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| 2. |
- Berglund, Britt, et al.
(författare)
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Estimating genetic parameters for fertility in dairy cows from in-line milk progesterone profiles
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 5763-5773
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to define endocrine fertility traits from in-line milk progesterone (P4) records and to estimate genetic parameters for these traits. Correlations of classical fertility (calving interval and calving to first service) and milk production traits with endocrine fertility traits were also estimated. In-line milk P4 records (n = 160,952) collected from June 2009 through November 2013 for 2,273 lactations of 1,561 Holstein-Friesian cows in 12 commercial herds in the Netherlands were analyzed for (the log of) the number of days from calving till commencement of luteal activity (1nC-LA), proportion of samples between 25 and 60 d in milk with luteal activity (PLA), presence or absence of luteal activity for a cow between 25 and 60 d in milk, interval from commencement of luteal activity to first service (CLAFS), first luteal phase length, length of first interluteal interval, and length of first interovulatory interval. Milk P4 records were sampled, on average, every 2 d. Genetic parameters were estimated using a mixed linear animal model. Heritability estimates ( SE) of endocrine fertility traits were 0.12 +/- 0.05 for 1nC-LA, 0.12 0.05 for PLA, and 0.11 +/- 0.06 for CLAFS, and their repeatability estimates were 0.29 +/- 0.04, 0.21 +/- 0.04, and 0.15 +/- 0.06, respectively. The genetic correlation of 1nC-LA with PLA was 0.91 +/- 0.06 and with CLAFS was 0.56 +/- 0.25. The genetic correlations of 1nC-LA were 0.26 +/- 0.33 with calving interval and 0.37 +/- 0.21 with calving to first service. Genetic correlations of the milk production traits with 1nC-LA ranged from 0.04 to 0.18 and 0.07 to 0.65 with classical fertility traits. The phenotypic correlations of all endocrine fertility traits with milk production traits were close to zero (0.01 to 0.07). This study shows that in-line P4 records can be used to define and explore several heritable endocrine fertility traits in dairy cows and might help in selection for improved fertility.
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| 3. |
- Carlström, Caroline, et al.
(författare)
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Genetic Associations of In-line Recorded Milkability Traits and Udder Conformation with Udder Health
- 2016
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Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 66, s. 84-91
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Tidskriftsartikel (refereegranskat)abstract
- Milkability and udder conformation traits of Swedish Holstein (SH) and Swedish Red (SR) cows from 93 herds with automatic milking systems or conventional milking parlors were used to study genetic relationships to lactation average somatic cell score (LSCS) and incidence of clinical mastitis (CM). Estimated genetic correlations between measures of milking speed (average flow rate, milking time and box time) and LSCS ranged between 0.29 and 0.57 and showed that high milking speed is associated with increasing LSCS. Regressions indicated a curvilinear relationship. Genetic correlations between milking speed and CM showed similar values as for LSCS in SH cows, but were inconsistent in SR cows. Shallow udder and strong fore udder attachment were consistently correlated with good udder health. The unfavorable relationships between milking speed and udder health traits should be considered together with a few udder conformation traits when selecting for better milkability.
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| 4. |
- Carlström, Caroline, et al.
(författare)
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Genetic associations of teat cup attachment failures, incomplete milkings, and handling time in automatic milking systems with milkability, temperament, and udder conformation
- 2016
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Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - : Informa UK Limited. - 0906-4702 .- 1651-1972. ; 66, s. 75-83
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Tidskriftsartikel (refereegranskat)abstract
- Automatic milking systems (AMS) allow recording of alternative milkability measures. Our objectives were to estimate genetic parameters for teat cup attachment failures (AtF), incomplete milkings (IM), and handling time (HT), and their genetic correlations with box time (BT), udder traits and temperament. Teat coordinates were to measure udder conformation and teat placement. Genetic correlations were estimated between these traits and linear classification traits. Data on Swedish Holstein and Swedish Red cows in 19 AMS herds and 74 herds with conventional milking parlors were analyzed. HT and IM had low heritabilities, but that of AtF was 0.21-0.31. Genetic correlations between AtF and temperament were 0.44-0.71 (calm cows having low AtF). Short BT was weakly genetically associated with shallow udders with short and thin teats. High genetic correlations (0.91-0.98) were found between teat coordinate traits and linear classification traits. Thus, AMS records can be effectively used to select for improved milkability and temperament.
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| 5. |
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| 6. |
- Eken Asp, Helena, et al.
(författare)
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Breed differences in everyday behaviour of dogs
- 2015
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Ingår i: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 169, s. 69-77
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Tidskriftsartikel (refereegranskat)abstract
- The domestication of the dog and the ensuing breed creation has resulted in a plethora of dog breeds that differ not only in morphology but also in terms of behaviour. In addition, a majority of the dogs today are no longer utilized for their working ability, but are mainly kept as companion animals. The main aim of this study was to estimate breed differences in everyday behaviour traits, as well as to study the phenotypic correlations between these traits. Dog owners described their dogs' everyday behaviour in a questionnaire. The responses to the questions were combined into 18 behavioural subscale scores (BSS). After editing, the material included dog owner responses for 3591 dogs from 20 different breeds. The breeds represent both working and non-working breeds.We can conclude that breed (and grouping into working vs non-working breeds), age and sex had significant effects on many everyday behaviour traits. The working breeds were about 10% more trainable, showed 30% more interest in playing with humans and were 10-60% less fearful. Furthermore, our results showed that fearful dogs were more aggressive, whereas more social dogs were less fearful and less aggressive. We also found that dogs that were more eager to play with humans were also easier to train. (C) 2015 Elsevier B.V. All rights reserved.
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| 7. |
- Ismael, Ahmed, et al.
(författare)
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Estrus traits derived from activity measurements are heritable and closely related to the time from calving to first insemination
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 3470–3477-
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate genetic parameters for estrus-related traits that could improve selection for increased fertility due to improved ability of the cow to return to cycling and go into heat after calving. We compared the time from calving to first insemination (CFI) to 3 physical activity traits: the interval from calving to first high activity (CFHA), estrus duration (ED), and estrus strength (ES). We calculated CFI based on data from commercial Holstein herds that included the insemination dates for 11,363 cows. The CFHA, ED, and ES traits were derived from electronic activity tags for 3,533 Holstein cows. Estimates of heritability were 0.07 for CFI, 0.16 for CFHA, 0.02 for ED, and 0.05 for ES. We found a strong genetic correlation between CFI and CFHA (0.96). Genetic correlations between ED and CFI and CFHA were -0.37 and -0.68, respectively. Genetic correlations between ES and CFI and CFHA were -0.50 and -0.58, respectively. The heritability of CFHA and its strong genetic correlation with CFI suggest that including CFHA in the genetic evaluation of female cow fertility could improve the effectiveness of selection, because CFHA reflects the ability to return to cyclicity and go into heat after calving.
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| 8. |
- Ismael, Ahmed, et al.
(författare)
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Genotype by environment interaction for activity-based estrus traits in relation to production level for Danish Holstein
- 2016
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 99, s. 9834–9844-
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate whether genotype by environment interaction exists for female fertility traits and production of energy-corrected milk at 70 d in milk (ECM70). Fertility traits considered were the activity-based estrus traits interval from calving to first high activity (CFHA), duration of high activity episode (DHA), as an indicator for first estrus duration, and strength of high activity episode (SHA), as an indicator for first estrus strength. The physical activity traits were derived from electronic activity tags for 11,522 first-parity cows housed in 125 commercial dairy herds. Data were analyzed using a univariate random regression animal model (URRM), by regressing the phenotypic performance on the average herd ECM70 as an environmental gradient. Furthermore, the genetic correlations between CFHA and ECM70 as a function of production level were estimated using a bivariate random regression animal model (BRRM). For all traits, heterogeneity of additive genetic variances and heritability estimates was observed. The heritability estimate for CFHA decreased from 0.25 to 0.10 with increasing production level and the heritability estimate for ECM70 decreased from 0.35 to 0.15 with increasing production level using URRM. The genetic correlation of the same trait in low and high production levels was around 0.74 for CFHA and 0.80 for ECM70 using URRM, but when data were analyzed using the multiple-trait analysis (MT), genetic correlation estimates between low and high production levels were not significantly different from unity. Furthermore, the genetic correlation of SHA between low and high production level was 0.22 using URRM, but the corresponding correlation estimate had large standard error when data were analyzed using MT. The genetic correlation between CFHA and ECM70 as a function of production environment was weak but unfavorable and decreased slightly from 0.09 to 0.04 with increasing production level using BRRM. Moreover, the same trend was observed when the data were analyzed using MT where the genetic correlation between CFHA and ECM70 in the low production environment was 0.29 compared with -0.13 in the high production environment, but these estimates had large standard errors. In conclusion, regardless of the trait used, in relation to average herd ECM70 production, the results indicated no clear evidence of strong genotype by environment interaction that would cause significant re-ranking of sires between low and high production environments.
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| 9. |
- Ismael, Ahmed, et al.
(författare)
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Genotype by environment interaction for the interval from calving to first insemination with regard to calving month and geographic location in Holstein cows in Denmark and Sweden
- 2016
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 99, s. 5498-5507
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Tidskriftsartikel (refereegranskat)abstract
- The objectives of this study were to investigate genotype by environment interaction effects, with environments defined as calving month and geographic location, on the interval from calving to first insemination (CFI) of Holstein cows in Denmark and Sweden. The data set included 811,285 records on CFI for first-parity cows from January 2010 to January 2014 housed in 7,458 herds. The longest mean CFI was 84.7 d for cows calving in April and the shortest was 76.3 d for cows calving in September. The longest mean CFI of 87.1 d was recorded at the northernmost location (LOC-8), whereas the shortest mean CFI of 73.5 d was recorded at the southernmost location (LOC-1). The multiple trait approach, in which CFI values in different calving months and different geographic locations were treated as different traits, was used to estimate the variance components and genetic correlations for CFI by using the average information (AI)-REML procedure in a bivariate sire model. Estimates of genetic variance and heritability were highest for January calvings and 3 times smaller for June calvings. Location 2 had the highest heritability and LOC-8 the lowest, with heritability estimates decreasing from LOC-2 to LOC-8. Genetic correlations of CFI between calving months were weakest between cold months (December and January) and warm months (June, August, and September); the lowest estimate was found between January and September calvings. Genetic correlations of CFI between the different geographic locations were generally strong, and the weakest correlation was between LOC-3 and LOC-8. These results indicate a genotype by environment interaction for CFI primarily regarding seasons described by calving months. The effect of geographic location was less important, mostly producing a scaling effect of CFI in different locations. We concluded that CFI is more sensitive to seasonal effects than geographic locations in Denmark and Sweden.
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| 10. |
- Ismael, Ahmed, et al.
(författare)
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Seasonality of fertility measured by physical activity traits in Holstein cows
- 2016
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 99, s. 2837-2848
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Tidskriftsartikel (refereegranskat)abstract
- Seasonality of female fertility traits, including the interval from calving to first high activity (CFHA), duration of high activity episode (DHA), and strength of high activity episode (SHA) of first estrus, were studied. The physical activity traits were derived from electronic activity tags for 20,794 Holstein cows in 135 commercial Holstein herds in Denmark. Data were categorized in 3 ways: (1) into 4 seasons of calving: winter (January-March), spring (April-June), summer (July- September), and fall (October-December); (2) into 2 seasons: a cold season (October-March) and a warm season (April-September); and (3) into an increasing light season (IL; January-June), where daylight hours gradually increased, and a decreasing light season (DL; July-December), where daylight hours gradually decreased. At the phenotypic level, least squares means of CFHA were highest at 55 d for cows calving in December and lowest at 31 d for cows calving in September. The highest least squares means of DHA and SHA were recorded for cows calving in November and lowest for cows calving in May and June. Genetic parameters for all traits were estimated using average information-REML in a bivariate animal model that treated the same trait in different calving seasons as different traits. Heritability estimates for CFHA were highest for the winter season (0.13) and low for the other seasons (0.03-0.04), whereas heritability estimates for DHA and SHA were lowest for winter and highest for fall. Heritability estimates for CFHA for the cold season (0.17) was higher than that for the warm season (0.10). Heritability estimates of CFHA for the IL season (0.12) was higher than for the DL season (0.07), but the opposite pattern was found for DHA and SHA. Genetic correlations (rA) of CFHA between winter and summer (rA = 0.34 ± 0.27), and winter and fall (rA = 0.65 ± 0.20) were significantly lower than unity. The corresponding correlations of DHA and SHA between seasons were all close to unity, except for the correlation of SHA between winter and fall (rA = 0.36 ± 0.34). When the year was split into only 2 seasons, the genetic correlation of CFHA between cold and warm seasons was only moderate (rA = 0.46 ± 0.15) but was slightly stronger between IL and DL seasons (rA = 0.63 ± 0.16); both significantly deviated from unity. These results indicate the existence of a genotype by environment interaction for CFHA regardless of calving season classification.
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