VN March 2024

VET Maart / March 2024 The Monthly Magazine of the SOUTH AFRICAN VETERINARY ASSOCIATION Die Maandblad van die SUID-AFRIKAANSE VETERINÊRE VERENIGING Histophilus somni Disease Complex in Cattle CPD THEME Pigs www.wvac2024.com nuus•news

Dagboek • Diary www.wvac2024.com Ongoing / Online 2023 March 2024 April 2024 May 2024 August 2024 SAVETCON: Webinars Info: Corné Engelbrecht, SAVETCON, 071 587 2950, corne@savetcon.co.za / https://app.livestorm.co/svtsos Acupuncture – Certified Mixed Species Course Info: Chi University: https://chiu.edu/courses/cva#aboutsouthafrica@tcvm.com SAVA Johannesburg Branch CPD Events Monthly - please visit the website for more info. Venue: Johannesburg Country Club Info: Vetlink - https://savaevents.co.za/ Online CPD Course: Animal doctor’s guide to managing humans! 03-23 March Venue: ONLINE Info: www.vetskillsts.co.za OP Village Centenary Festival 05-06 April 2024 Venue: OP Village Residence, Onderstepoort, Old Southpan Road, Pretoria Info: Marnus Zaaiman (082 779 8435) / OPVillage.Chairperson@tuks.co.za Online CPD Course: Animal doctor’s guide to managing humans! 05-25 May Venue: ONLINE Info: www.vetskillsts.co.za SAVA Oranje Vaal Branch Mini Congress 09-11 August Venue: Parys – venue to be confirmed. Info: conference@savetcon.co.za NVCG Bush Break 12-13 August Venue: Skukuza, Kruger National Park Info: https://vetlink.co.za/nvcg-2024/

March 2024 1 Contents I Inhoud President: Dr Paul van der Merwe president@sava.co.za Managing Director: Mr Gert Steyn md@sava.co.za/ +27 (0)12 346 1150 Editor VetNews: Ms Andriette van der Merwe vetnews@sava.co.za Bookkeeper: Ms Susan Heine accounts@sava.co.za/+27 (0)12 346 1150 Bookkeeper's Assistant: Ms Sonja Ludik bookkeeper@sava.co.za/+27 (0)12 346 1150 Secretary: Ms Elize Nicholas elize@sava.co.za/ +27 (0)12 346 1150 Reception: Ms Hanlie Swart reception@sava.co.za/ +27 (0)12 346 1150 Marketing & Communications: Ms Sonja van Rooyen marketing@sava.co.za/ +27 (0)12 346 1150 Membership Enquiries: Ms Debbie Breeze debbie@sava.co.za/ +27 (0)12 346 1150 Vaccination booklets: Ms Debbie Breeze debbie@sava.co.za/ +27 (0)12 346 1150 South African Veterinary Foundation: Ms Debbie Breeze savf@sava.co.za/ +27 (0)12 346 1150 Community Veterinary Clinics: Ms Claudia Cloete cvcmanager@sava.co.za/ +27 (0)63 110 7559 SAVETCON: Ms Corné Engelbrecht corne@savetcon.co.za/ +27 (0)71 587 2950 VetNuus is ‘n vertroulike publikasie van die SAVV en mag nie sonder spesifieke geskrewe toestemming vooraf in die openbaar aangehaal word nie. Die tydskrif word aan lede verskaf met die verstandhouding dat nóg die redaksie, nóg die SAVV of sy ampsdraers enige regsaanspreeklikheid aanvaar ten opsigte van enige stelling, feit, advertensie of aanbeveling in hierdie tydskrif vervat. VetNews is a confidential publication for the members of the SAVA and may not be quoted in public or otherwise without prior specific written permission to do so. This magazine is sent to members with the understanding that neither the editorial board nor the SAVA or its office bearers accept any liability whatsoever with regard to any statement, fact, advertisement or recommendation made in this magazine. VetNews is published by the South African Veterinary Association STREET ADDRESS 47 Gemsbok Avenue, Monument Park, Pretoria, 0181, South Africa POSTAL ADDRESS P O Box 25033, Monument Park Pretoria, 0105, South Africa TELEPHONE +27 (0)12 346-1150 FAX General: +27 (0) 86 683 1839 Accounts: +27 (0) 86 509 2015 WEB www.sava.co.za CHANGE OF ADDRESS Please notify the SAVA by email: debbie@sava.co.za or letter: SAVA, P O Box 25033, Monument Park, Pretoria, 0105, South Africa CLASSIFIED ADVERTISEMENTS (Text to a maximum of 80 words) Sonja van Rooyen assistant@sava.co.za +27 (0)12 346 1150 DISPLAY ADVERTISEMENTS Sonja van Rooyen assistant@sava.co.za +27 (0)12 346 1150 DESIGN AND LAYOUT Sonja van Rooyen PRINTED BY Business Print: +27 (0)12 843 7638 VET nuus•news Diary / Dagboek II Dagboek • Diary Regulars / Gereeld 2 From the President 4 Editor’s notes / Redakteurs notas Articles / Artikels 8 Effect of Pig Synthetic Pheromones and Positive Handling of Pregnant Sows on the Productivity of Nursery Pigs 15 Efficacy of Polyherbal Feed Supplements on Growth Performance and Nutrient Digestibility in Grower Pigs 20 Travelling with dogs. An Honours study in the Department of Business Management at the University of Pretoria Association / Vereniging 24 CVC News 26 SAVA News 34 In Memoriam 36 Legal Mews Events / Gebeure 5 Onderstepoort Centenary 7 World Veterinary Association Congress 2024 28 Onderstepoort residence. Student accommodation: then and now Vet's Health / Gesondheid 38 Life Coaching Technical / Tegnies 40 Ophthalmology Column Relax / Ontspan 48 Life Plus 25 Marketplace / Markplein 42 Marketplace Jobs / Poste 43 Marketplace/Jobs / Poste 46 Classifieds / Snuffeladvertensies 20 28 24 www.wvac2024.com

Vetnuus | Maart 2024 2 « BACK TO CONTENTS An association is a group of people organized for a joint purpose. A group is a collection of individuals who coordinate their efforts, while a team is a group of people who share a common goal. A group have individual goals that they work toward collectively. Some advantages to working as a group are: • Groups build temporary relationships: Since groups focus on individual members working in parallel to one another, they build temporary working relationships towards a collective outcome. • Groups are great for efficiency: While teams work to create efficiency for the greater good, groups focus on individual efficiency. It is therefore imperative that each member of the group contribute optimally to achieving the group’s joint purpose. • Groups focus on individual growth: Since groups support individual work, they also focus on individual growth. This can be seen in the form of individual experts rather than a team of experts. The history of the South African Veterinary Association (SAVA) had a useful prelude and a very eventful course. The first step towards the establishment of a locally organised veterinary profession dates from the inauguration of the Transvaal Veterinary Medical Association (TVMA) on 16 February 1903 in Johannesburg with the South African Veterinary Association (SAVA) officially inaugurated on 1 April 1920. The initial joint purpose of SAVA was to have the professional status of the South African veterinarian legally entrenched, a goal that was reached in 1933 when the Veterinary Act (Act No. 16 of 1933) was promulgated. Today, SAVA’s mission (joint purpose) is to serve its members and to further the status and image of the veterinarian. SAVA is committed to upholding the highest professional and scientific standards, and to utilising the professional knowledge, skill and resources of its members, to foster close ties with the community and thus promote the health and welfare of animals and mankind. This mission is supported by individuals organised in various committees, groups and branches, supported by a dedicated administrative team, working collectively to realise this joint purpose. I want to extend a hand of gratitude to each individual who contributes their time and effort towards this joint purpose. That said, SAVA is continuously challenged by other organizations, veterinarians, para-veterinarians, the public at large and even members to what it is actually doing for its members to attain its joint purpose especially fostering closer ties with the community and thus promoting health and welfare of animals and mankind. Comments recently passed were that SAVA is an organization only serving the needs of the previously advantaged, and an organization that only presents CPD opportunities, opportunities that can be accessed on various platforms, even for free. Is this the perception of SAVA? Yes, SAVA is presenting numerous CPD opportunities and is ideally placed to present such opportunities due to its organizational structure and individual commitments. The World Veterinary Association Congress to be presented in April 2024 in Cape Town is a prime example. However, the congress is not only presented as a CPD opportunity but also an opportunity to further the status and image of veterinarians, especially South African veterinarians by creating networking opportunities. If you have not registered yet for this prestigious event, do so at https://wvac2024.com. These comments/onslaughts were discussed in a recent SAVA Board of Directors meeting and, though the board will do some introspection, I want to challenge every member to also spend some time reflecting on the joint purpose of SAVA and what we should and should not do. We should even be so bold in questioning if SAVA’s mission is still relevant. Is that still the expectation of our members and the community at large? As a starting point, the board will use the SAVA Credo and interrogate each point as to what is being done and what needs to be done. It will be supportive of our efforts if all members can reflect accordingly and forward comments to president@sava.co.za. In my eyes, veterinarians are the salt of the earth. We are and can make such a major impact on the health and welfare of animals, humans and the environment alike. However, in the words of Israelmore Ayivor: “You are the salt of the earth. But remember that salt is useful when in association, but useless in isolation.” SAVA is dependent not only on our members but every veterinarian to be “useful” to attain the joint purpose of creating a better community. Members have to become “useful” in being active SAVA members but also to recruit as many non-members to become SAVA members to build the strength. Be the salt of the earth in being associated. Go above and beyond, and encourage other colleagues to also become the salt of the earth. v Kind regards, Paul van der Merwe From the President Dear members,

March 2024 3 “The South African Veterinary Association aims to serve its members and to further the status and image of the veterinarian. We are committed to upholding the highest professional and scientific standards by utilising the professional knowledge, skill and resources of our members, to foster close ties with the community and thus promote the health and welfare of animals and mankind”. MISSION STATEMENT Servicing and enhancing the veterinary community since 1920! Tel: 012 346 1150 E-mail: vethouse@sava.co.za www.sava.co.za EARLY EXPOSURE TO ANIMAL CARE DURING YEAR 1 TRAINING AT ANTIBIOTIC-FREE FARMS AND QUANTITATIVE GENETICS TRAINING (FARM ANIMALS) EU ACCREDITED VETERINARY DEGREE ALLOWING PRACTICE WORLDWIDE FINANCIAL AID SCHOLARSHIPS AVAILABLE GLOBAL FACULTY EXPERTISE IN SMALL AND LARGE ANIMAL MEDICINE ADVANCED FACILITIES INCLUDING ANATOMY AND CLINICAL SKILLS LABORATORIES CURRICULUM ALIGNED AS REQUIRED BY RCVS AVMA, EAEVE, AND WORLD ORGANIZATION FOR ANIMAL HEALTH. unic.ac.cy/vet STUDY VETERINARY MEDICINE IN CYPRUS DOCTOR OF VETERINARY MEDICINE (DVM) 5-Year Undergraduate Degree Programme Targeted for High School Leavers

Vetnuus | Maart 2024 4 « BACK TO CONTENTS Dear Members, The “Parable of the Talents”, in Matthew 25:14–30 tells of a master who was leaving his house to travel, and, before leaving, entrusted his property to his servants. According to the abilities of each man, one servant received five talents, the second had received two, and the third received only one. Upon returning home, after a long absence, the master asks his three servants for an account of the talents he entrusted to them. The first and the second servants explain that they each put their talents to work, and have doubled the value of the property with which they were entrusted; each servant was rewarded. The third servant, however, had merely hidden his talent, burying it in the ground, and was punished by his master. This seems like a very cruel and unfair situation. How can some people receive more and others less? In today’s time and age, there would be a riot. Then I read this: Equality means each individual or group of people is given the same resources or opportunities. Equity recognizes that each person has different circumstances and allocates the exact resources and opportunities needed to reach an equal outcome. Read it again. At face value, it seems a very innocent easily understood statement. But on closer inspection, it carries so much weight. Suddenly there has to be a kind of differentiation or judgement of the person on the receiving end of such resources and opportunities to facilitate an equal outcome. There are three distinct groups/persons/institutions in this scenario. Group 1 is the group that is doing the giving or handing out. Group 2 receives more and Group 3 less. Herein lies a great responsibility for Group 1, he/she/it/they have the choice between equality and equity. One would think that equality holds the key to the successful outcome of a person or a task. Looking at the parable it is obvious that it is not true. The master who handed out the property to the servants did not do it equally. He made a specific distinction between the receivers. Two of the receivers doubled the value of the property. They did not look at each other and try to equal the outcome. They merely took what they received and worked with it. The third servant decided he received too little to do anything with and returned it without a dividend. Fairness is very much in the eye of the receiver. It is like the receiver wants to dictate to the giver what they are entitled to. Every one of us receives property or talents, things that we did not necessarily earn. Maybe it is resources to do your job, or abilities to make a difference in your own or other people’s lives. Maybe somebody is entrusting you with time or money. What do you do with this? Afrikaans has such an lekker word “woeker”. When translated to English it is “usury”, a word that does not give me the same warm feeling when I look at the definition. Woeker means to take that money or talent or property and work with it diligently to make it more. It is more to exert oneself. As the Vetnews, we would like to welcome the Nurses on board as Associate Grouping to SAVA. I am excited to see how this association is going to enrich the knowledge of both veterinarians and nurses alike. Next month there are 2 very big events for members. The first is the Centenary celebration of Op Residence with the big reunion on 4 and 5 April and the Festival on 6 April. Get your early bird tickets. Details on the flyer. Then from 16 to 19 April the World Vet Ass Congress in Cape Town. If you have not registered yet, why wait? Not only will you receive CPD points, but you will get great content and you get to meet up with old friends and even maybe some who have left the country. Do not miss out on this. And it is in Cape Town!! I hope to meet many members there. I hope that there will be no Ides of March for anybody and that the first month of Autumn will treat you well. Andriette v From the Editor Editor’s notes / Redakteurs notas

March 2024 5

Vetnuus | Maart 2024 6 « BACK TO CONTENTS

March 2024 7

Vetnuus | Maart 2024 8 « BACK TO CONTENTS Effect of Pig Synthetic Pheromones and Positive Handling of Pregnant Sows on the Productivity of Nursery Pigs Simple Summary: Weaning is one of the most important stress events in the life of pigs, increasing the risk for health problems and reduced performance. This study investigated the effect of pheromones on the performance of nursery pigs. In total, 24 batches of weaned piglets from a commercial farm (216 piglets per batch) were included. Half of the batches were treated, while the other half served as controls. Piglets of treated groups were exposed to a synthetic analog of the maternal pig appeasing pheromone (PAP) (SecurePigR, Signs, Avignon, France). The product consisted of a gel block containing the product and the pheromones diffused slowly in the room. The treatment with pheromones did not significantly influence the performance of the piglets (p > 0.05). The median values of average daily gain (318 vs. 305 g/day), feed conversion ratio (1.64 vs. 1.70), and number of antimicrobial treatment days (16.9 vs. 17.3 days) were numerically better in the nursery pigs exposed to the pheromones compared with the control groups. Mortality however was numerically higher in the treated groups (4.4 vs. 3.2%). In this farm, pigs exposed to the pheromone treatment during the nursery did not show a significant performance increase. Abstract: Weaning is one of the most important stress events in the life of pigs, increasing the risk for health problems and reduced performance. The release of pheromones in pig stables can be considered an environmental enrichment and alleviate the negative effects of weaning stress in nursery pigs. The present study investigated the effect of synthetic pheromones on the performance of nursery pigs. The effect of positive handling of sows in the farrowing house on the performance of the offspring in the nursery was also investigated. The study was performed in a commercial pig farm and included 24 batches of weaned piglets (216 piglets per batch). Half of the batches originated from sows exposed to positive handling. This implied that music was played from 6.00 a.m. to 6.00 p.m. from the moment the sows entered the farrowing house until weaning and that they were subjected to backscratching from the day they entered the farrowing unit the day of farrowing. During the nursery period, half of the batches were treated, and half served as controls. Piglets of treated groups were exposed to a synthetic analog of the maternal pig appeasing pheromone (PAP) (SecurePigR, Signs, Avignon, France). The product consisted of a gel block from which the pheromones were slowly released into the room. Different performance parameters were measured during the nursery period. Neither the sow treatment nor the treatment with pheromones significantly influenced the performance of the piglets during the nursery period (p > 0.05). The median values (95% confidence interval) of average daily gain, namely 318 (282–338) vs. 305 (272–322) g/day, feed conversion ratio, namely 1.64 (1.51–1.71) vs. 1.70 (1.57–1.75), and number of antimicrobial treatment days, namely 16.9 (9.6–25.0) vs. 17.3 (9.5– 25.0) days, were numerically better in the nursery pigs exposed to the pheromones compared to the control groups. Mortality however was numerically higher in the treated groups, namely 4.4 (2.8–6.8) vs. 3.2 (0.9–4.2)%. Under the conditions of the present production system, pigs exposed to the pheromone treatment during the nursery did not show a significant performance increase. 1. Introduction Olfaction plays a significant role in social recognition and discrimination of animals, and in establishing social hierarchy (Kristensen et al., 2001 [1]). Recognition of individuals will allow the animals to alter their behavioral response based on previous experience and help in sustaining a group structure. Piglets can detect maternal odors and can discriminate between mother and non-mother odors from 12 h after birth onwards (Faucitano and Schaefer, 2008 [2]). After birth, mammalian neonates including the pig must recognize the mother as this is essential for survival. This is particularly important for piglets as they need to compete with many littermates and find the nipple rapidly to survive (GuiraudieCapraz et al., 2005 [3]). During gestation, the mammalian fetus is exposed to various chemosensory stimuli (Smotherman and Robinson, 1987, Lecanuet and Schaal, 1996 [4,5]). This leads to the imprinting of the fetuses since newborns recognize the odors from amniotic fluid within 1 h after birth (Schaal and Orgeur, 1992 [6]), and are attracted by the odors from the maternal ventral skin (Morrow-Tesch and Mc Glone, 1990 [7]). This is also the case for pigs. Piglets use odor cues mediated by maternal fluids such as milk, colostrum, and amniotic fluid, for identifying the mother and teat position (Pageat and Teissier, 1998; Orgeur et al., 2002 [8,9]). Females and newborns develop a positive orientation toward these fluids (Lévy et al., 1. Unit of Porcine Health Management, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Salisburylaan 133, 9820 Merelbeke, Belgium; ilias.chantziaras@ugent.be (I.C.); arthi.amalraj@ugent.be (A.A.); dominiek.maes@ugent.be (D.M.) 2. Vedanko, Knijffelingstraat 15, 8851 Koolskamp, Belgium 3. Unit of Veterinary Epidemiology, Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Salisburylaan 133, 9820 Merelbeke, Belgium Dimitri De Meyer 1,2,* , Ilias Chantziaras 1,3 , Arthi Amalraj 1,3 and Dominiek Maes 1

March 2024 9 1983; Marlier et al., 1998, Schaal et al., 1994 [6,10,11]). This process involves nasal chemoreceptors, as flushing an anesthetic into the nose of newly born piglets strongly impaired their ability to locate a teat and initiate suckling (Morrow-Tesch and McGlone, 1990 [12]). The ethological basis of this is well known but little is known about the nature of these cues nor the potential carrier molecules in maternal fluids such as amniotic fluids, colostrum, and milk (Pageat and Teissier, 1998 [9]). The odor components are likely maternal pheromones that are species-specific and composed of different fatty acids. The putative maternal pheromone of sows is composed of six fatty acids in the following relative proportions (Pageat, 2001 [13]): hexadecanoic acid (C16:0, 35%), cis-9-octadecenoic acid (C18:1, 26%), (cis,cis)-9,12-octadecadienoic acid (C18:2, 22%), dodecanoic acid (C12:0, 8%) tetradecanoic acid (C14:0, 7%), and decanoic acid (C10:0, 2%). The same fatty acids in similar patterns were found using gas chromatography and mass spectroscopy in amniotic fluid, milk, and colostrum (Guiraudi-Capraz et al., 2005 [3]). The binding site of these putative pheromones are olfactory binding proteins (OBPs) in the nasal and vomeronasal mucosae of piglets (Guiraudie et al., 2003 [14]) Four main OBPs belonging to the lipocalin superfamily (Flower, 1996; Sivaprasadaro et al., 1993 [15,16]) have been identified: Alpha-1-acid glycoprotein (AGP), Odorant-binding protein (OBP), Salivary lipocalin (SAL), and Von Ebner’s gland protein (VEG). The role of these OBP’s in odor discrimination is still under discussion but it has been shown that OBP’s that exhibit ligand specificity (SAL and VEG) can bind other ligands in vitro (Guiraudie et al., 2003 [14]). It is suggested that binding site and shape are defined by the ligand and that OBP’s in several conformations are always present in the nasal and vomeronasal mucosae capable of binding multiple ligands with different affinities. In older pigs, olfactory cues help in discriminating between familiar and unfamiliar conspecifics, and in the recognition of pen mates (Wells and Hepper, 2017 [17]). Under natural conditions, piglets are weaned at 3 to 4 months of age, and it is a gradual process (Weary et al., 2008; Broom and Fraser, 2015 [18,19]). In intensive systems, however, piglets are often weaned between 3 and 4 weeks, or even at a younger age. It is an abrupt process with many stressors occurring at the same time, e.g., separation from the sow, changes in housing and feed, and mixing of piglets from different litters. Therefore, it is considered one of the most critical and stressful periods in the life of piglets (MartínezMiró et al., 2016 [20]), and it may result in the development of psychobiological disturbances and welfare problems (Faucitano and Schaefer, 2008 [2]). Weaning causes an elevation in stress hormones (Held and Mendl. 2001 [21]), which may lead to a lower immune response and increased susceptibility to diseases (Kanitz et al., 2002 [22]). While establishing social hierarchy, fighting and aggressive interactions among pigs can occur in some farms and impair animal welfare and performance. The European Union Directive 2008/120/EC [23] stresses the need for environmental enrichment to improve pig welfare (Vanheukelom et al. 2012 [24]). The release of pheromones in the pig stable could be considered an environmental enrichment method. Odor masking agents (OMA) may block olfactory signals from other pigs and disrupt social recognition causing temporary cessation of aggression (Kristensen et al., 2001; Marchant-Forde and Marchant-Forde, 2005). Guy et al. (2009 [1,25,26]) showed that the synthetic pheromone (SuilenceR, Ceva Sante Animale, Libourne, France) may reduce aggression and fighting behavior between pigs, and influence feed intake during the post-weaning period. McGlone and Anderson [27] found an increase in daily weight gain after using the product. The application of a synthetic Pig Appeasing Pheromone (PAP) (SecurePigR, Signs, Avignon, France) in a slow-release format after weaning showed an increase in exploratory behavior with reduced agonistic behavior among weaned pigs (Temple et al., 2016 [28]). These effects were no longer statistically different at 24 h post-mixing. However, the abovementioned studies did not show statistically significant effects on live weight, growth rate, or feed conversion efficiency. Overall, data on olfactory behavior, sensory enrichment, and their effects on piglet welfare and productivity in farm animals is limited. This is particularly the case for the use of odors in commercial swine farms. Hence the study investigated the effect of exposure to synthetic pheromones on different performance parameters of nursery pigs. The study is a continuation of a previous study (De Meyer et al., 2020 [29]) in which positive effects were shown on the preweaning survival of piglets when sows in the farrowing unit were exposed to music and when backscratching was done on the sows once per day. Therefore, the effect of this positive handling of sows on the performance of the offspring in the nursery was also investigated in this follow-up study. 2. Materials and Methods 2.1. Animals, Housing, and Management This study was performed in a commercial pig farm located inWest Flanders, Belgium, that practiced a 2-week batch production system. The genetics of the sows originated from a commercial breeding company (Pig Improvement Company, PIC, Hendersonville, NC, USA). The sows were inseminated using semen from Piétrain boars. One batch of sows, comprising 56 sows, farrowed every two weeks. From weaning until four weeks of gestation the sows were housed in individual crates at the insemination unit, after which they were moved to a group housing system. Sows were fed a commercial gestation ration throughout the gestation period. A commercial feed containing barley, wheat, and wheat bran was given for the first 28 days after insemination at a ratio of 2.7 kg per day. A pelleted feed using trickle feeders (one for eight sows) was given while they were housed in groups. This was also a commercial diet containing wheat bran, beet pulp, and wheat and they received 2.3 kg per day. When the sows entered the farrowing rooms, they received a transition feed containing wheat, barley, and wheat bran, 2.5 kg per day. From 4 days after farrowing until weaning the sows received a lactation feed containing wheat, barley, and maize, 3 times per day on a classical schedule that is meant to reach a maximum (at libitum) before weaning. Between weaning and insemination, the sows receive a special diet for heat stimulation containing wheat, barley, mais, and extracted roasted soya at libitum. Sows (parity ≤ two) were vaccinated with Porcilis coliclos R (MSD) and porcilis ART R (MSD) at six and three weeks before farrowing. Sows (parity ≥ three) received a single vaccination, three weeks before farrowing. All sows irrespective of parity were vaccinated with CircoflexR, MycoflexR, and PRRSflex R (Boehringer ‘triflex’) every four months. Post-farrowing vaccines include porcilis Ery-parvoR (MSD) and respiporc fluR (IDT). Prophylactic anthelminthic treatment with PanacurR (MSD) was done before farrowing. The piglets had received a dose of iron injection, 1 mL/piglet (FerrajectR, Dechra) during the first 24 h of birth. Tail docking and teeth grinding were also performed on day 1. Three days prior to weaning, piglets were Leading Article (Effect of Pig Synthetic Pheromones....)

Vetnuus | Maart 2024 10 « BACK TO CONTENTS vaccinated with PorcilisR PCV M. Hyo (MSD Animal Health, Boxmeer, The Netherlands) and PorcilisR PRRS (MSD Animal Health, Boxmeer, The Netherlands). At the end of the lactation (approximately 21 days), piglets were moved to off-site nursery units with two types of barn systems; 30 piglets per pen (‘A’ system) or 15 piglets per pen (‘B’ system). In the nurseries, the piglets were raised on partly slatted floors, and partitions between pens allowed physical contact with piglets from neighboring pens. In the large pens (30 piglets per pen), there were 6 feeding places and 2 drinking nipples; in the small pens (15 piglets per pen), there were 3 feeding places and 1 drinking nipple. The air spaces of the nursery units were separated from each other, and the units were ventilated with a mechanical (channel) ventilation system. A delta tube hot water system provided heating. The farm followed an all-in all-out system, and a hygiene lock was provided for visitors. The study took place in 2018. Zinc oxide (GutalR— Huvepharma) at 3100 ppm was added to the feed for the first 14 days after weaning. Amoxycillin trihydrate (OctacillineR 697 mg/ kg—Eurovet) at 20 mg/kg was added to the drinking water for 8 to 10 days post-weaning to control Streptococcus suis infection. Piglets received ad libitum dry feed and drinking water. 2.2. Experimental Design The present study is a continuation of a previous study in which the effect of positive handling of the sows (treatment T) in the farrowing unit was investigated (De Meyer et al., 2020 [29]). Music was played from 6.00 a.m. to 6.00 p.m. from the moment they entered the farrowing unit until weaning. Simultaneously, farm personnel backscratched all sows of the T group once daily for 15 s with both hands in the middle of the back, from the day they entered the farrowing unit to the day of farrowing. For sows of the control (C) group, no music was played, nor backscratching was performed. The study included weaned piglets from 12 sow batches: the sows of six batches had been treated, and the sows of six batches had not been treated. From each sow batch, 432 piglets were selected at weaning and randomly allocated to two weaning batches, namely a treatment (n = 216) and a control group (n = 216). The combination of sow treatment and treatment of the nursery pigs resulted in four different groups: TT (treatment of sow and piglets), TC (treatment of sow, control piglets), CT (control sow, treatment of piglets), and CC (control sow and piglets). In total, 5174 weaned piglets were included namely 24 batches of 216 piglets each. A sample size of 6 batches for each group (i.e., a total sample size of 12, assuming equal group sizes) allowed for a statistical power of 80% and a level of significance of 5% (two-sided), to detect a true difference between the treated and the control group of 10 g and assuming a pooled standard deviation of 6 g. For logistic reasons, weaning pigs from 4 out of the 6 sow batches that had been treated were housed in the nurseries of the A system (30 pigs per pen), whereas pigs from 2 sow batches were housed in the B system (15 pigs per pen). Similarly, weaning pigs from 4 out of the 6 sow batches that had not been treated, were housed in the nurseries with the A system; weaning pigs from 2 of the 6 sow batches that had not been treated were housed in the nursery room with the B system. During the nursery period, piglets of groups TT and CT were exposed to a synthetic analog of the maternal pig appeasing pheromone (PAP) (SecurePigR, Signs, Avignon, France). The active components of the PAP include methyl caprate, methyl laurate, methyl myristate, methyl palmitate, methyl linoleate, and methyl oleate. According to the manufacturer, PAP prevents the negative effects of stress and optimizes the performance potential of the animals. One PAP gel block of 250 g was used per 25 m2. The blocks were hung up at a height of approximately one meter above floor level, allowing the pheromones to slowly diffuse over the different pens of a compartment during a period of six weeks after the package was opened. Control piglets (TC and CC) received no treatment. As control and treated pigs were housed in separate compartments, control animals were not exposed to the pheromones released in the compartments of treated pigs. 2.3. Parameters of Comparison 2.3.1. Weight of the Piglets and Average Daily Gain (ADG) The weight of the piglets at the weaning and end of the nursery was determined at the batch level. The end weight was determined at 42 days for the first 6 batches (3 controls and 3 treated), and at 39 days for the remaining 6 batches (3 controls and 3 treated). The dates when the piglets died were recorded. The weight of the dead pigs was estimated based on the age of the animal and a visual assessment. The average daily weight gain (ADG) was calculated by dividing the difference between the end weight (the sum of the weights that reached the end of the nursery period and the weight of the piglets that died) and the starting weight, divided by the number of pig days lived by the group (the pigs that reached the end of the nursery period and the piglets that died during the nursery). 2.3.2. Feed Intake and Feed Conversion Ratio (FCR) The feed intake was measured at the batch level. Feed silos were emptied at the end of every nursery period (approximately 6 weeks) and feed remaining in the silos was weighed to calculate the group feed intake. For each batch, feed consumption was calculated by subtracting the quantity of feed remaining in the silo at the end of one nursery group from the total amount of feed that was delivered into the silo for that nursery group. The feed conversion ratio (FCR) was calculated by dividing the feed consumption of the batch by the weight gain of the batch. 2.3.3. Mortality The date and the estimated weight of the dead pigs were recorded. No necropsies or additional laboratory testing were performed on the dead pigs. Antimicrobial Use The number of days the pigs received antimicrobial medication during the nursery period, was recorded. 2.4. Statistical Analyses The ADG, FCR, mortality, starting- and end weight of the piglets, and the number of antimicrobial treatment days were compared between the four groups CC, CT, TC, and TT. The normal distribution of the data was assessed with Q–Q plots, skewness and kurtosis ratio results, and the Shapiro-Wilk test. All parameters, except for FCR, end-weight, and mortality, were assessed as normally distributed. FCR was transformed using the reflect and square root method. Per the model, the effects of sow and piglet treatment were taken into account. Interactions between sow and piglet treatment were Leading Article (Effect of Pig Synthetic Pheromones....)

March 2024 11 examined and if found to be below p < 0.1 were kept in the model. For the parameters end weight and mortality that were also not normally distributed, the median values in the different groups were compared using the non-parametric Kruskal-Wallis test. The p-values were adjusted for all pairwise comparisons using the Bonferroni correction. In addition, for end weight and mortality, separate analyses were performed to assess the effect of sow treatment in the farrowing unit regardless of piglet treatment (Table A1) and the effect of piglet treatment regardless of sow treatment (Table A2). The median values in the two groups were compared using the non-parametric Mann-Whitney test. The results were expressed as the mean (standard deviation SD) and the median (confidence interval CI) values. The confidence interval of the median was calculated using a standard method as described by Zar [30]. The data were analyzed using SPSS software (SPSS version 27R; IBM Corp, Armonk, NY, USA). A p-value of 0.05 or lower was considered significant for all analyses. 3. Results No interactions between sow and piglet treatment were found to be p < 0.1, and as such, they were not included in the final models. The effect of positive handling in sows in the farrowing unit and/ or pheromone treatment in nursery pigs on average daily gain (ADG), feed conversion ratio (FCR), weight gained during nursery, mortality, and number of antimicrobial treatment days of nursery pigs are shown in Table A3 with their estimated means. Overall, only small and numeric differences were found in the mean values for these parameters between the different groups. The highest ADG and the lowest number of antimicrobial treatment days were found in group TT, and FCR was lowest in group CT. For end weight and mortality, we compared the medians of all groups, and no statistically significant (p < 0.05) differences were found. End weight was highest in group CT and mortality lowest in group TC. When looking at the effect of positive handling of the sows regardless of piglet treatment, piglets originating from sows that had received positive handling in the farrowing unit had a numerically lower median ADG, but also a lower FCR, mortality, and number of antimicrobial treatment days during the nursery period (p > 0.05) (Table A1). The weight at the start of the nursery was slightly higher (p < 0.05) in the pigs originating from sows that had been treated in the farrowing unit compared with the weight of the piglets from control sows (5.89 vs. 5.57 kg). Alternatively, when looking at the effect of pheromone treatment in the nursery pigs regardless of positive handling of the sows, piglets that received pheromone treatment in the nursery performed numerically better for ADG, FCR, and antimicrobial treatment but the mortality was also higher (4.37 vs. 3.22%) (p > 0.05) (Table A2). 4. Discussion Separation of the offspring from the sows at weaning is often accompanied by social and physical changes in the piglets. The resulting stress might result in aggressive behavior and cause changes in feeding habits resulting in poor weight gain (MartinezMiró et al., 2016 [20]). To create a familiar environment for the piglets, a synthetic pheromone product that mimics maternal presence in nurseries was used as an environmental enrichment method. The effects of this kind of enrichment on piglet performance were studied. The present study however could not demonstrate significant improvements in the performance of the nursery pigs exposed to the pheromone treatment. Average daily gain, efficiency of feed utilization, and treatment incidence with antimicrobials were slightly, numerically better in the treated batches, but no statistically significant differences were found. In a previous experimental study using a similar pheromone (SuilenceR, Ceva Sante Animale, France), McGlone and Anderson [27] found a significant improvement in ADG and FCR. In the latter study, the pheromone was applied to the feeder, or directly to the snouts of the piglets. In the present study, the product was used according to the recommendations of the manufacturer namely, a gel block containing the product was hung up in the rooms and the product was released in the environment. Another study using PAP reported a temporary improvement in the explorative behavior of weaned piglets, but the performance of the pigs was not investigated (Temple et al., 2016 [28]). The effects of the pheromone treatment during the nursery were not significantly influenced by the treatment of the sows (exposed to music and backscratching) of these piglets in the farrowing unit. Positive handling of the sows in the farrowing unit only resulted in a slightly significant increase in the weaning weight of the piglets. This means that the positive effects of sow treatment observed during the farrowing period (De Meyer et al., 2020 [29]) did not result in better performance of the piglets post-weaning. The present study focused on performance parameters and did not include other parameters such as fighting or other behavior characteristics of the piglets (Temple et al. 2016 [28]). According to the farmer and the herd veterinarian, there were no major problems with aggression post-weaning or poor performance of the piglets. It is possible that significant and more pronounced benefits would be obtained in farms that have problems with fighting piglets in the period post-weaning. This warrants further investigation. As only one production system was included in the present study, care should be taken when extrapolating the results to other pig farms. However, the farm characteristics as well as the performance results of the piglets are representative of other pig farms in Belgium (Malik et al., 2021; Declerck et al., 2016; Griffioen et al., 2023 [31–33]), and different successive batches including many piglets were included. 5. Conclusions The treatment might have improved the welfare of the animals, but under the present conditions, pigs exposed to the pheromone treatment during the nursery did not show a significant performance increase independently of the sow treatment in the farrowing rooms. Author Contributions: Conceptualization, D.M., D.D.M. and A.A.; data curation, I.C.; supervision, D.M.; writing—original draft, D.D.M. All authors have read and agreed to the published version of the manuscript. Funding: This work was partially conducted within the PROHEALTH project. The project received funding from the European Union 7th Framework Programme for Research, Technological Development and Demonstration under grant agreement NO. 613574. Institutional Review Board Statement: Animal Welfare statement: there were no invasive samples taken, therefore no approval of the ethical committee for animal experiments was needed. >>> 12 Leading Article (Effect of Pig Synthetic Pheromones....)

Vetnuus | Maart 2024 12 « BACK TO CONTENTS Informed Consent Statement: An informed Consent Statement has been obtained from the farmer. Data Availability Statement: Restrictions apply to the availability of these data. Data was obtained from the farmer and are available with the permission of the farmer. Acknowledgements: The authors are grateful to the farmer for collaborating with the trial. Conflicts of Interest: The authors declare no conflict of interest. Appendix A Leading Article (Effect of Pig Synthetic Pheromones....) Table A1. Effects of positive handling of sows in the farrowing house (exposure to music and backscratching), regardless of treatment in the nursery, on average daily gain (ADG), feed conversion ratio (FCR), mortality, and antimicrobial treatment incidence of the nursery pigs. Piglets from Control Sows (n = 12 Batches) Piglets from Treated Sows (n = 12 Batches) Mean (SD) Median (CI) Mean (SD) Median (CI) ADG (g/day) 305.7 a (28.17) 317.7 a (271.86–323.29) 314.7 a (31.07) 310.7 a (291.35–337.50) Starting weight (kg) 5.55 a (0.33) 5.57 a (5.50–5.78) 5.91 a (0.27) 5.89 b (5.69–6.25) End weight (kg) 22.84 a (2.94) 22.99 a (19.61–25.87) 23.09 a (3.98) 21.29 a (19.58–27.95) Weight gained during nursery (kg) 17.46 a (2.95) 16.90 a (14.57–21.33) 17.64 a (4.18) 15.84 a (14.07–23.22) FCR 1.65 a (0.09) 1.68 a (1.59–1.71) 1.61 a (0.17) 1.66 a (1.51–1.75) Mortality % 4.55 a (2.79) 3.61 a (2.64–6.82) 3.40 a (2.50) 3.22 a (0.93–6.02) Number of antimicrobial treatment days 17.79 a (6.06) 17.85 a (12.72–23.92) 17.28 a (10.21) 16.94 a (5.67–28.28) Values in the same row not sharing the same superscript are significantly different at p < 0.05 in the two-sided test of equality for medians using non-parametric tests (Mann-Whitney test). Table A2. Effect of pheromone treatment in the nursery pigs, regardless of sow treatment in the farrowing house, on average daily gain (ADG), feed conversion ratio (FCR), mortality, and antimicrobial treatment incidence of the nursery pigs. Piglets Not Treated during the Nursery (n = 12 Batches) Treated Piglets during the Nursery (n = 12 Batches) mean (SD) Median (CI) mean (SD) Median (CI) ADG (g/day) 304.4 (28.92) 305.3 (271.86–322.14) 316.0 (29.89) 317.7 (281.76–337.50) Starting weight (kg) 5.75 (0.39) 5.75 (5.50–6.05) 5.71 (0.31) 5.74 (5.55–5.92) End weight (kg) 22.73 (3.58) 21.39 (19.32–27.08) 23.20 (3.41) 22.39 (19.90–26.35) Weight gained during nursery (kg) 17.05 (3.51) 15.84 (13.75–21.78) 18.05 (3.66) 17.12 (14.23–21.78) FCR 1.65 (0.13) 1.70 (1.57–1.75) 1.61 (.14) 1.64 (1.51–1.71) Mortality % 3.25 (2.82) 3.22 (0.93–4.17) 4.70 (2.38) 4.37 (2.78–6.82) Number of antimicrobial treatment days 17.45 (8.28) 17.28 (9.54–24.96) 17.62 (8.52) 16.94 (9.56–24.96)

March 2024 13 References 1. Kristensen, H.H.; Jones, R.B.; Schofield, C.P.; White, R.P.; Wathes, C.M. The use of olfactory and other cues for social recognition by juvenile pigs. Appl. Anim. Behav. Sci. 2001, 72, 321–333. [CrossRef] [PubMed] 2. Faucitano, L.; Schaefer, A.L. (Eds.) Welfare of Pigs from Birth to Slaughter;Wageningen Academic Publishers: Wageningen, The Netherlands; Éditions Qua: Versailles, France, 2008; p. 315. ISBN 97890-8686-066-1/978-2-7592-0086-3. 3. Guiraudie-Capraz, G.; Slomianny, M.-C.; Pageat, P.; Malosse, C.; Cain, A.-H.; Orgeur, P.; Nagnan-Le Meillour, P. Biochemical and chemical supports for a transnatal olfactory continuity through sow maternal fluids. Chem. Senses 2005, 30, 241–251. [CrossRef] [PubMed] 4. Lecanuet, J.P.; Schaal, B. Foetal sensory competencies. Eur. J. Obstet. Gynecol. Reprod. Biol. 1996, 68, 1–23. [CrossRef] [PubMed] 5. Smotherman, W.P.; Robinson, S.R. Prenatal expression of speciestypical action patterns in the rat foetus (Rattus norvegicus). J. Comp. Psychol. 1987, 101, 190–196. [CrossRef] 6. Schaal, B.; Orgeur, P. Olfaction in utero: Can rodent model be generalized? Q. J. Exp. Psychol. B 1992, 44, 245–278. [PubMed] 7. Morrow-Tesch, J.; McGlone, J.J. Sources of maternal odors and the development of odor preferences in baby pigs. J. Anim. Sci. 1990, 68, 3563–3571. [CrossRef] [PubMed] 8. Orgeur, P.; Le Dividich, J.; Colson, V.; Meunier-Salaun, M.C. La relation mère-jeune chez les porcins: De la naissance au sevrage. INRA Prod. Anim. 2002, 15, 153–163. [CrossRef] 9. Pageat, P.; Teissier, Y. Usefulness of a porcine pheromone analogue in the reduction of aggression between weaners on penning: Behavioural study. In Proceedings of the 15th IPVS Congress, Birmingham, UK, 5–9 July 1998; p. 413. 10. Lévy, F.; Poindron, P.; LeNeindre, P. Attraction and repulsion by amniotic fluids and their olfactory control in the ewe around parturition. Physiol. Behav. 1983, 31, 687–692. [CrossRef] 11. Marlier, L.; Schaal, B.; Soussignan, R. Neonatal responsiveness to odor of amniotic and lacteal fluids: A test of perinatal chemosensory continuity. Child Dev. 1998, 69, 611–623. [CrossRef] 12. Morrow-Tesch, J.; McGlone, J.J. Sensory system and nipple attachment behavior in neonatal pigs. Physiol. Behav. 1990, 47, 1–4. [CrossRef] 13. Pageat, P. Pig Appeasing Pheromones to Decrease Stress, Anxiety and Aggressiveness. U.S. Patent No. 6,169,113, 2 January 2001. 14. Guiraudie, G.; Pageat, P.; Cain, A.H.; Madec, I.; Nagnan-Le Meillour, P. Functional characterization of olfactory binding proteins for appeasing compounds and molecular cloning in the vomeronasal organ of pre-pubertal pigs. Chem. Senses 2003, 28, 609–619. [CrossRef] [PubMed] 15. Flower, D.R. The lipocalin protein family: Structure and function. Biochem. J. 1996, 318, 1–14. [CrossRef] [PubMed] 16. Sivaprasadaro, A.; Boudjelal, M.; Findlay, J.B.C. Lipocalin structure and function. Mol. Recogn. 1993, 21, 619–622. [CrossRef] [PubMed] 17. Wells, D.L.; Hepper, P.G. The Role of Olfaction in Animal Housing and as Enrichment. In Olfaction in Animal Behaviour and Welfare; Nielsen, B.L., Ed.; CABI Publishing: Wallingford, UK, 2017; pp. 151–160. 18. Broom, D.M.; Fraser, A. Domestic Animal Behaviour and Welfare 2, 5th ed.; CABI:Wallingford, UK, 2015; p. 472. 19. Weary, D.M.; Jasper, J.; Hotzel, M.J. Understanding weaning distress. Appl. Anim. Behav. Sci. 2008, 110, 24–41. [CrossRef] 20. Martínez-Miró, S.; Tecles, F.; Ramón, M.; Escribano, D.; Hernández, F.; Madrid, J.; Orengo, J.; Martínez-Subiela, S.; Manteca, X.; Cerón, J.J. Causes, consequences and biomarkers of stress in swine: An update. BMC Vet. Res. 2016, 12, 171. [CrossRef] Leading Article (Effect of Pig Synthetic Pheromones....) Table A3. Effect of positive handling in sows in the farrowing house (exposure to music and backscratching) and/or pheromone treatment in nursery pigs on average daily gain (ADG), feed conversion ratio (FCR), mortality, and antimicrobial treatment incidence of nursery pigs. CC (n = 6 Batches) CT (n = 6 Batches) TC (n = 6 Batches) TT (n = 6 Batches) Mean (SD) Median (CI) Mean (SD) Median (CI) Mean (SD) Median (CI) Mean (SD) Median (CI) ADG (g/day) 299.8 (26.99) 310.0 (271.86– 322.14) 311.7 (30.53) 317.7 (281.76– 332.69) 309.10 (32.54) 303.6 (291.35– 321.18) 320.4 (31.45) 320.2 (305.10– 337.50) Starting weight (kg) 5.55 (0.38) 5.60 (5.50– 5.78) 5.56 (0.31) 5.57 (5.50– 5.78) 5.96 (0.31) 5.98 (5.73– 6.25) 5.87 (0.25) 5.86 (5.69– 5.94) End weight (kg) 22.64 (3.16) 22.54 (19.61– 24.92) 23.05 (2.99) 23.34 (19.90– 25.87) 22.83 (4.26) 21.25 (19.32– 27.42) 23.36 (4.07) 21.85 (20.05– 27.95) Weight gained during nursery (kg) 16.85(2.91) 16.35(14.57– 18.28) 18.06(3.14) 17.9 (15.26– 21.33) 17.25(4.30) 15.84(13.55– 21.94) 18.03(4.43) 16.39 (14.23– 23.22) FCR 1.67(0.09) 1.70(1.59– 1.72) 1.62(0.09) 1.63 (1.59– 1.71) 1.63 (0.17) 1.68(1.57– 1.75) 1.59(0.19) 1.64 (1.51– 1.73) Mortality % 4.04 (3.36 3.40 (1.90– 4.17) 5.05 (2.28) 4.59 (3.23– 6.82) 2.46 (2.16) 2.29 (0.93– 3.24) 4.35 (2.64) 4.35 (2.78– 6.28) Number of antimicrobial treatment days 17.61 (6.23) 17.85 (12.72– 22.74) 17.96 (6.47) 18.07 (13.19– 23.92) 17.29 (10.58) 17.28 (5.67– 27.36) 17.27 (10.84) 16.94 (5.43– 28.28)

Vetnuus | Maart 2024 14 « BACK TO CONTENTS 21. Held, S.; Mendl, M. Behaviour of the young weaner pig. In The Weaner Pig: Nutrition and Management, Proceedings of a British Society of Animal Science Occasional Meeting, University of Nottingham, UK, September 2000; Varley, M.A.,Wiseman, J., Eds.; CAB International: Wallingford, UK, 2001. 22. Kanitz, E.; Tuchscherer, M.; Tuchscherer, A.; Stabenow, B.; Manteuffel, G. Neuroendocrine and immune responses to acute endotoxemia in suckling and weaned piglets. Biol. Neonate 2002, 81, 203–209. [CrossRef] 23. Council Directive 2008/120/EC of 18 December 2008 Laying Down Minimum Standards for the Protection of Pigs (Codified Version). Available online: http://data.europa.eu/eli/ dir/2008/120/2019-12-14 (accessed on 29 December 2023). 24. Vanheukelom, V.; Driessen, B.; Geers, R. The effects of environmental enrichment on the behaviour of suckling piglets and lactating sows: A review. Livest. Sci. 2012, 143, 116–131. [CrossRef] 25. Guy, J.H.; Burns, S.E.; Barker, J.M.; Edwards, S. Reducing postmixing aggression and skin lesions in weaned pigs by application of a synthetic maternal pheromone. Anim. Welf. 2009, 18, 249– 255. [CrossRef] 26. Marchant-Forde, J.N.; Marchant-Forde, R.M. Minimizing inter-pig aggression during mixing. Pig News Inf. 2005, 2005, 26, 63–71. 27. McGlone, J.J.; Anderson, D.L. Synthetic maternal pheromone stimulates feeding behavior and weight gain in weaned pigs. J. Anim. Sci. 2002, 80, 3179–3183. [CrossRef] 28. Temple, D.; Barthélémy, H.; Mainau, E.; Cozzi, A.; Amat, M.; Canozzi, M.E.; Pageat, P.; Manteca, X. Preliminary findings on the effect of the pig appeasing pheromone in a slow releasing block on the welfare of pigs at weaning. Porc. Health Manag. 2016, 2, 13. [CrossRef] [PubMed] 29. De Meyer, D.; Amalraj, A.; Van Limbergen, T.; Fockedey, M.; Edwards, S.; Kyriazakis, I.; Aerestrup Moustsen, V.; Chantziaras, I.; Maes, D. Effect of positive handling of sows on litter performance and pre-weaning piglet mortality. Animal 2020, 14, 1733–1739. [CrossRef] [PubMed] 30. Zar, J.H. Biostatistical Analysis, 5th ed.; Pearson Schweiz AG: Cham, Switzerland, 2010; pp. 548–549. ISBN 10-0131008463. 31. Declerck, I.; Dewulf, J.; Sarrazin, S.; Maes, D. Long-term effects of colostrum intake in piglet mortality and performance. J. Anim. Sci. 2016, 94, 1633–1643. [CrossRef] [PubMed] 32. Griffioen, F.; Aluwé, M.; Maes, D. Effect of Extended Photoperiod on Performance, Health, and Behavioural Parameters in Nursery Pigs. Vet. Sci. 2023, 10, 137. [CrossRef] 33. Malik, M.; Schoos, A.; Chantziaras, I.; Donkers, D.; Croubels, S.; Doupovec, B.; Maes, D. Porcine ear necrosis in weaned piglets: Prevalence and impact on daily weight gain. Porc. Health Manag. 2021, 7, 61. [CrossRef] Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. v * Correspondence: dimitri.de.meyer@vedanko.be Original article Leading Article (Effect of Pig Synthetic Pheromones....) We, the members of the Association, resolve at all times: • To honour our profession and the Veterinary Oath • To maintain and uphold high professional and scientific standards • To use our professional knowledge, skills and resources to protect and promote the health and welfare of animals and humans • To further the status and image of the veterinarian and to foster and enrich veterinary science • To promote the interests of our Association and fellowship amongst its members. Ons, die lede van die Vereniging, onderneem om te alle tye: • Ons professie in ere te hou en die Eed na te kom • ‘n Hoë professionele en wetenskaplike peil te handhaaf en te onderhou • Ons professionele kennis, vaardigheid en hulpbronne aan te wend ter beskerming en bevordering van die gesondheid en welsyn van dier en mens • Die status en beeld van die veearts te bevorder en die veeartsenykunde te verryk • Die belange van ons Vereniging en die genootskap tussen sy lede te bevorder. CREDO

RkJQdWJsaXNoZXIy OTc5MDU=