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| 2. |
- Bezerra Lima Verde, Isabel, et al.
(författare)
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Effect of freezing bull semen in two non-egg yolk extenders on post-thaw sperm quality
- 2018
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Ingår i: Reproduction in Domestic Animals. - : Wiley. - 0936-6768 .- 1439-0531. ; 53, s. 127-136
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, extenders for bull semen included egg yolk or milk, but recently there has been a move to avoid material of animal origin. The aim of this study was to evaluate the effects of two commercial extenders (based on soya lecithin and liposomes) on bull sperm quality after cryopreservation. Post-thaw sperm quality was evaluated by computer-assisted sperm analysis and flow cytometric assessment of membrane integrity, chromatin integrity, mitochondrial membrane potential, production of reactive oxygen species and tyrosine phosphorylation. Furthermore, an artificial insemination (AI) trial was conducted, and 56-day non-return rates were evaluated. Semen frozen in the liposome-based extender showed similar membrane integrity and higher mitochondrial membrane potential compared to those in the soya lecithin-based extender. Chromatin integrity and production of live H2O2+ reactive oxygen species were similar in both extenders. Less superoxide was produced in the samples extended with liposome-based extender, with or without menadione stimulation. Chromatin integrity and tyrosine phosphorylation were not affected by either type of extender. No differences in 56-day non-return rate between extenders containing soya lecithin and liposomes were observed in the AI trial (66%+/- 0.8 and 65%+/- 0.8, respectively). In conclusion, the sperm quality of bull semen frozen in the two extenders that do not contain material of animal origin was similar, although the semen frozen in the liposome-based extender had higher mitochondrial membrane potential. Either extender could be used in situations where extenders containing material of animal origin are to be avoided.
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| 3. |
- Brandt, Y., et al.
(författare)
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Effects of continuous elevated cortisol concentrations during oestrus on concentrations and patterns of progesterone, oestradiol and LH in the sow
- 2009
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Ingår i: Animal Reproduction Science. - : Elsevier Masson. - 0378-4320 .- 1873-2232. ; 110:1-2, s. 172-185
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of continuous elevated cortisol concentrations during standing oestrus on time of ovulation and patterns Of progesterone. oestradiol and luteinising, hormone (LH) in sows. The elevation of cortisol concentrations was achieved through repeated intravenous injections of synthetic adrenocorticotropic hormone (ACTH) every 2 It for approximately 48 h, from the onset of the second standing oestrus alter weaning. Treatment was terminated when ovulation was detected (monitored by transrectal ultrasonography every 4h) or when (lie sow had received a maximum of 24 injections. The close of ACTH (2.5 mu g/kg) was chosen to mimic the cortisol concentrations seen during mixing of unfamiliar SOWS. The sows (n = 14) Were surgically fitted with jugular vein catheters and randomly divided into a control (C group) where only NaCl solution were injected) or an ACTH group. Blood samples were collected every 2 h. In parallel with the blood sampling, saliva samples for cortisol analyses were taken from eight sows before onset of treatment and from four of the sows during treatment. There was no difference in time from onset of standing, oestrus to ovulation between the two groups. The interval between the peaks of oestradiol and LH to ovulation was prolonged in the ACTH group compared to the C group (p less than 0.05). with a tendency towards all earlier decline of oestradiol in the ACTH group. Cortisol and progesterone Concentrations were significantly elevated during treatment in the ACTH group (p less than 0.001). with cortisol peak concentrations occurring between 40 and 80 min after each ACTH injection. Cortisol concentrations in saliva and Plasma were highly correlated (p less than 0.001). In conclusion, elevated cortisol concentrations from the onset of standing oestrus increase progesterone concentrations and prolong the interval between oestradiol and LH peaks to ovulation, the latter possible due to an early decline in oestradiol concentrations and a change of the LH peak outline. the effect these hormonal changes have on reproductive performance need to be further investigated. (C) 2008 Elsevier B.V. All rights reserved.
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| 4. |
- Chalkias, Helena, et al.
(författare)
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Genetic analysis of functional and non-functional teats in a population of Yorkshire pigs
- 2013
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 152, s. 127-134
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Tidskriftsartikel (refereegranskat)abstract
- Litter size is included in the goal of most pig breeding programmes. With an increased litter size, the number of functional teats, which are needed to achieve piglet weight gain and uniform litters,becomes increasingly important. The non-functional (e.g. inverted, blind,or small) teats might have a lower value for the nursing of the piglets. In Sweden, within the pig breeding company Nordic Genetics, the total number of teats, as well as the numbers of functional and non-functional teats, are recorded for purebred Yorkshire pigs both at 3 weeks of age (identity marking) and at about 5 months of age (performance testing). In 2010, 13% of the Swedish purebred Yorkshire pigs had at least one non-functional teat at performance testing (100 kg live weight). The aim of this study was to analyse both genetic and phenotypic variation among the teat traits and to analyse the associations among the teat traits,age and side fat thickness at 100 kg live weight. In the phenotypic analyses there were significant differences between males and females for all analysed teat traits. Males showed a higher number of functional teats and females three times more non-functional teats at 100kg live weight. In the genetic analyses there cords for males and females were treated as representing different traits. The estimated heritability of total number of teats and the number of functional teats, both at 3 weeks of age and at 100 kg live weight, was in the range 0.36-0.42. The heritability of the number of non-functional teats at 3 weeks of age was low, 0.02, for both males and females. Surprisingly, at 100 kg live weight, the heritability of non-functional teats was moderate,0.29, for females, but still low, 0.03, formales. Further studies are required to investigate whether there is a biological explanation for this finding, or if there is a difference between the genders in the recording procedure of this trait.The only significant genetic correlation found between the teat traits and performance traits was for male pigs; the genetic correlation for the relationship between the number of non- functional teats at 3 weeks of age and the age at 100 kg was 0.2. Thus, slowly growing pigs have a lower number of non-functional teats. Our results show that the teat number efficiently can be improved by selection. However non-functional teats is a complex trait and further studies need to be performed to investigate the possibilities to improve selection against the non-functional teats.
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| 6. |
- Chalkias, Helena, et al.
(författare)
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Identification of novel candidate genes for the inverted teat defect in sows using a genome-wide marker panel
- 2017
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Ingår i: Journal of Applied Genetics. - : Springer Science and Business Media LLC. - 1234-1983 .- 2190-3883. ; 58, s. 249-259
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Tidskriftsartikel (refereegranskat)abstract
- The number of functional teats is an important selection criterion in pig breeding. Inherited defects of the udder, such as the inverted teat, do have a considerable negative impact on the nursing ability of the sow. To investigate the genetic background of this defect and the number of functional teats in Swedish maternal lines, samples from 230 Yorkshire pigs were selected for genotyping using the PorcineSNP60K BeadChip (Illumina Inc.), each pig with at least one inverted teat was matched with one non-affected pig (fullsib or pairs with matching herd and gender). A genome-wide association study on these 230 pigs was performed using the two-step approach implemented in GenABEL using 46,652 single nucleotide polymorphisms across all autosomes and the X chromosome. A number of significant regions were identified for the inverted teat defect on chromosomes 2, 10, and 18. Many of the regions associated with the number of functional teats were located in the same or close regions, except two associated markers on the X chromosome and one on chromosome 3. We identified some of the regions on chromosomes previously reported in one linkage and one gene expression study. We conclude, despite being able to suggest new candidate genes, that further studies are needed to better understand the biologic background of the teat development. Despite the in-depth comparison of identified regions for the inverted teat defect done here, more studies are required to allow a clear identification of genetic regions relevant for this defect across many pig populations.
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| 7. |
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| 8. |
- Chalkias, Helena, et al.
(författare)
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Inverted teats (Mammillae invertitae) in gilts - Effect on piglet survival and growth rate
- 2014
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Ingår i: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 92, s. 2587-2594
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Tidskriftsartikel (refereegranskat)abstract
- In the modern pig industry, the increasing number of piglets born per litter augments the importance of the number of functional teats in the sow. The aim of this study was to evaluate the function and importance of inverted teats during nursing and to analyze structural and functional differences between the mammary glands of inverted teats versus normal teats. Nine farrowing gilts (8 purebred Swedish Yorkshire gilts and 1 cross between Swedish Yorkshire and Norwegian Landrace) and 94 piglets (59 piglets suckling normal teats, 32 piglets suckling protruded teats [i.e., previously inverted], 2 piglets suckling inverted teats, and 3 piglets suckling considerably smaller teats) were included in the study. Teat fidelity (keeping the same teat between the nursings) was registered, excluding the first 48 h postpartum. Piglet weight was recorded daily during the first week of life and thereafter once a week until weaning at 4 wk of age. Weight and growth rate were analyzed using repeated observation mixedmodel analysis of variance. The 2 piglets that suckled the inverted teats were not able to emerge the teats and they were euthanized 4 and 8 d after birth, respectively, due to loss of BW. The average weight at weaning (28 d of age) was 8.1 kg (range 3.2-13.8 kg). In the normal teats (n = 53), the weight of the corresponding mammary gland tissue at necropsy was positively correlated to the piglet average daily weight gain during wk 2 (r = 0.33, P < 0.05), 3 (r = 0.55, P < 0.001), and 4 (r = 0.47, P < 0.001). In the protruded teats (n = 32), the weight of the corresponding mammary gland tissue was positively correlated to the piglet average daily weight gain during wk 2 (r = 0.63, P < 0.001) and 3 (r = 0.43, P < 0.05). Among the piglets nursing normal teats, 82% kept fidelity to its teat and the corresponding percent for the protruded teats was 26%. In 7 of the 9 sows, the weaning weight of the piglets suckling protruded teats was numerically lower compared to the piglets suckling normal teats, although the difference was not statistically significant. Piglets nursing small teats had lower weaning weight (4.8 kg) and the corresponding mammary tissue also had lower weight (335 g). This study indicates the importance of an adequate number of well-developed and well-functioning teats in healthy sows for the growth and development of the piglets but also emphasizes the complexity of the interaction between the nursing sow and her piglets.
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| 9. |
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| 10. |
- Chalkias, Helena, et al.
(författare)
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Vägen till bättre spenar
- 2014
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Ingår i: Grisföretagaren. - 2000-8333. ; , s. 32-33
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Tidskriftsartikel (populärvet., debatt m.m.)
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