ANIMAL PRODUCTION AND HEALTH SCIENCES

APH01 BOVINE MASTITIS IN MALTA: AN EPIDEMIOLOGICAL SURVEY
 

Mastitis is considered to be the most important disease of dairy cattle world-wide. The scope of this survey was to determine the prevalence and distribution of bovine mastitis in Malta and the major factors affecting this prevalence/distribution.
Multiple Bulk Milk (BM) samples from 39 randomly selected Maltese bovine herds were tested for Somatic Cell Counts (SCCs), Total Bacterial Counts (TBCs), Staphylococcus aureus, Streptococcus agalactiae, Strep. dysgalactiae and esculin-fermenting Streptococci from July 1996 to March 1997. The herdsman responsible for these milk supplies were interviewed about mastitis control practices and other variable factors assumed to influence mastitis prevalence/incidence. Twenty farms were also visited to observe conditions in local farms. Ninety-three aseptically taken milk samples from separate quarters, of cows in 2 low BM SCC herds, were used to identify causative agents of clinical or subclinical mastitis in these herds.
The geometrical mean SCC of herd BM samples in Malta was approximately 630,000 cells/ml. Herds with this BM SCC had an estimated 20% quarters infected. Herds with the minimal BM SCC of 180,000 cells/ml  had an estimated 5% quarter infected, while herds with the minimal BM SCC of 1,400,000 cells/ml had an estimated 45% quarters infected.
Using the Chi-squared test, significant associations were found between herds having a BM SCC > 600,000 cells/ml and:
(1) high numbers (> 103 CFU/ml) of [Staph. aureus/ Strep. agalactiae/ Step. dysgalactiae] in BM
(2) small herds,
(3) inadequate housing,
(4) poor education/knowledge  of herd owner,
(5) inadequate milking machine maintenance
(6) lack of culling chronically mastitis cows,
(7) inadequate premilking hygiene,
(8) no segregation practices,
(9) no use of teat drips and/or
(10) dry cow treatment not being used for all cows.
No significant associations were found between herds having a BM SCC > 600,000 cells/ml and:
(1) geographical distribution of farms,
(2) use of antibiotics  during lactation,
(3) irregular use of  dry cow treatment,
(4) age of milking machine, or
(5) [TBCs/resazurin reduction/fat content] of BM.
Clinical mastitis in the two selected low BM SCC herds was mainly due to “environmental” microorganisms, with Escherichia coli being the most common pathogen.
Based on these results, a national mastitis control program aimed at reducing “contagious mastitis” micro-organisms is recommended, along with an improvement in environmental hygiene of farms, to avoid an increase in the incidence of “environmental mastitis.”
Research  Worker: Stephan Mifsud
Project Supervisor: Dr. Trevor Zammit
 

APH02 THE INCIDENCE OF BRUCELLOSIS AND ITS CONTROL IN THE MALTESE ISLANDS
 

In this study, concerning the incidence of brucellosis in the Maltese Islands, the first recorded evidence and manifestation of disease together with the repeated occurrence of the disease and its management in the early days are discussed. Furthermore. the microbiological and epidemiological aspects of the disease in conjunction with the zoonotic nature of brucellosis are examined. Particular emphasis has been made on the control, prevention and the possibility of totally eradicating this infectious disease from the Maltese Islands. A thorough insight at the expenditure, the number of slaughtering carried out, the compensation meted out, where applicable, and the relevant legislative measures enacted, throughout the years since the implementation of the Animal Disease Eradication Scheme in 1956 to date, is also included.
Statistical data vividly picture the goat as being a prime reservoir for harbouring Brucella melitensis, the cow being less prone,  whereas the sheep is to a greater or lesser extent free from infection with this particular pathogen. Evolution of human brucellosis during the twentieth century is also given due consideration with a marked decrease in incidence being clearly visible as the Animal Disease Eradication Scheme started to make headway in the early 1960's, culminating in the accomplishments of the recent years by the present administration. Last year's sudden outbreak is also highlighted. Overseas programmes of control, eradication and prevention are also reviewed, with Turkey, Spain and Kuwait being cited.
Research  Worker: Anton Spiteri
Project Supervisor: Dr. Trevor Zammit
 

APH03 HELMINTHIASIS OF LOCAL DOGS: A VETERINARY PROSPECTIVE
 

The problem of helminthic infestation in local dogs manifests itself as being a relatively common one locality. This fact poses obvious health hazards to man, as the intimate relationship between man and dogs implies the possibility of zoonosis.
A survey was carried out amongst registered local veterinarians to assess their opinions about the problem and the use of anthelminthics. Many of them emphasised the need of enforcing existing legislation and the enactment of new ordinance to counteract the problem, together with education of pet owners and promotion of their interest in the health of their pet.
Analytical methods were employed to evaluate the local incidence of helminthiasis in dogs and to establish the most common species of helminths which occur in local dogs. These are based an indirect microscopical analysis (based on concentration and flotation principles) of faecal samples of dogs.
Despite the preliminary nature of the study, the results show that incidence of helminths in local dogs is relatively common (12%).
Research  Worker: Peter Zammit
Project Supervisor: Dr. Trevor Zammit
 

APH04 A PHARMACOLOGICAL APPROACH TO TREATING BEHAVIOUR PROBLEMS IN CATS
 

The domestic cat, Felis catus, is favoured as a pet for its combination of an affectionate nature with a degree of independence, as well as more prosaic qualities such as
cleanliness and convenience. Changes in the relationship between people and their pets, coupled with an increase in feline popularity as a pet, have resulted in veterinarians seeing more feline behavioural problems. The treatment of such conditions may include the combined use of medical, surgical, and pharmacological therapy, as well as behaviour modification. The drugs used are usually anxiolytics, e.g. benzodiazepines, amitriptyline, buspirone, and progesterones.
Inappropriate elimination account for 25-33% of behavioural problems encountered in cats, and is the most inconvenient. The therapeutical approach to inappropriate urination and defecation focuses on litter box training, but that for urine spraying/marking is mainly a pharmaceutical one, since it results from the introduction of a stressful environment (e.g. territorial intrusion).
Aggression is the most serious behaviour exhibited by cats. Treatment does not necessarily eliminate the behaviour, but its incidence and frequency can often be
reduced. It varies according to the type of aggression diagnosed but usually consists of identification and avoidance of the eliciting stimuli, surgery (castration), and drug therapy. The ideal drug should act almost exclusively in controlling aggression without interfering with other behavioural components.
Stereotypic behaviour, which arises from chronic conflict, confinement, and sensory deprivation, probably provides some relief from stress. It is more responsive if treated during an early stage of development. Antidepressants (e.g. fluoxetine and clomipramine) have been found particularly effective.
In an investigation on feline behaviour in Malta, 90% of the 53 cats studied showed some type of behavioural condition: fear (89%), aggression (75%), furniture scratching (53 %), and inappropriate elimination (29%). Female cats show more fear-induced aggression, and engage in clawing of furniture more than males, who in turn are more aggressive when petted and are more involved in spraying/marking. Maltese cat owners seem to tolerate these problems and only 18% of the respondents were willing to treat their cats. Buspirone was successfully used on a neutered male cat that was spraying urine. In Malta, feline psychopharmacology is, as yet, not fully developed, but interest will definitely grow in the future.
Research  Worker: Sarah Meli
Project Supervisor: Dr. Trevor Zammit
 

APH05 THE IMPORTANCE OF HYDRO-THERAPY IN EQUINES
 

The following research is based on the experience of trainers in Malta, and also on the veterinarian medical reports of agricultural universities and veterinary schools in Europe and the USA. The benefit of swimming correctly, with all four limbs working, will never replace work on the ground, but is a useful adjunct in both a rehabilitation and training program. The two main forms of hydro-therapy used in horses, hydro-exercise and hydro-massage were studied. Case studies were carried out on horses attending the hydro-exercise centre, Luqa, Malta, in order to have a general overview of the methodology that Maltese trainers are using. In another study heart rates were also measured and recorded by means of a heart rate monitor, during hydro-exercise. Surveys were carried out to understand the extent of the trainers' knowledge on this form of treatment. The difficulty with hydro-therapy is to establish the correct parameters in order to provide safe access to the horses. This project emphasised on these parameters and gives recommendations in order to attain a high potential benefit from this type of treatment.
Research  Worker: Ivan Said Pullicino
Project Supervisor: Dr. Trevor Zammit
 

APH06 THE USE OF ANTIBIOTICS IN THE POULTRY INDUSTRY
 

The main aim of this study was to set up a Pilot project for identifying antibiotics and/or their active metabolites in broiler meat and poultry eggs.
Samples of poultry meat and eggs were randomly collected from authorised and non-authorised points of sale distributed all over the Maltese islands.
These samples were tested using the Brilliant Black Reduction Test method (BR Test), specifically far meat, ophils and whole-egg material. Results obtained indicated that such residues were present in some of the samples collected. 5.77 % of the femoral muscle samples tested positive. Similarly 11.11 % of breast muscle samples and 27.78 % of skin samples were positive. In addition, for all three types of poultry meat samples, a considerable fraction of the samples gave an intermediate result, 11.54% in femoral samples, 5.56% in breast muscle samples and 16.67% in skin samples. Overall broiler skin samples were found to be the most contaminated. Of the forty eight whole egg samples that were screened, 20.83% tested positive or intermediate.
A review of the latest literature concerning the use of antibiotics in poultry diseases was conducted. On similar lines, data on the general state of the local industry vis a vis the world situation was also included.
Research  Worker: David Coleiro
Project Supervisor: Dr. Trevor Zammit
 

APH07 THE NEMATODE POPULATION IN EQUINES, UNDER LOCAL CONDITIONS
 

A qualitative and quantitative study of the nematode population amongst equines was carried out locally. The species were identified through the egg flotation method, and the extent of infestation of the equines under study (n=70) was tested by means of the McMaster Egg Counting technique. The factors which could possibly affect the equine nematode population were also analysed by interviewing the owners on the horses' characteristics and management. Nematode eggs were present in 44.3% (n=31) of the equines. The species identified were the following (prevalence rates are indicated in brackets); Strongylus (71%, n=22); Cyathostoma (54·8% n=17); Trichostrongylus (38.7%, n=12); Triodontophorus (35.5%,n=11).
The species were most common in horses aged 6-11 years. The majority of the equines (67.2%, n=47) had an egg count value of 0 eggs per gram (epg); 24.7% (n = 1 7) - 200 epg; 4.3% (n = 3) - 400 epg and another 4.3% (n=3) - 600 epg. The equines were all regularly administered anthelmintic pastes (Eqvalon (R) and Equitel (R)) for the control of nematodes and were all in good nutritional condition. They also had little or no contact with other horses and had no history of any major diseases. There was a good level of hygiene of both horses and stables. This study confirmed that the most prevalent of the nematode species in equines are large and small strongyles, and has reported that parasite control is dependant not only on the use of anthelmintics but also on appropriate management of the horse and the surrounding environment.
Research  Worker: Joseph Quintano
Project Supervisor: Dr. Trevor Zammit
 

APH08 A STUDY ON THE SELENIUM CONTENT OF LOCAL SOIL AND LOCAL FODDER CROP IN RELATON TO THE SELENIUM CONTENT OF COWS’ BLOOD

Selenium was only considered as an important element for animals when it was identified as a toxic principle in plants which induced lameness, hoof sloughing and death in grazing livestock.  This condition being referred to as alkali disease.  Later, selenium was also considered as an essential microelement.  Symptoms such as white muscle disease, reduced reproductive disease and an increase in the incidence of mastitis, have all been associated with a low selenium index.
The major biological role of selenium is the formation of the enzyme glutathione peroxidase and constituent of selenocysteine, which is being considered as the twenty-first amino acid.  Selenium also has a narrow therapeutic index, that is the safety margin between the safe and toxic level.
Being an island of sedimentary origin, there was much concern on the selenium levels present.  The alkaline nature of our soil permits selenium to be present in the reduced (selenate or selenite) form.  In this study the selenium status of local soil, fodder and all other forms of selenium intake, together with the selenium level in cow`s serum were investigated.
Random samples were taken.  After digestion with mineral acids in the case of soil and food, all other samples were analysed using the Spectra AA-30 graphite furnace atomic absorption spectrometer.  Maltese soil was found to have an average selenium content of 0.645 mg/kg DW.  Selenium content in tap water is adequate, the amount of selenium being ingested by cattle averaged 0.141 ppm.  This satisfies the allowance of the National Research Council.  Local cattle had a mean selenium blood content of 0.185ppm.  This was lower when compared to the selenium status of Dutch cattle but higher than that of calves and sheep.
Research  Worker: Gilbert Cauchi
Project Supervisor: Dr. Trevor Zammit
 

APH09 “CHICK IN THE DARK” - THE EFFECT OF DIFFERENT LIGHTING PROGRAMMES ON BROILER PRODUCTION PARAMETERS AND PLASMA ASPARTATE AMINOTRANSFERASE

The purpose of this dissertation was to evaluate the effects of intermittent lighting (IL) programmes on broiler production parameters and on plasma aspartate aminotransferase (AST) concentrations. It also sought to identify and establish the use of a haematological technique as a health indicator in broiler production.
80 day-old male Ross 308 broilers were used in a 2x4 factorial design utilising different lighting programmes. The live weights of the broilers were recorded per week. On day 35, blood samples were collected from their upper wing veins. The activity of AST in the plasma was determined by a coupled indicator reaction using oxaloacetate which catalyses NADH to NAD+. The rate of change of NADH was then measured at 340 nm and recorded.
 Results show that IL affected the following broiler production parameters: weight gain, FCR, fat-pad deposition and carcass weight. Over a 35-day IL grow-out period, broilers showed compensatory growth. The final weights achieved by birds subject to IL (1.62 kg) compare well with Ross 308 production targets (1.82 kg). Carcass weights of the different groups indicate that low intensity lighting programmes over a 35-day period may affect male growth more than female growth, where sexes show a different response to intermittent lighting schedules. In addition, females were found to have larger liver and heart weights, showing that intermittent lighting programmes affect female internal organs more than male organs. Birds subjected to intermittent lighting deposited more fat when re-fed, then controls. On the other hand, males subject to intermittent lighting have higher feed intake and abdominal fat content than other male controls. In females, abdominal fat content is lower with intermittent lighting programmes. Consequently, the results indicate that intermittent lighting affects fat deposition in females more than it does in males. This indicates that broiler sex should be chosen according to the further processing.
 Results show that lighting programmes do not effect plasma AST concentrations significantly on day 21 and 35. In addition, plasma AST concentration is not correlated to broiler production parameters (fat-deposit, weight gain, FCR, carcass weight). Thus AST values could be used to indicate the health status of birds. It is strongly suggested that the use of haematological tests should become a standard procedure in broiler production.
In conclusion, intermittent lighting programmes decreased stunting syndromes, ascites, sudden death syndromes, mortality and leg problems. Hence the economical benefits of utilising intermittent lighting programmes are clear and the use of such programmes by Maltese producers is strongly advised.
Research  Worker: John Joseph Borg
Project Supervisor: Mr. George Attard
 

APH10 A STUDY OF THE EFFECT OF STARCH SOURCE ON LACTATION AND GROWTH IN THE RABBIT

 The evaluation of different dietary starch sources, maize, barley, oats, wheat and milo, on lactation and growth performance of the rabbit were investigated. Five diets, each formulated to provide 18% crude protein, 20% acid detergent fibre, 25% starch and 2.55 Mcal kg-1 of digestible energy, varying only in the dietary starch source, were utilised in this investigation.
 Lactation trials where 100 New Zealand white rabbit does grouped randomly to 20 does, were conducted over a 3-month period. Each group of does was fed one of the diets containing the different starch sources. Milk production, doe feed intake and litter weights were measured over the first 21 days of lactation. The source of dietary starch had no significant effect on the doe feed intake during the first 21 days of lactation, 7230.6 ? 214g. Also, no significant differences were observed during the 21 days of lactation for the milk production when does are fed different dietary starch sources, 3360.2 ?139g. Similarly, the litter weights, after 21 days of lactation, had no significant differences, 2323.1 ?80g. No significant differences in doe feed efficiency and litter milk efficiency were observed when lactating does are fed different dietary starch sources.
 Another trial using 50 (28-day-old) rabbits of both sexes, grouped in 10 (5 males and 5 females) per diet, was conducted over a period of 32 days. Weight gains, feed intake and food conversion ratios at 44 days and 60 days were measured to observe the effect of dietary starch source.
Significant differences (P<0.05) were observed at weaning (28 day) between weights of rabbits from different diets. The heaviest weaning weights were observed in the diet containing oats as a starch source, 648.4g and the smallest weights were observed in the diet containing milo, 416.0g. Other significant differences (P<0.05) were observed between the diets containing maize and oats, difference of means of 119.20, maize and milo, difference of means of 104.60, barley and milo, difference of means of 127.80 and oats and wheat with a difference of means of 129.85. A less significant difference (P<0.1) was observed between diets containing barley and oats.
 In the 44-day old rabbits another significant difference (P<0.05) between diets was observed. The heaviest weights were observed in rabbits fed the barley diet, 1261.50g and the smallest were observed in rabbits fed the milo diet, 910.67g. Comparison of weights between the different diets showing significant differences (P<0.05) were rabbits fed maize and milo diets, difference of means of 295.54, barley and milo diets, difference of means of 350.84 and oats and milo diets, difference of means of 325.74. Also, a less significant (P<0.1) observation was obtained between diets containing milo and wheat, difference of means of 272.99.
Weight differences at day 60 were not significant, 1717.7g. No significant differences were observed between weight gains from day 28 to day 60.
Feed intake during the first stage, 28 to 44-day-old and the second stage, 44 to 60-day-old, showed no significant differences, 112.7g day-1, between the rabbits fed the different dietary starch sources.
Significant differences (P<0.05) in the food conversion ratio during day 28 and day 44 were observed. The most significant difference (P<0.01) was observed between rabbits fed the barley and milo containing diets, 2.10 and 3.06 respectively. Other significant differences (P<0.05) were observed between rabbits fed diets containing maize and milo, oats and milo and milo and wheat.
 No significant differences were observed in the food conversion ratios, 3.88, during day 44 to day 60. Similarly no significant differences were observed in the overall food conversion ratios, 3.05, when the rabbits are grown up to 60 days on diets containing different dietary starch sources.
The results obtained are of economic importance to the rabbit industry. Further research is required to study the effect of different starch sources on the blood parameters and other physiological parameters such as hormones. These studies could then be related to human physiological parameters.
Research  Worker: Raymond Spiteri
Project Supervisor: Dr. Peter Jackson
 

APH11 THE EFFECT OF HEAT ON LYSINE WITH SPECIAL REFERENCE TO AMASOL AMINO

The effect of heat on Lysine has been extensively studied, however, several problems were encountered when determining the available lysine after early or late Maillard reactions have taken place.
This study investigates the possibility of a new chemical methodology, designed by Paul Moughan et al., (1996) patented in New Zealand (Patent Number 272486) to determine lysine damage taking place in a commercially produced anti-stress tonic.  The results carried out by the new chemical methodology were compared to a guinea pig bioassay.
A diet deficient in lysine was formulated, pelleted, and air dried.  This was fed ad libitum to 12 guinea pigs.  The source of lysine under test was Amasol Amino, an anti-stress tonic, and was subjected to different heat treatments, 5C, 30C, 37C, 43C, 48C for a one month period. The Guinea pigs, and the amount of feed consumed were weighed daily at 7:00am.  The amount of lysine to meet NRC requirements was recorded, and the corresponding amount of Amasol Amino was administered to the guinea pigs through the mouth in three divided portions.  The study was carried out over a three week period.
There was a significant correlation between guinea pig weight with time, however, the live weight gain of the guinea pigs resulting from the administration of Amasol Amino previously treated at different temperatures, did not reach statistical significance.  One cannot conclude that there is a significant destruction of lysine in Amasol Amino when considering the guinea pig assay.  In fact it is doubtful whether the guinea pig assay was the appropriate animal to use in a live weight gain experiment.  In the case of the chemical assay, the decrease in lysine activity from 5C to 48C for the period of one month was that of 2.9% as shown in the graph below.  This decrease will undoubtedly not affect the overall performance of the anti-stress tonic in regular field practice.
Research worker:  Ingrid Elizabeth Ross
Project supervisor: Mr. George Attard

APH12 A PRELIMINARY STUDY TO EVALUATE THE POTENTIAL OF HELICICULTURE IN MALTA

Heliciculture is the process of farming or raising snails. Snail farming in Malta is an innovative agricultural animal rearing activity which is still being discussed, sometimes even ridiculed, though cultivated snails are all of the same size and more hygienic, are cleaned from mucus and the flesh is of good quality.
Snail meat quality together with improving human nutritional habits has resulted in increasing snail meat consumption. The outcome is an ever-increasing presence of live pre-packed snails in Maltese supermarkets, which demand cannot be further sustained through wild snail picking. The fast increase in the world-wide snail meat market demand, together with Malta’s climatic conditions, may generate the possibility for the Maltese farmer to invest in snail farming and enter into an expanding local and export niche market, with resulting economic benefits to the local agricultural industry.
The study did not investigate the nutritional aspect of snails but evaluated the potential of rearing snails in Malta using local, available, commercial feeds as an experimental pilot backyard snail rearing activity. This study describes the growth pattern of the snail Cantareus aspersus, fed on three different feeds and reared under a sheltered environment by measuring the live snail body weight and shell diameter.
It was observed that the snails reached market size and were classified as No. 12, ‘Type Medium’, alive weight; 9 – 11g, confirming that this study achieved its aim as a pilot back yard snail rearing farm activity. The evaluation also reports the heterogeneity that is commonly observed in snail farming, attributed a linear relationship between the shell diameter and the live snail weight and identified a difference in growth rate between the three feeds, with the compound feed group giving a better biological growth response.
The duration of study was too short and just gives an indication of what might be the situation. The need of further research on snail farming as a continuation is emphasised both for the ecological and the economic impact of this industry.
Research worker:  Maria Salvina Camilleri
Project supervisors: Prof. Anthony Scicluna-Spiteri & Mr. George Attard
 
APH13 THE MALTESE SWINE INDUSTRY AND BACON QUALITY

The swine population which was in existence twelve thousands years ago was genetically different from the swine bred nowadays. Today’s pigs are genetically superior. They produce a lot of offspring, they grow fast and they are efficient food converters. All of this maximises profit for the pork producer. However, for a swine producer to maximise on profits good management practices are essential. Good management practices enhance pork quality. Management practices include good swine housing, swine nutrition and swine health. Swine producers sell their pigs to the local abattoir. In Malta swine breeders are paid according to the pigs’ weight and back fat thickness. The abattoir is then responsible for the distribution of carcasses to the meat processors. Unlike health conscious consumers, pig breeders and meat processors find fatter carcasses easier to grow and process. Carcasses shrink during curing procedures. Fatter carcasses shrink less than leaner carcasses.

 Since Malta’s accession into the European Union (EU) farmers and meat processors are legally bound to follow the EU directives. Swine farmers will have to follow directives that deal with swine husbandry. The EU also regulates processing and packaging of pork products, these will effect the pork processor. The Maltese Ministry of Agriculture will be controlling both the swine breeder and the meat processors, to make sure that they abide by the EU regulations. These regulations will ensure better pork quality.

 The EU unlike USDA (United States Department of Agriculture) does not pose restrictions on the meat to lean ratio of streaky bacon. The USDA imposes restrictions on the lean to fat ratio, the size of the bacon rashers, the presence of bone, cartilage and any foreign material. Experiments were carried out to investigate locally produced streaky bacon. The bacon rashers have a high lean to fat ratio. However, the rashers also have too much bone and the shape of bacon rashers is not uniform. The USDA would have these bacon rashers discarded.

Consumers tend to visually appraise vacuum-packed streaky bacon. Health conscious consumers prefer leaner bacon, which has a bright red colour. Consumers prefer back and collar bacon to streaky bacon, since the latter has a very high calorific value and a lot of unsaturated fats. Bright red bacon is thought to be fresher. Consumers do not know that the colour is due to the additives used during the curing process.

Research worker:  Melanie Gatt
Project supervisor: Dr. George Attard

 
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