A scoping review of the analytical literature concerning nonambulatory dairy cattle.

Nonambulatory dairy cattle pose a complex problem due to the challenges associated with prevention, appropriate treatment and management, and arriving at an accurate prognosis. There is a breadth of literature regarding this topic, of which there is currently no formal synthesis. The objective of this scoping review was to describe and characterize the literature investigating risk factors, sequela, preventions, treatments, and prognostic factors for nonambulatory conditions in dairy cattle, with the intent of qualitatively synthesizing knowledge of the topic and identifying gaps in the literature. A literature search was conducted in 6 databases and 2 conference proceeding archives, which returned 7,568 unique articles. Initial screening of abstracts resulted in 1,544 articles reviewed at the full-text stage, of which 379 were included for data extraction. Over 75% of the included literature was published after 1980, and the most common countries in which these studies took place were the United States (n = 72), Canada (18), Sweden (17), and Germany (17). Common eligibility criteria used for inclusion were geographic region (97) and parity (92). Of the 379 studies included in this review, 144 were randomized controlled trials and 235 were observational studies. The majority of the controlled trials assessed prevention of nonambulatory conditions (116), most commonly through supplementation of vitamin D (27) and calcium (25) or the provision of anionic salts (22). Of the 28 studies focusing on treatment of nonambulatory conditions, 26 focused on calcium administration. Becoming nonambulatory was evaluated as an outcome in 165 of the observational studies. Frequently measured risk factors for becoming nonambulatory included hematological variables, such as blood calcium (73), phosphorus (53) and magnesium (42), and other factors such as parity (35) and breed (22). Recovery from a nonambulatory condition was the outcome in 31 of the observational studies, with commonly measured prognostic indicators being calcium (9), phosphorus (9), and duration of recumbency (7). Nonambulatory disorders were measured as risk factors in 53 of the observational studies, with the most commonly assessed outcomes including disorders of the transition period (11), and death or euthanasia (11). The most common terms used to describe nonambulatory conditions were "milk fever" (199) and "parturient paresis" (147). These terms were only further defined with explicit symptomatic criteria in 193 of the 379 studies in this review. Recumbency was the most commonly used of these criteria (144), followed by inability to rise (55). Potential gaps in the literature concerning nonambulatory dairy cattle that were identified in the present review included investigation of prognostic indicators for recovery from nonambulatory conditions that are applicable on farm, treatment alternatives to calcium administration, and guidance regarding the appropriate usage of terms meant to categorize nonambulatory dairy cattle.

[Etiology, therapy and prophylaxis of bovine parturient paresis (hypocalcaemia)]. / Wesen, Ursachen, Therapie und Prophylaxe der hypokalzämischen Gebärparese beim Rind.

Due to the sudden increase of calcium demand at the onset of lactation many high yielding dairy cows experience a certain level of hypocalcaemia following parturition. The incidence of hypocalcaemia (parturient paresis) increases with age but also depends on many other factors such as the acid-base status and the availability of calcium as well as other minerals and trace elements. Hypocalcaemia can easily be treated by supplementation of calcium parenterally or orally, nonetheless, prophylaxis of the condition should be the main focus in modern dairy farming, in order to avoid its negative effects. Oral administration of calcium around parturition is the simplest way of prophylaxis, but results in a high work load and requires exact knowledge of the date of parturition. The latter also applies for the parenteral administration of vitamin D3, which should be injected 1 week before parturition. Additionally, repeated treatment with vitamin D increases the risk for calcinosis. Reducing the calcium concentration of the ration fed during the late dry period also decreases the risk for hypocalcaemia by activating the mechanisms for calcium homeostasis within the body. The induction of a mild (compensated) metabolic acidosis to increase the sensitivity of parathormone receptors and enhance intestinal calcium uptake may also be employed to prevent milk fever. For this purpose, a DCAD (dietary cation anion difference) diet is fed during the late dry period, in which the concentrations of strong cations (potassium and sodium) as well as strong anions (sulfate and chloride) are altered. This may either be achieved by reducing the potassium concentration (partial-DCAD) or by adding anionic salts (full-DCAD). This method, especially the full-DCAD variant, requires a substantial level of surveillance and monitoring. Suitable prophylactic measures for the prevention of hypocalcaemia must be chosen individually for each farm, depending on the incidence of hypocalcaemia as well as personnel and structural resources.

Effect of subclinical and clinical hypocalcemia and dietary cation-anion difference on rumination activity in periparturient dairy cows.

Rumination involves a complex series of muscle contractions that bring a bolus of ingesta to the mouth for further mastication before it is swallowed again. Healthy cows ruminate 8 to 9 h/d. Hypocalcemia is known to disrupt nerve and muscle function. Our hypothesis was that hypocalcemia in periparturient cows would reduce rumination activity. Twenty-six Holstein cows entering their third lactation or greater were fed a control diet [dietary cation-anion difference (DCAD) = +196 mEq/kg of dry matter (DM)] or a low DCAD diet supplemented with anions (DCAD = -9 mEq/kg of DM) prepartum. Periparturient plasma Ca concentration and rumination rate were determined. Four of 12 control cows developed clinical milk fever, necessitating intravenous Ca therapy. Rumination rate decreased in all cows around the time of calving. Rumination rate on the first and second day of lactation was highly correlated with the cow's plasma Ca concentration on the first day of lactation. In one of our statistical models, a normocalcemic cow was defined as a cow whose plasma Ca concentration remained above 2.00 mM. Cows were retrospectively classified as normocalcemic, subclinically hypocalcemic, or clinically hypocalcemic (milk fever). Only 4 cows were considered normocalcemic, and all had been fed the low DCAD diet. Normocalcemic cows spent more time ruminating on the first day after calving than subclinically hypocalcemic cows or cows with milk fever. Cows with milk fever had a lower rumination rate than normocalcemic cows through d 3 of lactation. Rumination activity in cows with milk fever was almost nondetectable in the hours before and after intravenous Ca treatment for an extended period, despite the return of muscle function that allowed the cows to stand and eructate following treatment. Other statistical models using different definitions of normocalcemia gave qualitatively similar results. Diet had a great effect on plasma Ca concentration and rumination rate. Even when cows with clinical milk fever were removed from the control cow data set, cows on the low DCAD diet had significantly greater plasma Ca concentrations in the first 36 h after calving and a higher rumination rate on d 1 of lactation (248 ± 26 min) than control cows (158 ± 32 min).

Hypocalcemia-Cow-level prevalence and preventive strategies in German dairy herds.

Hypocalcemia around calving is considered a gateway disease that can lead to health disorders and decreased milk production. The objective of this cross-sectional study was to evaluate the prevalence of clinical and subclinical hypocalcemia 0 to 48 h after calving. Blood samples were drawn from 12 animals of each dairy farm (n = 115) and analyzed for serum calcium, magnesium, and phosphorus concentration. Cows not affected clinically but with a serum calcium concentration below 2.0 mmol/L were characterized as subclinical hypocalcemic animals. Recumbent cows with a serum calcium concentration below 2.0 mmol/L were defined as cows suffering from clinical milk fever. Herds were classified into negative (0 to 2/12), borderline (3 to 5/12), and positive (≥6/12) according to the number of animals with hypocalcemia. Strategies to control hypocalcemia were documented. Prevalence of clinical milk fever was 1.4, 5.7, and 16.1% for second, third, and ≥fourth parity cows, respectively. None of the cows in first lactation were suffering from clinical milk fever. Based on the threshold of 2.0 mmol/L, 5.7, 29.0, 49.4, and 60.4% of cows in first, second, third, and ≥fourth lactation were suffering from subclinical hypocalcemia, respectively. Fourteen, 51, and 50 herds were classified as negative, borderline, and positive, respectively. A positive association was observed between serum calcium and serum phosphorus concentration. Serum calcium and magnesium concentration were negatively associated. Only 50 of 115 farms had a control strategy implemented to avoid hypocalcemia. Most common was the use of oral calcium products (40/115 herds), followed by feeding of anionic salts in the close-up diet (10/115 herds). These results indicate that the prevalence of clinical and subclinical hypocalcemia in German dairy herds was high and that an active control strategy was not implemented on all farms. The negative association between calcium and magnesium warrants further research regarding the physiological regulation of these 2 minerals around parturition.

Effects of a sustained release formulation of 1,25-dihydroxyvitamin D3-glycosides for milk fever prevention on serum 1,25-dihydroxyvitamin D3, calcium and phosphorus in dairy cows.

Milk fever (MF) is a metabolic disease in dairy cows around parturition. The clinical lead sign is muscular paresis leading in severe cases to paralysis of the affected animal. Multiparturient animals of high performing dairy breeds are most likely to be affected and have a high probability of recurrence. An acute drop in blood calcium levels causes the disease when the demand for calcium at the onset of lactation exceeds the ability to replete blood calcium levels through mobilization from bone and intestinal uptake. With the understanding of the underlying mechanism, calcium supply management and vitamin D supplementation became prime candidates for MF prevention and therapy. Several strategies have been developed for MF prevention. Application of the active form of Vitamin D, 1,25(OH)2D3, was found to prevent MF effectively. In order to prevent a delayed hypocalcemia, which was occasionally seen after stopping the treatment with 1,25(OH)2D3, a new approach was chosen by applying Solanum glaucophyllum extract (SGE), which contains 1,25(OH)2D3-glycosides, as instant-release (irSGE) in combination with slow-release (srSGE) tablets. In a first study, non-lactating cows were treated with a single bolus of either synthetic 1,25(OH)2D3, irSGE, or srSGE and the results were compared to a control group without treatment. Blood serum levels of 1,25(OH)2D3 (1,25D), calcium (Ca), phosphate (P) and magnesium (Mg) were followed for 11days and the area under the curve (AUC) was calculated. Calcium and phosphate excretion in urine were determined during 15days. While serum concentration of 1,25(OH)2D3 was back to pre-treatment level in the irSGE, srSGE and 1,25(OH)2D3 treated group within 3days, calcium and phosphate levels remained elevated for up to 9days. AUC of serum 1,25(OH)2D3 was 2.89 (1,25D), 3.13 (irSGE) and 4.21 (srSGE) times higher than control. Serum calcium levels were 1.07* (for 1.25D); 1.08* (for irSGE) and 1.12* (for srSGE) times higher than control. Serum phosphate levels were 1.20* (for 1,25D); 1.30* (for irSGE) and 1.41* (for srSGE) times higher than control, with * p<0.05. In a second field study calving cows treated with one bolus containing ir- and sr- tablets of SGE were compared to an untreated control group and to a group treated with 4 boli of commercial calcium salts. As a result, calcium serum levels increased (+19% compared to baseline) around calving after treatment with the single bolus of SGE. The single bolus of SGE lead also to an increase of serum phosphate (+31% compared to baseline). These calcium and phosphate increases were statistically significant (p<0.001) 0-24h after calving compared to the control group and to the group treated with calcium salts. The sample size of the study was too small to draw a conclusion on the effect on MF prevention. In conclusion, application of a single bolus of a SGE extract lead to an increase of serum calcium and phosphate for up to 9days and may thus have the potential to prevent a hypocalcemia and -phosphatemia, an important cause for clinical milk fever.

[Potential involvement of selenium in the occurrence of milk fever in cattle]. / Potenzielle Bedeutung des Spurenelements Selen für die Entstehung der Gebärparese beim Rind.

OBJECTIVE: Frequent occurrence of parturient paresis (milk fever [MF]) and a partly unsatisfactory treatment success raises the question as to whether in addition to the known causes, other factors influence the incidence and success of MF treatment. Trace elements, including selenium (Se), are involved in bone metabolism, however, there is little knowledge regarding the influence of Se on MF development. The aim of this study was to analyse the concentrations of Se and the statistical relationships to parameters associated with Se influence in downer cows. MATERIAL AND METHODS: A total of 195 Simmental cows, downer cows and clinically healthy control animals were divided into five groups: a) control group (CG, n = 21), b) all cows with MF (n = 174), c) MF cows without additional diseases (n = 145), d) cows with MF and mastitis (n = 10) and e) cows with MF and retained placenta or endometritis (n = 19). Se, calcium (Ca), inorganic phosphate (Pi), tumour necrosis factor α (TNFα), haptoglobin (Hp), antioxidants (Trolox Equivalent Antioxidative Capacity: TEAC) and further metabolic parameters were analysed in the blood serum. RESULTS: The serum concentrations of Se, Ca, Pi and TEAC were lower in groups b) to e), whereas Hp was higher than in the CG (p ≤ 0.05). Se was positively correlated with Pi in the CG, in groups b) and c) with Ca, Pi, K and Mg and in group c) with Hp (p ≤ 0.05). Both Ca and Pi were significantly lower in group c) compared to group d) (p ≤ 0.05). TNFα was increased in groups b) and c) compared to group a) and correlated with Se in group e) (p ≤ 0.05). Alkaline phosphatase activity in groups b) and e) was lower than in the CG and correlated with Se in the CG and group b) (p ≤ 0.05). CONCLUSION: These results, in agreement with the literature data, support the hypothesis that Se could be directly involved in bone metabolism and therefore in the pathogenesis of MF. Se acts via cytokines on Ca mobilization from bone. The concentrations of Hp and TEAC support this interpretation. Therefore, control of the Se status and Se supplementation of cows should be included in the prevention and advanced therapy of MF.

[The relevance of the trace elements zinc and iron in the milk fever disease of cattle]. / Bedeutung der Spurenelemente Zink und Eisen bei der Gebärparese des Rindes.

OBJECTIVE: The aim of this study was to analyse the concentrations of Zn and Fe as well as their relationships to metabolic parameters in milk fever cows. MATERIAL AND METHODS: A total of 195 Simmental cows, downer cows and clinically healthy control animals were divided into five groups: a) control group (CG, n = 21), b) all cows with milk fever (MF) (n = 174), c) MF cows without additional diseases (n = 145), d) cows with MF and mastitis (n = 10) and e) cows with retained placenta or endometritis (n = 19). Selenium (Se), zinc (Zn), iron (Fe), calcium (Ca), inorganic phosphorus (Pi), tumour necrosis factor α (TNFα), haptoglobin (Hp), antioxidants (Trolox Equivalent Antioxidative Capacity: TEAC), non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), bilirubin, urea, creatinine, glucose, cholesterol, gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were analysed in the blood serum. RESULTS: The concentrations of Zn, Fe, Ca, Pi and TEAC were lower in groups b) to e) whereas Hp was higher than in the CG (p ≤ 0.05). In group c), lower Ca and Pi concentrations were found when compared to groups d) and e) (p ≤ 0.05). In group e), Zn concentrations were significantly lower than in group c) (p ≤ 0.05). Zn was negatively correlated with K (CG) and positively correlated with TEAC, Cu, Mn and Fe (groups b and c) and with Mn (group e) (p ≤ 0.05). Fe was positively correlated with Ca (group c), Pi (group c), K (groups b and c) and Mg (groups b-d) as well as with Zn, Cu and Se (groups b and c) (p ≤ 0.05). In groups b) and c), TNFα was increased and negatively correlated with Fe (p ≤ 0.05). AP activity in groups b) and e) was lower than in the CG (p ≤ 0.05). CONCLUSION: These results and literature data support the hypothesis that Zn and Fe could be engaged in bone metabolism and be involved in the pathogenesis of MF. The concentrations of Hp and TEAC support this interpretation. Control of the Zn and Fe status of cows and Zn supplementation should be included in the prevention and advanced therapy of MF.

Survey on the occurrence of milk fever in dairy cows and the current preventive strategies adopted by farmers in New South Wales, Australia.

OBJECTIVE: The aim of this study was to investigate general and specific strategies adopted by New South Wales (NSW) farmers to prevent milk fever (MF) and its occurrence at calving within their dairy herds. DESIGN AND METHODS: Of 300 dairy farmers in NSW randomly chosen and sent questionnaires, descriptive analysis of the returned data was performed for 102 questionnaires. To identify the various strategies used to prevent MF and its incidence, farms were classified as having a low (<3%) or high (>3%) incidence of MF. The data were analysed using a multivariable logistic regression model and backwards stepwise elimination to identify significant preventive strategies adopted by farmers having a low or high incidence of MF. RESULTS: Based on the 102 responses, the median incidence of MF in the NSW dairy region was 3% (range 0-30%). The farms with low MF incidence practised specific MF control strategies, such as feeding dry cows separately, grain supplementation and feeding a low-potassium ration before calving and using a commercial ration mix immediately after calving. The time to first milking post-calving was on average 13.6 h on the low-incidence farms compared with 21.1 h on the high-incidence farms. CONCLUSIONS: The low median incidence of MF (3%) in NSW was probably related in part to awareness of the importance of feeding a low-potassium, high-grain diet before calving. However, the incidence of MF was high on the farms not practising specific MF preventive methods.

Effects of folic acid and vitamin B12 supplementation on culling rate, diseases, and reproduction in commercial dairy herds.

This study was undertaken to determine the effect of a combined folic acid and vitamin B12 supplement given in early lactation on culling rate, metabolic disorders and other diseases, and reproduction in commercial dairy herds. A total of 805 cows (271 primiparous and 534 multiparous cows) in 15 commercial dairy herds were involved. Every 2mo from February to December 2010 and within each herd, cows were assigned according to parity, previous 305-d milk production, and calving interval to 5mL of either (1) saline 0.9% NaCl (control group) or (2) 320mg of folic acid + 10mg of vitamin B12 (vitamin group). Treatments were administered weekly by intramuscular injections starting 3wk before the expected calving date until 8wk after parturition. A total of 221 cows were culled before the next dry period. Culling rate was not affected by treatment and was 27.5%; culling rate was greater for multiparous (32.2%) than for primiparous cows (18.8%). Within the first 60d in milk (DIM), 47 cows were culled, representing 21.3% of total culling, and no treatment effect was noted. Ketosis incidence based on a threshold ≥100µmol/L of ß-hydroxybutyrate in milk was 38.3±2.9% for the vitamin group and 41.8±3.0% for the control group and was not affected by treatment. The combined supplement of folic acid and vitamin B12 did not decrease incidence of retained placenta, displaced abomasum, milk fever, metritis, or mastitis. However, the incidence of dystocia decreased by 50% in multiparous cows receiving the vitamin supplement, although no effect was observed in primiparous cows. The first breeding postpartum for multiparous cows occurred 3.8d earlier with the vitamin supplement compared with controls, whereas no treatment effect was seen for primiparous cows. Days open, first- and second-breeding conception rates, number of breedings per conception, and percentage of cows pregnant at 150 DIM were not affected by treatment. The reduced percentage of dystocia combined with the earlier DIM at first breeding for multiparous cows receiving the combined supplementation in folic acid and vitamin B12 indicates that the vitamin supplement had a positive effect in older cows.

Relationship between incidence of milk fever and feeding of minerals during the last 3 weeks of gestation.

This study evaluated whether differences in milk fever incidence among Swedish dairy herds could be explained partly by differences in mineral feeding during the last weeks of gestation. A case-control study was performed on dietary risk factors for a high incidence of milk fever at the herd level using information regarding feeding and management of the dry cows collected in a written questionnaire distributed by post in spring 2008. The study was conducted from September 2004 to August 2007. Data on the diets fed to dry cows, with an emphasis on the amounts of minerals (Ca, P, Mg and K) fed 3 weeks before calving and at calving, were obtained from 30 herds belonging to the 100 Swedish herds with the highest recorded incidence of veterinary treatment for milk fever (>8.8%) and from 22 herds with no recorded milk fever treatments. Multivariable logistic regression analysis showed that a linear increase in the total amount of K and less than 26 g of Mg/day fed to dry cows 3 weeks before calving was associated with an increased risk of high milk fever incidence. A large increase in the amount of dry matter (DM) fed (>3.1 kg DM extra per day at calving compared with 3 weeks before calving) was associated with a higher incidence of milk fever, but no differences were found for Ca or P intake. Breed composition, herd average milk yield and age composition of the herd did not explain any of the observed differences between the case and the control herds. The results indicate that differences in the frequency of milk fever among herds can be associated with differences in mineral feeding of the dry cows. A high amount of K in the diet may increase the risk of milk fever linearly, whereas Mg should probably be fed at a higher level than the current Nordic recommendation to prevent milk fever.

Treatment of cows with milk fever using intravenous and oral calcium and phosphorus.

Fifteen cows with milk fever were treated with 500ml of 40 % calcium borogluconate (group A) administered intravenously. Fifteen other cows with milk fever received the same treatment, supplemented with 500ml of 10 % sodium phosphate administered intravenously, and 80g calcium as calcium lactate and 70g inorganic phosphorus as sodium phosphate administered orally in drinking water. The cows were monitored and blood samples collected for 3 days to measure the concentrations of total and ionized calcium, inorganic phosphorus and magnesium and the activity of creatine kinase. The two groups did not differ significantly with respect to the course of the disease. In each group 14 cows were cured. A rapid and significant increase in serum calcium concentration from the hypo- to the hypercalcaemic range occurred in both groups within 10min of the start of treatment, followed by a slow and steady decrease to the hypocalcaemic range. Calcium lactate did not prevent the calcium concentration from returning to the hypocalcaemic range, and the calcium profiles of the two groups did not differ significantly. As expected, treatment had little effect on the concentration of inorganic phosphorus in group A. In group B, treatment caused a rapid increase in the concentration of inorganic phosphorus to a maximum 20min after the start of treatment. This was followed by a slow decrease in the phosphorus concentration to the normophosphataemic range. Our findings confirmed that combined intravenous and oral administration of sodium phosphate in cows with periparturient paresis attributable to hypocalcaemia and hypophosphataemia results in a rapid and sustained increase in serum phosphorus, but not in serum calcium concentration. This modified therapy did not improve the success rate of milk fever treatment and further studies are needed to improve treatment of periparturient paresis.

[The effect of oral calcium lactate in postpartum cows]. / Untersuchungen zur Wirkung von Kalziumlaktat bei Kühen post partum.

The oral administration of calcium lactate for prophylaxis of bovine parturient paresis has been promoted for a number of years. The goal of the present study was to investigate the effect of this treatment on the serum concentrations of calcium, inorganic phosphorus and magnesium in parturient cows. Five fresh calved cows were given a drench containing calcium lactate and 5 control cows received the same drench but without calcium lactate. There were no significant differences in the serum concentrations of total and ionised calcium and magnesium between treated and control cows within 24 hours of treatment. Because the calcium lactate drench did not significantly affect calcium concentrations in the blood of fresh cows, it appears highly questionable whether the administration of calcium lactate decreases the risk of bovine parturient paresis. Based on our results, the oral administration of calcium lactate can not be recommended for prophylaxis of bovine parturient paresis.

Urinary calcium excretion in non-lactating dairy cows in relation to intake of fat-coated rice bran.

At calving, many older cows fail to compensate the sudden demand of calcium by an adequate activation of intestinal absorption. This results in a variable degree of hypocalcaemia. Reducing intestinal availability of calcium during the close-up period can prevent milk fever. Fat-coated rice bran (FCRB) was investigated for its potential to reduce Ca availability in pre-calving cows. Fat-coated rice bran was incubated in situ to estimate ruminal degradation of dry matter and phytic acid. Also, seven dry multiparous dairy cows were used for a feeding trial in three periods of approximately 1 week each: P1: adaptation; P2: feeding of 2 kg of FCRB and P3: withdrawal of FCRB. Feed intake was recorded and daily urine samples were analysed for pH, Ca and creatinine. The bypass fraction of phytic acid (passage rate: 5%/h) was 30%. Fat-coated rice bran depressed dry matter intake in P2, resulting in a lower Ca intake. In P2 urine pH and calcium excretion were lower. Daily calcium excretion decreased after introduction of FCRB, peaked after withdrawal and dropped 2 days later. Changes in urinary Ca excretion by feeding FCRB indicate that FCRB affected Ca homeostasis in dry multiparous dairy cows.

Effect of intravenous calcium borogluconate and sodium phosphate in cows with parturient paresis.

Thirty cows with parturient paresis were divided into three groups of 10. All the cows were given 500 ml of a 40 per cent calcium borogluconate solution intravenously over a period of 10 minutes, and 20 were also given 500 ml of a 10 per cent solution of sodium phosphate intravenously; in 10 of the cows this solution was administered over a period of 10 minutes immediately after the calcium borogluconate solution, and in the other 10 cows 200 ml of the solution was administered rapidly and the remaining 300 ml was added to 10 litres of sodium chloride and glucose solution and infused slowly over six hours. There were no significant differences between the groups with respect to the outcome of the treatments; six or seven of the cows in each group stood within eight hours of the treatment. There were no significant differences between the changes in serum calcium concentrations among the groups. The mean concentrations of inorganic phosphorus in the groups given sodium phosphate were increased above the normal range initially, but after eight hours there were no significant differences between the groups in terms of the numbers of cows that were hypophosphataemic. There were no significant differences between the three groups with respect to changes after treatment in the serum concentrations of magnesium or parathyroid hormone.

The monitoring, prevention, and treatment of milk fever and subclinical hypocalcemia in dairy cows.

The periparturient cow undergoes a transition from non-lactating to lactating at calving. The animal is tremendously challenged to maintain calcium homeostasis. Those that fail can develop milk fever, a clinical disorder that is life threatening to the cow and predisposes the animal to a variety of other disorders. Guidelines for monitoring the incidence of hypocalcemia and methods for treating milk fever are reviewed. The physiological factors that cause milk fever and strategies for prevention of milk fever are discussed, focusing on the effects diet cation-anion difference can have on tissue sensitivity to parathyroid hormone. Another major risk factor for milk fever is hypomagnesemia, which is observed when animals are fed inadequate amounts of magnesium, or some factor is present in the diet that prevents adequate absorption of magnesium. Moderate hypomagnesemia impairs the ability of the cow to maintain calcium homeostasis and hypocalcemia occurs.

Effect of intravenous calcium and oral sodium phosphate in cows with parturient paresis.

The goal of this study was to determine whether oral administration of sodium phosphate in conjunction with intravenous calcium is more efficaceous than intravenous calcium alone for the treatment of parturient paresis. Thirty cows with parturient paresis were examined and treated by the same veterinarian. The cows were divided randomly into two groups of 15 cows each. Cows in group A received 500 ml of a 40 per cent calcium borogluconate solution containing 15.65 g calcium gluconate and borogluconate, with a supplement of 6 per cent magnesium hypophosphite (9.85 g magnesium hypophosphite) intravenously over a period of approximately 15 min. Cows in group B received the same treatment as well as 350 g of monobasic sodium phosphate (70 g inorganic phosphate, NaH2PO4 2 H2O, Streuli) dissolved in 0.5 litres of distilled water orally via a stomach tube. After treatment, the heart rate, respiratory rate, rectal temperature, superficial body temperature, rumen motility, appetite and defecation of the cows were monitored every hour for eight h. The cows' attempts to rise and their ability to stand were also noted. Initially, the results of clinical examination and serum electrolyte analyses did not differ between the two groups of cows. Within one hour of treatment, stupor was not observed in any of the cows. The general demeanour after treatment did not differ significantly between the two groups. In both groups, the average rectal temperature increased within two hours of the initiation of treatment, from 38.0 +/- 0.95 degrees C to 38.5 +/- 0.40 degrees C. There was no significant difference in the recovery rate between the groups. Of the 30 cows, 22 (73.3 per cent) stood within eight hours of treatment (10 cows from group A and 12 cows from group B). The type of treatment did not affect the time required to stand: cows in group A stood within 47.3 +/- 44 minutes and cows in group B stood within 24.2 +/- 32 minutes after the start of treatment. Our findings do not support the hypothesis that oral treatment with 350 g of sodium phosphate together with intravenous infusion of calcium in cows with parturient paresis results in an improved outcome, even though all the cows had hypophosphataemia as well as hypocalcaemia.

Clinico-pathological findings in peripartum dairy cows fed anion salts lowering the dietary cation-anion difference: involvement of serum inorganic phosphorus, chloride and plasma estrogen concentrations in milk fever.

In our previous study, it was demonstrated that the administration of anion salts, which slightly lower the dietary cation-anion difference (DCAD), in the prepartum period is safe and effective for preventing milk fever in multiparous cows. In the present study, several clinico-pathological constituents in serum and urine, which might be related to milk fever, were analyzed using stored samples from the previous study to identify clinico-pathological parameters for easily evaluating the efficacy of lowering DCAD and to further investigate the mechanism by which lowering DCAD prevents milk fever. Among the parameters analyzed in the present study, inorganic phosphorus (iP) was involved in milk fever because the serum concentration and urinary excretion of iP were significantly higher in the group of primiparous cows (heifer group), which did not develop hypocalcemia, than those in other groups of multiparous cows. Serum chloride concentrations in the heifer group and the group of multiparous cows fed anion salts (anion group) tended to remain higher than those in other control groups of multiparous cows suggesting that serum chloride concentration may be utilized for evaluating the status of metabolic acidosis and the efficacy of lowerng DCAD in dairy cows fed anion salts. In addition, plasma estradiol-17beta concentration in the heifer group tended to be lower at parturition compared with that in other multiparous groups suggesting that estrogen known as a potent inhibitor of bone resorption may be involved in developing milk fever.

Milk fever and alert downer cows: does hypophosphatemia affect the treatment response?

The purpose of this prospective cohort study was to identify factors that place a dairy cow with uncomplicated milk fever (MF) at significant risk of becoming an alert downer cow (ADC) and to verify if these factors could be used to predict treatment outcome. Recumbent MF cows were examined before treatment and 52 were excluded due to complications. In all, histories and pretreatment serum samples were taken and the serum of 86 cows was analyzed for electrolyte levels (calcium, phosphorus, magnesium, and potassium). In total, 36 of the 86 samples were from ADCs and 50 from animals that responded to MF treatment (MFT). A binary-two-factor logistic model determined that a MF cow with a phosphorus pretreatment level of > or = 0.9 mmol/L was 12 times more likely not to become an ADC than one with a phosphorus level < 0.9 mmol/L (CI: 6.3,23.1). Also, a binary multivariable logistic regression analysis showed that a MF cow with a pretreatment calcium level > or = 1.7 mmol/L was 14 times more likely to become an ADC than one with a serum level < 1.7 mmol/L (CI: 2.0,98). Age and the other serum electrolytes were not statistically significant risk factors at the 0.05 level. The rigorous pretreatment examination and stringent adherence to protocol reduced ADC misclassification and fostered the strong association between single factor serum phosphorus levels and ADCs. By using a cutoff level of serum phosphorus at > or = 0.9 mmol/L, a practitioner could correctly predict that 95% of the MFs would not become ADCs and, therefore, this level would be a useful pretreatment predictor.

Preventive effect of mildly altering dietary cation-anion difference on milk fever in dairy cows.

In the present study, we examined whether mildly altering dietary cation-anion difference (DCAD) contributes to the prevention of milk fever in dairy cows. Thirty multiparous cows and ten primiparous cows (heifer group) were used in this study and the multiparous cows were randomly divided into three groups of ten animals each (anion, non-anion and control groups). The cows in the anion group were given supplemental salts that slightly lowered DCAD. These salts consisted of 115 g of CaCO3, 42 g of CaHPO4, 65 g of MgSO4 x 7 H2O and 80 g of CaCl2 x 2 H2O as a daily dose for each cow, using a catheter from 21 days before the expected date of parturition until parturition. The cows in the non-anion group were given only the same Ca, Mg and ip supplement but no sulfate and chloride salts as that in the anion group. The cows in the control and heifer groups were not given any additional supplement. The incidence of hypocalcemia in the anion group decreased to approximately half of those in the non-anion and control groups, while the heifer group did not develop hypocalcemia at all. In addition, the number of days spent for the treatment of hypocalcemia and the number of drug bottles (calcium borogluconate solution) used for the treatment decreased to less than half in the anion group compared with those in the non-anion and control groups. At parturition, the serum Ca concentration in the control (6.2 +/- 1.9 mg/dl, mean +/- standard deviation) and non-anion groups (6.4 +/- 1.7 mg/dl) were significantly lower than that in the heifer group (8.3 +/- 0.4 mg/dl), and the level in the anion group was intermediate (7.3 +/- 1.3 mg/dl). The change in ionized Ca concentration was almost the same as that in serum Ca concentration, but only the concentration in the anion group tended to increase slightly from a week before parturition and was significantly higher than that in all other groups three days before parturition. Urinary pH in the anion group was maintained at a mildly acidic level (6.8-7.0) for the last two weeks before parturition, compared with those in the control (7.3-7.5) and non-anion groups (7.9-8.1), and similar to that in the heifer group (6.3-7.3). The urinary Ca excretion was the highest in the anion group among all groups during the prepartum period. There were no specific changes in the excretion of parathyroid hormone and 1,25-dihydroxyvitamin D in all groups of multiparous cows while the levels of these hormones remained low in the heifer group throughout the experimental period. The data in the present study indicates that the administration of anion salts that slightly lowered DCAD in the preparum period was effective for preventing milk fever in multiparous cows. Safe and mild metabolic acidosis induced by the anion salts could be evaluated by urinary pH (6.8-7.0), and might increase the responsiveness to Ca requirement at parturition through some complex mechanisms unrelated to the excretion of Ca-related hormones. In addition, it was clarified that primiparous cows have a high potential to respond to sudden Ca demand unrelated to hormone excretion, and their Ca metabolism was in some respects similar to that in multiparous cows fed anion salts. Therefore, manipulating mildly DCAD is expected to be an effective, safe and natural method for preventing milk fever in dairy cows.

[Treatment of parturient paresis with high-dose calcium]. / Behandlung der Gebärparese mit hochdosiertem Kalzium.

The goal of the present study was to evaluate a calcium dose that was higher than the conventional dose for treatment of parturient paresis in cows. Thirty cows with parturient paresis received 1000 ml of 40 per cent calcium borogluconate solution supplemented with 6 per cent magnesium hypophosphite. Cows in group A received 200 ml of the solution intravenously over a 10-minute period, and the remaining 800 ml via a slow intravenous drip over a six-hour period. Cows in group B received 500 ml of the solution intravenously over a 20-minute period, and the remaining 500 ml via a slow intravenous drip over a six-hour period. Afterwards, the cows were monitored continuously and examined every hour for eight hours. Samples of blood were collected from all the cows before treatment and at 10, 20, 40, 60, 90, 120, 180, 240, 300, 360, 420 and 480 minutes and 24, 48 and 72 hours after treatment. The concentrations of total calcium, ionised calcium, inorganic phosphorus and magnesium were determined. Cows that did not stand within 12 hours of treatment received one or more additional treatments. There was no significant difference in the recovery rate between the two groups. Of the 30 cows, 14 (47 per cent) rised after one treatment and 15 others (50 per cent) were cured after two or more treatments. One cow did not respond to repeated treatments and was euthanased four days after the start of treatment. The results of electrolyte analyses before treatment did not differ significantly between the two groups. In 27 (90 per cent) cows, the concentrations of calcium and inorganic phosphorus were lower than normal and in 3 (10 per cent) cows, only the concentration of inorganic phosphorus was lower than normal. The concentration of total calcium increased markedly ten minutes after the start of treatment in both groups, and at eight hours, the mean concentration of calcium was within the normal range. At 24 and 48 hours, the mean concentration of calcium was below normal, but at 72 hours it was again within the normal range. The concentration of inorganic phosphorus increased slowly in both groups, although it was not within the normal range at eight hours. In both groups, it achieved normal values at 24, 48 and 72 hours. The mean electrolyte concentrations did not differ significantly at any measuring point between cows that stood within eight hours of treatment and those that did not. Our results indicate that increasing the dose of calcium administered does not improve the recovery rate of cows with parturient paresis.