eye out for direct and indirect impacts on other products. A hierarchy seems to exists, in which reuse as food has priority over use as feed or biomass (energy or green chemistry), and with a sustained faith as waste as the least preferable option. The by-products that one wants to use in feed production, will have to be selected based on type (e.g. category 3 animal by-products should be safe), traceability (single sourced products are preferred) and goal (e.g. is the target animal omnivorous).