| 1. |
- Ask Gullstrand, Patricia, et al.
(författare)
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Genetic parameters of pregnancy loss in dairy cows estimated from pregnancy-associated glycoproteins in milk
- 2023
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Ingår i: Journal of Dairy Science. - 0022-0302 .- 1525-3198. ; 106, s. 6316-6324
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Tidskriftsartikel (refereegranskat)abstract
- This study examined the feasibility of using pregnancy-associated glycoproteins (PAG) in milk within breeding for pregnancy maintenance and assessed the genetic variation in pregnancy loss traits. A total of 374,206 PAG samples from 41,889 Swedish Red (SR) and 82,187 Swedish Holstein (SH) cows were collected at monthly test-day milkings in 1,119 Swedish herds. Pregnancy status was defined based on PAG levels and confirmed by data on artificial insemination (AI), calving, and culling from d 1 postinsemination to calving. Pregnancy loss traits were defined as embryonic loss (diagnosed 28 d to 41 d after AI), fetal loss (42 d after AI until calving), and total pregnancy loss. Least squares means (± standard error, %) and genetic parameters were estimated using mixed linear models. Heritability was estimated to be 0.02, 0.02, and 0.03 for embryonic loss, fetal loss, and total pregnancy loss, respectively. Cows with pregnancy loss had lower PAG concentrations than cows which successfully maintained pregnancy and calved. PAG recording was limited to monthly test-day milking, resulting in low estimated embryonic loss (17.5 ± 0.4 and 18.7 ± 0.4 in SR and SH, respectively) and higher fetal loss (32.8 ± 0.5 and 35.1 ± 0.5 in SR and SH, respectively). Pregnancy loss might have occurred earlier but remained undetected until the next test-day milking, when it was recorded as fetal loss rather than embryonic loss. Estimated genetic correlation between embryonic and fetal pregnancy loss traits and classical fertility traits were in general high. Identification of novel genetic traits from PAG data can be highly specific, as PAG are only secreted by the placenta. Thus, PAG could be useful indicators in selection to genetically improve pregnancy maintenance and reduce reproductive losses in milk production. Further studies are needed to clarify how these results could be applied in breeding programs concurrent with selection for classical fertility traits.
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| 2. |
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| 3. |
- Eriksson, Susanne, et al.
(författare)
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Different beef breed sires used for crossbreeding with Swedish dairy cows - effects on calving performance and carcass traits
- 2020
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 232
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Tidskriftsartikel (refereegranskat)abstract
- Improved potential for weight gain and carcass classification traits in calves aimed at slaughter from dairy herds would increase the calves' economic value, and enable an increased beef production. At present, relatively low economic weights are placed on beef traits in the comprehensive Nordic dairy cattle breeding goal. An effective way to improve beef production from dairy herds is therefore to inseminate a larger proportion of dairy heifers and cows with beef bull semen. In the choice of beef bull breed, both effects on calving traits, carcass weight gain and carcass traits need to be considered. The aim of this study was therefore to compare different beef x dairy crosses regarding calving performance and carcass traits. Field data comprising in total close to 1.6 million calving records from Swedish herds, and more than 1.1 million carcass records from commercial slaughter houses, were analyzed using linear models. Differences in least-square means between different breed combinations were estimated for percentage of calving difficulty, stillbirth, daily carcass gain, carcass weight, EUROP conformation and fat classification. The dams were purebred Swedish Red (SR) or Swedish Holstein (SH), and the sires were either of purebred dairy (SR or SH) or of the beef breeds Angus, Hereford, Limousin, Simmental or Charolais. The results showed that crossbreeding dairy cows with beef bulls, especially of late maturing breeds, has potential to considerably improve beef production from dairy herds. Improvement of carcass characteristics and carcass gain were most noticeable in young crossbred bulls, where the highest increase for single breed combinations was 67% for conformation and 17% for carcass gain. Offspring of different beef x dairy combinations displayed varying average carcass gain and characteristics in terms of fatness and conformation in heifers, steers and young bulls, and would fit different types of production systems. Whereas crossbreeding had small or favorable effects on stillbirth, the use of late maturing beef breed sires negatively influenced the calving performance, especially in primiparous dairy cows. By choosing individual beef bulls with high estimated breeding values for calving ease, the percentage of calving difficulty could be reduced, even when using late maturing beef breed sires for crossbreeding.
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| 4. |
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| 5. |
- Gullstrand, Patricia, et al.
(författare)
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Genetic parameters for reproductive losses estimated from in-line milk progesterone profiles in Swedish dairy cattle
- 2021
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 104, s. 3231-3239
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Tidskriftsartikel (refereegranskat)abstract
- This study assessed the extent of reproductive losses and associated genetic parameters in dairy cattle, using in-line milk progesterone records for 14 Swedish herds collected by DeLaval's Herd Navigator. A total of 330,071 progesterone samples were linked to 10,219 inseminations (AI) from 5,238 lactations in 1,457 Swedish Red and 1,847 Swedish Holstein cows. Pregnancy loss traits were defined as early embryonic loss (1–24 d after AI), late embryonic loss (25–41 d after AI), fetal loss (42 d after AI until calving), and total pregnancy loss (from d 1 after AI until calving). The following classical fertility traits were also analyzed: interval from calving to first service, interval from calving to last service, interval between first and last service, calving interval, and number of inseminations per service period. Least squares means with standard error (LSM ± SE), heritabilities, and genetic correlations were estimated in a mixed linear model. Fixed effects included breed, parity (1, 2, ≥3), estrus cycle number when the AI took place, and a linear regression on 305-d milk yield. Herd by year and season of AI, cow, and permanent environmental effect were considered random effects. Extensive (approximately 45%) early embryonic loss was found, but with no difference between the breeds. Swedish Red was superior to Swedish Holstein in the remaining pregnancy loss traits with, respectively: late embryonic loss of 6.1 ± 1.2% compared with 13.3 ± 1.1%, fetal loss of 7.0 ± 1.2% compared with 12.3 ± 1.2%, and total pregnancy loss of 54.4 ± 1.4% compared with 60.6 ± 1.4%. Swedish Red also had shorter calving to first service and calving to last service than Swedish Holstein. Estimated heritability was 0.03, 0.06, and 0.02 for early embryonic, late embryonic, and total pregnancy loss, respectively. Milk yield was moderately genetically correlated with both early and late embryonic loss (0.52 and 0.39, respectively). The pregnancy loss traits were also correlated with several classical fertility traits (−0.46 to 0.92). In conclusion, Swedish Red cows had lower reproductive loss during late embryonic stage, fetal stage, and in total, and better fertility than Swedish Holstein cows. The heritability estimates for pregnancy loss traits were of the same order of magnitude as previously reported for classical fertility traits. These findings could be valuable in work to determine genetic variation in reproductive loss and its potential usefulness as an alternative fertility trait to be considered in genetic or genomic evaluations.
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| 7. |
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| 8. |
- Gullstrand, Patricia
(författare)
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Tjurens ras påverkar kalvningen
- 2017
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Ingår i: Husdjur. - 0046-8339. ; , s. 46-46
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 9. |
- Hannius, Linda Marie, et al.
(författare)
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Effects of early social mixing and genetic line on female piglet activity, pen location and social interactions pre- and post-weaning under Swedish commercial pig production conditions
- 2023
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Ingår i: Acta Agriculturae Scandinavica, Section A - Animal Science. - 0906-4702 .- 1651-1972. ; 72, s. 135-148
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated activity, preferred pen location and social interactions in female piglets (0-10 weeks of age, N = 98) intended for breeding. Piglets were housed in pens where the sow and the piglets were loose-housed without (CP) or with access to the neighbouring pen week 2-5 (AP). Female piglets of two genetic lines (Dutch and Swedish Yorkshire (DY, SY)) from 26 litters were selected within 24 h after birth. DY piglets in the AP treatment spent more time in the neighbouring pen than SY (24.0% vs 19.0%), while AP piglets of both genetic lines spent less time lying down before weaning than CP. At weaning, CP piglets increased their time in the piglet corner and spent less time lying. SY piglets were less responsive to social interactions. The results confirm previous findings on favourable effects of early social mixing on piglets' behavioural responses to weaning also when sows are individually loose-housed.
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