Vitamin B₁₂ deficiency has been difficult to diagnose, mainly due to the vitamin's lack of biological significance in serum in which it is usually assayed. This research has investigated the marker of vitamin B₁₂/cobalt (Co) deficiency in sheep, methylmalonic acid (MMA), in comparison with serum and liver vitamin B₁₂ concentrations in farm situations where vitamin B₁₂ deficiency is expected in order to establish more accurate reference ranges for serum and liver vitamin B₁₂, and MMA. In addition, an attempt was made to ascertain the vitamin B₁₂ requirements of preruminant (PR) lambs, and to determine whether metabolic demand for vitamin B₁₂ influences tissue concentrations. Furthermore, since the vitamin is active in biological tissues in form of its coenzymes, 5’ -deoxyadenosylcobalamin and methylcobalamin, a preliminary assessment of variation in the distribution of these coenzymes in liver in different situations has been sought. The first trial was set up to find out if the addition of propionate to the PR lamb's diet stimulated the uptake and/or storage of vitamin B₁₂ in the liver as a reflection of the need to deal with the incoming propionate. Sixteen ten day old lambs (Dorset Down/Coopworth cross-bred) were housed indoors soon after birth and fed on milk replacer. For half of the lambs 7.5 % (w:w) of the milk powder was replaced by propionate. Within each group, four lambs were treated with 250 µg vitamin B₁₂ twice weekly. Supplementation with vitamin B₁₂ increased liver concentrations from ~250 to ~900 nmol/kg fresh tissue, but there was no effect of propionate. Propionate addition did, however, result in increased plasma vitamin B₁₂ concentrations in vitamin B₁₂ supplemented groups, values being 3323 and 2355 pmol/l in propionate supplemented and control groups, respectively. This suggested that diet could influence plasma vitamin B₁₂ concentrations. An attempt was made to quantify the PR lamb's ability to absorb vitamin B₁₂ from the alimentary tract by comparing the ability of intra-muscular (IM) and oral vitamin B₁₂ to raise plasma and liver vitamin B₁₂ concentrations. Twenty-seven three to four day old lambs from a farm with marginal Co status were housed indoors and fed on milk replacer. They were divided into three groups: control (n=3), IM treatment (n=12) and oral treatment (n=12). The two treatment groups were further subdivided into five sub-groups. These received, respectively, 0.2 (n=3), 0.4 (n=2), 0.8 (n=2), 1.6 (n=2) and 3.2 µg OH-cbl/d (n=3). The oral groups received tenfold the amount of the comparable IM groups, on the assumption that if oral absorption of the vitamin is about 10 % both groups would show similar increases in plasma and liver vitamin B₁₂ concentration. None of the IM groups showed any significant change in plasma or liver vitamin B₁₂. In the oral groups only the group on the highest dose of vitamin B₁₂, viz 32 µg/d, showed increases in plasma and liver concentrations. It was concluded that either absorption of vitamin B₁₂ was greater than 10 % or that the vitamin was retained better when administered orally. The amount retained in the livers of the lambs in the highest oral group was calculated to represent ~ 7.5 % of the dose. In a follow-up 24 h trial, 14 of the above lambs were divided into three groups: Control (n=3), oral (n=6) and IM (n=5) treatment. The IM group received 3.2 µg OH-cbl and the oral group tenfold the amount as single doses at 0800 h. Blood samples were taken at regular intervals throughout the 24 h period and assayed for vitamin B₁₂, Vitamin B₁₂ concentrations in the IM group rose steeply within the first hour after injection to a concentration that was calculated to reflect 100 % uptake of the vitamin. It rose more slowly over about 8 h in the oral group. From the area under the curve absorption of the oral dose was estimated to be ~ 7 %. The next experiment involved a farm where Co deficiency had been reported previously. In the first year, 50 pregnant two-tooth Half-bred ewes were divided randomly into two groups of 25. One group received a Co bullet plus 1000 µg OH-cb1 IM, the other group remained unsupplemented. In the following year the trial was repeated. Ewes from the previous year's trial (by then four-tooths) were augmented by a new cohort of pregnant two-tooths to make up numbers to 75. After lambing the lambs were divided into four groups: first by their dams' vitamin B₁₂ treatment, then half of each group received injections of vitamin B₁₂ at approximately three weekly intervals while the other half remained untreated. The trials lasted about five months, from mid-pregnancy until weaning. Pasture Co was at its lowest at lambing in both years, 0.09 and 0.10µg/g DM, respectively. In the first year, vitamin B₁₂ concentrations in the untreated ewes rose from 340 to 950 pmol/l in plasma and decreased in liver from 330 to 170 nmol/kg fresh tissue. In the Co treated group, vitamin B₁₂ concentrations in plasma rose from 500 to 1550 pmol/l and in liver from 310 to 560 nmol/kg fresh tissue. In the second year, vitamin B₁₂ concentrations in serum in the unsupplemented groups fell from 500 to 260 pmol/l around lambing before rising again to starting values at weaning, and liver vitamin B₁₂ concentrations fell from 450 at the start to 230 nmol/kg fresh tissue at the end of the trial. Serum vitamin B₁₂ concentrations in the two-tooth supplemented group rose from < 500 to > 3000 pmol/l whereas in the four-tooth supplemented group serum vitamin B₁₂ levels started at ~2800 and rose to nearly 5000 pmol/l. The supplemented four-tooths maintained higher liver vitamin B₁₂ concentrations throughout compared to the supplemented two-tooths, viz 680 compared to below 400 at the start and 900 versus 650 nmol/kg fresh tissue at weaning, respectively. MMA in the untreated groups rose to 15 and to 8 µmol/l during early lactation in the first and second years, respectively, whereas MMA in the treated groups stayed below 3 µmol/l in the first season and below 1.5 µmol/l in the second season. There was a live weight response to treatment in the ewes as the unsupplemented groups showed a significantly lower weight gain during the trials than the supplemented groups, viz 10.0 versus 13.6 kg in the first year, and 10.6 versus 13.3 kg in the four-tooths and 9.9 versus 12.1 kg in the two-tooths in the second year. There was also a significant difference in faecal egg count (FEC) in the first year. FEC in the untreated group was higher during lactation than in the treated group, viz 590 versus 170 eggs per gram wet faeces (epg), respectively. In the second year, the two-tooths had a higher FEC than the four-tooths, viz 120 versus 40 epg during the same time span, respectively. While there was a trend for treatment having an effect on FEC similar to that in the first year it was not significant. Supplementation of ewes in the first year increased mean milk vitamin B₁₂ concentrations at lambing from 800 to 1400 pmol/l and at weaning from 1750 to 4000 pmol/l. In the second year, Co bullet treatment increased milk vitamin B₁₂ concentrations in the four-tooths and two-tooths from 1500 and 2300 to 4000 and 2900 pmol/l at lambing, and from 1800 and 1400 to 6200 and 4500 pmol/l at weaning, respectively. Treatment of ewes increased vitamin B₁₂ concentrations in the lambs which were not themselves supplemented. Plasma values in the first year increased from 160 to 325 pmol/l soon after birth and from 650 to 900 pmol/l at weaning, and liver values from 75 to 140 nmol/kg fresh tissue soon after birth and from 150 to 240 nmol/kg fresh tissue at weaning. In the second year, plasma vitamin B₁₂ concentrations increased from 160 to 380 pmol/l soon after birth and from 500 to 700 pmol/l at weaning, and in liver from 130 to 260 nmol/kg fresh tissue soon after birth and from 220 to 340 nmol/kg fresh tissue at weaning. There was also a significant effect of ewe supplementation on lamb MMA in 1997/1998 when values decreased from 19 to 8 µmol/l around the time of rumen development. MMA in the second year stayed below 3 µmol/l throughout in all groups of lambs. There was no difference in LWG between any groups of lambs. FEC was lowest in the group where both ewes and lambs were supplemented and highest in the group where neither ewes nor lambs were treated. Further investigations were conducted on farms in Southland with lambs post-weaning in order to compare changes in serum and liver vitamin B₁₂ with serum MMA and LWG to determine the critical time and level of deficiency. In the first year, three farms with 50 lambs each participated. Lambs from each farm were allocated to five groups of 10 animals each. The first group received a Co bullet at weaning, and each month another group was treated with a Co bullet. The lambs were weighed monthly, and blood and liver samples were taken prior to treatment and each subsequent month from five lambs of the first supplemented group. The trial lasted about four months. Serum vitamin B₁₂ concentrations in lambs at weaning were between 500 and 1000 pmol/l. Although supplementation increased serum levels for the first month this was followed by a drop to near or below starting concentrations. An exception was Farm 3 where serum vitamin B₁₂ concentrations rose again at the end of the trial. Liver vitamin B₁₂ concentrations also showed an overall decline from starting levels (200 to 300 nmol/kg fresh tissue) to the end of the trial (100 to 200 nmol/kg fresh tissue). MMA started around 2 µmol/l and reached between 6 and 7 µmol/l in the untreated lambs on Farms 1 and 3 two months after weaning before decreasing to around 3 µmol/l at the end of the trial, whereas the treated lambs maintained MMA concentrations around 2 µmol/l. On Farm 2 MMA started just below 5 µmol/l, decreased to around 1 µmol/l for treated and untreated lambs one month later and rose again to between 2.5 and 4 µmol/l, respectively, at the end of the trial. LWG was below average for all lambs (between 0.20 and 0.04 kg/d except for Farm I in the first month after weaning) but no significant differences were noted between treated and untreated lambs on any of the farms. Another trial was conducted on one of these farms in the following year. One hundred lambs were divided into two groups of 50 each at weaning and sampled monthly for about six months. One group was treated with two Co bullets, the other group remained untreated. Pasture Co was between 0.04 and 0.07 µg/g DM, yet serum levels for the untreated group stayed ~500 pmol/l throughout the trial. Serum vitamin B₁₂ concentrations for the treated group started at ~500 pmol/l, rose to ~2500 pmol/l before falling back to ~2000 pmol/l. Liver vitamin B₁₂ concentrations for the untreated and treated groups were 529 and 427 nmol/kg fresh tissue at weaning, respectively. This decreased for both groups to ~350 nmol/kg fresh tissue one month after weaning. In the untreated lambs liver values decreased further to ~290 nmol/kg fresh tissue whereas they increased to ~450 nmol/kg fresh tissue for the treated group at the end of the trial. MMA concentrations started between 2 and 3 µmol/l for both groups and increased to 4.5 µmol/l for the untreated group one month later before falling back to 3.2 µmol/l. In the treated group MMA decreased to ~1µmol/l and stayed at that level throughout the trial. There was no difference in weight gain. In order to obtain an understanding of the distribution of corrinoids in biological tissues a High Performance Liquid Chromatography method was developed. The sensitivity of the analytical method meant that it was only practical to assay mainly liver samples because of the higher vitamin B₁₂ concentrations than in other tissues. The general finding was that the coenzyme 5’ –deoxyadenosylcobalamin (ado-cbl) constituted the highest proportion of corrinoids in liver (45 %), followed by analogues (28 %), OH-cbl (24 %) and lastly methy1cobalamin (3 %). Ado-cbl did tend to be proportionately higher in supplemented than in unsupplemented animals (56 and 42 %, respectively), whereas biologically non-active analogues tended to be higher in untreated than in treated sheep (29 and 21 %, respectively). It was concluded that in the farm trials Co deficiency was only mild or not present although deficiency would have been predicted from the low vitamin B₁₂ concentrations in serum and liver and from raised MMA values. Therefore, currently used thresholds in New Zealand appear to be too high for vitamin B₁₂, and overseas values for MMA do not seem to be appropriate. Revised marginal ranges of 100 to 200 pmol/l for serum, 100 to 200 nmol/kg fresh tissue for liver and 10 to 20 µmol/l for MMA are suggested. Further, this work shows that Co bullets were effective in elevating blood and liver vitamin B₁₂concentrations for longer than one year. In the trials with preruminant lambs it was found that maintenance requirements were met by the vitamin B₁₂ content of milk replacer. There is evidence from indoor and farm trials that vitamin B₁₂ from milk was much more readily absorbed than vitamin B₁₂ from supplements. It was estimated that suckling lambs probably require between 1200 and 4000 pmol vitamin B₁₂/d, depending on age.

One of the major constraints limiting the efficiency of sheep production is the control of gastrointestinal nematode parasites. Parasite control by strategic use of anthelmintics is threatened by the emergence of nematode populations that are resistant to the drugs available. It is therefore increasingly apparent that steps toward maintaining sustainable productivity in the growing face of anthelmintic resistance (AR) is required by farmers. To facilitate the uptake of sustainable approaches to parasite management, a comprehensive understanding of the various factors that may influence farmers’ decision-making processes is required. In order to establish which factors are influential, and determine their impact on farmers’ roundworm control behaviours, both qualitative and quantitative research methods were used including focus groups as well as attitudinal and behavioural questionnaires. A retrospective analysis was initially conducted of historical surveys designed to identify farm specific characteristics and parasite management practices including anthelmintic usage. The objectives of the analysis were to identify factors associated with uptake of best practice advice including farm characteristics and information sourcing. In addition, the implementation of sustainable roundworm control practices was investigated using two surveys conducted in 2000 and 2010. Logistic regression models were applied for univariable and multivariable analysis of dependent and independent variables. The next step was to conduct a series of focus groups in different geographic regions of Scotland. The main purposes were to explore sheep farmers’ attitudes towards different aspects of roundworm management, as well as to identify potential motivators and barriers to uptake of sustainable parasite control practices. The findings aided in the development of an attitudinal questionnaire used to canvass opinions representative on a national level. The concluding study involved a telephone survey of 400 Scottish sheep farmers, designed to elicit attitudes regarding roundworm control, AR and sustainable roundworm control practices. A quantitative statistical analysis technique (Structural Equation Modelling) was then used to test the relationships between socio-psychological factors and the uptake of sustainable roundworm control practices. The analysis of historical questionnaire data demonstrated evidence of a shift towards the use of practices to reduce the rate of AR development, most notably a decline in the practice of ‘dose and move’ as well as an overall reduction in treatment frequency. Statistical analysis identified significant associations between farm characteristics and specific treatment strategies. For example, larger farms were more likely to adopt a set treatment regimen (P=0.036), compared with smaller farms, which were more likely to treat based on clinical signs of infection (P=0.021). Sourcing of roundworm control information primarily from veterinarians was most associated with treatment timings with no parallels between time points. From the qualitative focus group studies conducted we identified four overarching themes impacting on sheep producers’ attitudes to roundworm control and best practice advice. These themes comprised: a lack of perceived need to change, the complexity of advice, the ease of implementation of recommended practices and the effectiveness of extension approaches. Additionally, the most important and implementable guidelines identified by sheep farmers were: ‘working out a roundworm control strategy with an advisor’ and ‘administering anthelmintics effectively’ with regard to correct drenching practice i.e. appropriate dosing, administration and drug storage procedures. These findings exhibited similarities with veterinarians’ rankings with also, ‘testing for AR’, ‘preserving susceptible parasites’ and ‘reducing dependence on anthelmintics’ receiving the lowest rankings for importance and implementability. The quantitative analysis from the attitudinal/behavioural questionnaire identified eleven factors with significant influences on the adoption of sustainable roundworm control practices. The key influences on overall adoption were farmers’ baseline understanding about roundworm control and self-reported confirmation of anthelmintic resistance in their flock. Additional positive influences included, positive attitudes to veterinary services, enterprise type and perceived risk of AR. Factors that were shown to have the greatest relative effects on individual parasite control practices included; the perceived resource requirements for implementing a quarantine strategy, farmers’ AR suspicions for instigating AR testing and the confirmation of AR for adopting faecal egg count monitoring. The findings have highlighted several factors which can influence sheep farmers’ decisions to reject or adopt recommended roundworm control practices. It is evident that the perceived complexity, lack of need and practicality of the current recommendations necessitates changes to how extension is designed and disseminated to farmers. The findings also suggest that improving farmers’ acceptance and uptake of diagnostic testing and improving underlying knowledge and awareness about nematode control is a significant target to influencing adoption of best practice behaviours. The importance of veterinarians as highly-trusted information resources validates the need for further engagement with veterinarians concerning sustainable parasite control approaches, to facilitate collaboration with farmers. The need for interaction between farmers and their advisors is key to resolving the issues raised to enable the necessary explanation, justification and execution of recommended practices to suit farmers’ needs and farming conditions.

The pig production in Sweden is divided into conventional and organic production, with the organic production divided into EU organic and KRAV production. Pigs are divided into different age categories: weaned pigs, growing pigs, fattening pigs, gilts/sows before farrowing and dry sows. Roundworm, nodular worm, whipworm, coccidia, red stomach worm, threadworm and lungworm are common parasites in pigs affecting growth, feed conversion and economy. Organic pigs are more exposed to parasites because of outdoor stay and deworming could help if used with care. The aim of this project was to investigate parasites in pig herds with organic production. The investigation would increase the knowledge of parasites in different age categories in currently used production systems and contribute to good recommendations about parasite control and treatment. A modified McMaster technique was used to identify and quantify parasite eggs with microscope. Larval culturing and microscopy were used to distinguish eggs from nodular worm and red stomach worm. Roundworm, nodular worm, whipworm and coccidia were found in all age categories. Threadworm was only identified in dry sows and gilts/sows before farrowing. Nodular worm and coccidia showed highest quantity of positive samples at herd and sample level followed by roundworm and whipworm. Roundworm and nodular worm had highest quantity of eggs per gram faeces followed by whipworm and threadworm. The results corresponded to previous studies in parasite occurrence despite new conditions. More samples, herds and environmental factors should be investigated in conjunction with parasite occurrence to get broader knowledge and to give good recommendations in parasite control and treatment.