Search

Background: Milk fever (MF), a metabolic disorder in dairy cows characterized by low blood calcium concentrations postpartum, is well‐recognized clinically. However, comprehensive data on the alteration of metabolites associated with this condition remains sparse. Hypothesis: Delineate serum metabolite profiles and metabolic pathways preceding, coinciding with, and after the onset of MF. Animals: Twenty‐six cows, including 20 healthy cows and 6 cows initially affected by MF. Because of culling, the number of MF‐affected cows decreased to 4 at MF week, +4 weeks, and +8 weeks postpartum. Methods: A nested case‐control longitudinal study was conducted, with blood samples collected at −8 and −4 weeks prepartum, MF week, and +4 and +8 weeks postpartum. Serum analysis utilized direct injection/liquid chromatography/tandem mass spectrometry (DI/LC/MS/MS) techniques. Results: Key findings included the identification of diverse metabolites such as hexose, amino acids, phosphatidylcholines, lysophosphatidylcholines, and sphingomyelin, which varied between studied groups (P <.05). The most marked metabolic alterations were observed 4 weeks prepartum. In total, 42, 56, 38, 29, and 24 metabolites distinguished the MF group at the respective time points (P <.05). Additionally, 33 metabolic pathways, including amino acid, antioxidant metabolism, fatty acid degradation, and carbohydrate processing, were impacted (P <.05). Conclusions and Clinical Importance: Metabolic disruptions in dairy cows begin several weeks before the clinical manifestation of MF and persist up to 8 weeks postpartum. These findings emphasize the complexity of MF, extending beyond only hypocalcemia and indicate the necessity for preemptive monitoring in dairy herd management. [ABSTRACT FROM AUTHOR]

Abstract Background Milk fever (MF), a metabolic disorder in dairy cows characterized by low blood calcium concentrations postpartum, is well‐recognized clinically. However, comprehensive data on the alteration of metabolites associated with this condition remains sparse. Hypothesis Delineate serum metabolite profiles and metabolic pathways preceding, coinciding with, and after the onset of MF. Animals Twenty‐six cows, including 20 healthy cows and 6 cows initially affected by MF. Because of culling, the number of MF‐affected cows decreased to 4 at MF week, +4 weeks, and +8 weeks postpartum. Methods A nested case‐control longitudinal study was conducted, with blood samples collected at −8 and −4 weeks prepartum, MF week, and +4 and +8 weeks postpartum. Serum analysis utilized direct injection/liquid chromatography/tandem mass spectrometry (DI/LC/MS/MS) techniques. Results Key findings included the identification of diverse metabolites such as hexose, amino acids, phosphatidylcholines, lysophosphatidylcholines, and sphingomyelin, which varied between studied groups (P

This preliminary study explored potential serum biomarkers for predicting the onset of milk fever (MF), a bovine parturient disease with hypocalcemia. We conducted two-dimensional gas chromatography mass spectrometry-based metabolomics in 8 and 17 pregnant Holstein cows that did and did not develop MF 3 weeks later, respectively. In principal component analysis (PCA) applied to a dataset containing 1,498 metabolites, serum metabolites exhibited highly similar chemical profiles between cows with and without MF. PCA with a limited dataset of metabolites containing fatty acids, which had significantly different values between the groups and/or correlation coefficients of >0.5 for the serum calcium concentration, distinguished the two groups. These suggest the possibility of developing serum biomarkers for predicting bovine MF. [ABSTRACT FROM AUTHOR]

Abstract Background High concentrations of NEFA relative to a defined reference or ‘cut‐point’ values before calving can predict the risk of specific or collective periparturient disease events. Objectives A field‐based cohort study was conducted to evaluate the value and critical points of serum nonesterified fatty acids (NEFA) at the precalving time to predict the occurrence of postpartum diseases and reproductive performance in dairy cows. Methods Blood samples were taken from 521 high‐yielding dairy cows at 1 week (±3 days) before calving and NEFA levels were measured. Health and reproduction information of each cow includes dystocia, retained placenta, milk fever, metritis, mastitis, pregnancy in the first insemination and pregnancy in the first two inseminations, and culling in the first 60 days of lactation and milk production. Results Our results show that there are significant relationships between precalving NEFA with the probability of pregnancy at the first and the first two inseminations after calving. The cows that had NEFA concentrations less than 0.5 mmol/L at the last week of pregnancy were 3.51 and 3.15 times more likely to be pregnant at first insemination and the first two inseminations, respectively. Also, our results showed that there are significant relationships between precalving NEFA concentration and the likelihood of dystocia and milk fever. The probability of dystocia and milk fever occurrence were 2.56 and 1.91 times greater in those cows that had NEFA concentrations more than 0.3 mmol/L, respectively. Conclusions The present results indicated that Increasing NEFA during the prepartum period could adversely affect the reproductive efficiency of dairy cows.

Background: High concentrations of NEFA relative to a defined reference or 'cut‐point' values before calving can predict the risk of specific or collective periparturient disease events. Objectives: A field‐based cohort study was conducted to evaluate the value and critical points of serum nonesterified fatty acids (NEFA) at the precalving time to predict the occurrence of postpartum diseases and reproductive performance in dairy cows. Methods: Blood samples were taken from 521 high‐yielding dairy cows at 1 week (±3 days) before calving and NEFA levels were measured. Health and reproduction information of each cow includes dystocia, retained placenta, milk fever, metritis, mastitis, pregnancy in the first insemination and pregnancy in the first two inseminations, and culling in the first 60 days of lactation and milk production. Results: Our results show that there are significant relationships between precalving NEFA with the probability of pregnancy at the first and the first two inseminations after calving. The cows that had NEFA concentrations less than 0.5 mmol/L at the last week of pregnancy were 3.51 and 3.15 times more likely to be pregnant at first insemination and the first two inseminations, respectively. Also, our results showed that there are significant relationships between precalving NEFA concentration and the likelihood of dystocia and milk fever. The probability of dystocia and milk fever occurrence were 2.56 and 1.91 times greater in those cows that had NEFA concentrations more than 0.3 mmol/L, respectively. Conclusions: The present results indicated that Increasing NEFA during the prepartum period could adversely affect the reproductive efficiency of dairy cows. [ABSTRACT FROM AUTHOR]

Production diseases arise from management practices, leading to metabolic imbalances in high-yielding dairy cows. Milk fever, or parturient paresis, is a significant production ailment occurring during the periparturient phase. The heightened milk production during this period places an increased demand on calcium, often resulting in milk fever (hypocalcemia) characterized by abnormally low blood calcium levels. Clinical manifestations of milk fever include reduced appetite, tetanus, low body temperature, paresis, lateral recumbency, and, if untreated, progression to coma and death. Although sporadic, the incidence of milk fever can be high among susceptible cows on individual farms, particularly those with high milk production. Various factors contribute to increased milk fever incidence, including parturition, lactation initiation, advanced age, breed, and diet. Intravenous treatment with calcium borogluconate is the standard approach for parturient paresis. Early and proper treatment results in an excellent prognosis for affected cows. Economic losses due to milk fever encompass deaths, premature culling, treatment expenses, and reduced milk production in subsequent lactations. Consequently, effective milk fever management is crucial not only for mitigating production losses but also for preserving the well-being of the animals. [ABSTRACT FROM AUTHOR]

Increasing the productive capacity of dairy cows increases the incidence of non-communicable animal diseases, including such metabolic diseases as ketosis, osteodystrophy, postpartum hypocalcemia, etc. Under conditions of excessive physiological stress, violation of the optimal mode of feeding and keeping animals, technological stresses often lead to disruption of neurohumoral regulation and the appearance of diseases similar to postpartum hypocalcemia. The wide distribution of postpartum hypocalcemia, its insufficient knowledge in conditions of intensive animal husbandry determined the scientific direction of our work.The main goal of our work was to study the effect of increasing calcium in the ration of cows during the drying period of milk in highyielding cows in large specialized farms on the frequency of postpartum hypocalcemia. [ABSTRACT FROM AUTHOR]

Transition period of 2-3 weeks before and after calving is greatly increased risk of metabolic diseases. Hypocalcaemia around this period is a risk factor for many diseases and is an indirect risk factor for increased culling. This study was intended to reduce the number of milk fever cases by nutritional manipulation in the transition period using ammonium chloride salt supplementation. After detecting a deficiency of Ca, total 30 pregnant buffaloes were selected, in which 15 buffaloes were given same diet, taken as control group and rest 15 buffaloes' diet supplemented with ammonium chloride @ 90 gm per animal per day. During supplementation, on the day of calving all were have normal serum calcium level. The pH of their urine were also recorded and negative relation was found out between pH of urine and calcium level in blood. So, it is recommended to supplement animal feeds with ammonium salt during transition period, as its cost is very much less than the cost of treatment of milk fever. [ABSTRACT FROM AUTHOR]

Konsep dan permasalahan budidaya ternak ruminansia sesuai dengan 3 pilar peternakan yaitu feeding, breeding, dan manajemen. Manajemen merupakan pilar penting dalam menjaga produktivitas dan kesehatan ternak terutama yang berhubungan dengan penyakit-penyakit akibat kesalahan dan kegagalan metabolisme. Beberapa penyakit yang menyerang sistem metabolisme antara lain bloat atau kembung, ketosis atau acetomia, milk fever, fatty liver, dan asidosis yang berdampak pada perlambatan pertumbuhan sehingga berdampak negatif pada produksi ternak. Setiap penyakit memiliki cara pencegahan dan penanganan yang berbeda-beda. Pencegahan yang paling umum dilakukan adalah dengan vaksinasi dan penerapan biosekuriti termasuk perbaikan manajemen pemeliharaan. Pengembangan obat, vaksin, dan suplemen herbal dapat dijadikan alternatif potensial untuk meningkatkan produktivitas dan kesehatan ternak.

Objective: To study the impact of early metabolic profiling and intervention measures in the peri¬parturient period on the occurrence of postparturient metabolic diseases in cows. Materials and Methods: Using a cohort of dairy cows from two selected areas of Bangladesh, we routinely tested the serum calcium level and ketone bodies in the urine at periparturient periods. In addition, milk samples were tested for the presence of mastitis at different stages of lactation. Animals showing reduced serum calcium levels, high ketone bodies in the urine or the presence of clinical and subclinical mastitis received appropriate therapeutic intervention immediately after detection. After the intervention, the number of animals that got sick with diseases or conditions like milk fever, ketosis, mastitis, and dystocia, which are caused by metabolic problems, was recorded. Results: In the periparturient period, most of the animals had lower serum calcium levels (8.13 ± 1.2 mg/dl), which were significantly increased by the following intervention (10.05 ± 1.4 mg/dl). On the other hand, there was a higher number of ketosis-affected animals (33.9%, 20/59) during the periparturient period, which decreased (18.6%, 11/59) during the postparturient period. Similarly, the number of mastitis-affected cows was also decreased in postparturient cows (30.9%, 13/42) than in periparturient cows (59.5%, 25/42), following improved hygienic measures. After early intervention, the number of study animals with metabolic diseases decreased from 51.7% before intervention to 15.3% after intervention. Conclusions: Early metabolic profiling significantly reduced the occurrence of metabolic diseases in cows. Therefore, we recommend regular metabolic profiling of dairy cows and receiving early intervention measures to reduce the occurrence of metabolic diseases on the farm. [J Adv Vet Anim Res 2022; 9(2.000): 295-300]

A significant part of a complete dairy feeding program is the mineral-vitamin component. Physiologically, minerals are involved in reproduction, lactation, cow/calf health during pregnancy and cow recovery after calving and general herd health. Highly productive dairy animals have much greater needs for minerals and vitamins than low-producing. Concentrations of minerals and vitamins in feeds can be extremely variable. Dairy animals commonly need 3 vitamins and 17 mineral for their optimal productivity. Even the deficiency of any of these can result in health, reproduction and milk production problems. The antioxidant, vitamin E and carotene are beneficial in reducing mastitis. Vitamins (D, E, C and carotene) and minerals (Cu, Zn, and Se) are needed for enhanced immune response. Almost all the members of B.comlex group, C vitamin K2are synthesized in rumen but ruminant diet should contain sufficient cobalt for B12 synthesis. Vitamin A is neither synthesized in the body nor contributed by bacteria and it is the only vitamin, which may be deficient supply under many conditions. Therefore its supply seems to be critical. Vitamin E content of forage is highly variable and is effective in reducing gossypol toxicity. Generally it is assumed that the dairy animals with functional rumen do not develop deficiency. Different research reports suggest the need for supplemental biotin, thiamin and niacin for dairy cattle. Pre-partum anionic diets should be supplemented to avoid Milk fever. High phosphorus diets do not improve milk production or reproduction but there is environmental concern from use of excess P. Manganese has its role in ovulation and fertility of dairy animals. Grazing dairy animals should have access to high quality freechoice mineral mixtures. Mineral and Vitamin supplementation should especially be managed before the periods of increased trace mineral demand such as calving, joining, dry-off and growth. [ABSTRACT FROM AUTHOR]

Hypocalcaemia prevention programmes have been widely studied in experimental settings, but their feasibility has not been assessed under field conditions. The main objective of this study was to evaluate, in the context of small dairy farms in western France, whether and how dairy farmers implement prevention programmes and manage the feeding of dry cows to prevent hypocalcaemia. Seventy-nine commercial Holstein dairy farms in Brittany (France) were enrolled in a qualitative study in 2019. We conducted in-person interviews with the farmers to 1) understand the rationale behind the type and seasonality of prevention programmes they implemented and 2) assess how closely they followed common recommendations when implementing them. Most farmers (80 %) used at least one prevention programme, especially supplying a mineral mix formulated to meet the needs of dry cows in late gestation (53 %), acidifying the diet in late gestation (37 %), and supplying calcium at calving (oral or injectable form, 37 %). The use of programmes depended on whether the diet composition varied throughout the year. Among farmers who provided an acidified diet, 25 % did not supply a specific mineral mix to dry cows to ensure an adequate amount of P, Ca, and Mg, which could decrease the effectiveness of the acidification programme. A lack of reliability in feeding practices, such as not weighing feed or not delivering feed frequently enough, was identified for 61 % of contributing farms. Management practices could result in supplying an unsuitable amount of P, Ca, or Mg immediately before calving; for example, inappropriate batching practices around calving were identified for 22 % (cows) to 32 % (heifers) of farms. In addition, nearly all contributing farmers had no processes in place to monitor the effectiveness of the programmes implemented. Reasons for this overall lack of compliance should be explored.

Hypocalcemia remains a common metabolic disorder of dairy cattle; therefore, an efficient prevention is still challenging. Among the various prevention strategies for hypocalcemia is the use of anionic compounds to induce a mild metabolic acidosis during the prepartum period. Acid-base status can be readily assessed through urine pH. Accordingly, a target urine pH during the prepartum period between 6.0 and 6.8 has been recommended for Holstein cows; however, in several countries, including the US, certain nutritional strategies are still focused on benchmarking the urine pH to below 6.0. Unfortunately, over-acidification can have no advantages and/or detrimental effects on both the dam and her offspring. In this review, updated information regarding the use of anionic diets on prepartum dairy cows and the potential negative impact of such diets on both cow and calf performance are discussed. There is an urgent need for studies that will elucidate the pathophysiological mechanisms by which very acidotic diets may impact the well-being and productive efficiency of dairy cows, and the transgenerational effects of such diets on offspring performance and survival.

Milk fever is a metabolic disorder that predominantly affects dairy animals during the periparturient period and within four weeks of calving. Milk fever is primarily attributed to a decrease in the animal's serum Ca2+ levels. Clinical milk fever occurs when Ca2+ concentration drops below 1.5 mM (6 mg/dL). Without prompt intervention, clinical milk fever leads to noticeable physical symptoms and health complications including coma and fatality. Subclinical milk fever is characterized by Ca2+ levels between 1.5 and 2.12 mM (6–8.48 mg/dL). Approximately 50% of multiparous dairy cows suffer from subclinical milk fever during the transition to lactation. The economic impact of milk fever, both direct and indirect, is substantial, posing challenges for farmers. To address this issue, we developed a low-cost electrochemical sensor that can measure bovine serum calcium levels on-site, providing an opportunity for early detection of subclinical and clinical milk fever and early intervention. This calcium sensor is a scalable solid contact ion sensing platform that incorporates a polymeric calcium-selective membrane and ionic liquid-based reference membrane into laser-induced graphene (LIG) electrodes. Our sensing platform demonstrates a sensitivity close to the theoretical Nernstian value (29.6 mV/dec) with a limit of detection of 15.6 μM and selectivity against the species in bovine serum. Moreover, our sensor can detect Ca2+ in bovine serum with 91% recovery. [Display omitted] • Low cost calcium sensor is developed by modification of laser engraved carbon electrodes with a calcium sensing membrane. • A liquid-junction free ion-liquid doped reference membrane is deposited on a laser-induced graphene electrode for development of a liquid-junction free portable reference electrode. • Bovine serum calcium levels can be measured on-site with more than 90% accuracy. • Accessible and low cost platform is developed for early on-site diagnosis of milk fever, allowing timely intervention [ABSTRACT FROM AUTHOR]

Objective: To study the impact of early metabolic profiling and intervention measures in the periparturient period on the occurrence of postparturient metabolic diseases in cows. Materials and Methods: Using a cohort of dairy cows from two selected areas of Bangladesh, we routinely tested the serum calcium level and ketone bodies in the urine at periparturient periods. In addition, milk samples were tested for the presence of mastitis at different stages of lactation. Animals showing reduced serum calcium levels, high ketone bodies in the urine or the presence of clinical and subclinical mastitis received appropriate therapeutic intervention immediately after detection. After the intervention, the number of animals that got sick with diseases or conditions like milk fever, ketosis, mastitis, and dystocia, which are caused by metabolic problems, was recorded. Results: In the periparturient period, most of the animals had lower serum calcium levels (8.13 ± 1.2 mg/dl), which were significantly increased by the following intervention (10.05 ± 1.4 mg/dl). On the other hand, there was a higher number of ketosis-affected animals (33.9%, 20/59) during the periparturient period, which decreased (18.6%, 11/59) during the postparturient period. Similarly, the number of mastitis-affected cows was also decreased in postparturient cows (30.9%, 13/42) than in periparturient cows (59.5%, 25/42), following improved hygienic measures. After early intervention, the number of study animals with metabolic diseases decreased from 51.7% before intervention to 15.3% after intervention. Conclusions: Early metabolic profiling significantly reduced the occurrence of metabolic diseases in cows. Therefore, we recommend regular metabolic profiling of dairy cows and receiving early intervention measures to reduce the occurrence of metabolic diseases on the farm. [ABSTRACT FROM AUTHOR]

Walter Verhoef,1 Sjoert Zuidhof,2 Brenda Ralston,3 Joseph A Ross,4 Merle Olson5 1Bureau Vétérinaire de Richmond, Richmond, Quebec, Canada; 2Sjoert Zuidhof Consulting, Okotoks, Alberta, Canada; 3Alberta Agriculture and Forestry, Airdrie, Alberta, Canada; 4Chinook Contract Research Inc., Airdrie, Alberta, Canada; 5Alberta Veterinary Laboratories, Calgary, Alberta, CanadaCorrespondence: Walter VerhoefBureau Vétérinaire de Richmond, 44 Rue Des Cèdres, Richmond, QC, J0B 2H0, CanadaTel +1 819-212-4091Email verhoefw@videotron.caPurpose: Calcium supplement boluses vary greatly in content and bioavailability.Methods: In vivo dissolution and bioavailability studies were conducted to compare commercial calcium supplement boluses with various contents of calcium chloride and calcium carbonate. The products studied included: Bolus 1 (high calcium chloride, no calcium carbonate), Bolus 2 (medium calcium chloride, medium calcium carbonate), and Bolus 3 (low calcium chloride, high calcium carbonate). A bolus was placed in a pre-weighed coarse mesh net for 30, 60, 90, 120, 180, and 240 minutes to measure dissolution rates in the rumen of fistulated animals. To measure calcium uptake, 27 Holstein cows (second and third lactation) were randomly allocated to one of three oral calcium protocols: Treatment 1 (two high calcium chloride boluses at time 0); Treatment 2 (one high calcium chloride bolus at time 0 with a second bolus 12 hours later); or Treatment 3 (two high calcium carbonate boluses at time 0). Treatments were initiated within 12 hours following calving and this was considered time 0.Results: Bolus 1 was the quickest to dissolve (< 90 minutes), followed by Bolus 2 (< 240 minutes). The high calcium carbonate bolus (Bolus 3) remained after 240 minutes in vivo with a minimum of 75% of the original bolus weight still intact. Cows with severe hypocalcemia (< 1.8 mmol/L) responded with a higher serum calcium increase than cows with milder hypocalcemia (> 1.8 mmol/L, < 2.12 mmol/L). The high calcium carbonate bolus group (Treatment 3) did not show a rapid increase in serum calcium as compared to the high calcium chloride groups (Treatments 1 and 2). The animals receiving Treatment 1 had a greater and more persistent serum calcium response than animals receiving Treatment 2.Conclusion: The study outcome suggests that calcium chloride/calcium sulfate boluses are more effective at generating a serum calcium response than boluses containing high amounts of calcium carbonate and that two boluses administered rapidly after calving may be more effective than the traditional treatment of giving 2 boluses 12 hours apart.Keywords: sub-clinical hypocalcemia, milk fever, calcium chloride, calcium carbonate, calcium bolus, dissolution

We investigated whether prepartum levels of serum bone biomarkers are related to the degree of parturient hypocalcaemia and risk of milk fever (MF) in dairy cows with advancing parity. A total of 58 late-pregnant cattle were assigned to four groups: nulliparous, primiparous, multiparous in the 2nd lactation and multiparous in the 3rd–5th lactation. The multiparous cows were further assigned to MF and non-MF groups according to the onset of MF. Serum samples were obtained from the cows during the 3 weeks prepartum to 5 d postpartum period for the measurement of serum calcium (Ca) and three bone biomarkers: tartrate-resistant acid phosphatase isoform 5b (TRAP5b), osteoprotegerin (OPG) and bone isoenzyme of alkaline phosphatase (ALP3). The ratios of OPG to TRAP5b (O/T ratio) and ALP3 to TRAP5b (A/T ratio) were calculated. The data from all cattle showed that the severity of hypocalcaemia at parturition increased with advancing parity/age. The MF cows had elevated serum TRAP5b activity and a decreased O/T ratio after parturition, suggesting an increased number of osteoclasts due to osteoclastogenesis, in response to severe hypocalcaemia. The MF cows showed lower serum ALP3 activity during the 3 weeks prepartum than the non-MF cows, therefore, prepartum osteoblast function was likely weak in the MF cows. During the 2–3 weeks prepartum, serum ALP3 activity and the A/T ratio had moderate associations with the serum Ca concentration at day 0 (day of calving) in the multiparous cows, and receiver operating characteristic curve analysis revealed that ALP3 activity had excellent ability to predict MF. In conclusion, prepartum serum ALP3 activity is a promising biomarker to predict MF in multiparous cows. [ABSTRACT FROM AUTHOR]

The milk fever and mastitis that occur during the colostrum period in dairy cattle cause great damage in the dairy industry by causing a rapid decline in the cattle’s health and decreasing milk production. In order to prevent this, gradual milking (GM), calcium injection with gradual milking (CG), and calcium injection with complete milking (CC) methods are used. However, differences in effectiveness between these methods have not been established. Therefore, this study was conducted to determine the effects of each preventive method on milk fever and mastitis. The results of this study showed that while there was a significant negative correlation of GM with milk fever and mastitis (r = –0.657, p < 0.05), there was no correlation of CG and CC with milk fever and mastitis. The incidence of milk fever was significantly lower in CG and CC than in GM (p < 0.05) but no differences in the incidence of mastitis were observed between the three groups. No significant differences in the rate of recovery from milk fever and mastitis were observed between the three groups. The recurrence rate of milk fever was significantly higher in CG and CC than in GM (p < 0.05), though no differences in the recurrence rate of mastitis were observed. This study showed an inverse relationship between the incidence rates of milk fever and mastitis when calcium injection was not used during the colostrum period. When calcium injections were used, the incidence of milk fever was reduced without affecting the incidence of mastitis regardless of the milking method, but the recurrence rate of milk fever was increased. The results of this study would be useful for controlling blood calcium concentrations and establishing efficient milking strategy in order to effectively prevent milk fever and mastitis in dairy cattle during the colostrum period.

Little information is available regarding the calcium (Ca) dynamics and how its concentration is influenced following the Ca treatment (injection or bolus) after calving in dairy cows. To evaluate the short- and long-term effects of different sources of Ca supplement to animals fed anionic diets during the pre-partum period, 36 multiparous Holstein cows were randomly assigned to 1 of 3 treatments: (1) control group without Ca supplement (CON); (2) subcutaneous injection of 500 ml of 40% w/v Ca borogluconate immediately post-calving (SUB) and (3) oral supplement of Ca bolus containing 45 g Ca immediately and 24 h post-calving (BOL). Serum concentrations of Ca, P and Mg were measured. Serum concentration of Ca was affected by treatments at 48 h of post-calving (P < 0.01). The mean Ca at 6 h was greater in SUB compared to CON group (2.34 v. 2.01 mmol/l; P < 0.002). The lowest Ca concentration at 12 h was related to CON cows compared with BOL and SUB cows (1.90, 2.16 and 2.14 mmol/l, respectively; P < 0.02); a similar trend was observed 24 h post-calving (P < 0.02). Serum concentrations of P and Mg were not influenced by treatments. Yield of milk, milk protein and fat-corrected milk were lowest (P < 0.05) in SUB cows within 3 weeks of lactation in comparison with CON and BOL cows. However, milk yield and milk composition did not show any difference among treatments throughout the first 3 months post-calving. In general, under conditions of this experiment, Ca supplements to fresh cows as an oral bolus are recommended in comparison with subcutaneous injection.

Periparturient hypocalcaemia is a widespread metabolic disorder in dairy cows. Clinical and subclinical cases occur primarily in multiparous (Multi) cows, but subclinical cases have also been reported in primiparous (Primi) cows. A preventive strategy was investigated by administering the physiologically active vitamin D3 metabolite, 1,25-dihydroxyvitamin D3 (1,25-dihydroxycholecalciferol, 1,25(OH)2D3) as a rumen bolus. The bolus contained tablets of 1,25(OH)2D3 glycoside extract from Solanum glaucophyllum (SGE), releasing SGE over several days. The aim was to study the effect of a bolus containing 0 (C) or 500 µg (SGE) of 1,25(OH)2D3 on 1,25(OH)2D3 and mineral status in periparturient cows up to three weeks into lactation and on colostrum, milk and calves’ blood mineral contents. The bolus was administered three to four days prior to expected calving to Primi and Multi cows fed a herbage-based diet (dietary cation-anion difference of +522 mEq/kg DM). One C or SGE bolus was applied to 12 Primi and 12 Multi cows. Blood was regularly sampled (and selected a posteriori for antepartum samples) in regard to the actual calving day (d0), immediately prior to bolus application and at day −2, 0.5, 1, 1.5, 2, 4, 8, 11, 15, 18 and 22. Additional samples included urine (at bolus application, d0.5 and d2), colostrum, milk samples (weekly) and calves’ blood (d2). Blood serum 1,25(OH)2D3 increased between d0.5 and d2 in Primi-SGE, but remained unchanged in Primi-C, as did parathyroid hormone (PTH) and Ca in all Primi. Urinary Ca of Primi-SGE was increased on d2, indicating regulation of Ca excess. Three Multi-C cows with confirmed clinical hypocalcaemia needed treatment and thus were excluded from the dataset and replaced. Blood serum 1,25(OH)2D3 and PTH increased while Ca dropped by 40% between d0.5 and d2 in Multi-C, whereas 1,25(OH)2D3, Ca and PTH remained unchanged in Multi-SGE. Blood serum carboxyterminal telopeptide of type I collagen was higher in Primi than in Multi and increased with time, except in Primi-C. Mineral contents in colostrum, milk and blood serum of calves were not influenced to a relevant degree. In conclusion, Primi-C did not, in contrast to Multi-C, develop subclinical hypocalcaemia (

The objectives of this study were to evaluate the effect of a single vitamin D3 intramuscular injection on calcium metabolism and bone markers in close-up cows, which fed a diet with negative DCAD (dietary cation anion difference). Twenty-four Holstein cows were randomly assigned to the treatment/control groups 21 days before parturition: twelve cows received a single 8,000,000 IU intra-muscular vitamin D3 injection as the treatment group and the other group received placebo injection (controls). Jugular blood was collected on days − 7, − 5, 1, 2, 4, 7, and 14 relating calving. Following Vit. D3 injection, serum 25(OH)D levels increased. Treated cows had significantly lower parathyroid hormone (PTH) than the control group at days 2 and 7. However, the serum ionized Ca (ICa) concentration was statistically lower in the treatment group. Furthermore, treated cows had lower crosslaps (CrL) than the controls and osteocalcin (OsC) concentrations exhibited a significant decrease at day 7 after calving in the treatment group. This study showed that a single IM injection of Vit. D3 pre-partum in dairy cows resulted in lower PTH, lower CrL, and decreased ICa post-partum. There was no benefit of a single intramuscular injection of vitamin D3 in close-up cows fed negative DCAD diets on Ca metabolism. [ABSTRACT FROM AUTHOR]

Milk fever is a metabolic condition that occurs in dairy cattle before or immediately after parturition as a result of low calcium (Ca++) levels in the blood (hypocalcaemia). Based on its pathological changes, milk fever (hypocalcaemia) can be clinical or subclinical, being particularly prevalent in high-producing cows during the calving period. The most common factors leading to milk fever include milk production, breed, parity, age, body condition score (BCS), and the composition of the cow's diet. The economic effects of milk fever are represented by decreases in milk production and fertility, finally resulting in culling of high-producing dairy cattle within herds. In order to establish the diagnosis of milk fever in dairy cattle, clinical and paraclinical examinations are used. Milk fever prevention is economically essential for dairy farmers since it helps them avoid production and culling losses, and also increased veterinary expenses related with this condition. Numerous approaches have been introduced in order to mitigate hypocalcaemia, which include anionic salt feeding, low-calcium diets, vitamin D supplements, magnesium supplements, and peripartum body condition management. As a final conclusion, preventing milk fever is crucial for overcoming disease's economic impact on the dairy industry. [ABSTRACT FROM AUTHOR]

Daniel A Shock,1 Steven M Roche,1 Rachel Genore,1,2 Merle E Olson3 1Agricultural Communications and Epidemiological Research (ACER) Consulting, Guelph, Ontario, Canada; 2Heartland Veterinary Services, Listowel, Ontario, Canada; 3Solvet Animal Health, Calgary, Alberta, CanadaCorrespondence: Daniel A ShockAgricultural Communications and Epidemiological Research (ACER) Consulting, 100 Stone Road West, Unit 103A, Guelph, Ontario N1G 5L3, CanadaTel +1-519-362-1142Email dshock@acerconsult.caBackground: The initiation of lactation challenges the ability of the modern lactating cow to maintain calcium homeostasis, and typically results in a drop in blood calcium levels, leading to mobilization of calcium reserves from skeletal stores. As such, the recommendation to provide supplemental calcium at parturition to older cows has become an industry-standard practice.Methods: Mature cows were treated at calving and 12 hrs later with either the novel calcium bolus (NB) or a commercially available calcium bolus (CB). Blood was collected from animals at 0, 1, 6, 12, 13, and 24 hrs following calving, and the resulting serum samples were analyzed.Results: Overall, there was no statistical difference between the NB and CB groups for blood calcium levels within the first 24 hrs following parturition (P = 0.50). Cows in both groups experienced a significant increase in serum calcium by 1 hr after parturition; however, this increase was not sustained through subsequent sampling times.Conclusion: This pilot study demonstrates that both boluses have a similar effect in the elevation of blood calcium.Keywords: hypocalcemia, milk fever, calcium supplementation, parturition, dairy cow

Background and hypothesis Visceral pain is a common incidence in cesarean delivery under spinal anesthesia. Dexmedetomidine (DEX) has analgesic, sedative, anxiolytic effect, as it is an α 2-receptor agonist. Intraoperative visceral pain resulting from manipulation of the uterus and traction of the peritoneum is still a challenge for anesthetists. The present study hypothesized that single intravenous bolus dose of DEX added as a supplement to intrathecal anesthesia for an elective cesarean section could reduce intraoperative visceral pain, lessen blood pressure swings, and produce an acceptable sedative effect, with minimal fetal and maternal consequences. Patients and methods A randomized double-blinded placebo-controlled study was conducted. A total of 70 patients were randomly allocated to receive either intravenous DEX or placebo (saline) before spinal anesthesia. The primary outcomes were decreased intraoperative visceral pain. Secondary outcomes included the stability of hemodynamic parameters (blood pressure and heart rate), sedation score, time to rescue analgesia reduction, neonatal APGAR score, and any adverse effects (nausea and vomiting). Results There was a significant difference between the groups in the incidence of moderate to severe visceral pain (P<0.001), intraoperative fentanyl requirements (P=0.004), and longer time to rescue analgesia (P<0.001). Both groups had comparable mean blood pressure (P>0.005); however, there was a highly significant difference in heart rate (P=0.01). Moreover, a significantly higher sedation score was seen in the DEX group (2.08±0.8) in comparison with the control group (1±0). APGAR score was comparable in the studied groups. Conclusion As a single intravenous bolus, DEX seems to be an excellent supplement to intrathecal anesthesia for an elective cesarean section. It can reduce intraoperative visceral pain and lessen blood pressure swings and produce an acceptable sedative effect with minimal fetal and maternal influence. [ABSTRACT FROM AUTHOR]

Metabolic disorders cause severe losses to dairy farmers, with adverse effects on milk yield and dairy cattle's reproductive efficiency. Hypocalcemia is the most common metabolic defects affecting dairy cows during transition periods and affecting reproductive efficiency. This research aimed to study the relationship between the most common metabolic disorder (hypocalcemia) and reproductive efficiency in dairy cows. Fifty-three dairy cows were grouped based on blood calcium level into normal and subclinical hypocalcemic cows. Body condition scours and reproductive disorders were recorded. Moreover, reproductive efficiency was reported until 280 days in milk. Results reported a significant increase and positive correlation between reproductive disorder (dystocia, stillbirth, retained placenta, metritis, and vaginitis) in animals suffering from subclinical hypocalcemia. These results conclude that subclinical hypocalcemia impairs reproductive efficiency in dairy cows and subsequently it lowers the benefit from dairy farming. [ABSTRACT FROM AUTHOR]

Metabolic disorders cause severe losses to dairy farmers, with adverse effects on milk yield and dairy cattle's reproductive efficiency. Hypocalcemia is the most common metabolic defects affecting dairy cows during transition periods and affecting reproductive efficiency. This research aimed to study the relationship between the most common metabolic disorder (hypocalcemia) and reproductive efficiency in dairy cows. Fifty-three dairy cows were grouped based on blood calcium level into normal and subclinical hypocalcemic cows. Body condition scours and reproductive disorders were recorded. Moreover, reproductive efficiency was reported until 280 days in milk. Results reported a significant increase and positive correlation between reproductive disorder (dystocia, stillbirth, retained placenta, metritis, and vaginitis) in animals suffering from subclinical hypocalcemia. These results conclude that subclinical hypocalcemia impairs reproductive efficiency in dairy cows and subsequently it lowers the benefit from dairy farming. [ABSTRACT FROM AUTHOR]

This preliminary study explored potential serum biomarkers for predicting the onset of milk fever (MF), a bovine parturient disease with hypocalcemia. We conducted two-dimensional gas chromatography mass spectrometry-based metabolomics in 8 and 17 pregnant Holstein cows that did and did not develop MF 3 weeks later, respectively. In principal component analysis (PCA) applied to a dataset containing 1,498 metabolites, serum metabolites exhibited highly similar chemical profiles between cows with and without MF. PCA with a limited dataset of metabolites containing fatty acids, which had significantly different values between the groups and/or correlation coefficients of >0.5 for the serum calcium concentration, distinguished the two groups. These suggest the possibility of developing serum biomarkers for predicting bovine MF.

Little information is available regarding the calcium (Ca) dynamics and how its concentration is influenced following the Ca treatment (injection or bolus) after calving in dairy cows. To evaluate the short- and long-term effects of different sources of Ca supplement to animals fed anionic diets during the pre-partum period, 36 multiparous Holstein cows were randomly assigned to 1 of 3 treatments: (1) control group without Ca supplement (CON); (2) subcutaneous injection of 500 ml of 40% w/v Ca borogluconate immediately post-calving (SUB) and (3) oral supplement of Ca bolus containing 45 g Ca immediately and 24 h post-calving (BOL). Serum concentrations of Ca, P and Mg were measured. Serum concentration of Ca was affected by treatments at 48 h of post-calving (P < 0.01). The mean Ca at 6 h was greater in SUB compared to CON group (2.34 v. 2.01 mmol/l; P < 0.002). The lowest Ca concentration at 12 h was related to CON cows compared with BOL and SUB cows (1.90, 2.16 and 2.14 mmol/l, respectively; P < 0.02); a similar trend was observed 24 h post-calving (P < 0.02). Serum concentrations of P and Mg were not influenced by treatments. Yield of milk, milk protein and fat-corrected milk were lowest (P < 0.05) in SUB cows within 3 weeks of lactation in comparison with CON and BOL cows. However, milk yield and milk composition did not show any difference among treatments throughout the first 3 months post-calving. In general, under conditions of this experiment, Ca supplements to fresh cows as an oral bolus are recommended in comparison with subcutaneous injection. [ABSTRACT FROM AUTHOR]

Two experiments were carried out in order to evaluate the efficacy of a partially decreased dietary cation-anion difference (pDCAD) of dry period rations of dairy cattle ((DCAD ~ 0 mEq/Kg DM) in prevention of postpartum subclinical hypocalcemia (SCH). The primary goal of the Experiment I was to compare the efficacy of a pDCAD strategy in minimizing SCH against a full DCAD (fDCAD ~ − 50 mEq/Kg DM) and a low calcium diet (LCD) in late (21 days (d)) pregnancy in Farm 1, using 66 multiparous cows (parity ≥ 3). The primary goal of Experiment II was to evaluate the effect of extension of a pDCAD to whole dry period (expDCAD-60 days), enrolling 40 cows (parity ≥ 3) to compare a pDCAD vs. expDCAD strategy. In both experiments, a primiparous heifers group was included as well. Serum Ca, Pi, Mg, and energy status indicators β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) were monitored pre- and post-partum, serially. Experiment I showed a significantly lower Ca, a numerically higher prevalence of SCH, and significantly lower NEFA and BHB in pDCAD vs. fDCAD. The prevalence of subclinical ketosis (SCK) was significantly higher in fDCAD peripartally. In Experiment II, a significantly higher Ca and lower prevalence of SCH were observed in expDCAD vs. pDCAD postpartum, while BHB, NEFA, and the prevalence of SCK were not significantly different. The prevalence of SCH in primiparous heifers in both experiments was about 30%. Overall, compared to common ordinary fDCAD strategy, pDCAD could be potentially regarded as a practical intervention, when the adverse effects of fDCAD are unavoidable. [ABSTRACT FROM AUTHOR]

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 m M. 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). [ABSTRACT FROM AUTHOR]

Postpartum hypocalcemia is a problem in dairy cows. Both the Jersey vs. Holstein breed and increasing parity are known risk factors. Our objectives were: (1) to evaluate a simple approach to provide dietary acidogenic salts suitable for application on small dairies and (2) to evaluate the combined effects of degree of acidification and oral Ca supplementation along with breed and parity group on periparturient Ca status of Holstein and Jersey cows. Cows were moved weekly from the far-off dry pen at 260 days pregnant to the close-up pen, where all cows received the acidogenic diets. The diet was offered as a total mixed ration and CaCl2, and our source of acidogenic salts was top-dressed in liquid form and mixed in by hand. Thirty-six cows were blocked by parity group (parity = 2 vs. parity ≥ 3) and breed (Holstein vs. Jersey) and assigned to one of two treatments (no intervention or postpartum oral Ca bolus supplementation) in an alternating fashion, based on expected date of parturition. Urinary acidification appeared complete within 3–4 days. Increased urinary Ca excretion was >93% of maximum from 7–21 days before falling to

Milk fever and subclinical hypocalcemia are the most important macro-mineral metabolic disorders that affect transition dairy cows. Many studies have shown that cows with subclinical hypocalcemia are also prone to many diseases and disorders. The drain of Calcium (Ca) during early lactation represents a significant increase in Ca demand over that for late fetal growth and physiological maintenance. The requirements of the mammary gland for Ca often exceeds the ability of the cow to replenish the plasma Ca pools. Blood Ca concentrations remarkably decline in dairy cows around calving, with the lowest concentrations occurring about 12 to 24 hours after calving. To maintain Ca homeostasis after calving, at the start of lactation, Ca compensating mechanisms are activated. These mechanisms involve a coordinated effort among the hormones 1,25-dihydroxyvitamin D3, parathyroid hormone (PTH), and calcitonin. Hypocalcemia is associated with an increased risk of several important health conditions such as mastitis, retained placenta, metritis, abomasum displacement and immune insufficiency, particularly in transition period. The incidence of subclinical hypocalcemia approaches 40-50% in multiparous cows after calving in dairy herds. In spite of developments in preventive approaches, tremendous economical impact of hypocalcemia on health, production and fertility of dairy cows is a major concern for dairy herd owners. The paramount advances in dairy health have been the paradigm shift from treatment of clinical illness to disease prevention and redefining disease more broadly, to include subclinical conditions. Herd-based tests are now available for use in routine herd monitoring and for investigating dairy herds with metabolic subclinical problems. This review provides the criteria for hypocalcemia monitoring and interpretation of the results in dairy herds.

Circulating serotonin (5-hydroxytryptamine; 5-HT) appears to be associated with various energetic disorders and hypocalcemia during the transition period. The objective of this study was to evaluate the effects of ketosis, feed restriction (FR), and endotoxin challenge (models in which energetic and calcium metabolism are markedly altered) on circulating 5-HT in lactating Holstein cows. Blood samples were obtained from 3 separate experiments; circulating β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), and glucose were measured in all 3 experiments, whereas ionized calcium (iCa2+) was measured only in the endotoxin challenge. In the ketosis study, blood samples from cows clinically diagnosed with ketosis (n = 9) or classified as healthy (n = 9) were obtained from a commercial dairy farm at d −7, 3, and 7 relative to calving. Ketosis was diagnosed using a urine-based test starting at 5 d in milk. There was no effect of health status on circulating 5-HT and no association between 5-HT and BHB, NEFA, or glucose; however, 5-HT concentrations progressively decreased following calving. In the FR experiment, mid-lactation cows were either fed ad libitum (n = 3) or restricted to 20% of their ad libitum intake (n = 5) for 5 d. There were no FR effects on circulating 5-HT, nor was FR correlated with energetic metabolites. In the immune activation model, mid-lactation cows were intravenously challenged with either lipopolysaccharide (LPS; 1.5 µg/kg of BW; n = 6) or sterile saline (control; n = 6). Administering LPS decreased (56%) blood iCa2+ but had no effect on circulating 5-HT, nor was there a correlation between circulating 5-HT and NEFA, BHB, or iCa2+. Circulating 5-HT tended to be positively correlated (r = 0.54) with glucose in Holstein cows administered LPS. In summary, in contrast to expectations, circulating 5-HT was unaffected in models of severely disturbed energetic and Ca2+ homeostasis. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to review the predisposing factors and advances in controlling principles of milk fever in high yielding dairy cows. Dietary imbalances in dairy cows can be one of fundamental cause of numerous and complicated types of health problems that are usually categorized as metabolic disorders. High producing dairy cows are among highly susceptible animal to such metabolic disorders during their transitional periods; three weeks before and after calving. In these periods, the animal struggles to maintain their calcium homeostasis; which is the most common metabolic disorder of high yielding dairy cows, due to their underlying physiological and pathological factors. Thus, those factors predisposing dairy cows to milk fever are age, stage of lactation and parity, body condition and diet. Usually, the basic principle of controlling milk fever is feeding the cows from diet constituting lower calcium and potassium contents in dry period. So that calcium mobilization from bone would be promoted, which ensures the increased metabolic processes of calcium mobilization during the transition period? Furthermore, supplementations of various anionic salts which includes magnesium sulfate, calcium sulfate, ammonium sulfate, calcium chloride, ammonium chloride and magnesium chloride are commonly used to raise blood calcium level, thus, minimizes risks of milk fever. Also, body condition management of cows during dry period is used to prevent milk fever. Finally, a recent research indicates that serotonin intravenous injections have significantly reduced the incidence of hypocalcemia in high yielding dairy cows. [ABSTRACT FROM AUTHOR]

Periparturient hypocalcemia is frequently observed and considered as a gateway disease that is associated with various health issues. The objective of this study was to evaluate the association of hypocalcemia with early-lactation milk yield, reproductive performance, and culling across a large number of different managerial systems. A prospective cohort study was conducted based on a convenience sample of 125 dairy herds from 8 federal states of Germany between February 2015 and August 2016. A blood sample was drawn from 1,709 animals within 48 h after parturition and analyzed for serum calcium concentration. After discarding cows (n = 283) with missing data, a total of 1,426 cows were considered for final analyses. The median time from calving to sampling was 14.0 h (interquartile range = 5.0–24.9 h). For each herd, a record of the herd management software was requested 150 d after the last cow was sampled. Serum calcium concentration of each cow was associated with early-lactation milk yield (Dairy Herd Improvement Association equivalent test 1 to 3), reproductive performance [days in milk (DIM) at first artificial insemination (AI), pregnancy at first AI, time to pregnancy within 150 DIM], and culling (until 60 DIM) data. Generalized linear mixed models were used to analyze continuous or categorical data. Shared frailty models were used for time to event data. Five different thresholds were used to define hypocalcemia. Thresholds ranged from 1.8 to 2.2 mmol/L using 0.1-mmol/L increments. Clinical hypocalcemia was defined as serum calcium concentration <2.0 mmol/L in combination with clinical signs (e.g., recumbency). The effect of hypocalcemia on milk yield was conditional on parity. In primiparous cows a serum calcium concentration <2.0 mmol/L (6.4% of cows were below this threshold) had no effect on milk production, whereas there was a tendency for multiparous cows with a serum calcium concentration <2.1 mmol/L (63.2% of cows were below this threshold) to produce 0.80 kg/d more milk compared with multiparous cows at or above the threshold. Multiparous cows suffering from clinical hypocalcemia produced 2.19 kg/d less milk compared with normocalcemic cows in early lactation. Calcium status was not associated with days to first insemination. Cows with a serum calcium concentration <1.9 mmol/L (34.6% of cows below this threshold) had decreased odds (odds ratio = 0.56) of pregnancy at first AI. A serum calcium concentration <1.8 mmol/L (24.1% of cows below this threshold) had a significant effect on time to pregnancy. Compared with animals with a serum calcium concentration ≥1.8 mmol/L, the hazard of becoming pregnant within 150 DIM was reduced when cows had a serum calcium concentration <1.8 mmol/L (hazard ratio = 0.68). Cows with a serum calcium concentration <2.0 mmol/L (44.3% of cows were below this threshold) had a 1.69 times greater hazard of being culled within the first 60 DIM compared with normocalcemic animals. The present study shows that the association of hypocalcemia with milk yield was conditional on parity and serum calcium concentration measured once within 48 h after calving. Considering reproductive performance and culling in early lactation, a negative effect of postpartum hypocalcemia was demonstrated. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate additive genetic and heterosis effects for milk fever (MF) in Costa Rican dairy cattle. A farm-based management information software was used to collect 223,783 parity records between years 1989 and 2016, from 64,008 cows, 2 breeds (Jersey, Holstein × Jersey crosses, and Holstein), and 134 herds. The pedigree file comprised 73,653 animals distributed across 10 generations. A total of 4,355 (1.95%) clinical cases of MF were reported within this population, affecting 3,469 (5.42%) cows. Data were analyzed using 2 animal models, both accounting for repeatability and assuming different distributions for MF event: normal (linear model) or binomial (threshold model). The models included parity as fixed effect, breed and heterosis as fixed regressions, and herd-year-season, additive genetic, and permanent environment as random effects. The models were fit using a generalized linear mixed model approach, as implemented in ASReml 4.0 software. We noted significant regression on the percentage of Holstein breed, depicting a −0.0086% [standard error (SE) = 0.0012] decrease in MF incidence for each 1-unit increase in percentage of Holstein breed. A favorable heterosis of 5.9% for MF was found, although this was not statistically significant. Heritability and repeatability were, respectively, 0.03 (SE = 0.002) and 0.05 (SE = 0.002) for the linear model, and 0.07 (SE = 0.007) and 0.07 (SE = 0.007) for the threshold model. The correlation between BLUP (all animals in pedigree) for linear and threshold models, was 0.89. The average accuracy of the estimated BLUP for all animals were 0.44 (standard deviation = 0.13) for the linear model and 0.29 (standard deviation = 0.14) for the threshold model. Heritability and repeatability for MF within this population was low, though significant. [ABSTRACT FROM AUTHOR]

The publication covers issues of distribution and etiology of lactation tetany in horses. This disease occurs as a result of a disturbance of calcium metabolism in the mare's body. This pathological condition is associated with a sharp decrease in the level of ionized calcium in the blood serum, and sometimes with changes in the concentration of magnesium and phosphorus in it. Lactation tetany is a rather rare disease of horses. This pathology is diagnosed after a kidling with the onset of lactation, in the mares, when hypocalcaemia develops in organism of animal, after prolonged physical activity or transport (transport tetany), eclampsia. Signs of the disease are variable and associated with neuromuscular hyperresistibility. Lactation tetany is more likely to be affected by shire horse breeds. The mortality rate of animals is high and reaches more than 60%. Hypocalcemic tetany occurs in mare, which feeds the foal - on average 10 days after kidfling or 1-2 days after it is weaned. Mechanisms of hypocalcemia development in the mare's organism, which feeds the foal, consist of reducing the absorption of this element from the intestine, increasing its loss through the kidneys, sweat or milk (in the presence of lactation); or inhibition of osteolysis due to changes in the level of parathyroid hormone (parathormone), calcitonine or vitamin D, in stress states. [ABSTRACT FROM AUTHOR]

Milk fever or hypocalcemia still is one of the most prevalent metabolic diseases as a consequence of the continued selection for the productivity of the dairy cattle. The present manuscript reviews the new aspect of the disease, mineral interactions, treatments and preventive measurement under either cattle in confinement or on pasture. [ABSTRACT FROM AUTHOR]

Background: Adjusting the dietary cation–anion difference (DCAD) is one of the most efficient ways to stimulate calcium homeostasis in periparturient dairy cattle. However, adjusting DCAD to the recommended negative values (−100 to −150 mEq/kg) is associated with decreased food intake and metabolic acidosis. The critical conditions of the animals at peripartum (i.e. drastic hormonal changes, decreased appetite and negative energy balance) can be detrimental to the health, productivity and welfare of the animals if combined with decreased feed intake caused by unpalatable acidogenic salts. Methods: In a cross‐sectional study, we analysed the ration of eight small to large dairy herds with intensive husbandry systems, including 6949 dry cows. Sodium, potassium, chlorine and sulfur concentrations in the feed were determined and DCAD was calculated. The DCAD of the ration of the farms ranged from –33.5 to +24.7 mEq/kg. Parturient paresis (PP, or milk fever) prevalence was investigated and correlated to DCAD values. Results: Clinical PP occurrence in the dairies of this investigation on average declined by 87% (ranging from a 97% decline to 5% increase). This indicates that adjusting DCAD at neutral values (0 ± 30 mEq/kg range) may both lower the PP prevalence and increase ration palatability by lowering acidogenic salts in the ration. Conclusions: Further research is recommended to investigate the effects of neutral DCAD on subclinical hypocalcaemia and food intake of the cattle. [ABSTRACT FROM AUTHOR]