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Den här rapporten är framtagen av SLUs vetenskapliga råd för djurskydd i syfte att utvärdera djurvälfärden hos minkar inom svensk pälsdjursproduktion och bedöma om den vetenskapliga litteraturen ger stöd för att produktionen, så som den bedrivs i dag, ger djuren möjlighet att bete sig naturligt. Minkar som föds upp för pälsproduktion i Sverige måste hållas och skötas enligt Statens jordbruksverks föreskrifter och allmänna råd (SJVFS 2012:14) om uppfödning och hållande av pälsdjur. Rapporten har tagits fram på uppdrag av Jordbruksverket som en del i ett regeringsuppdrag om minkhållning. Den beskriver minkens ursprung och domesticering, naturligt beteende hos vild mink, inhysning och skötsel vid pälsuppfödning, onormalt beteende, miljöberikningar, smittskydd, förekommande sjukdomar och avlivningsmetoder. I rapporten ges rekommendationer baserat på tillgänglig vetenskaplig litteratur, och behov av framtida forskning identifieras. Minken är en opportunistisk köttätare som behöver äta relativt ofta. I pälsdjursproduktionen tillämpas i princip fri tillgång på foder till digivande honor och växande valpar men inför parningssäsongen innebär den fria tillgången ökad risk för komplikationer vid valpningen på grund av övervikt hos honan. Fodringen behöver därför anpassas under vintern för att minska risken för feta honor och därmed ökad dödlighet vid valpningen. Neddragen fodertillgång kan orsaka frustration som då visar sig i beteendestörningar. Olika aspekter på utfodring bör därför beaktas i framtida forskning. Den vilda minken lever solitärt under stora delar av året, dock kan en till flera honor leva inom en hanes revir. I pälsdjursproduktionen bör därför vuxna minkar hållas individuellt, undantaget är växande ungminkar som med fördel kan hållas tillsammans. Att hålla två minkar tillsammans är det vanligaste, dock fungerar det att hålla tre ungminkar i etagebur om de ges extra foder och god tillsyn. Grupper med fler än tre djur bör undvikas då riskerna för aggression ökar. En lya fastsatt utanpå buren är viktigt för alla minkar året runt då de naturligt vilar mycket i sina bohål, samt även för att minkhonan ska kunna ta hand om de outvecklade ungarna första tiden efter födelsen. I fångenskap används halm för att skapa ett varmt bo under den kalla årstiden samt för att bygga ett bo för ungarna under uppfödningsperioden. Systematisk genetisk selektion för önskat beteende (temperament) förbättrar välfärden hos minken. Systemet tillämpas på svenska gårdar genom att minkar som uppvisar rädsla eller stress selekteras bort vid avelsurvalet. Urvalet av avelsdjur görs kontinuerligt från det att valparna föds, då reproduktion, valpöverlevnad och temperament registreras tidigt och är viktiga parametrar att ta hänsyn till i urvalet. Det slutliga urvalen sker på hösten då längd, vikt och pälsegenskaper graderas. Ju tidigare dessa urval görs desto tidigare kan utfodringen anpassas för att undvika att avelsdjuren blir överviktiga under hösten. Det är viktigt att aveln inte resulterar i för stora djur, då detta kan leda till välfärdsproblem i framtiden. Mink i vilt tillstånd använder vatten i sin jakt på bytesdjur, men är inget vattenlevande djur, per se. Badvatten till mink bedöms däremot vara en positiv berikning, dock inte vetenskapligt belagt, som ett grundläggande beteendebehov. Forskning visar att beteendestörningar kan förebyggas genom att minkarna ges fri tillgång på foder, hålls i etageburar med bolåda, hyllor, strömedel och berikningar som byts ut regelbundet. I svenska djurskyddsföreskrifter ingår dessa som krav för hållande av mink för pälsdjursproduktion. Mer kunskap behövs för hur ofta berikningar bör skiftas. Djurvälfärd i samband med livdjurstransport och avlivning av mink lyfts fram som angelägna forskningsområden. En snabb avlivning vid hemmaburen bedöms vara det bästa ur djurvälfärdssynpunkt. För att minska risken för spridning av sjukdomar bör importerade minkar hållas i karantän och hög biosäkerhet tillämpas på gården.

I Sverige tillåts idag generellt avvänjning av smågrisar i praktiken vid en individuell ålder om tidigast 28 dagar. Detta skiljer från EUs grisdirektiv där avvänjning tillåts från 21 dagars ålder. En digivningsperiod på 21 dagar ger en högre produktion eftersom medeltalet kullar per sugga och år teoretiskt då kan öka med 4,5 % (från 2,2 till 2,3 kullar per år). Det har även föreslagits att en kortare digivningsperiod skulle innebära mindre påfrestningar på suggorna, och därigenom medföra förbättrad välfärd för dessa. Rådet finner att det finns mycket få studier som jämför avvänjning vid just 21 och 28 dagar. De vetenskapliga studier som studerar detta mer i detalj är i de flesta fall genomförda i alternativa system, så som grupphållnings-system eller så kallade ”getaway pens” där suggan kan gå ifrån sina smågrisar. Resultat från dessa studier går därmed inte att generalisera till konventionella system där suggor med smågrisar hålls individuellt med små möjligheter för suggan att reglera t.ex. digivning eller födosöksbeteende. Trots bristen på vetenskapligt granskade rapporter konstaterades att en avvänjning vid 28 dagars ålder var att föredra sett ur smågrisens perspektiv, eftersom matsmältningsapparat och immunsystem är mer utvecklade den fjärde levnadsveckan. Det förefaller dock finnas en ganska tydlig skillnad i fysiologisk mognad mellan grisar som är yngre (

Breeding programs are crucial for boosting productivity and increase sustainability of aquaculture. Over years, Tanzania has witnessed fluctuation in its capture fisheries production from 320,900 to 375, 535 and back to 362,595 metric tonnes in the years 2000, 2005 and 2016, respectively (URT 2016). The declining trend in fish production has made fish supply in the country unstable and conversely, increased the demand for fishes to about 730,000 metric tonnes in 2017. However, the local aquaculture production has not increased accordingly. Tanzania is importing fish mainly from Asia to meet its increased demand. In 2017, a total of 2,055,721 kg of frozen tilapia were imported from China and Mozambique (URT 2017). The introduction of exotic fish species in Tanzania should be carefully managed because introduced species have many negative impacts to the indigenous species. Tanzania should have a moderate scale tilapia breeding program that will produce good quality fingerlings at affordable price for smallholder fish farmers. The availability of reliable good quality fingerlings is key to improve aquaculture production in the country. Among 17 existing hatcheries, only 12 hatcheries are active, however these hatcheries are not performing well due to low investment and technology leading to the production of low quantity and quality fingerlings. The need for a structured sustainable Tilapia breeding program with bio secured and reliable hatcheries to enhance aquaculture production in Tanzania is given in this review.Keywords: Aquaculture, Breeding programs, Nile tilapia, Local strains.

Biotechnology can provide innovative and efficient tools to support sustainable development of aquaculture. It is generally accepted that use of the term 'genetically modified' causes controversy and conflict among consumers, but little is known about how using the term 'biotechnology' as a salient feature on product packaging affects consumer preferences. In an online discrete choice experiment consisting of two treatments, a set of 1005 randomly chosen Swedish consumers were surveyed about use of hormone and triploidization sterilization techniques for salmonids. The information given to the treatment group included an additional sentence stating that the triploidization technique is an application of biotechnology, while the control group received the same text but without reference to biotechnology. Analysis using a hierarchical Bayes approach revealed significant consumer reactions to the term biotechnology. When the term was included in information, variation in consumer willingness-to-pay (WTP) estimates increased significantly. Moreover, some participants were dissuaded towards an option guaranteeing no biotechnological intervention in production of fish. These results have multiple implications for research and for the food industry. For research, they indicate the importance of examining the distribution of variation in WTP estimates for more complete characterization of the effects of information on consumer behavior. For the food industry, they show that associating food with biotechnology creates more variability in demand. Initiatives should be introduced to reduce the confusion associated with the term biotechnology among consumers.

BackgroundIn this paper, we simulate deleterious load in an animal breeding program, and compare the efficiency of genome editing and selection for decreasing load. Deleterious variants can be identified by bioinformatics screening methods that use sequence conservation and biological prior information about protein function. Once deleterious variants have been identified, how can they be used in breeding?ResultsWe simulated a closed animal breeding population subject to both natural selection against deleterious load and artificial selection for a quantitative trait representing the breeding goal. Deleterious load was polygenic and due to either codominant or recessive variants. We compared strategies for removal of deleterious alleles by genome editing (RAGE) to selection against carriers. Each strategy varied in how animals and variants were prioritized for editing or selection.ConclusionsGenome editing of deleterious alleles reduces deleterious load, but requires simultaneous editing of multiple deleterious variants in the same sire to be effective when deleterious variants are recessive. In the short term, selection against carriers is a possible alternative to genome editing when variants are recessive. The dominance of deleterious variants affects both the efficiency of genome editing and selection against carriers, and which variant prioritization strategy is the most efficient. Our results suggest that in the future, there is the potential to use RAGE against deleterious load in animal breeding.

Because mastitis is very frequent and unavoidable, adding recovery information into the analysis for genetic evaluation of mastitis is of great interest from economical and animal welfare point of view. Here we have performed genome-wide association studies (GWAS) to identify associated single nucleotide polymorphisms (SNPs) and investigate the genetic background not only for susceptibility to – but also for recoverability from mastitis. Somatic cell count records from 993 Danish Holstein cows genotyped for a total of 39378 autosomal SNP markers were used for the association analysis. Single SNP regression analysis was performed using the statistical software package DMU. Substitution effect of each SNP was tested with a t-test and a genome-wide significance level of P-value < 10-4 was used to declare significant SNP-trait association. A number of significant SNP variants were identified for both traits. Many of the SNP variants associated either with susceptibility to – or recoverability from mastitis were located in or very near to genes that have been reported for their role in the immune system. Genes involved in lymphocyte developments (e.g., MAST3 and STAB2) and genes involved in macrophage recruitment and regulation of inflammations (PDGFD and PTX3) were suggested as possible causal genes for susceptibility to – and recoverability from mastitis, respectively. However, this is the first GWAS study for recoverability from mastitis and our results need to be validated. The findings in the current study are, therefore, a starting point for further investigations in identifying causal genetic variants or chromosomal regions for both susceptibility to – and recoverability from mastitis.

Bone fracture in egg laying hens is a growing welfare and economic concern in the industry. Although environmental conditions and management (especially nutrition) can exacerbate it, the primary cause of bone weakness and the resulting fractures is believed to have a genetic basis. To test this hypothesis, we performed a genome-wide association study to identify the loci associated with bone strength in laying hens. Genotype and phenotype data were obtained from 752 laying hens belonging to the same pure line population. These hens were genotyped for 580,961 SNPs, with 232,021 SNPs remaining after quality control. Each of the SNPs were tested for association with tibial breaking strength using the family-based score test for association. A total of 52 SNPs across chromosomes 1, 3, 8, and 16 were significantly associated with tibial breaking strength with the genome-wide significance threshold set as a corrected P value of 10e−5. Based on the local linkage disequilibrium around the significant SNPs, 5 distinct and novel QTLs were identified on chromosomes 1 (2 QTLs), 3 (1 QTL), 8 (1 QTL) and 16 (1 QTL). The strongest association was detected within the QTL region on chromosome 8, with the most significant SNP having a corrected P value of 4e−7. A number of candidate genes were identified within the QTL regions, including the BRD2 gene that is required for normal bone physiology. Bone-related pathways involving some of the genes were also identified including chloride channel activity, which regulates bone reabsorption, and intermediate filament organization, which plays a role in the regulation of bone mass. Our result supports previous studies that suggest that bone strength is highly regulated by genetics. It is therefore possible to reduce bone fractures in laying hens through genetic selection and ultimately improve hen welfare.

Mastitis in dairy cows is an unavoidable problem and variation in recovery from mastitis is therefore of interest, in addition to resistance to mastitis. Genetic parameters for mastitis resistance and recovery were estimated for Danish Holstein-Friesian cows using data from Automatic Milking Systems equipped with online somatic cell count (OCC) measuring units. The OCC measurements were converted to elevated mastitis risks (EMR), a continuous variable (on a [0-1] scale) indicating the risk of mastitis. EMR values above 0.6 were assumed to indicate that a cow had mastitis. For each cow and lactation the sequence of health states (mastitic or healthy) was converted to weekly transitions: 0 if the cow stayed within the same state and 1 if the cow changed state. The result was two series of transitions: one for healthy to diseased (HD, to model mastitis resistance) and the other for diseased to healthy (DH, to model recovery). The two series of transitions were analyzed with a bivariate threshold model including a linear combination of systematic effects and of a function of time. The model included effects of herd and parity, herd-test-week, permanent environment (to account for the repetitive nature of transition records from a cow) plus two time-varying effects (lactation stage and time within episode). In early lactation, there was an increased risk of getting mastitis but the risk remained stable afterwards. Mean recovery rate was 45.7%. Posterior mean of correlations between the traits were -0.853 (PSD=0.108), -0.909 (PSD=0.076), -0.292 (PSD=0.105) and 0.052 (PSD=0.157) for the random effects of genetic, permanent environment, cow-parity interaction, and herd-test-week, respectively. Heritabilities were 0.080 (PSD=0.026) for HD and 0.075 (PSD=0.030) for DH. Recovery could be considered as a new trait for selection even though the negative correlation suggests that a cow that easily contracts mastitis has greater difficulty to recover.

Non-coagulating (NC) milk, defined as milk not coagulating within 40 min after rennet-addition, can have a negative influence on cheese production. Its prevalence is estimated at 18% in the Swedish Red (SR) cow population. Our study aimed at identifying genomic regions and causal variants associated with NC milk in SR cows, by doing a GWAS using 777k SNP genotypes and using imputed sequences to fine map the most promising genomic region. Phenotypes were available from 382 SR cows belonging to 21 herds in the south of Sweden, from which individual morning milk was sampled. NC milk was treated as a binary trait, receiving a score of one in case of non-coagulation within 40 min. For all 382 SR cows, 777k SNP genotypes were available as well as the combined genotypes of the genetic variants of αs1-β-κ-caseins. In addition, whole–genome sequences from the 1000 Bull Genome Consortium (Run 3) were available for 429 animals of 15 different breeds. From these sequences, 33 sequences belonged to SR and Finish Ayrshire bulls with a large impact in the SR cow population. Single-marker analyses were run in ASReml using an animal model. After fitting the casein loci, 14 associations at −Log10(P-value) > 6 identified a promising region located on BTA18. We imputed sequences to the 382 genotyped SR cows using Beagle 4 for half of BTA18, and ran a region-wide association study with imputed sequences. In a seven mega base-pairs region on BTA18, our strongest association with NC milk explained almost 34% of the genetic variation in NC milk. Since it is possible that multiple QTL are in strong LD in this region, 59 haplotypes were built, genetically differentiated by means of a phylogenetic tree, and tested in phenotype-genotype association studies. Haplotype analyses support the existence of one QTL underlying NC milk in SR cows. A candidate gene of interest is the VPS35 gene, for which one of our strongest association is an intron SNP in this gene. The VPS35 gene belongs to the mammary gene sets of pre-parturient and of lactating cows.

Genomic selection is a promising development in agriculture, aiming improved production by exploiting molecular genetic markers to design novel breeding programs and to develop new markers-based models for genetic evaluation. It opens opportunities for research, as novel algorithms and lab methodologies are developed. Genomic selection can be applied in many breeds and species. Further research on the implementation of genomic selection in breeding programs is highly desirable not only for the common good, but also the private sector (breeding companies). It has been projected that this approach will improve selection routines, especially in species with long reproduction cycles, late or sex-limited or expensive trait recording and for complex traits. The task of integrating genomic selection into existing breeding programs is, however, not straightforward. Despite successful integration into breeding programs for dairy cattle, it has yet to be shown how much emphasis can be given to the genomic information and how much additional phenotypic information is needed from new selection candidates. Genomic selection is already part of future planning in many breeding companies of pigs and beef cattle among others, but further research is needed to fully estimate how effective the use of genomic information will be for the prediction of the performance of future breeding stock. Genomic prediction of production in crossbreeding and across-breed schemes, costs and choice of individuals for genotyping are reasons for a reluctance to fully rely on genomic information for selection decisions. Breeding objectives are highly dependent on the industry and the additional gain when using genomic information has to be considered carefully. This review synthesizes some of the suggested approaches in selected livestock species including cattle, pig, chicken and fish. It outlines tasks to help understanding possible consequences when applying genomic information in breeding scenarios.