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| 2. |
- Agenäs, Sigrid, et al.
(författare)
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The effect of 17 beta-estradiol on lactose in plasma and urine in dairy cows in late lactation
- 2019
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 86, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effect of 17 beta-estradiol on mammary tight junctions in cows in late lactation. The experiment included five non-pregnant cows around day 290 in lactation. The cows received injections of 17 beta-estradiol for six days. The effect of exogenous 17 beta-estradiol on milk yield, milk composition and lactose in plasma and lactose in urine was investigated before, during and after the treatment. Milk yield decreased after 17 beta-estradiol injections and lactose in plasma and urine increased, showing an effect on the integrity of the mammary tight junctions. However, there was a delay between hormone injections and the decrease in milk yield and opening of tight junctions, indicating that other factors are involved. A high correlation between lactose in urine and blood plasma was found. More than 30% of the total lactose production was lost in urine after 17 beta-estradiol treatment.
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| 3. |
- Andrée O´ Hara, Elisabeth, et al.
(författare)
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An observational study of the dry period length and its relation to milk yield, health, and fertility in two dairy cow breeds
- 2020
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Ingår i: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 175
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated associations between dry period length (DPL) in dairy cows and energy-corrected milk (ECM) production, health, and fertility, using a dataset involving 78 577 lactations in cows of two breeds, Swedish Red (SR) and Swedish Holstein (SH). Herds with at least 20 cows and at least 20 % purebred SR and at least 20 % SH during the year 2015/2016 were included in the dataset. Cows were divided into parity groups 2 and 3 or older and DPL was classified into six 10-day groups (30-39 to 80-89 d). Associations between DPL and the outcome variables were assessed with linear and generalized linear mixed models. Production of ECM at the first three test milkings and the 305-d lactation was highest in the 50-59 d and 60-69 d DPL groups, and lowest in the 30-39 d and 80-89 d groups (p<0.001). Mastitis and somatic cell count (SCC) did not differ between DPL groups, except at the third test milking, where cows in the 40-49, 50-59, and 60-69 DPL groups had lower SCC (p<0.001) than cows in the 70-79 and 80-89 d groups. The odds ratio (OR) for retained placenta was 1.9 for cows with 30-39 d DPL relative to cows with 60-69 d DPL. Cows in DPL groups 40-49 d and 50-59 ha d the lowest odds of culling (OR=0.89 and 0.92). The OR for culling in cows with DPL 70-79 d and 80-89 was 1.2 and 1.4, respectively, relative to cows with 60-69 d DPL. The conception rate at first insemination did not among between DPL groups. The SR cows produced less ECM than the SH cows, but had lower SCC and lower OR for mastitis, retained placenta, puerperal paresis, and culling within 90 DIM. Although DPL <40 days or >80 days reduced milk production in early lactation and the 305-d lactation, the estimated additional milk production in the preceding lactation in cows with short DPL compensated for this reduction. A DPL of 40 days did not affect health and fertility in comparison with a conventional 60 d DPL, while a DPL of >70 d was unfavorable due to low milk production, increased risk of culling, and decreased fertility. The response to DPL was not affected by breed or parity.
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| 4. |
- Andrée O´ Hara, Elisabeth, et al.
(författare)
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Effects of dry period length on metabolic status, fertility, udder health, and colostrum production in 2 cow breeds
- 2019
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 102, s. 595-606
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Tidskriftsartikel (refereegranskat)abstract
- Shortening the dry period improves postpartum energy balance, which has potential positive effects on metabolic health. This concept has been mainly studied in Holstein cows. The aim of this study was to assess the effect of a short dry period of 4 wk, compared with a standard dry period of 8 wk, on the metabolic status, progesterone profiles, health, and colostrum quality of dairy cows of 2 breeds, Swedish Red (SR) and Swedish Holstein (SH), not treated with antibiotics at dry off. The IgG uptake in calves was also studied to reflect the colostrum quality when shortening the dry period. Cows of both SH and SR were blocked by breed and parity and then randomly allocated to a short dry period of 4 wk (4W, n = 43) or a conventional dry period of 8 wk (8W, n = 34). Blood samples were collected wk 8, 4, 2, 1 and 1, 2, 3, 4, 6, 9, and 12 relative to calving. Prepartum, cows with a 4-wk dry period had higher concentrations of nonesterified fatty acids and lower concentrations of insulin-like growth factor-1. and insulin than 8W cows. Postpartum, plasma concentration of nonesterified fatty acids was lower, whereas plasma insulin and insulin-like growth factor-1 tended to be higher for 4W cows than for 8W cows. Plasma concentration of beta-hydroxybutyrate did not differ between dry period lengths. Swedish Holstein cows with a 4W dry period responded with a lower concentration of insulin prepartum than SR and SH on an 8W dry period. The dry period length had no effect on the proportion of disturbed progesterone profiles; disturbed progesterone profiles occurred in 30% of the 4W cows and 47% of the 8W cows. In this trial, only 48.8% of the SR cows had a normal progesterone profile, which differed from the SH where 76.5% had a normal profile. Fertility-related diseases (endometritis, pyometra, anestrus, ovarian cyst) did not differ between the 2 dry period groups: 21% in the 8W group versus 12% in the 4W group, whereas mastitis tended to be more common: 26% of the 4W cows versus 9% of the 8W cows. A short dry period resulted in less colostrum but with a higher content of protein and somatic cell count. Calves were fed colostrum from their dam, and the IgG and total protein in plasma did not differ between calves to mothers with different a dry period length. Shortening the dry period could improve metabolic status in cows of both SH and SR breed postpartum, without compromising the colostrum quality. Health and progesterone profiles were not affected by the dry period length for SH or SR in this study.
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| 5. |
- Andrée O´ Hara, Elisabeth, et al.
(författare)
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Effects of dry period length on milk production and energy balance in two cow breeds
- 2018
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 12, s. 508-514
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Tidskriftsartikel (refereegranskat)abstract
- Shortening the dry period (DP) has been proposed as a strategy to improve energy balance (EB) in cows in early lactation. This study evaluated the effects of shortening the DP on milk yield (MY), EB and residual feed intake (RFI) in two breeds; Swedish Red (SR) and Swedish Holstein (SH). Cows were blocked by breed and parity and then randomly assigned to one of two treatments; short DP of 4 weeks (4W, n = 43) or conventional DP of 8 weeks (8W, n = 34). Cows were kept and fed under the same conditions, except for the 4 weeks when the 4W group were still lactating prepartum and thus kept with the lactating cows. Milk yield and BW were recorded and body condition score (BCS) was rated from 10 weeks prepartum to 12 weeks postpartum. Dry matter intake (DMI) was recorded for lactating cows postpartum. Milk yield was reduced by 6.75 kg/day during the first 12 weeks postpartum ( P< 0.001) for the 4W cows compared with 8W cows, but there was no significant difference in total MY (3724 kg compared with 3684 kg, P = 0.7) when the milk produced prepartum was included. Protein content was higher in 4W cows (3.42%) than in 8W cows (3.27%) ( P<0.001) postpartum. In the 8W group, cows lost more BCS after calving ( P<0.05). Cows of SR breed had higher BCS than cows of SH breed (SR = 3.7, SH = 3.2, P< 0.001), but no differences in BW were found between breed and treatment. Energy balance was improved for cows in the 4W group ( P< 0.001), while feed efficiency, expressed as RFI, was reduced for 4W cows than for 8W cows (5.91 compared with −5.39, P<0.01). Shortening the DP resulted in improved EB postpartum with no difference between the breeds and no milk losses when including the milk produced prepartum.
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| 6. |
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| 7. |
- Andrée O´ Hara, Elisabeth, et al.
(författare)
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The impact of body condition after calving on metabolism and milk progesterone profiles in two breeds of dairy cows
- 2016
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 58
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Tidskriftsartikel (refereegranskat)abstract
- Background: Optimal body condition in early lactation is generally accepted as a prerequisite for good reproductive performance. Examination of milk progesterone profiles offers an objective method for characterization of postpartum ovarian activity in dairy cows. The present study investigated the relationship between body condition after calving, some metabolic parameters in blood plasma, and fertility, as reflected by milk progesterone profiles in the two dairy breeds Swedish Red (SR) and Swedish Holstein (SH).Results: Multiparous dairy cows (n = 73) of SR and SH breeds were selected and divided into three groups based on their body condition score (BCS) after parturition. Selected plasma metabolites were determined, milk progesterone profiles were identified and body condition was scored. Over-conditioned cows and atypical progesterone profiles were more common among SR cows. Insulin sensitivity was lower and IGF 1 higher among SR cows. Insulin was positively related to body condition, but not related to breed.Conclusions: Atypical progesterone profiles were more common and insulin sensitivity lower in SR than in SH cows, but the SR breed had a higher proportion of over-conditioned SR cows. It is reasonable to assume that breed differences in body condition contributed to these results.
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| 8. |
- Blanco Penedo, Isabel, et al.
(författare)
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The status of essential elements and associations with milk yield and the occurrence of mastitis in organic and conventional dairy herds
- 2014
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 168, s. 120-127
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Tidskriftsartikel (refereegranskat)abstract
- There is a lack of detailed information on the impact of organic feeding regulation on the health and well-being of cows. This has become especially important since January 2008 when the EU required 100% organic ration for organic dairy herds. The aim of this investigation was to determine and compare the levels of essential elements in organic and conventional dairy herds, and to associate them with milk yield and the occurrence of mastitis. The field study was carried out in 10 organic and 10 conventional herds from 2005 to 2010. This period included the point in time when the ration became 100% organic in organic dairy herds. Essential element concentrations (Cu, Co, Se, Zn, Mn, Mo, I and Fe) were determined by inductively coupled plasma-mass spectrometry in 158 serum samples. Associations between concentrations of elements and milk yield and mastitis were determined with mixed linear and logistic regression models, respectively. No significant differences in metal levels between organic and conventional herds were found. No severely deficient concentrations of essential elements were observed in organic herds, either before or after the change in regulation. Cows with low serum concentrations of Se had lower somatic cell counts. Daily milk yield was significantly influenced by deficient concentrations of Cu. For the evaluation of clinical mastitis occurrence, herds were classified for each element, based on the individual values of the sampled cows. Low levels of some elements (Se, I) were associated with a reduced risk of mastitis occurrence. However, other elements indicated a protective effect against mastitis. (C) 2014 Elsevier B.V. All rights reserved.
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| 9. |
- Churakov, Mikhail, et al.
(författare)
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Milk fatty acids as indicators of negative energy balance of dairy cows in early lactation
- 2021
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Ingår i: Animal. - : Elsevier BV. - 1751-7311 .- 1751-732X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Most dairy cows experience negative energy balance (NEB) in early lactation because energy demand for milk synthesis is not met by energy intake. Excessive NEB may lead to metabolic disorders and impaired fertility. To optimize herd management, it is useful to detect cows in NEB in early lactation, but direct calculation of NEB is not feasible in commercial herds. Alternative methods rely on fat-to-protein ratio in milk or on concentrations of non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) in blood. Here, we considered methods to assess energy balance (EB) of dairy cows based on the fatty acid (FA) composition in milk. Short- and medium-chain FAs (primarily, C14:0) are typically synthesized de novo in the mammary gland and their proportions in milk fat decrease during NEB. Long-chain FAs C18:0 and C18:1 cis-9 are typically released from body fat depots during NEB, and their proportions increase. In this study, these FAs were routinely determined by Fourier-transform infrared spectroscopy (FTIR) of individual milk samples. We performed an experiment on 85 dairy cows in early lactation, fed the same concentrate ration of up to 5 kg per day and forage ad libitum. Daily milk yield and feed intake were automatically recorded. During lactation weeks 2, 4, and 6 after calving, two milk samples were collected for FTIR spectroscopy, Tuesday evening and Wednesday morning, blood plasma samples were collected Thursday morning. Net energy content in feed and net energy required for maintenance and lactation were estimated to derive EB, which was used to compare alternative indicators of severe NEB. Linear univariate models for EB based on NEFA concentration (deviance explained = 0.13) and other metabolites in blood plasma were outperformed by models based on concentrations of metabolites in milk: fat (0.27), fat-to-protein ratio (0.18), BHB (0.20), and especially C18:0 (0.28) and C18:1 cis-9 (0.39). Analysis of generalized additive models (GAM) revealed that models based on milk variables performed better than those based on blood plasma (deviance explained 0.46 vs. 0.21). C18:0 and C18:1 cis-9 also performed better in severe NEB prediction for EB cut-off values ranging from −50 to 0 MJ NEL/d. Overall, concentrations of C18:0 and C18:1 cis-9 in milk, milk fat, and milk BHB were the best variables for early detection of cows in severe NEB. Thus, milk FA concentrations in whole milk can be useful to identify NEB in early-lactation cows.
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