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Customized voluntary waiting period (VWP) before first insemination was tested in 18 commercial dairy herds in Sweden, to assess milk production, fertility and health in primiparous cows expected to be suited for extended VWP. Cow selection for extended VWP was based on 3 criteria in early lactation: 1) the 10% of cows with highest genomic persistency index, 2) cows with a difficult calving or disease during the first month of lactation, and 3) cows with higher yield during d 4-33 after calving than the herd average for primiparous cows. Cows meeting at least one of these criteria were randomly assigned to either the ExtExt treatment (extended VWP of at least 175 d, n = 174; calving interval (CInt) = 16.3 mo) or the ExtConv treatment (conventional VWP of maximum 100 d n = 173; CInt = 12.4 mo). Cows not meeting any of the criteria were assigned to the ConvConv treatment (conventional VWP, n = 183; CInt = 12.0 mo). There were no differences in milk yield per day in the CInt between treatments, although 305-d and whole-lactation (WL) milk yields were higher for ExtExt cows (10,371 and 13,803 kg) than ExtConv cows (9,812 and 10,257 kg). Milk yield at the last test milking before dry-off was lower in ExtExt compared with ExtConv cows (24.9 vs 28.3), however the results showed no difference in dry period length between the treatments. Regarding reproductive performance, the ExtExt cows had higher first service conception rate (FSCR; 60% vs. 45%) and lower number of inseminations per conception (NINS; 1.67 vs. 2.19), compared with the ExtConv cows. As expected, ConvConv cows had the lowest milk yield in 305-d, in WL, and per day in the CInt, however, FSCR and NINS did not differ between ConvConv cows and cows in the other 2 VWP treatments. Disease incidence was higher for cows in the ExtConv compared with the ConvConv treatment, but there was no difference between ExtExt and the 2 other VWP treatments. Further, no difference in proportion of cows with good udder health or culling rate was detected between any of the treatments, though due to low prevalence the study lacked power to draw major conclusions on these results. Thus prolonging VWP for suitable primiparous cows can produce benefits such as improved fertility in the form of higher FSCR and lower NINS, as well as lower dry-off yield, without compromising milk yield or prolonging dry period length.
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Extending the voluntary waiting period (VWP) for primiparous cows can have a positive impact on fertility without a negative impact on milk production per day in the calving interval (CInt). We investigated the effect of extended VWP during first lactation on milk yield (MY) during 2 consecutive lactations in primiparous cows. The study involved 16 commercial herds in southern Sweden. A total of 533 Holstein and Red dairy cattle (Swedish Red, Danish Red, Ayrshire) dairy cows were randomly assigned to a conventional 25 to 95 d VWP (n = 252) or extended 145 to 215 d VWP (n = 281). Data on calvings, inseminations, and test-day yields were retrieved from the Swedish Milk Recording System. Cows with VWP according to plan and completing 1 or 2 CInt with a second or third calving were included in the data analysis. Whole lactation and 305-d energy-corrected milk (ECM) yield were higher for the extended VWP group than the conventional VWP group in both the first lactation (12,307 vs. 9,587 and 9,653 vs. 9,127 kg ECM) and second lactation (12,817 vs. 11,986 and 11,957 vs. 11,304 kg ECM). We found no difference between the VWP groups in MY per day during the first CInt or during the first and second CInt combined, although MY per day during the second CInt was around 1.5 kg higher for cows with extended VWP than for cows with conventional VWP. Thus extended VWP for primiparous cows can be used as a management tool without compromising MY.
Assuntos
Lactação , Leite , Gravidez , Feminino , Bovinos , Animais , Fertilidade , Paridade , SuéciaRESUMO
When the voluntary waiting period (VWP), defined as the days between calving and when the cow is eligible to receive the first insemination, is extended, high-yielding dairy cows may have better opportunities to regain energy balance before first insemination. This study investigated the effect of an extended (145-215 days in milk [DIM], n = 280) or conventional (25-95 DIM, n = 251) VWP treatment on fertility, disease incidence, and culling rate in cows during their first lactation. The cows were also followed through a second lactation without intervention regarding VWP, during which the farmers could decide when they wished to start the inseminations. This was done in a randomized-controlled study on 16 high-yielding commercial herds in southern Sweden, containing a total of 531 primiparous cows of the Holstein and Red Dairy Cattle breeds. Data from the Swedish national dairy herd recording scheme collected between August 2018 and September 2021 were used in the analysis, including records on breed, calvings, estrus intensity, inseminations, disease, somatic cell count, culling date, and culling reason. During first lactation, more cows receiving the extended VWP treatment showed strong estrus intensity (score 4-5, 55% vs. 48%) and fewer showed moderate estrus intensity (score 3, 35% vs. 43%) at first insemination, compared with cows receiving the conventional VWP treatment. First service conception rate (FSCR) was higher (67% vs. 51%) and number of inseminations per conception (NINS) was lower (1.6 vs. 2.0) during the first lactation for cows receiving the extended compared with the conventional VWP treatment. For disease incidence rate or culling rate expressed as number of events per cow-time in the study, we found no differences between the cows receiving the 2 VWP treatments in any lactation. Calving to first service interval during second lactation was longer (86 vs. 74 d) for cows with extended compared with conventional VWP. In conclusion, primiparous cows with extended VWP showed improved reproductive functions, in the form of higher estrus intensity, greater FSCR, and lower NINS, during the first lactation. However, we observed no apparent effect on these fertility measures during the following lactation (without VWP intervention) and no differences in disease prevalence or culling between cows receiving the 2 different VWP treatments in either lactation. Compliance with the planned VWP treatment was lower for cows with planned extended compared with planned conventional VWP treatment. We studied the "intention-to-treat" effect (i.e., the results for all cows randomized to each treatment regardless of whether the planned VWP was achieved or not) to identify any bias arising due to degree of compliance. However, we found no difference in culling rate between cows randomized to an extended VWP compared with those randomized to a conventional VWP. These findings can be used to support management decisions on VWP length in high-yielding dairy herds.
Assuntos
Inseminação Artificial , Reprodução , Feminino , Bovinos , Animais , Inseminação Artificial/veterinária , Inseminação Artificial/métodos , Lactação , Fertilidade , Leite , Indústria de Laticínios/métodosRESUMO
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 ß-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.
Assuntos
Bovinos/fisiologia , Colostro/metabolismo , Fertilidade , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Ácido 3-Hidroxibutírico/sangue , Animais , Cruzamento , Dieta/veterinária , Metabolismo Energético , Ácidos Graxos não Esterificados/sangue , Feminino , Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Leite/química , Leite/metabolismo , Paridade , Período Pós-Parto , Gravidez , Progesterona/análise , Especificidade da Espécie , SuéciaRESUMO
This study investigated the fate of glycerol entering the rumen, in particular whether glycerol could be absorbed across the rumen epithelium. Three non-lactating rumen-fistulated cows were used to calculate the overall disappearance rate of glycerol in vivo and evaluate the rate of ruminal glycerol absorption. Rumen epithelial tissues isolated from sheep were used to characterise glycerol transport properties. The rate of rumen microbial degradation of glycerol was then studied in an in vitro system under anaerobic and thermo-regulated conditions. The results showed that glycerol can be absorbed from the rumen in significant amounts. The fractional rate of absorption of glycerol was not affected by variations in glycerol concentration in the buffer solution in the in vivo study. The glycerol absorption apparently occurred largely by passive diffusion and was probably not facilitated by carriers. Glycerol also disappeared via microbial digestion and outflow from the rumen through the omasal orifice.
Assuntos
Bovinos/fisiologia , Glicerol/metabolismo , Rúmen/metabolismo , Ovinos/fisiologia , Animais , Transporte Biológico/fisiologia , Absorção Gástrica/fisiologia , Fatores de TempoRESUMO
This experiment studied the effect of pre-partal milk removal on calcium metabolism at start of milking and at calving. Nine cows of the Swedish Red breed were milked for 1-7 days pre-partum. The average milk yield at the first milking was 4.8 l, and the average yield the last day prior to calving was 13.4 l. Five cows were used as control cows and were only milked post-partum. Samples of plasma and urine were taken to determine the effect of pre-partum milking and calving on levels of calcium, magnesium, parathyroid hormone and plasma C-terminal crosslinked telopeptide of type 1-collagen (CTx), used as a marker of bone resorption. Pre-partum milking resulted in a decrease in plasma calcium that was evident 2 days after the first milking. Parathyroid hormone increased at the same time, and CTx started to increase from 24 h after the first milking. There were no effects on plasma magnesium or urinary output of calcium or magnesium. The first week after calving, there were no differences between pre-partum milked cows and control cows in plasma or urine variables, or in milk yield. In conclusion, pre-partum milking activated the calcium-restoring mechanisms but did not improve calcium status at calving.
Assuntos
Criação de Animais Domésticos/métodos , Cálcio/metabolismo , Bovinos/metabolismo , Lactação/fisiologia , Parto/fisiologia , Animais , Biomarcadores , Reabsorção Óssea/metabolismo , Cálcio/sangue , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Indústria de Laticínios , Feminino , Regulação da Expressão Gênica/fisiologia , Leite , Hormônio Paratireóideo/genética , Hormônio Paratireóideo/metabolismo , GravidezRESUMO
In this pilot study, the effects of phosphorus (P) supply on inorganic phosphorus (Pi ) net absorption in dairy cows were investigated. Three non-lactating, non-pregnant, rumen-fistulated Swedish Red breed dairy cows were studied in a 3 × 3 Latin square design. Monosodium dihydrogen orthophosphate dihydrate (NaH2 PO4 *2H2 O) was continuously infused into the abomasum for 4 days. The solutions provided 0, 14.4 or 28.8 g Pi /day. Rumen fluid volume and outflow rate were estimated at day four of each experimental period using cobalt-lithium EDTA as an external marker. Acid insoluble ash in feeds and faecal samples was used to quantify P faecal excretion. Concentrations of Pi in collected samples of rumen fluid, blood, faeces and urine were determined. Pi flow into the small intestine increased (p < 0.05) with Pi infusion. Pi net absorption tended to increase (p = 0.08) but proportion of absorbed Pi tended to decrease (p = 0.08). Urinary Pi excretion was negligible and did not affect P homoeostasis (p = 0.50). There was no change in plasma Pi concentration (p = 0.45) in response to Pi infusion. The increase in total faecal P excretion (p < 0.05) with increasing level of infused Pi was solely because of increased soluble faecal Pi (p < 0.05). It is suggested that at P overfeeding, intestinal Pi net absorption is saturable in dairy cows.
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Abomaso/fisiologia , Bovinos/metabolismo , Fósforo/administração & dosagem , Fósforo/farmacocinética , Animais , Líquidos Corporais , Bovinos/sangue , Fezes/química , Feminino , Fósforo/sangue , Fósforo/urina , Projetos Piloto , Rúmen/químicaRESUMO
Eight male cattle of the Local Yellow breed with an average live weight of 121 kg and an average age of 18 months were used to evaluate the effects of different levels of sun-dried cassava (Manihot esculenta) foliage supplementation on mineral metabolism in growing cattle fed rice straw and para grass as basal diet. Rice straw ad libitum and para grass (Brachiaria mutica) at 1% DM of BW comprised the basal diet. The study was arranged as a 4×4 double Latin square design, with cassava foliage contributing 0, 0.8, 1.6 or 2.4 g CP/kg BW. The cassava foliage intake was lower than the planned levels. DM consumption was significantly affected by cassava foliage supplementation, with the largest intake observed at the two highest levels of cassava foliage supplementation. Rice straw intake showed the opposite pattern, with lower intake at higher cassava foliage supplementation. No refusals occurred for para grass in any of the treatments. Ca, P, Mg, K, S and Mn intake increased significantly with increasing intake of cassava foliage, but Na intake was not affected by treatment. Faecal excretion of Ca, Mg, S and Mn increased significantly with increasing cassava foliage intake. There were no differences between P, K and Na excretion in faeces. There was a significant diet effect on Mg, S and Mn digestibility. Mg and Mn digestibility increased with increasing cassava foliage supplementation, while S digestibility decreased. Ca, P, K and Na digestibility was not affected by diet. There was a significant effect of treatment on P retention, with the highest value observed for supplementation with 1.6 g CP/kg BW cassava foliage. Ca and Mg showed similar trends, with the highest retention again for supplementation with 1.6 g CP/kg BW cassava foliage. There were weak but significant positive correlations between nitrogen retention and the macro minerals Ca, P and Mg. Furthermore, retention of all these minerals was positively correlated. Mineral losses in urine were not affected by dietary treatment with the exception of P excretion, which was affected by treatment. In conclusion, cassava foliage is a good Ca source which compensates for the low Ca content in rice straw and para grass, but P deficiency appears to be exaggerated in cattle with higher cassava intake. The results suggest that under these conditions growing cattle on a high cassava intake would benefit from P and S supplementation.
RESUMO
Eight male cattle of Local Yellow breed with an average live weight of 121 kg and an average age of 18 months were used to evaluate the effects of different levels of sun-dried cassava foliage supplementation (Manihot esculenta) on intake, digestibility and N retention. Rice straw ad libitum and para grass (Brachiaria mutica) at 1% DM of BW comprised the basal diet. The study was arranged as a 4×4 double Latin square design, with cassava foliage contributing 0, 0.8, 1.6 or 2.4 g CP/kg BW. The cattle selected cassava leaves in preference to petioles. Petiole intake decreased from 64 to 48% of offered petioles when the cassava foliage proportion increased from the lowest to the highest level. The cattle consumed all the leaves at the two lower levels of cassava foliage inclusion and 91% at the highest level. Rice straw intake decreased significantly as the level of cassava foliage increased. Intake of DM, OM, NDF, and ADF increased significantly with increasing intake of cassava foliage. Daily DM intake per 100 kg BW increased from 2.7 to 3.2 kg with increasing cassava foliage intake. No effect on CP digestibility was detected when the level of cassava foliage increased. Digestibility of DM, OM, NDF and ADF was significantly higher in the group fed no cassava foliage than in the other groups. N retention increased from 16 to 28 g/d with the first level of cassava foliage inclusion, but levelled out at the two highest levels. N excretion increased in both faeces and urine as a response to higher intake of cassava foliage. Maximum N retention occurred when 40% of total N intake came from cassava foliage (equivalent to 1.3 g CP/kg BW).
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The aim of this study was to investigate the effects of dietary Ca level (4.9, 9.3, and 13.6 g/kg of DM) on Ca and Mg homeostasis in dairy cows around parturition. Cows of the Swedish Red breed (n = 29) with no previous veterinary treatment for milk fever were divided into 3 groups, and each group was fed one of the different diets during the last 15 to 32 d of gestation. Calcium was added as ground limestone, and the Mg concentration was 1.8 g/kg of DM in all diets. After calving the cows were fed similar diets. Plasma was sampled twice per week until calving, and 6, 12, and 24 h, 2, 4, and 7 d after calving. Spot urine samples were collected twice weekly until calving and creatinine was used as a marker of daily urinary excretion. Fecal samples were collected 2 times per day for 5 d starting 2 wk before expected calving, and acid-insoluble ash was used as an indigestible marker to estimate digestibility. Apparent digestibility of Mg and daily Mg excretion in the urine were lower in the dry period for cows fed the highest Ca level. Plasma Mg concentration was lower on 2, 4, and 7 d after calving in cows fed the highest level of Ca. Treatment groups did not differ in plasma Ca concentration, parathyroid hormone concentration, or bone mobilization, evaluated using crosslinked carboxyterminal telopeptides of type I collagen (CTx) as a marker. Plasma Ca concentration decreased and plasma CTx concentration increased 6 h after calving. The apparent digestibility of Ca during the dry period was not affected by dietary Ca, but the cows fed 4.9 g Ca/kg of DM excreted 1.2 g of Ca/d in the urine, which was higher compared with 0.4 g/d and 0.6 g/d for the cows fed 9.3 g of Ca/kg of DM and 13.6 g of Ca/kg of DM, respectively. The results show that feeding 13.6 g of dietary Ca/kg of DM impaired the Mg absorption during the dry period, and resulted in decreased plasma Mg concentration after calving, but prepartum dietary Ca level did not affect plasma Ca, parathyroid hormone, or CTx concentrations.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Cálcio da Dieta/administração & dosagem , Cálcio/sangue , Bovinos/metabolismo , Magnésio/sangue , Animais , Dieta/veterinária , Feminino , Período Periparto , GravidezRESUMO
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 ß-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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Ácidos Graxos , Leite , Ácido 3-Hidroxibutírico , Animais , Bovinos , Dieta , Metabolismo Energético , Ácidos Graxos não Esterificados , Feminino , LactaçãoRESUMO
An observational study was carried out in Swedish dairy herds to investigate differences between cows with and without displaced abomasum (DA), in concentrations of glucose, insulin, fructosamine, nonesterified fatty acids (NEFA), ß-hydroxybutyrate, cholesterol, haptoglobin, increased enzyme activity of aspartate aminotransferase and glutamate dehydrogenase, and the revised Quantitative Insulin Sensitivity Check Index (RQUICKI). A secondary aim was to study how blood profiles for DA cows vary with time in relation to calving. Sixty-nine DA cows within 2 to 56 d postpartum, in 60 herds, were clinically examined and blood samples were drawn at the time DA was diagnosed. At the same time, 104 healthy control cows matched by herd and stage of lactation were also sampled. The blood parameters were studied using mixed linear models, including herd as a random effect, and DA (case or control), parity, breed, sampling time in relation to calving, other diseases, and the interaction between DA and time as fixed effects. Concentrations were higher in DA cows than in control cows for NEFA (least squares means 1.36 vs. 0.34 mmol/L), ß-hydroxybutyrate (1.56 vs. 0.90 mmol/L), aspartate aminotransferase (1.96 vs. 0.97 µkat/L), glutamate dehydrogenase (197 vs. 78 µkat/L), and haptoglobin (0.76 vs. 0.17 g/L), whereas concentrations were lower in DA cows than in control cows for insulin (3.61 vs. 8.48 mU/L) and cholesterol (3.04 vs. 3.75 mmol/L). Glucose (2.83 vs. 2.79 mmol/L) and fructosamine (266 vs. 252 µmol/L) concentrations were similar in both groups; however, a tendency toward lower RQUICKI values (0.42 vs. 0.46) in the DA cows was found, indicating reduced insulin sensitivity. For most blood parameters, differences between DA cows and controls remained constant over time. Seventy-two percent of the DA cows had at least one other disease in the period from 1 wk antepartum to 1 wk after the DA was diagnosed. Haptoglobin could potentially be used to detect treatable infectious or inflammatory conditions in the early postpartum period, possibly reducing the incidence of DA. Consequently, there were major changes in blood profiles in cows with DA compared with healthy control cows, indicating a negative energy balance, liver cell damage, and an inflammatory response. The results contribute to an understanding of the metabolic changes in DA cows.
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Abomaso , Doenças dos Bovinos/sangue , Gastropatias/veterinária , Animais , Estudos de Casos e Controles , Bovinos , Doenças dos Bovinos/metabolismo , Metabolismo Energético/fisiologia , Feminino , Hepatócitos/metabolismo , Reprodução/fisiologia , Gastropatias/sangue , Gastropatias/metabolismoRESUMO
The objective of the present study was to investigate the interactions of dietary K intake typical for forage-based diets on Mg balance in lactating dairy cows. Six lactating multiparous cows of the Swedish Red and White breed in midlactation were used. Two concentrations of Mg (1.9 and 4.3 g/kg of dry matter) and 3 concentrations of K (19, 28, and 37 g of K/kg of dry matter) were obtained by adding appropriate amounts of MgO and KHCO(3) to the diet. The experimental setup was a 6 x 6 Latin square design with a 2 x 3 factorial arrangement of treatments. Each experimental period lasted 14 d (9-d treatment adaptation period and 5-d data collection). There was no effect of Mg or K dietary supplementation on milk yield. Supplementing the ration with K did not significantly affect the Mg apparent absorption, urinary Mg excretion, or plasma Mg concentration. The Mg balance, estimated as the Mg losses in milk and urine, was positively related to Mg intake but not affected by K intake. The amount of apparently digested Mg was related to the Mg balance. The apparent digestibility ranged from 0.12 to 0.24 with no effect of mineral supplementation. There was a significant curvilinear relationship between plasma Mg and urinary Mg excretion, with a more marked increase in urinary Mg excretion at higher plasma levels of Mg.
Assuntos
Bicarbonatos/administração & dosagem , Bovinos/metabolismo , Óxido de Magnésio/administração & dosagem , Óxido de Magnésio/farmacocinética , Compostos de Potássio/administração & dosagem , Rúmen/metabolismo , Silagem , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bovinos/sangue , Bovinos/urina , Ingestão de Alimentos/fisiologia , Feminino , Absorção Intestinal , Lactação , Óxido de Magnésio/sangue , Óxido de Magnésio/urina , Leite/química , Leite/metabolismo , Distribuição AleatóriaRESUMO
The main objective of this study was to investigate associations between serum concentrations of several blood variables related to metabolic and immunological status around calving, and udder health measured as milk somatic cell counts (SCC), Box-Cox transformed to bcSCC, at first test-milking in 287 primiparous cows in 20 Swedish dairy herds. Possible systematic effects of breed and age at calving on blood profiles were also investigated. Ordinary linear regression models, with robust standard errors and adjusting for clustering within herds, were used to investigate associations between blood variables and bcSCC. Hierarchical linear regression models, with herd as random factor, were used to investigate systematic effects on blood variables. The results showed that greater concentrations of beta-hydroxybutyrate (BHBA) and glucose before calving were associated with lesser bcSCC at first test-milking, whereas greater concentrations of nonesterified fatty acids (NEFA) before calving and greater delta NEFA (describing the difference in concentrations before and after calving) were associated with greater bcSCC at first test-milking. In addition, greater alpha-tocopherol concentrations in the period -5 to +5 d relative to calving were associated with lesser bcSCC at first test-milking, whereas greater concentrations of collectin of 43 kDa (CL-43) postpartum (1 to 21 d after calving) were associated with greater bcSCC. Postpartum concentrations of conglutinin and haptoglobin were also associated with bcSCC, but not independently of each other. Moreover, significant breed differences were observed for insulin, urea nitrogen, conglutinin, cholesterol, NEFA, and CL-43, the latter 3 as an interaction with period. Overall, cows of the Swedish Red breed had greater concentrations of insulin, cholesterol, urea nitrogen, and conglutinin, and lesser concentrations of NEFA and CL-43 than cows of the Swedish Holstein breed. Age at calving as main effect was significantly associated with BHBA, glucose, insulin, NEFA, urea nitrogen, and conglutinin. Heifers calving at >27 mo of age had greater BHBA and NEFA values, and lesser glucose, insulin, and urea nitrogen values compared with heifers calving at <27 mo. Heifers calving at an age <25 mo had greater conglutinin and urea nitrogen values, and lesser NEFA values compared with heifers calving at >25 mo. The results show that there are several associations among metabolites, immunological variables, and udder health of primiparous cows, but also that these variables vary between breeds and between cows of different age at first calving.
Assuntos
Bovinos/sangue , Bovinos/imunologia , Leite/citologia , Paridade , Fatores Etários , Animais , Análise Química do Sangue , Cruzamento , Contagem de Células , Indústria de Laticínios , Feminino , Modelos Lineares , Gravidez , Proteínas/metabolismo , SuéciaRESUMO
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.
Assuntos
Bovinos/fisiologia , Metabolismo Energético , Leite/metabolismo , Animais , Cruzamento , Dieta/veterinária , Feminino , Lactação , Leite/química , Paridade , Período Pós-Parto , Gravidez , Distribuição AleatóriaRESUMO
We conducted a case-control study to investigate factors associated with the incidence rate of veterinary-treated clinical cases of mastitis (IRVTCM) in Swedish dairy herds with the overall objective to reduce the incidence of clinical mastitis (CM) and excessive use of antibiotics. Herds with documented high milk yield, low prevalence of subclinical mastitis and high (27.3-67.5 cases/100-cow years=case) or low (0.0-10.8 cases/100-cow years=control) IRVTCM were selected for this study. One hundred and fifty-eight herds participated. Logistic-regression models were used to assess statistically significant risk factors associated with a high or low IRVTCM. HI-herd farmers more often contacted a veterinarian for treatment of a cow with CM as soon as the milk appearance was altered, compared to LO-herd farmers that more often waited until the general condition of a cow was altered. HI-herd farmers also treated more cows due to high somatic-cell counts during lactation and/or at drying off. There were more high-yielding cows with dirty lower hind-legs, a higher percentage of first-parity cows and a higher incidence of veterinary-treated teat injuries in HI-herds. HI-herd farmers had their cows claw-trimmed more than once per year, compared to LO-herd farmers that had their cows claw-trimmed only once per year, and the condition of silage storage at HI-farms more often had one or more remarks. LO-herds consisted more often of cows of the Swedish Red and White breed, and their roughage diet was more often complemented with only commercial concentrates compared to HI-herds that more often fed grain in combination with commercial concentrates. The herds participating in this study were all well managed herds, and the attitude towards treatment and production seemed to influence the IRVTCM more than environmental factors.
Assuntos
Antibacterianos/uso terapêutico , Contagem de Células/veterinária , Indústria de Laticínios/métodos , Mastite Bovina/epidemiologia , Leite , Animais , Estudos de Casos e Controles , Bovinos , Feminino , Incidência , Lactação , Modelos Logísticos , Mastite Bovina/diagnóstico , Mastite Bovina/tratamento farmacológico , Leite/citologia , Leite/metabolismo , Leite/microbiologia , Fatores de Risco , Suécia/epidemiologiaRESUMO
With increasing milk production and short calving intervals, high daily milk yields at dry-off are rather common, making the dry-off procedure difficult and increasing the risk for health problems during the dry-off period. The objective of the following study was to compare the effects of 2 dry-off protocols, using different nutrient supplies, on health, as measured by clinical findings, intramammary infections, milk somatic cell count, and plasma concentrations of cortisol, serum amyloid A, haptoglobin, and Mg, in dairy cows. Twenty-one primi- and multiparous dairy cows were randomly assigned to 2 different feeding treatments. One group was fed ad libitum straw (straw), whereas the other group was fed 4 kg of DM silage daily and ad libitum straw (silage) during dry-off (i.e., for 5 d). All cows were milked in the morning of d 3 and 5 during this period. At the start of dry-off (d 0), the average daily milk yield was 17.1 +/- 0.8 kg. The plasma cortisol concentration increased during dry-off only in cows fed straw. There was no significant effect of treatment on plasma serum amyloid A, but the concentration increased during dry-off in both groups. The plasma Mg concentration decreased during dry-off, and the values tended to be lower in the straw group. The milk somatic cell count increased in both groups during dry-off but did not differ between groups. In both groups the heart rate decreased at dry-off, but the decrease was more pronounced in the straw group. Overall, this study (together with a previous report) shows that the common dry-off procedure of feeding straw only may give rise to metabolic disturbances. However, this might be avoided without any apparent negative effects on udder health if a limited amount of silage is added during dry-off.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Bovinos/fisiologia , Indústria de Laticínios/métodos , Lactação , Animais , Contagem de Células , Dieta , Feminino , Haptoglobinas/análise , Hidrocortisona/sangue , Magnésio/sangue , Mastite Bovina/epidemiologia , Leite/citologia , Leite/microbiologia , Paridade , Gravidez , Rúmen/fisiologia , Proteína Amiloide A Sérica/análise , SilagemRESUMO
The effects of milk yield at dry-off (DO), different calving intervals (CI; 12 and 15 mo) and breed on metabolism and udder health were studied in 56 primiparous and multiparous cows of the Swedish Red and White (SRB) and Swedish Holstein (SH) breeds. The cows were dried off 55 +/- 5 d prior to expected parturition. They were fed 4 kg of DM as silage and wheat straw ad libitum for 5 d, and were milked in the morning of d 2 and 5. Depending on their daily milk yield, the cows were divided into 3 numerically equal groups on 2 d during the week prior to DO: low (LY; 5.0 to 11.4 kg of milk/d, n = 19), medium (MY; 11.5 to 17.7 kg of milk/d, n = 19), and high (HY; 17.8 to 29.5 kg of milk/d, n = 18). The plasma cortisol concentration increased during DO only in MY and HY cows. Plasma nonesterified fatty acids increased during DO in all groups, but the maximum nonesterified fatty acid concentration was related to the milk yield prior to DO. The plasma glucose level during the DO period was not significantly affected by yield, but the insulin concentration decreased after DO, with a more pronounced drop in the HY group. The CI 15-mo group had a higher glucose level and tended to have a higher insulin level in plasma than the CI 12-mo group before DO. They also had a higher body condition than the CI 12-mo group. The results indicate that the CI 15-mo cows had a more positive nutrient balance. There were no effects of CI on milk production or composition during DO. The SRB and SH breeds did not differ in any of the measured plasma parameters or milk production. However, the lower somatic cell counts in SRB than in SH observed before and during DO, as well as after parturition, were attributed to being an effect of breed. The proportion of cows with intramammary infections (IMI) was significantly lower just after calving in the LY group than in the other yield groups. At 2 and 3 wk after DO, significantly fewer cows in the LY group had open teat canals compared with the HY and MY groups, respectively, but teat-end condition did not differ between yield groups. The yield before DO did not significantly influence the somatic cell counts during the first 4 wk after parturition or the presence of IMI 4 wk after parturition. We concluded that in the present study, higher milk yield prior to DO gave rise to a more pronounced metabolic response and a higher risk of contracting IMI during the dry period, at calving, or both, but yield at DO did not have any long-term effects on udder health. A prolonged CI did not facilitate a rapid decrease in milk production. The SRB and SH breeds responded equally in decreasing the milk production during DO, but the SRB breed had lower somatic cell counts.
Assuntos
Cruzamento , Bovinos/metabolismo , Lactação/fisiologia , Glândulas Mamárias Animais/fisiologia , Animais , Bactérias/isolamento & purificação , Glicemia/análise , Nitrogênio da Ureia Sanguínea , Ingestão de Alimentos/fisiologia , Ácidos Graxos não Esterificados/sangue , Feminino , Hidrocortisona/sangue , Incidência , Insulina/sangue , Análise dos Mínimos Quadrados , Mastite Bovina/epidemiologia , Mastite Bovina/microbiologia , Leite/citologia , Leite/metabolismo , Leite/microbiologia , Modelos Biológicos , Gravidez , Reprodução/fisiologia , Fatores de TempoRESUMO
The objectives of this study were to investigate different feeding strategies of high-yielding dairy cows during dry-off. With a 12- to 13-mo calving interval and increasing milk yield, metabolic and health problems during the dry-off period will increase. Twenty-two dairy primiparous and multiparous cows were randomly assigned to 2 feeding treatments. One group was fed straw ad libitum (straw), and the other group was fed silage (4 kg/d of dry matter) daily and straw ad libitum (silage). At the dry-off point (d 0), the cows had an average milk yield of 17.1 +/- 0.8 kg/d. All cows were milked in the morning on d 3 and 5 during the dry-off period. Rumen fluid was analyzed for volatile fatty acids (VFA), pH, NH3-N, and protozoa were counted from samples collected at d -3, 4, and 17. Total VFA concentration decreased at dry-off in both treatments and the drop was most pronounced among cows fed straw. Rumen pH increased significantly in both groups, and cows fed straw had significantly higher pH during dry-off. Ammonia N in rumen decreased significantly at dry-off and there was a tendency to lowered NH(3)-N in cows fed straw at dry-off. The plasma concentration of nonesterified fatty acids was markedly elevated during the dry-off period among cows in the straw treatment group, but was less pronounced among the cows fed silage with straw. The glucose level in plasma was not significantly affected during the dry-off period, and the insulin concentration was markedly reduced in both treatment groups. Plasma leptin concentration was lower in the lactating state than in the dry period. Both the beta-hydroxybutyrate and urea concentrations in plasma were significantly reduced during dry-off. Our results indicate that dry-off markedly affected the metabolism in the blood and in the rumen of the cows, and that the cows offered only straw during the dry-off were most affected.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Bovinos/metabolismo , Lactação/fisiologia , Ácido 3-Hidroxibutírico/sangue , Amônia/análise , Animais , Glicemia/análise , Líquidos Corporais/química , Dieta , Ácidos Graxos não Esterificados/sangue , Ácidos Graxos Voláteis/análise , Feminino , Concentração de Íons de Hidrogênio , Leptina/sangue , Paridade , Gravidez , Rúmen/química , Rúmen/metabolismo , Rúmen/parasitologia , Silagem , Ureia/sangueRESUMO
We measured a bone-formation marker recognizing osteocalcin, and a bone-resorption marker recognizing C-telopeptide (CT(x)) fragments of collagen type I, in a longitudinal study. The levels of these markers in the plasma of dairy cows (n=11) were recorded over a 12 month postpartum period, including a full lactation and a dry period. The plasma concentration of CT(x) was highest in the first week after parturition. It then declined slowly over the next 33 weeks and remained low until the next parturition. Osteocalcin concentration was lowest around parturition, reached a plateau during mid-lactation, then fell again towards term. There were large variations in bone metabolism during a lactation, that were not directly related to milk production. These results may be used to facilitate appropriate adjustments to calcium and phosphorous concentrations in the diet, reflecting the specific needs of each stage of the reproductive cycle.