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- Ahlman, Therese, et al.
(författare)
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Culling reasons in organic and conventional dairy herds and genotype by environment interaction for longevity
- 2011
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 94, s. 1568-1575
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Tidskriftsartikel (refereegranskat)abstract
- Dairy cow longevity combines all functional traits and is thought to be especially important in organic production, which is an established, increasing part of Swedish dairy production, representing approximately 6% of the market. The aim of this study was to compare dynamics in culling reasons between organic and conventional production and to analyze genotype by environment interactions for longevity. The data contained information from all organic herds with information available from official recording (n = 402) and from approximately half of the conventional herds (n = 5,335). Records from Swedish Holsteins (n = 155,379) and Swedish Red cows (n = 160,794) that had their first calf between January 1998 and September 2003 were included. The opportunity period for longevity was at least 6 yr. Six longevity traits were defined: length of productive life; survival through first, second, and third lactations; fertility-determined survival; and udder health-determined survival. Twenty codes were used to describe the cause of culling, and these were divided into 8 groups: udder health, low fertility, low production, leg problems, metabolic diseases, other diseases, other specified causes, and unspecified cause. The main reason for culling cows in organic herds was poor udder health, whereas for cows in conventional herds it was low fertility. Furthermore, the shift in main culling reason from fertility, which was most common in first lactation regardless of production system, to udder health occurred at a lower age in organic production. Heritabilities and genetic correlations for the longevity traits expressed in organic and conventional herds were estimated from a bivariate animal model. The genetic correlations were close to unity (>0.88), except for fertility-determined survival in the Swedish Red breed (0.80). Heritabilities were low to moderate, and no clear pattern was identified for production system or breed. In general, the results indicate that farmers' culling criteria differ between organic and conventional production. Different preferences may influence the need for alternative selection indexes for organic production, with different weightings of traits, or a separate breeding program. However, no genotype by environment interaction of importance was found between the production systems.
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| 2. |
- Ahlman, Therese, et al.
(författare)
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Differences in preferences for breeding traits between organic and conventional dairy producers in Sweden
- 2014
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 162, s. 5-14
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Tidskriftsartikel (refereegranskat)abstract
- Development of sustainable breeding goals for dairy production has to consider the producers' preferences which are likely to differ between production systems. The number of dairy producers with herds certified according to the standards of organic production has increased during the last decades. Traditionally, organic producers use animals selected in conventional production systems but the traits important in organic herds have been suggested to differ due to the different production conditions. The aim of this study was to assess what traits Swedish organic and conventional daily producers consider to be important for the cows in their herds, and the relative importance of traits in the two production systems.An advanced web questionnaire with an underlying selection index was developed. The selection index was not shown to the respondents but it enabled them to weight traits against each other based on the genetic progress obtained. The questionnaire also included questions about what traits the producers intuitively considered important for the cows in their herds and how they ranked 15 given production and functional traits. The questionnaire was answered by 468 Swedish dairy producers of which 122 had a certified organic herd and 346 had a conventional herd.The results of this study show that the trait longevity was ranked first by both organic and conventional Swedish dairy producers. However, the ranking differed to some extent between the production systems for other traits, e.g. mastitis resistance and milk production. Swedish producers with organic herds tended to desire a higher genetic gain in disease resistance, including mastitis and parasite resistance, compared with producers with conventional herds. The results also reflect a somewhat lower interest in milk production level among producers with organic production. However, as the traits most important for Swedish producers with organic herds are already considered in the current Nordic breeding goal they can continue the use of this animal material. (C) 2014 The Authors. Published by Elsevier B.V.
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| 3. |
- Ahlman, Therese, et al.
(författare)
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Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds
- 2009
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 126, s. 176-182
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Tidskriftsartikel (refereegranskat)abstract
- The share of organic dairy production in EU is increasing and this study describes the herd structure and cow performance in organic and conventional dairy production systems in Sweden. The data included records from 2902718 lactations, collected in organic (n=471) and conventional (n = 13976) herds between 1998 and 2005. Compared with conventional herds, the organic herds were larger and increased more rapidly in size. The replacement rate was slightly lower in organic herds and fewer Swedish Holsteins were used. The statistical analysis of cow performance in the first three lactations showed lower milk, fat and protein production in organic herds, but the increase in production from first to second lactation was larger when expressed in kg milk. Fertility was better for organically managed cows compared to conventionally managed cows, but the somatic cell count (SCC) was higher. However. at a given production level the fertility was slightly worse in organic herds while there was no difference in SCC. No interactions of importance were found between production system and breed for any trait.The results showed that organic and conventional dairy production differed regarding herd structure and cow performance. However, the differences in fertility and SCC found were to a high extent explained by the lower milk yield in organic production and no breed was found to perform better in either system. (C) 2009 Elsevier B.V. All rights reserved.
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| 8. |
- Arvelius, Per, et al.
(författare)
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Does the Swedish Armed Forces’ temperament test give information on genetic differences between dogs?
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With the purpose to select breeders and dogs for training, all German Shepherd dogs in the Swedish Armed Forces (SAF) breeding program go through a temperament test. During the test, the dog's behavioural responses are rated with two different methods. In a previous study, using PCA on the test items, five and three underlying behavioural dimensions from each rating method were defined. Three of the dimensions correlated significantly to training success. Using test results from 873 dogs, we estimated heritabilities of, and genetic correlations between, the 38 test items plus the eight underlying behavioural dimensions. Parameters were estimated using a linear animal model including fixed effects of sex, educational level, test age and interaction between test year and test arena, and random effect of litter, genetic effect of the individual and residual. Heritabilities ranged from 0.00 to 0.28 (SE=0.05- 0.10), which is similar to what has been reported in previous studies on traits defined and measured in a comparable way. Genetic correlations were high (rg=0.92-0.98, SE=0.08-0.12) between dimensions derived from each registration method and defined as confidence, engagement and aggressiveness, but relatively weak between these dimensions within registration method (rg=0.00-0.45, SE=0.29-0.41). Our results imply that the test measures three separate behavioural dimensions and that the SAF temperament test as a whole is possible to utilize for selection of dogs for breeding, but also that some test items should be measured differently to be meaningful for selection purposes. Furthermore, aggregating variables based on a PCA performed on phenotypic data might be sub-optimal when defining dimensions for breeding purposes.
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| 9. |
- Arvelius, Per, et al.
(författare)
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Genetic analysis of a temperament test as a tool to select against everyday life fearfulness in Rough Collie
- 2014
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Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 92, s. 4843-4855
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Tidskriftsartikel (refereegranskat)abstract
- Fear-related problems are common among Rough Collies in Sweden. Annually, on average, >200 Rough Collies are subjected to the dog mentality assessment (DMA), a temperament test during which 33 behavioral reactions are rated. Previous research has shown that a dog's DMA result can be condensed into 5 underlying personality traits. The aim of the study was to evaluate if it is possible to use the DMA for selection for temperament in Swedish Rough Collies, in particular to decrease everyday life fearfulness. We also wanted to compare 2 methods to compute the personality traits: summated scales (SS) and factor scores (FS). The DMA data for 2,953 Rough Collies were used to estimate genetic parameters for the 5 personality traits (both SS and FS), using a linear animal model including fixed effects of sex, year and month of test, and random effects of litter, judge, test occasion, genetic effect of the individual, and residual. Age at test was included as linear and quadratic regressions. The DMA personality trait heritability estimates ranged from 0.13 to 0.25. The SS showed greater or equal heritability estimates compared with the FS. To validate the DMA, data on everyday life behavior of 1,738 Rough Collies were collected using an extended version of the Canine Behavioral Assessment and Research Questionnaire. Each dog's questionnaire result was condensed into 18 underlying behavioral subscales. Genetic parameters for the subscales were estimated using a linear animal model, including a fixed effect of sex and random genetic effect of the individual and residual. Age when the questionnaire was completed was included as linear and quadratic regressions. Heritability estimates for the questionnaire subscales were 0.06 to 0.36. There were high and significant genetic correlations between DMA personality traits and questionnaire subscales. For instance, the DMA personality trait Curiosity/Fearlessness correlated strongly genetically to the questionnaire subscale Non-social fear (-0.70), DMA Sociability to Stranger-directed interest (0.87) and Stranger-directed fear (-0.80), DMA Playfulness to Human-directed play interest (0.63), and DMA Chase-proneness to Chasing (0.73). We could not detect any obvious difference in validity between DMA SS and FS. We conclude that the DMA is an effective tool for selection of breeding animals with the goal to decrease everyday life fearfulness among Swedish Rough Collies. The DMA can also be used for breeding for other traits. The SS method seems to perform at least as good the FS method.
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| 10. |
- Arvelius, Per, et al.
(författare)
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Good Possibilities to Select Against Fearfulness in Rough Collie
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Fear-related problems are common among Swedish Rough Collies. Genetic analyses were performed on 4 composite behavioral traits based on 2953 Rough Collie results from a temperament test. Heritabilities ranged from 0.13-0.25. Validation of the test was done using a dog owner questionnaire, which generated information about everyday life behavior for 1738 Rough Collies. There were high and significant genetic correlations between traits measured in the test, and the everyday life behavior of the dogs as described by the owners. For instance, Curiosity/fearlessness in the test was negatively genetically correlated with Nonsocial fear in the questionnaire (-0.70, SE 0.10). We conclude that data from the analyzed test is possible to use for selection to decrease everyday life fearfulness in the Swedish Rough Collie population.
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