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Reducing cation-anion difference of diets (DCAD) fed just before parturition can prevent milk fever. However this dietary regimen does not entirely eliminate hypocalcemia. Milk fever can also be prevented by exogenous administration of the calcium regulating hormone 1,25-dihydroxyvitamin D. Unfortunately 1,25-dihydroxyvitamin D treatment remains expensive and the pre-partal diets used in most trials would be classified today as high in cations. Solanum glaucophyllum (Sg) is a plant that contains high levels of a glycoside form of 1,25-dihydroxyvitamin D. S. Glaucophyllum is widely distributed in the province of Buenos Aires in Argentina and in Brazil and causes the development of a calcinotic disease in cattle called "Enteque Seco". In order to become active the glycoside must be cleaved to liberate the 1,25(OH) 2 D 3 . Rumen microbes are very efficient at this process. Could administration of Sg leaves to cows that were already being fed a low DCAD pre-partum diet further improve calcium status at calving? Nine multiparous Jersey cows were fed a low DCAD diet prior to calving. Urine pH of cows was maintained below 7.0 in all cows the week prior to parturition. Five cows were daily given 2 or 3 g Sg leaves in gelatin boluses beginning 6 days (on average) before calving and continuing for the first 14 days of lactation. None of the four cows fed the low DCAD diet only developed milk fever. Their blood calcium concentration was 7.6, 7.0 and 8.0 mg/dl the day of calving and d 1 and 2 after calving respectively. Cows receiving Sg in addition to low DCAD diet had significantly higher blood calcium concentration during the periparturient period with blood calcium concentrations of 7.8, 8.8 and 9.3 mg/dl the day of calving and d 1 and 2 after calving respectively. Defining subclinical hypocalcemia as blood calcium

AIM Milk fever is well known disease in metabolic diseases and almost there are no clinical signs that are obvious for veterinarians but the complete ethiology and the best way of prevention is controversial. The most important objective of this study is following these factors. Due to formal data the incidence of BPP in this area was high and it was one of the important compliant of owners, so we decided that follow the ethiologies and recommend the possible preventive methods.

Introduction: As milk production levels from New Zealand cows increase so too does the incidence of parturient milk fever and other disorders associated with sub-clinical hypocalcaemia. Pastures typically contain 4-5g Ca (and 25-45g K) /kg DM, high enough prepartum to down-regulate physiological mechanisms that can supply extra Ca, yet too low in Ca to meet requirements of the milking cow. Supplementation of grazing cows with minerals is difficult, and it is particularly impractical to provide sufficient anionic salts to reach recommended DCAD values without experiencing palatability problems. Recently, a means of specifically stimulating the capacity of ewes to absorb Ca from their diet during late pregnancy, thereby making them more resistant to fasting-induced hypocalcaemia, was discovered (Calcigard concept; Wilson, 2001). This nutritional strategy involved feeding a vegetable oil supplement, which formed poorly digestible Ca soaps in the GIT for a period of 3 weeks, and resulted in a marked activation of Ca homeostasis. Aim: The objective of the current experiment was to examine the effects of a prototype feed supplement (Calcigard Concentrate, CC), designed to reduce the availability of dietary calcium during late pregnancy, on the incidence of milk fever and other aspects of health and production in grazing dairy cows. Methods: Mixed breed dairy cows (n=176) in 4 commercial herds were fed CC (at 1 kg/day) for up to three weeks immediately prior to parturition. The incidences of health problems, and productivity in early lactation, were compared with data from a similar untreated control group (n=224). Mineral concentrations in the pre- and post-calving feeds were also determined. Results: The incidence of milk fever was markedly reduced (23 to 7%), milksolids (fat+protein) production in early lactation increased (8%), and other aspects of herd health (Somatic Cell Counts, calf losses, retained placenta) improved by CC feeding.

Commentaries to contributions Roche et al. (New Zealand) The study of Roche et al. was performed in a pasture based milk production system in New Zealand. This study may be characterised as frontline aetiology in the middle of the battle on the relative role of risk factors. In short they found no effect of ration K+ before day 2 pp whereas after day 2 a positive effect of K+ was recorded. This contrasts with findings from USA, possibly because of the often comparatively much higher level of K+ found in US forage. On the other hand, the positive response observed after day 2 needs an explanation. Introduction Parturient hypocalcaemia, and its clinical manifestation Milk Fever (paresis puerperalis) is still one of the most important diseases in cattle production medicine. Judged by the number of contributions given, it also continuous to be one of the cornerstones of this conference despite the fact, that a satellite meeting was organised by this university specifically on the subject (Abildgaard Symposium: Hypocalcaemia, acidosis and calcium homeostasis). It appears from Table 1, that 10 contributions were identified. In the table, these are grouped by the present author according to their most important keywords.

It is not acceptable to compromise animal welfare in any system of farming. Feeding should be aimed at meeting the nutritional requirements at the various stages of production. This paper deals with the detrimental effects that organic, extensive or low input farming systems may have on the energy status in early lactation of the high potential dairy cow. Bovine ketosis is the most important disease resulting from insufficient energy intake in early lactation. It is also important to realize that ketosis is a part of the so-called periparturient disease complex, which includes milk fever, mastitis, retained placenta, endometritis and poor fertility also. All these diseases are interrelated and reflect to a large extent the nutritional status of the animal. If organic dairy farming is to be successful the breeding programmes have to divert from selection for high yields as a main goal, to more emphasis on a flatter lactation curve, less production diseases and longevity.

This paper presents the first part of a questionnaire survey carried out in 2148 Danish dairy herds during 1994, as well as results from a similar survey carried out in 1983. The welfare status in Danish dairy herds with respect to disease management routines currently applied is discussed. In detail this was: recording of mastitis incidents, use of veterinarian for milk fever cases, farmer’s effort in reducing incidence of mastitis, milk fever, ketosis, calving problems, and lameness, as well as frequency of claw trimming, reasons for culling, and way of replacing cullings. Furthermore, trends during the 11 year period are discussed. The results show that the Danish dairy farmers in 1994 in general have a substantial knowledge of prevention and treatment of disease. However, adjustments in the following areas would be appropriate: 1) farmers should avoid making intravenous infusions, 2) they should be encouraged to use calving boxes for parturitions, 3) there should be more attention on claw health, and 4) to comply with the new Danish legislation, antibiotic dry cow treatment should only be carried out on the individual cow if pathogenic microorganisms have been isolated within 35 days prior to drying off.

The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1), the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2), control ration following a period with supplementation (3) and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4). Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets.

Ever since 1970, when Jonsson and Pehrson published some field trials with prophylactic treatment of parturient paresis, all preventive programs in the Northern part of Europe have consisted of 4 oral doses around calving of approximately 50 g calcium given either as calcium chloride or calcium propionate. This oral dosing program starts around 24 hours prior to calving, and is repeated again at calving, and around 12 and 24 hours post calving. In 1996, a new calcium chloride paste product (ReCovin Calcium, JORGEN KRUUSE A/S, Denmark) for oral administration was developed. Some indications, however, were suggested that 4 doses of 50 g calcium around calving might interfere with a normal calving cow's own ability to mobilize calcium. Furthermore, it was hard for the producer to predict that a cow would calf approximately 24 hours from the first administration of 50 g calcium. Consequently, a new "less calcium-fewer doses" program was invented and tested in a field pharmacokinetic and pharmacodynamic study. 32 dairy herds from 32 different veterinary practices were enrolled in the study. Each herd provided 1 pair of Friesian cows (parity 3+), i.e., 1 test cow and 1 control cow per herd. Test cows received 50 g calcium as 180 g of calcium chloride in a paste formulation (ReCovin Calcium) when signs of calving began. This formulation is known to increase plasma calcium rapidly and to obtain sustained concentrations for 8-12 hours. Post calving treatments consisted of a new paste formulation with 125 g calcium propionate (25 g calcium) mixed with 30 g propylene glycol. This formulation was designed to provide both energy (1736 kJ) and more slowly released calcium. This formulation was given twice following calving, i.e., at 6 hours and again 18 hours p.p. Study outcomes were plasma calcium concentrations, clinical milk fever, and subclinical milk fever. Blood samples were drawn from all cows at calving, 6, 18, 36, and 60 hours p.p., and analyzed for plasma calcium concentration. All clinical cases were treated with calcium i.v. Clinical milk fever was recorded when cows were unable to rise, apathetic, and had cold extremities. Subclinical milk fever was recorded when cows had at least one plasma calcium value below 1.5 mmol/l yet did not have clinical milk fever. 21.9% of control cows and 3.1% of test cows were diagnosed with clinical milk fever, and 44.0% of control cows and 19.4% of test cows suffered from subclinical milk fever. Reductions in clinical and subclinical milk fever cases were statistically significant (p

Farmer's choice of feasible strategies for preventing milk fever/subclinical hypocalcaemia amongst several options is motivated and influenced by many factors. When developing strategies for milk fever control in modern dairy herds it is relevant to know what strategies are currently preferred in the herds; but this knowledge is scarce. During the year 1998/99 a cohort study was performed among a selected group of 38 modern Danish dairy herds on the farmers use of relevant and feasible strategies for preventing milk fever. The requirements to be met by the farms were, that a. The cows should be stalled in loose housing systems b. The herd size should be at least 100 dairy cows and c. The farmer should be member of the National Danish Milk Recording Scheme. In addition to this some variation between farms were wanted concerning breed, milk yield per cow, housing, feeding etc. A technician from DIAS visited each farm four times during 1.5 year for data collection: recordings and interviews. The farmer continuously recorded all cases where he observed clear milk fever symptoms and subsequently treated by himself. The herds in the survey were relatively large (> 120 dairy cows) and most practised TMR and group feeding. Dry cows were grouped separately in all 38 herds. The average milk fever incidence for all parities in all 38 herds was 5.3% (0 - 21%). The incidence was lowest for cows in first and second parity, but increased progressively with higher parity, thus 17.0% for cows in 4th or later lactation. There was a large variation in incidences between herds also in same parity, thus from 0 to 3 % in first parity, 0 to 13 % in second parity and 0 to 47 % for cows in 4th or later lactation. Options for control of milk fever/subclinical hypocalcaemia were used systematically in 32 of the 38 herds. The proportion of herds using various options was following: 1. Low Calcium content in rations for dry cows 21 % 2. Low Ca/P-ratio in rations for dry cows

Milk fever is a metabolic disease of dairy cows occurring at the onset of lactation and characterized by a rapid decline in the concentrations of calcium in plasma. Significant advances have been made during the last decade in the understanding of the pathogenesis of milk fever. The etiology of the disease, however, still remains unclear. The goal of the present study was to search for the presence of an acute phase response (APR) during the peripartal period in normal and milk fever dairy cows and the role that APR might play in the etiology of milk fever. Eight clinically healthy, pregnant Holstein dairy cows were selected. Approximately 3 wk before the expected date of calving as well as 2 wk after calving, animals were brought into individual tie stalls to be fed a diet with a cation-anion difference of +40 meq/100g. Three cows showed clinical signs of milk fever and were treated intravenously with a solution containing calcium borogluconate and magnesium gluconate, whereas the rest of the cows showed no clinical signs of postparturient diseases. Blood samples were obtained from jugular vein at 10, 5, and 1 d before parturition, on the day of parturition, as well as at 1, 5, and 10 d after parturition. Plasma samples were analyzed for serum amyloid A (SAA), calcitonin generelated peptide (CGRP), tumor necrosis factor-alpha (TNF-α), lactate, iron, and total calcium. Results show that concentrations of SAA in plasma from all cows increased from 706 µg/dL at 10 d before calving to 3096 µg/dL 1 d after calving and then declined to prepartal values. Concentrations of lactate in plasma also increased from 0.5 mmol/L at 10 d before parturition to 1.3 mmol/L on the day of parturition and then dropped to precalving values. Concentrations of iron and total calcium in plasma declined in both control and milk fever cows from 57 µg/dL and 8.7 mg/dL at 10 d before calving to 41 µg/dL and 6.4 mg/dL, respectively, on the day of parturition and then increased to precalving concentrations. Analysis showed detectable amounts of TNF-α in plasma of only one clinically normal cow. Concentrations of CGRP in plasma were high in both milk fever and normal cows before parturition at 59 pg/mL and then declined after calving at 27 pg/mL. Concentrations of SAA and iron in plasma were greater in milk fever cows compared with clinically normal ones at the day of parturition. Overall, data from the present study indicate the presence of an APR in both normal and milk fever cows. Calcitonin gene-related peptide, a 37-amino acid peptide generated by alternative tissue-specific splicing of the transcript of the calcitonin gene and a well-known inhibitor of calcium mobilization from bone in rodents, might play a significant role in regulation of calcium homeostasis as well as in the etiology and pathogenesis of milk fever in dairy cows. Further investigation is warranted to better understand the role of APR in the etiology and pathogenesis of milk fever of dairy cows.

Three main preventive principles against milk fever were evaluated in this literature review, and the efficacy of each principle was estimated from the results of controlled investigations. Oral calcium drenching around calving apparently has a mean efficacy of 50%–60% in terms of milk fever prevention as well as prevention of milk fever relapse after intravenous treatment with calcium solutions. However, some drenches have been shown to cause lesions in the forestomacs. When using the DCAD (dietary cation-anion difference) principle, feeding rations with a negative DCAD (measured as (Na + K) – (Cl + S)) significantly reduce the milk fever incidence. Calculating the relative risk (RR) of developing milk fever from controlled experiments results in a mean RR between 0.19 and 0.35 when rations with a negative versus positive DCAD are compared. The main drawback from the DCAD principle is a palatability problem. The principle of feeding rations low in calcium is highly efficient in milk fever prevention provided the calcium intake in the dry period is kept below 20 g per day. Calculating the relative risk (RR) of developing milk fever from controlled experiments results in a very low mean RR (between 0 and 0.20) (daily calcium intake below versus above 20 g/d). The main problem in implementing the low-Ca principle is difficulties in formulating rations sufficiently low in calcium when using commonly available feeds. The use of large doses of vitamin D metabolites and analogues for milk fever prevention is controversial. Due to toxicity problems and an almost total lack of recent studies on the subject this principle is not described in detail. A few management related issues were discussed briefly, and the following conclusions were made: It is important to supply the periparturient cow with sufficient magnesium to fulfil its needs, and to prevent the dry cows from being too fat. Available information on the influence of carbohydrate intake, and on the effect of the length of the dry period and prepartum milking, is at present insufficient to include these factors in control programmes.

The intravenous Na2EDTA infusion technique allows effective specific chelation of circulating Ca2+ leading to a progressive hypocalcaemia. Methods previously used were not described in detail and results obtained by monitoring total and free ionic calcium were not comparable due to differences in sampling and analysis. This paper describes a standardized EDTA infusion technique that allowed comparison of the response of calcium, phosphorus and magnesium between 2 groups of experimental cows. The concentration of the Na2EDTA solution was 0.134 mol/l and the flow rate was standardized at 1.2 ml/kg per hour. Involuntary recumbency occurred when ionised calcium dropped to 0.39 – 0.52 mmol/l due to chelation. An initial fast drop of ionized calcium was observed during the first 20 min of infusion followed by a fluctuation leading to a further drop until recumbency. Pre-infusion [Ca2+] between tests does not correlate with the amount of EDTA required to induce involuntary recumbence. Total calcium concentration measured by atomic absorption remained almost constant during the first 100 min of infusion but declined gradually when the infusion was prolonged. The concentration of inorganic phosphate declined gradually in a fluctuating manner until recumbency. Magnesium concentration remained constant during infusion. Such electrolyte responses during infusion were comparable to those in spontaneous milk fever. The standardized infusion technique might be useful in future experimental studies.

The effect of daily oral doses of 1,25-dihydroxy vitamin D(3) (1,25-(OH)(2)D(3)) on plasma mineral concentrations and incidence of milk fever was tested in 39 aged cows. Three dose levels of 1,25-(OH)(2)D(3) (0, 100 and 200 µg/d) were compared in cows supplemented with 100 g Ca/d (250 g CaCO(3)) and in cows receiving no Ca supplement. 1,25-(OH)(2)D(3) treatments were given from day 5 before expected calving (day –5) until the day after calving (Calving = day 0). Expected minima in Ca concentrations in plasma were seen on day 1 in placebo treated cows, while Ca concentrations in 1,25-(OH)(2)D(3) treated cows were normal or increased in the period from start of treatment until day 3–5. In the parturient period (day –1 to +2) 1 of 21 treated cows developed milk fever, as compared to 4 of 18 untreated. A pronounced hypocalcaemia developed, however, in the 1,25-(OH)(2)D(3) treated cows from day 3 to 5 onwards, culminating day 8–11 with 7 cases of milk fever. Ca supplements reduced the development of hypocalcaemia in the 1,25-(OH)(2)D(3) treated cows, but could not completely prevent the occurrence of milk fever.

In addition to the classic form of parturient paresis characterized by hypocalcemia and somnolence, which responds rapidly to calcium therapy, it is not unusual to encounter other forms of this disease. The most common aberration would seem to be that in which the animals do not rise after calcium treatment. Many of these cows show little or no drowsiness, their appetite is often good, and the results of a clinical examination often negative. Some authors, Blood & Henderson (1960) for instance, consider that this “downer cow syndrome” is an indépendant disease not connected wiht milk fever. Although the downer cow syndrome is a common disease and is of considerable significance, remarkably little has been written about it. Garm in 1950 noted that the frequency of downers had increased as compared with the numbers registered a few years earlier. He had also noticed that in many of these cows hypocalcemia was present on the first day of illness but not on subsequent days, despite the fact that they had marked signs of milk fever. Osinga, in an investigation in 1963, compared two types of milk fever: a typical form in which the cow is drowsy, lies on her side, and has partial anorexia, and an atypical form in which the animal is alert and has normal or only slight loss of appetite. Osinga remarked that the atypical cases had in-creased in number and suggested as an explanation the fact that the amount of protein in the fodder has increased, with the result that auto-intoxication and damage to parenchymatous organs may occur. The object of the present investigation was to study the difference between cows that recover after treatment (“uncomplicated milk fever”) and those that have not risen 24 hrs. after the first treatment (“downers”). We also wanted to ascertain whether any changes occurred in the downers between the first and second, and second and third days. In addition, the difference between cows with blood-calcium levels equivalent to or over 8.0 mg/100 ml serum and those with corresponding values under 8.0 mg at the first examination was also studied.

Twelve cows of 14 given a basic diet supplemented with Na(2)GO(3) and NaHCO(3) during four weeks pre partum and one week past partum were attacked by milk fever (hypocalcemic paresis puerperalis), while 12 cows of 13 receiving the same basic diet supplemented with sulfates and chlorides remained healthy. A mixture of CaCl(2), Al(2)(SO(4))(3) and MgSO(4) was found to be a convenient prophyllactic supplement. It was found possible to induce and prevent milk fever at successive parturitions in the same cow by altering the dietary conditions. The data give further support to the hypothesis that the alkali alkalinity of the diet is the major factor in induction or prevention of milk fever.

A concentrate was fortified with mineral salts by adding CaCl(2), Al(2)(SO(4))(3) and MgSO(4) to standard concentrate A and pelleting the product When used as feed supplement from 3 weeks pre partum to 1 week post partum this concentrate mixture produced the intended negative alkali alkalinity in the total feed ration in 20 out of 25 cows. Of these 17 remained healthy in spite of a history of milk fever for the majority of them. Two cows got milk fever and 1 showed weak symptoms.

Plasma cholinesterase (pChE) levels and erythrocyte acetylcholinesterase (eAChE) levels were studied in 6 cows before, during and after parturition (Group I), their calves (Group II), 38 cows suffering from parturient paresis (Group III) and 14 newly delivered non-paretic cows (Group IV). The mean of the pChE level in Group I was 1.5 μkat/1 ± 0.20 before parturition and decreased significantly (P ≦ 0.05) to 1.2 ukat/1 ± 0.16 after parturition. The eAChE level was before parturition ≅ 140 ukat/1 and decreased to ≅ 130 μkat/1 4–5 weeks after parturition. At birth the pChE level was 12.8 ukat/1 ± 5.9 in Group II. After 4 weeks the level had decreased to 2.3 ukat/1 ±0.3. In the bull calves the pChE level started to increase when they were 6 weeks old and reached a level of 5.7 μkat/1 ± 0.6 before slaughter at 6 months of age. The heifers did not show this increase. They had a level of around 2 μkat/1 throughout the investigation. The eAChE level at birth was 119 μkat/1 and increased slowly to a level of 145 μkat/1 at 6 months. No differences between the sexes were found. The cows suffering from parturient paresis had a pChE level of 1.80 μkat/1 ± 0.30 before treatment with calcium (Ca). The level decreased significantly (P ≦ 0.001) after Ca-infusion to a level of 1.67 ukat/1 ±0.29. Group IV had a pChE level of 1.65 μkat/1 ± 0.42 at parturition. Two to 4 months later the cows that had recovered from milk fever had a level of 1.61 μkat/1 ± 0.31 and the control cows 1.66 ukat/1 ± 0.48. No differences between the groups were found for the eAChE level. The findings show that parturition influences the pChE level in cows and that sex influences the pChE level in calves between 6 weeks to at least 6 months of age. Furthermore the elevated pChE level found in the cows suffering from parturient paresis before Ca infusion may be a further sign of a disturbance in the cholinergic system with a special preference to the neuromuscular junctions.