Subclinical Hypocalcemia Research Articles

Evaluation of the respective relationships between rumination time within the first 10 days in milk and periparturient diseases, subclinical hypocalcemia, negative energy balance, and milk production in dairy cows

Healthy dairy cows ruminate approximately 400 to 500 minutes per day; however, rumination time can be affected by several factors such as diet composition, health status, environment, and stress. Increased rumination time can be associated with increased health because of increased saliva production, whereas decreased rumination time has been associated with negative health effects. Historically, evaluating rumination time was laborious and limited to a few animals at a time; however, adoption of new technology like rumination collars has allowed increased data collection and monitoring of rumination time at both the individual and herd level. The effect of rumination time early in the postpartum period, based on rumination collar data, on milk production has not been thoroughly evaluated. The objectives of this pilot study were to evaluate the maximum number minutes per day spent ruminating during the first 10 days-in-milk (DIM) for cows that developed displaced abomasum (DA), clinical ketosis (CK), subclinical hypocalcemia, or excessive negative energy balance, and to evaluate the association between rumination minutes and total milk production during the first 30 DIM after controlling for potential confounders.

Effect of induced subclinical hypocalcemia (SCH) on dry matter intake, energy status, and immune-cell function in dairy cows

Objectives were to create a model to induce subclinical hypocalcemia (SCH) (blood ionized calcium [Ca2+] < 1.0 mM), and to study the effects of induced SCH on clinical parameters and function of innate and adaptive immune cells in dairy cows.

Effects of postpartum calcium treatment on blood calcium concentration

To prevent the negative consequences of subclinical hypocalcemia, it is common practice to treat postparturient high-risk dairy cows with supplemental calcium prophylactically either by oral or IV administration; however, the effect of prophylactic calcium administration on blood calcium concentration has not been evaluated. The objective of this study was to evaluate the effects of prophylactic postpartum calcium treatments (IV and oral bolus) on postpartum blood calcium concentration.

Subclinical hypocalcemia, plasma biochemical parameters, lipid metabolism, postpartum disease, and fertility in postparturient dairy cows

A study was conducted to evaluate the potential association between Ca status at calving and postpartum energy balance, liver lipid infiltration, disease occurrence, milk yield and quality parameters, and fertility in Holstein cows. One hundred cows were assigned to 1 of 2 groups based on whole-blood ionized Ca concentration ([iCa]) on the day of calving [d 0; hypocalcemic [iCa] <1.0mmol/L (n=51); normocalcemic [iCa] ≥1.0mmol/L (n=49)]. Cows were blocked based on calving date and parity. Blood samples were collected approximately 14d from expected calving date (d −14), the day of calving (d 0), and on d 3, 7, 14, 21, and 35 postpartum for measurement of plasma nonesterified fatty acid, iCa, total Ca, glucose, and total and direct bilirubin concentrations, and plasma aspartate aminotransferase and gamma glutamyl transferase activities. Liver biopsies were obtained from a subset of cows on d 0, 7, and 35 for quantification of lipid content. Milk samples were collected on d 3, 7, 14, 21, and 35 postpartum for measurement of somatic cell count and percentages of protein, fat, and solids-not-fat. Data for peak test-day milk yield, services per conception, and days open were obtained from Dairy Herd Improvement Association herd records. Disease occurrence was determined based on herd treatment records. Hypocalcemic cows had significantly higher nonesterified fatty acids on d 0. Hypocalcemic cows also had significantly more lipid in hepatocytes on d 7 and 35 postpartum. However, no statistically significant differences were observed between groups for plasma aspartate aminotransferase and gamma glutamyl transferase activities or total and direct bilirubin concentrations. Milk protein percentage was lower in hypocalcemic cows on d 21 and 35. However other milk quality variables (somatic cell count, milk fat percentage, and solids-not-fat) and milk yield variables (peak test-day milk yield and 305-d mature-equivalent 4% fat-corrected milk yield) did not differ between groups. No differences were observed between groups in the occurrence of clinical mastitis, ketosis, displaced abomasum, dystocia, retained placenta, metritis, or fertility measures (percentage cycling at 50–60d postpartum, services per conception, or days open). These data suggest that early lactation fatty acid metabolism differs between cows with subclinical hypocalcemia and their normocalcemic counterparts.

EFFECT OF CALCIUM AND CHOLECALCIFEROL SUPPLEMENTATION ON SEVERAL PARAMETERS OF CALCIUM STATUS IN PLASMA AND URINE OF CAPTIVE ASIAN (ELEPHAS MAXIMUS) AND AFRICAN ELEPHANTS (LOXODONTA AFRICANA)

The aim of the current study was to assess the effect of oral calcium and cholecalciferol supplementation on several parameters of calcium status in plasma and urine of captive Asian (Elephas maximus; n=10) and African elephants (Loxodonta africana; n=6) and to detect potential species differences. Calcium and cholecalciferol supplementation were investigated in a feeding trial using a crossover design consisting of five periods of 28 days each in summer. From days 28-56 (period 2), elephants were fed the Ca-supplemented diet and from days 84-112, elephants were fed the cholecalciferol-supplemented diet (period 4). The control diet was fed during the other periods and was based on their regular ration, and the study was repeated similarly during winter. Periods 1, 3, and 5 were regarded as washout periods. This study revealed species-specific differences with reference to calcium and cholecalciferol supplementation. Asian elephants showed a significant increase in mean plasma total calcium concentration following calcium supplementation during summer, suggesting summer-associated subclinical hypocalcemia in Western Europe. During winter, no effect was seen after oral calcium supplementation, but a significant increase was seen both in mean plasma, total, and ionized calcium concentrations after cholecalciferol supplementation in Asian elephants. In contrast, evidence of subclinical hypocalcemia could be demonstrated neither in summer nor in winter in African elephants, although 28 days of cholecalciferol supplementation during winter reversed the decrease in plasma 1,25(OH)2-cholecalciferol and was followed by a significant increase in mean plasma total calcium concentration. Preliminary findings indicate that the advisable permanent daily intake for calcium in Asian elephants and cholecalciferol in both elephant species at least during winter might be higher than current guidelines. It is strongly recommended to monitor blood calcium concentrations and, if available, blood parathyroid hormone levels to adjust the nutritional supplementation for each individual elephant.

Prevalence of periparturient diseases and effects on fertility of seasonally calving grazing dairy cows supplemented with concentrates

The objectives were to characterize the prevalence of periparturient diseases and their effects on reproductive performance of dairy cows in seasonal grazing farms. A total of 957 multiparous cows in 2 farms (555 in farm A and 402 in farm B) were evaluated and diseases characterized. At calving, dystocia, twin birth, stillbirth, and retained fetal membranes were recorded and grouped as calving problems. On d 7±3 and 14±3 postpartum, cows were evaluated for metritis and on d 28±3 for clinical endometritis based on scoring of the vaginal discharge. From parturition to 30d after artificial insemination (AI), prevalence of mastitis, lameness, and digestive and respiratory problems were recorded. For subclinical diseases, diagnosis was based on blood samples collected from 771 cows and analyzed for concentrations of Ca, nonesterified fatty acids (NEFA), and β-hydroxybutyrate. Cows were considered as having elevated NEFA concentration if the concentration was ≥0.70mM, subclinical ketosis if the β-hydroxybutyrate concentration was ≥0.96mM, and subclinical hypocalcemia if the Ca concentration was ≤2.14mM. Ovaries were scanned on d 35±3 and 49±3 postpartum for determination of estrous cyclicity. All cows were enrolled in a timed AI program and inseminated on the first day of the breeding season: on average, 86d postpartum. Overall, 37.5% (359/957) of the cows presented at least 1 clinical disease and 59.0% (455/771) had at least 1 subclinical health problem. Prevalence of individual diseases was 8.5% for calving problems, 5.3% for metritis, 15.0% for clinical endometritis, 13.4% for subclinical endometritis, 15.3% for mastitis, 2.5% for respiratory problems, 4.0% for digestive problems, 3.2% for lameness, 20.0% for elevated NEFA concentration, 35.4% for subclinical ketosis, and 43.3% for subclinical hypocalcemia. Clinical and subclinical diseases had additive negative effects on reproduction, delaying resumption of estrous cyclicity and reducing pregnancy per AI (P/AI). Occurrence of multiple diseases further reduced reproductive efficiency compared with a single disease. Individually, subclinical hypocalcemia, elevated NEFA concentration, metritis, and respiratory and digestive problems reduced estrous cyclicity by d 49 postpartum. Elevated NEFA concentration, calving problem, metritis, clinical and subclinical endometritis, and digestive problems reduced P/AI on d 65 after AI. Moreover, calving problems and clinical endometritis increased the risk of pregnancy loss between gestation d 30 and 65. Serum concentrations of Ca and NEFA were negatively correlated, and both were associated with prevalence of uterine diseases. In conclusion, periparturient diseases were highly prevalent in seasonally calving grazing dairies and affected cows had delayed resumption of estrous cyclicity, reduced P/AI, and increased risk of pregnancy loss.

Feeding 5-hydroxy-l-tryptophan during the transition from pregnancy to lactation increases calcium mobilization from bone in rats

An increasing demand for calcium during pregnancy and lactation can result in both clinical and subclinical hypocalcemia during the early lactation period in several mammalian species, in particular the dairy cow. Serotonin (5-HT) was recently identified as a regulator of lactation and bone turnover. The purpose of this study was to determine whether supplementation of the maternal diet with a 5-HT precursor would increase maternal bone turnover and calcium mobilization to maintain appropriate circulating maternal concentrations of ionized calcium during lactation. Female Sprague-Dawley rats (n = 30) were fed either a control diet (n = 15) or a diet supplemented with the 5-HT precursor 5-hydroxytryptophan (5-HTP, 0.2%; n = 15) from day 13 of pregnancy through day 9 of lactation. Maternal serum and plasma (day 1 and day 9 of lactation), milk and pup weight (daily), mammary gland and bone tissue (day 9 of lactation) were collected for analysis. The 5-HTP diet elevated circulating maternal concentrations of 5-HT on day 1 and day 9 of lactation and parathyroid hormone related-protein (PTHrP) on day 9 of lactation (P < 0.033). In addition, 5-HTP supplementation increased total serum calcium concentrations on day 1 of lactation and total milk calcium concentration on day 9 of lactation (P < 0.032). Supplemental 5-HTP did not alter milk yield, maternal body weight, mammary gland structure, or pup litter weights (P > 0.05). Supplemental 5-HTP also resulted in increased concentrations of mammary 5-HT and PTHrP, as well as increased mRNA expression of rate-limiting enzyme in 5-HT synthesis, tryptophan hydroxylase 1, and Pthrp mRNA on day 9 of lactation (P < 0.028). In addition, supplementation of 5-HTP resulted in increased mRNA expression of maternal mammary calcium transporters and resorption of bone in the femur, indicated by increase osteoclast number and diameter as well as mRNA expression of classical markers of bone resorption on day 9 of lactation (P < 0.048). These results show that increasing 5-HT biosynthesis during the transition from pregnancy to lactation could be a potential therapeutic target to explore for prevention of subclinical and clinical hypocalcemia.

Evaluation of peripartal calcium status, energetic profile, and neutrophil function in dairy cows at low or high risk of developing uterine disease

In this prospective cohort study, Holstein cows considered to be at high risk of developing metritis (dystocia, twins, stillbirth, retained placenta, or their combination) were matched with herdmates at low risk of developing metritis (normal calving) and monitored daily for rectal temperature and uterine discharge during the first 12 d in milk (DIM). Blood was sampled on d 0, 1, and 3 postpartum for assessment of neutrophil phagocytic and oxidative burst activities. Blood was also sampled at 0, 1, 2, 3, 4, 7, and 12 DIM for determination of serum concentrations of Ca, K, Mg, nonesterified fatty acids, β-hydroxybutyrate, and glucose. On the basis of receiver operator characteristic curves, subclinical hypocalcemia (SCH) was defined as a serum Ca concentration ≤8.59mg/dL in at least 1 sample in the first 3 DIM. The overall incidences of metritis and puerperal metritis were 47.3 and 30%, respectively. Concentration in blood and percentages of neutrophils undergoing phagocytosis and oxidative burst were all reduced in cows with SCH compared with normocalcemic cows. Cows with SCH were at a greater risk of developing fever, metritis, and puerperal metritis compared with normocalcemic cows. Among cows at low risk of developing metritis, those with SCH had a greater incidence of metritis (40.7%) compared with normocalcemic cows (14.3%). Similarly, among cows at high risk of developing metritis, cows with SCH had a greater incidence of metritis (77.8%) compared with normocalcemic cows (20.0%). Cows with SCH had elevated concentrations of nonesterified fatty acids and β-hydroxybutyrate compared with normocalcemic cows. The relative risk of developing metritis decreased by 22% for every 1mg/dL increase in serum Ca. Neither metritis nor SCH influenced the resumption of estrous cyclicity by 38 DIM, but cows with SCH had a reduced pregnancy rate and a longer interval to pregnancy compared with normocalcemic cows. Finally, the population risk to develop uterine diseases attributable to SCH was 66.6% for metritis and 91.3% for puerperal metritis in the present study.

Effect of prostaglandin administration during the first hours after calving on blood calcium concentration in multiparous dairy cows

Subclinical hypocalcemia is a common metabolic disorder of dairy cows after parturition. The administration of prostaglandin (PGF2a) results in improvement of uterine health in some experiments, which may be explained by the effect of PGF2a on calcium and vitamin D metabolism.

Associations of subclinical hypocalcemia at calving with milk yield, and feeding, drinking, and standing behaviors around parturition in Holstein cows

The objectives of this study were to describe the associations of subclinical hypocalcemia with milk yield, and feeding, drinking, and resting behavior during the period around calving. Blood was sampled within 24h of calving and analyzed for serum total calcium. Fifteen Holstein dairy cows were classified as having subclinical hypocalcemia (serum calcium concentration ≤1.8mmol/L, without clinical milk fever) and were matched with 15 control cows (serum calcium concentration >1.8mmol/L) based on parity and presence of other diseases. Daily feeding and drinking behavior were monitored using an electronic feeding system (Insentec, BV, Marknesse, the Netherlands) and summarized by week relative to calving (wk −3, −2, −1, +1, +2, and +3). Standing behavior was monitored from 7 d before until 7 d after calving using dataloggers. Daily milk yields were obtained for all cows up to 280 d in milk (DIM). These data were summarized by week for the first 4 wk of lactation to assess short-term differences in milk yield, and were summarized into 4-wk periods to assess long-term (280 DIM) differences in milk yield between groups. Cows with subclinical hypocalcemia produced, on average, 5.7kg/d more milk during wk 2, 3, and 4 compared with control cows; however, only subclinically hypocalcemic cows in their third lactation sustained greater milk yields throughout 280 DIM. Despite greater milk yield during the weeks following calving, cows with subclinical hypocalcemia did not consume more water after calving and tended to have greater dry matter intake only during wk 2. However, these animals made fewer visits to the water bins during the first 2 wk after calving and tended to make fewer visits to the feed bins during wk 1 and 3, suggesting that they used these resources more efficiently. Dry matter intake was, on average, 1.7kg/d greater during wk −2 and −1 among cows subsequently diagnosed with subclinical hypocalcemia compared with control cows but neither group was lactating during this period. Cows with subclinical hypocalcemia stood for 2.6h longer during the 24-h period before parturition, which may suggest these animals experience increased discomfort at calving; these cows spent 2.7h less time standing during d +1. Although milk yield was greater among cows with subclinical hypocalcemia, this study controlled for the confounding effects of disease incidence; these results do not refute previous research that associates subclinical hypocalcemia with an increased risk for health disorders. The mechanisms by which subclinical hypocalcemia is associated with behavior and production require further investigation.

Death of a clinical sign

lettersDeath of a clinical sign Pankaj Kumar Garg Pankaj Kumar Garg Search for more papers by this author Published Online:1 Feb 2012https://doi.org/10.5144/0256-4947.2012.97aSectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionTo the Editor: Nothing is infallible in life. This fact further hammered itself in my mind when I recently took a ward round. There was a patient in the ward who had undergone total thyroidectomy with modified neck dissection for papillary carcinoma thyroid with cervical lymphadenopathy. A resident told me that the patient had not reported any symptom suggestive of hypocalcaemia and serum ionized calcium was normal. I asked if any of the residents had performed the Trousseau sign to look for subclinical hypocalcaemia. To my surprise, they replied that this sign could no longer be elicited as the mercury sphygmomanometer had been replaced with an electronic sphygmomanometer. It suddenly reminded me of the government drive to phase out mercury-based instruments. There has been a growing voice for mercury-free society and the World Health Organization issued a policy paper in 2005 calling for short-, medium-, and long-term measures to substitute mercury-based medical devices with safer alternatives.1 So what about the Trousseau sign as it requires a few minutes of sustained inflation of a sphygmomanometer cuff above systolic blood pressure to cause a carpopedal spasm, as a feature of the increased excitability of the nerves in the arm and forearm, ostensibly caused by hypocalcemia.2 I thought an aneroid sphygmomanometer would be there to demonstrate the Trousseau sign. However, the electronic sphygmomanometer has not left a role for the aneroid sphygmomanometer in wards in view of its simplicity, accuracy and trendy looks. An electronic sphygmomanometer is based on automatic inflation and deflation of the cuff, so cannot be used to demonstrate the Trousseau sign. It seems a simple and invaluable clinical sign will now be restricted to the books and will no longer be a part of clinical practice.ARTICLE REFERENCES:1. Singh R, Rustagi N. "A mercury free health care organization: A must" . Indian J Public Health. 2011; 55:52-3. Google Scholar2. Meininger ME, Kendler JS. "Images in clinical medicine. Trousseau’s sign" . N Engl J Med. 2000; 343:1855. Google Scholar Previous article Next article FiguresReferencesRelatedDetails Volume 32, Issue 1January-February 2012 Metrics History Published online1 February 2012 InformationCopyright © 2012, Annals of Saudi MedicineThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.PDF download

Evaluation of Peripartal Calcium Status and Neutrophil Function of Dairy Cows of Low or High Risk of Developing Uterine Diseases

Objectives were to establish the relationships among postpartum serum calcium (Ca) status, neutrophil function, and incidence of uterine diseases in dairy cows considered to be of low (LRM) or high risk (HRM) of developing metritis. Our hypothesis was that subclinical hypocalcemia (SCH) impairs in vitro neutrophil function and increases the incidence of metritis in early lactation in both LRM and HRM cows.

Fluctuation of Corrected Serum Calcium Levels Following Partial and Total Thyroidectomy

Objectives: To identify any fluctuation of corrected serum calcium levels and to determine the presence of sub-clinical hypocalcaemia following partial and total thyroidectomy with preservation of at least two parathyroid glands. Design: A prospective study. Setting: Tertiary Head & Neck referral unit. Patients: Eighty five patients undergoing partial or total thyroidectomy with or without laryngectomy from April 2003 to April 2009 were included in the study. Corrected serum calcium levels (CCSL) were noted preoperatively and postoperatively on day 1, day 7 and 6 months. Results: Forty six patients underwent hemi-thyroidectomy (HT), 29 underwent total thyroidectomy (TT) and 10 underwent total thyroidectomy with laryngectomy (TTL). Nine (19.56%) patients in the HT group, 6 (24.14%) in the TT group and 3 (30.0%) in the TTL group developed hypocalcaemia postoperatively which was most significant on 1st postoperative day. This improved by 7th postoperative day in each group when the change in calcium levels became statistically insignificant. Six patients (3 patients had HT, 2 had TT and 1 had TTL) developed sub-clinical mild hypocalcaemia which was persistent at 6 months follow-up. Conclusion: The most significant changes in corrected serum calcium levels occur within first 24 hours after thyroid surgery. Thereafter most patients return to normocalcaemia within a seven-day period. Despite preservation of parathyroid glands there is a subgroup of patients who develop sub-clinical hypocalcaemia which persists even at six months but does not require treatment.

Prevalence of subclinical hypocalcemia in dairy herds

The prevalence of subclinical hypocalcemia in the transition cow is unknown. Cows with subclinical hypocalcemia have no clinical signs of hypocalcemia but may be more susceptible to other diseases. The objective of this study was to determine the prevalence of subclinical hypocalcemia in the US dairy herds. As a part of the United States Department of Agriculture's National Animal Health Monitoring System 2002 Dairy study, serum samples were collected from 1462 cows within 48 h of parturition. The samples were sorted by lactation number: 1st (n=454), 2nd (n=447), 3rd (n=291), 4th (n=166), 5th (n=72), and 6th (n=32). Subclinical hypocalcemia (<2.0 mM) increased with age and was present in 25%, 41%, 49%, 51%, 54%, and 42% of 1st-6th lactation cows, respectively. Cows with serum calcium concentrations >2.0 mM had significantly lower serum non-esterified fatty acids indicating better energy balance than those with subclinical hypocalcemia. Subclinical hypocalcemia may make cows more susceptible to secondary diseases but more research will be required to determine if this is true.

Blood plasma mineral profile and health status in postpartum cows fed an anionic diet before parturition

The effects of an anionic versus cationic (control) diet on plasma mineral levels and health status were investigated in 24 dry pregnant Holstein-Friesian cows during the last 3 weeks of pregnancy. The cows were in their third or fourth parity, had a moderate level of milk production in their previous lactation, and did not have a history of milk fever. The anionic diet significantly improved plasma calcium status, as compared to the control (2.18 vs. 1.99 mmol L^{-1}) and nonsignificantly reduced the incidence of subclinical hypocalcemia (1/12 vs. 5/12) without affecting other periparturient diseases. Other plasma mineral levels were unaffected, except chloride, which was higher in the anionic group. The results show that an anionic diet could improve calcium status around the time of parturition and reduce the incidence of subclinical hypocalcemia when fed to moderate producing dairy cows not predisposed to milk fever.

Effects of anion supplementation to low-potassium prepartum diets on macromineral status and performance of periparturient dairy cows

Data from multiparous Holstein cows (n=43) were used to determine whether supplementation of anions to low-potassium (K) prepartum diets would improve periparturient energy and macromineral status and affect performance during the postpartum period. Beginning 21 d before expected parturition, cows were fed a control diet (1.29% K; +10mEq/100g; n=21) or a low dietary cation-anion difference (DCAD) diet (1.29% K; −15mEq/100g; n=22) with anions provided through a combination of sulfate from calcium sulfate dihydrate (0.40% S total ration) and chloride (1.17% Cl total ration) from SoyChlor 16–7 (West Central, Ralston, IA). All cows were fed the same postpartum diet from parturition through 63 d postpartum. Feeding anions decreased overall urine pH (8.17 vs. 6.70) during the prepartum period. Overall, peripartum concentrations of plasma Ca, P, and Mg were similar between treatments; however, concentrations of plasma Ca tended to be increased during the first 24h postcalving in cows fed the low DCAD diet. Overall, concentrations of plasma P tended to be increased by feeding the anionic diet prepartum; this effect was more pronounced during the immediate peripartal period. Anionic supplementation did not affect incidence of clinical (<5mg/dL) and subclinical (5 to 8mg/dL) hypocalcemia, clinical hypophosphatemia (<2mg/dL), or clinical (<1.1mg/dL) and subclinical (1.1 to 1.8mg/dL) hypomagnesemia. Nevertheless, subclinical hypophosphatemia (2 to 4mg/dL) tended to be decreased at 16h postcalving and was decreased at d 2 postpartum for cows fed the anionic diet prepartum. Anion supplementation decreased prepartum dry matter intake (15.6 vs. 14.4kg/d), but did not affect postpartum dry matter intake (22.4 vs. 23.0kg/d), milk yield (46.5 vs. 46.1kg/d), or content and yield of milk fat and true protein. Plasma concentrations of energy-related metabolites (glucose, nonesterified fatty acids, β-hydroxybutyrate) were similar for both groups during the prepartum and postpartum periods. Glucose rate of appearance was determined by continuous infusion of 6,6-dideuterated glucose in a subset of cows between 6 and 10 d prepartum (control, n=12; low DCAD, n=9) and 7 and 10 d postpartum (control, n=9; low DCAD, n=8) periods. Glucose rate of appearance was not affected by treatment during the prepartum or postpartum periods. Overall, anion supplementation of low K diets improved P status during the early postpartum period, but did not affect aspects of energy metabolism or periparturient performance.

Effect of several doses of zeolite A on feed intake, energy metabolism and on mineral metabolism in dairy cows around calving

The object of the present study was to determine the influence of different zeolite A doses on dry matter intake (DMI) and mineral metabolism, and to evaluate an optimum dosage for preventing hypocalcaemia. Eighty pregnant dry cows were assigned to four groups (I-IV). They were fed a total mixed ration (TMR) ad libitum. Groups II, III and IV received an average daily dose of 12, 23 and 43 g zeolite A/kg DM for the last 2 weeks prepartum. Individually DMI was recorded daily. Blood and urine samples were taken before, during and after zeolite A supplementation. Serum was analysed for Ca, Mg, P(i), K, non-esterified fatty acids and beta-hydroxybutyrate (BHB). Urine was analysed for Ca, Mg, P(i), K and net acid-base excretion (NABE). After calving, milk yield (fat corrected milk) and milk composition were determined. During zeolite A supplementation, mean DMI of Group IV (7.3 +/- 1.3 kg/cow/day) was significantly lower compared to Groups I-III (10.1, 10.9, 9.5 kg/cow/day). The reduced feed intake of Group IV resulted in significantly increased BHB as well as decreased NABE after calving. Zeolite A supplementation in higher doses (III and IV) had a stabilizing effect on Ca metabolism around calving for older cows, whereas cows in Groups I and II showed a subclinical hypocalcaemia. The mean serum Mg concentration decreased significantly in older cows in Group IV at calving. The mean P(i) concentration in cows of Group IV decreased into ranges of hypophosphataemia already 1 week after beginning of zeolite A feeding. The mean DMI postpartum as well as the milk yield was not affected by zeolite A supplementation. Feeding of 23 g zeolite A/kg DM TMR prepartum proved to be an adequate dosage for reducing subclinical hypocalcaemia frequency without significant effects on feed intake and P(i) concentration in serum.

Effect of Oral Calcium Propionate on Blood Calcium and Energy Metabolite Concentrations in Dairy Cows with Dystocia Fed a Prepartum Anionic Diet

Results from research on the calcium and energy status of cows affected with dystocia have not been conclusive. We hypothesize that during early post-partum (pp), similar to cows with retained placenta and uterine prolapse, cows with dystocia develop subclinical hypocalcemia, as well as ketosis. Therefore, the objectives of this study were : (1) to describe the total blood calcium (tCa), betahydroxybutyrate (BOHB) and non-esterified free fatty acid (NEFA) concentrations in blood during the first 12 days pp in dairy cows with dystocia, 2) to determine if an oral calcium propionate drench at calving and 72 hours later improves blood calcium concentration and energy status.

Incidencia de enfermedades metabólicas en vacas lecheras en Puerto Rico y su relación con el comportamiento productivo y reproductivo

Se obtuvieron datos de 89 vacas de la raza Holstein, distribuidas en siete hatos comerciales, para evaluar la incidencia de enfermedades metabólicas durante el periodo de transición parturienta. Los hatos estaban acogidos al Programa de Mejoramiento de Hatos Lecheros (DHIP, por sus siglas en inglés) y eran visitados rutinariamente por veterinarios que diagnosticaban cualquier desorden metabólico. Se observaron las vacas cada dos semanas para evaluar la condición corporal, recopilar el diagnóstico de enfermedades y obtener muestras de sangre para análisis químico. Aunque no se observaron enfermedades metabólicas clínicas, 34% de las vacas reflejaron hipocalcemia subclínica (valores promedio de calcio menor que 7.9 mg/dl) y 14% presentaron valores promedio de glucosa sanguínea menor que 39.9 mg/dl. Aunque no alcanzó significancia (P mayor que 0.05), la producción de leche diaria promedio en el 2d° y 3er pesaje fue mayor en las vacas normales que en las que mostraron hipocalcemia subclínica (27.5 y 25.6 vs. 25.1 y 23.6 kg, respectivamente). El intervalo entre el parto y el primer servicio fue menor (P menor que 0.05) para las vacas sin hipocalcemia subclínica en comparación con aquellas con la condición (74 vs. 91 días). La condición corporal promedio de las vacas sin hipocalcemia subclínica y de aquellas sin niveles sub-normales de glucosa sanguínea fue mayor que la de las vacas con estas condiciones (2.5 vs. 2.3, P menor que 0.05). Se concluye que la concentración de calcio en la sangre después del parto influye en el intervalo parto-primer servicio de las vacas y que la concentración de calcio en la sangre de las vacas antes del parto permite estimar la probabilidad de ocurrencia de hipocalcemia después del parto.

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.