Phosphorus content of muscle tissue and muscle function in dairy cows fed a phosphorus-deficient diet during the transition period.

Phosphorus (P) deficiency and hypophosphatemia are believed to be associated with muscle function disturbances in dairy cows, particularly around parturition. The objective of this study was to determine the effect of dietary P deprivation during late gestation and early lactation on muscle P homeostasis and muscle function in periparturient dairy cows. Thirty-six multiparous dairy cows in late gestation were randomly assigned either to undergo dietary P depletion or to be offered a diet with adequate P content from 4 wk before to 4 wk after parturition. Phosphorus-deficient rations for dry and lactating cows contained 0.15 and 0.20% P on a dry matter basis, respectively. Blood and muscle tissue for biopsy were obtained and electromyographic examinations were conducted on biceps femoris and intercostal muscles in regular intervals throughout the study. Muscle tissue was analyzed for the total P, adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, creatine phosphate, and tissue water content. Dietary P deprivation resulted in a pronounced and sustained decline of the plasma phosphate concentration, reaching a nadir at calving with mean values below 1.5 mg/dL and remaining below 2.0 mg/dL during the first 4 wk of lactation. Hypophosphatemia was not associated with signs of clinically apparent muscle weakness or disturbed muscle function and was not associated with a decline in the content of any of the studied P-containing compounds in muscle tissue. Accordingly, no association between plasma phosphate concentration and muscle tissue P content was found. Electromyographic examination identified subclinical effects on motor unit action potentials that are indicative of disturbed neuromuscular functionality. Increasing occurrence of pathologic spontaneous activity possibly resulting from membrane instability of nerve or muscle cells and suggestive of myopathy was also recorded as P deprivation progressed. These effects were predominantly observed in intercostal and to a lesser degree biceps femoris muscles. Electromyographic parameters affected by P deprivation were found to be associated primarily with the plasma phosphate and to a lesser extent with the amounts of energy storing P-containing compounds contained in muscle tissue. These results indicate that prolonged and pronounced dietary P deprivation in transition dairy cows leads to marked sustained hypophosphatemia without altering the muscle tissue P homeostasis or causing clinically apparent muscle function disturbances.

The effect of transient, moderate dietary phosphorus deprivation on phosphorus metabolism, muscle content of different phosphorus-containing compounds, and muscle function in dairy cows.

Hypophosphatemia is a common finding in periparturient and anorectic cattle. Although the clinical relevance of hypophosphatemia in cattle is uncertain, it has been empirically associated with persistent recumbency, specifically in periparturient dairy cows. The objective of the present study was to determine if transient dietary phosphorus (P) deprivation over a course of 5 wk, by feeding an approximately 40% P-deficient ration to lactating dairy cows, would result in altered muscle function or muscle P metabolism severe enough to present a risk for animal health and well-being. In addition, we wanted to determine the association between the plasma phosphate concentration ([Pi]) and muscle tissue P content to assess to what extent intracellular P deprivation of muscle cells could be extrapolated from subnormal plasma [Pi]. Ten healthy multiparous, mid-lactating dairy cows received a ration with a P content of 0.18% over a period of 5 wk. Following the P-deprivation phase, the same ration supplemented with P to obtain a dietary P content of 0.43% was fed for 2 wk. Blood and urine samples were collected regularly and muscle biopsies were obtained repeatedly to determine the P content in muscle tissue. Function of skeletal and heart muscles was evaluated by electrocardiography and electromyography conducted repeatedly throughout the study. Feeding the P-deficient ration resulted in the rapid development of marked hypophosphatemia. The lowest plasma [Pi] were measured after 9 d of P depletion and were, on average, 60% below predepletion values. Plasma [Pi] increased thereafter, despite ongoing dietary P depletion. None of the animals developed clinical signs commonly associated with hypophosphatemia or any other health issues. Urine analysis revealed increasing renal calcium, pyridinoline, and hydroxypyridinoline excretion with ongoing P deprivation. Biochemical muscle tissue analysis showed that dietary P depletion and hypophosphatemia were not associated with a decline in muscle tissue P content. Electromyographic examination revealed increased occurrence of pathological spontaneous activity in striated muscles after 2 wk of dietary P depletion in several cows, which could be suggestive of neuromuscular membrane instability. No effect on heart muscle activity was identified electrocardiographically. These results suggest that counter-regulatory mechanisms were sufficient to maintain normal muscle tissue P content during transient and moderate P deprivation. Muscle function was not grossly affected, although the increased occurrence of pathological spontaneous activity suggests that subclinical neuropathy or myopathy, or both, may have occurred with ongoing P deprivation. The results presented here indicate that plasma [Pi] is unsuitable for assessing muscle tissue P content in cattle.

Vitamin E supplementation during the dry period in dairy cattle. Part I: adverse effect on incidence of mastitis postpartum in a double-blind randomized field trial.

A randomized, controlled field trial with dairy cows demonstrated an adverse effect of vitamin E supplementation during the dry period on mastitis incidence in early lactation. This study was conducted on farms with historically high rates of mastitis to investigate the benefit of vitamin E supplementation on udder health; however, the outcome showed an adverse effect. The aim of the study was to evaluate whether daily supplementation of 3,000 IU of vitamin E to dairy cows during the dry period could improve udder health in commercial herds with a high incidence of mastitis. On 5 dairy farms, dry cows were randomly divided into 2 experimental groups: a high and a low group. Both groups received a dry cow mineral mix providing 3,000 or 135 IU of vitamin E/cow per day, respectively, between dry-off and calving for a mean period of 8 wk. Providing 3,000 IU of vitamin E exceeds NRC standards, but this amount has been used in previous studies. The experiment, as well as the majority of the statistical analysis, were carried out blinded. Blood was sampled 3 times before calving and on calving day. Serum was analyzed for vitamin E and cholesterol. Vitamin E and the vitamin E:cholesterol ratio were analyzed as dependent variables in mixed models and Student's t-tests to study trends in time and differences between groups. Relative risk calculation and survival analysis were used to study the effect of supplementation on mastitis incidence in the first 3 mo of lactation. The results showed that vitamin E supplements increased both absolute vitamin E and the ratio of vitamin E to cholesterol in blood. In the high group, significantly more subclinical and clinical cases occurred, showing the same trend on all farms. In this study, an initial vitamin E level at dry off above 14.5 µmol/L was a risk factor for clinical mastitis, suggesting that the vitamin E status at the start of the dry period is important. It is recommended to work out exactly at what threshold vitamin E is harmful for udder health before new trials with high dosages of vitamin E are started. Additionally, further research is required to investigate the mechanism by which vitamin E affects udder health.

Effects of vitamin E supplementation on and the association of body condition score with changes in peroxidative biomarkers and antioxidants around calving in dairy heifers.

The objective of this study was to investigate the effect of vitamin E supplementation on oxidative status in blood, liver, milk, and ovarian follicular fluid in periparturient heifers. Vitamin E supplementation started 8 wk before calving and continued until 8 wk postpartum. Grass silage was the main forage fed during the experiment. In addition, supplemented heifers (n=9) received 3,000I U of vitamin E daily on a carrier food; control heifers (n=9) consumed only the carrier food. Blood samples and liver biopsies were taken frequently throughout the study and ovarian follicular fluid was sampled at 8 wk postpartum. Body condition score was scored weekly and milk yield was measured daily. A marker of oxidative damage, determinable reactive oxygen metabolites (d-ROM), and a set of antioxidants were measured in blood, liver, milk, and ovarian follicular fluid. Control heifers had a low vitamin E status, and selenium status was marginal in control and supplemented heifers. Vitamin E supplementation increased vitamin E concentrations in blood, liver, and ovarian follicular fluid and increased triacylglycerol in liver. Serum d-ROM were not reduced by vitamin E supplementation. Superoxide dismutase and glutathione peroxidase activity in red blood cells and liver and glutathione peroxidase activity in ovarian follicular fluid were not affected by vitamin E supplementation and they were not increased around calving. Protein thiol groups and ratio of reduced glutathione to oxidized glutathione were also not increased around calving. These results suggest that heifers around calving experience a low level of oxidative processes. This might be caused by lower than expected milk production attributed to a low forage intake. Serum d-ROM were negatively correlated with protein thiol groups and positively correlated with the activity of glutathione peroxidase in red blood cells, oxidized glutathione, and the ratio of reduced glutathione and oxidized glutathione in serum. The lack of treatment effects allowed estimation of the effects of body condition 4 wk before calving and the loss of body condition on markers of lipid peroxidation and antioxidants. A trend that a body condition of >or=3 might result in more oxidative damage measured by serum d-ROM was observed, but fatter heifers had a significantly higher ratio of reduced glutathione to oxidized glutathione.

[Arm injuries due to sport climbing]. / Blessures aan de arm bij sportklimmers.

There are 26 large climbing centres and 44 smaller indoor or outdoor climbing walls in The Netherlands at this time. Hand and finger injuries are the most common types of sport climbing injuries. Most injuries are caused by overstraining. Injuries include avulsion fractures, arthrosis, pulley rupture, damage to joint capsule and collateral ligaments, 'gamekeeper's thumb', 'climber's finger', lumbrical shift syndrome, 'climber's elbow', shoulder injuries and nerve compression syndromes. Treatment is usually conservative. Depending on the extent of damage surgical intervention may be indicated.

The relationship between oxidative damage and vitamin E concentration in blood, milk, and liver tissue from vitamin E supplemented and nonsupplemented periparturient heifers.

This study investigated the relationship between oxidative damage and the effect of vitamin E supplementation in blood, milk, and liver tissue in 16 periparturient heifers. The question is whether measurements of oxidative and vitamin E status in blood of a periparturient cow are representative of the total body, given that blood concentrations of both vitamin E and oxidative stress products change around this period. The daily vitamin E intake of the vitamin E-supplemented Holstein-Friesian heifers (n = 8) was 3,000 international units and was started 2 mo before calving; the control heifers (n = 8) were not supplemented. Oxidative damage was determined on the basis of malondialdehyde (MDA) concentrations. Blood was sampled 9 times before calving, on calving day, and twice after calving. Liver biopsies were taken at wk -5, -1, and 2 relative to calving day. Milk was obtained from all heifers immediately after calving, the first 2 milkings and on d 3, 7, and 14 at 0600 h. Serum and liver tissue were analyzed for vitamin E, cholesterol, and MDA; and milk samples were analyzed for vitamin E, MDA, fat, protein, and somatic cell count. The results showed that vitamin E supplements increased both absolute vitamin E concentrations and the ratio of vitamin E to cholesterol in blood and liver tissue. Absolute vitamin E concentration in milk tended to be greater in supplemented cows. Based on the increased MDA blood concentrations at calving, it seems that dairy heifers experience oxidative stress. The effect of vitamin E on MDA differs between the blood, liver, and mammary gland. Vitamin E supplementation could not prevent the increase in blood MDA at calving, but the significantly lower MDA blood concentrations of supplemented cows in the 2 wk after calving suggest that vitamin E has a role in recovery from parturition-related oxidative stress. Vitamin E supplementation reduced oxidative damage in liver, whereas no obvious effect was found on milk MDA concentrations. A strong relationship was found between blood and liver vitamin E and the ratio of vitamin E to cholesterol. Concentrations of MDA in blood and milk were also strongly related. The results show that the relationship between oxidative damage and vitamin E differs within blood, liver tissue, and milk. This implies that oxidative and vitamin E status calculated on the basis of blood values alone should be interpreted with caution and cannot be extrapolated to the whole animal.

Genetic analysis of body condition score of lactating Dutch Holstein and Red-and-White heifers.

The aim of this study was to estimate phenotypic and genetic parameters for body condition scores (BCS) from the Dutch type classification system. Data included 108,809 Holstein (H) and 26,208 Red-and-White (R) heifers from 9701 herds that were scored once during lactation on a 1 to 9 scale (1 = emaciated and 9 = obese). Mean BCS for H and R data were 4.50 and 4.94, respectively. The BCS decreased as the percentage of Holstein genes increased. For both breeds, BCS after calving was about 5.6 and BCS was lowest around wk 11. For H heifers, mean BCS at drying off was about 0.8 lower than BCS at calving, whereas for R heifers BCS was at about the same level as at calving. Variance components were estimated using an animal model including the effects of herd x visit, classifier, age at calving, DIM, and genetic group. The random herd x visit effect explained about 10 to 15% of the phenotypic variation. Heritabilities ranged from 0.24 to 0.38, depending on breed and lactation period. Genetic correlations between BCS observations in bimonthly lactation periods were close to unity, especially for H. It was concluded that BCS data collected by type classifiers can well be used for genetic evaluation and that genetic variation between animals for BCS-change patterns is a small component of the overall variation in BCS.

Postpartum body condition score and results from the first test day milk as predictors of disease, fertility, yield, and culling in commercial dairy herds.

The study used field data from a regular herd health service to investigate the relationships between body condition scores or first test day milk data and disease incidence, milk yield, fertility, and culling. Path model analysis with adjustment for time at risk was applied to delineate the time sequence of events. Milk fever occurred more often in fat cows, and endometritis occurred between calving and 20 d of lactation more often in thin cows. Fat cows were less likely to conceive at first service than were cows in normal condition. Fat body condition postpartum, higher first test day milk yield, and a fat to protein ratio of > 1.5 increased body condition loss. Fat or thin condition or condition loss was not related to other lactation diseases, fertility parameters, milk yield, or culling. First test day milk yield was 1.3 kg higher after milk fever and was 7.1 kg lower after displaced abomasum. Higher first test day milk yield directly increased the risk of ovarian cyst and lameness, increased 100-d milk yield, and reduced the risk of culling and indirectly decreased reproductive performance. Cows with a fat to protein ratio of > 1.5 had higher risks for ketosis, displaced abomasum, ovarian cyst, lameness, and mastitis. Those cows produced more milk but showed poor reproductive performance. Given this type of herd health data, we concluded that the first test day milk yield and the fat to protein ratio were more reliable indicators of disease, fertility, and milk yield than was body condition score or loss of body condition score.

[Detection of hyperketonemia with the aid of monitoring milk production and two milk tests]. / Detectie van hyperketonemie met behulp van beoordeling van de melkproductie en twee melktesten.

In addition, it is relevant to know to what extent milk production data can provide information about hyperketonaemia. In 12 selected herds, milk samples were collected from 114 cows that had been lactating for maximally 70 days. During regular milk testing, two additional milk samples were taken to assess the 'Nitroprusside test' and the 'Ketolac BHB' test. After collection of milk samples, blood samples were taken to measure serum beta-hydroxybutyric acid. The prevalence of hyperketonaemia appeared to vary between herds from 1 to 9 per 10 lactating cows. The sensitivity of the Nitroprusside test was higher than the sensitivity of the Ketolac BHB test at threshold values of beta-HBA > 1.5 mmol/l. The Ketolac BHB test in comparison to the Nitroprusside test appeared to provide a smaller chance of false-positive test results at a given level of sensitivity. The serum beta-hydroxybutyric acid concentration was correlated with milk yield/day and the milk fat concentration of an individual cow.

Detection of ketosis in dairy cows by analysis of exhaled breath.

In four healthy cows an elevation of ketone bodies was induced by reduction of feed intake. Two cows became clearly ketotic while the other two cows showed only slight increases in ketone body concentrations in serum and milk. Acetone concentrations in exhaled breath were measured by gas chromatography combined with mass spectrometry. These values were correlated with concentrations of serum beta-hydroxybutyric acid (r = 0.81) and milk acetoacetate+acetone (r = 0.70). It is concluded that the ketotic state of dairy cows can be detected by analysis of exhaled breath. This offers a potential non-invasive method of determining the metabolic state of dairy cows.

Comparison of blood glucose concentrations measured by enzymatic and reflectance photometric methods in fasting piglets.

During a metabolic study of 22 fasting newborn piglets, blood glucose concentrations were measured by enzymatic and reflectance photometric methods. Use of the reflectance photometer is an accurate method of determining blood glucose levels even in hypoglycaemic range. In addition, the minimal quantity of blood needed for measurement allows the use of the same newborn piglets in longitudinal studies in which samples must be taken frequently.

[The usefulness of the refractometer in the assessment of colostrum and various factors affecting serum gamma globulin levels in newborn calves]. / Een onderzoek naar de bruikbaarheid van de refractometer bij de beoordeling van de biestverstrekking en naar een aantal factoren die van invloed zijn op het serum-gammaglobulinegehalte bij pasgeboren kalveren.

The effects of a number of factors on the concentration of gamma globulins in the serum of newborn calves were studied in 181 calves from six different dairy farms as was also the use of the refractometer test in controlling the ingestion of colostrum. The refractometer test was found to be reliable in controlling the concentration of gamma globulins in the serum of calves up to the sixth day of life. The factors 'time the first colostrum was ingested', 'amount of first colostrum ingested' and the 'concentration of gamma globulins in the colostrum' were found to account for 23.5 per cent of the variations in serum gamma globulin concentration; this became 42.4 per cent when the 'system of administration' and the 'farm-bound factors' were also taken into account. The first colostrum is best ingested when it is offered in a pail or bottle provided with a nipple. Calves of heifers were found to show a lower concentration of gamma globulins in the serum than did calves of older cows.

[Various aspects of the colostrum supply on dairy farms and the usefulness of the glutaraldehyde test in the evaluation of the colostrum supply]. / Een onderzoek naar een aantal aspecten van de biestverstrekking op melkveebedrijven en naar de bruikbaarheid van de glutaaraldehydetest bij de beoordeling van de biestverstrekking.

The serum gamma-globulin concentrations measured in 183 dairy calves on six farms (24-48 hours after parturition) were used to study the influence of quantity, time and method of administration of the first colostrum. It was established that the administration of 1.5-2 litres of colostrum within four hours after parturition results in the highest concentrations of gamma-globulins in serum. Assuming that in calves between 24 and 48 hours after parturition the lower acceptable limit of serum gamma-globulin concentrations is 10 g per litre, it can be concluded that the glutaraldehyde test is a simple and useful method in evaluating the supply of colostrum.

[Veterinary production and health policy on dairy farms: a model for the analysis of fluctuations in the Herd Standard Cow]. / Veterinaire produktie- en gezondheidsbegeleiding op melkveebedrijven: een model voor de analyse van fluctuaties in de Bedrijfs Standaard Koe (BSK).

A decrease in milk production on dairy farms may result in economic losses in the majority of cases. Veterinary herd health and production control programmes should deal with the prevention of these losses. Moreover, in the event of a decrease in milk production, efforts should be made to trace the possible cause, and corrective measures should be taken if required. The Herd Standard Cow (HSC) production is an important parameter in both production and farm management in the Netherlands. In the present paper, a model for the analysis of variations in the HSC is introduced. It concludes the steps to be taken by the practitioner to trace the causes of these variations.

[The farm calendar, an aid in veterinary-zootechnical production and health policy of dairy farms]. / De bedrijfskalender, een hulpmiddel bij de veterinair-zoötechnische produktie- en gezondheidsbegeleiding van melkveebedrijven.

A farm check-list is introduced in the present paper. For each month several points requiring attention are stated, which are of importance in herd health and production control on dairy farms from both both a veterinary and an agricultural point of view. A short explanation is given if necessary. To achieve optimum efficiency in herd health and production control, it is essential that communication between veterinarian and agricultural extension officer should function adequately. Advice from the two disciplines to the dairy farmer should be non-contradictory.

Veterinary herd health and production control on dairy farms I. Introduction to a coupled basic system and flexible system.

The veterinary herd health and production control program for year-round calving herds, presented in this paper, comprises a basic system and a flexible system. The basic system is a uniform system of data recording, standard veterinary activities and problem detection for all farms. Record keeping by the farmer includes the updating of a farm diary and a fertility-health chart and the preparation of an examination list before each veterinary farm visit. Record keeping by the veterinarian comprises the updating of a general inventory and four index lists at each monthly visit. The index lists contain all relevant parameters or index figures needed to monitor the various aspects of the farm. These lists serve to detect unwanted situations or problems and to initiate problem analysis. The farm checklist, with time-related veterinary and agricultural attention points, is consulted at each farm visit. In this way, no aspect is omitted in the control program. Problem analysis is performed in the flexible system. This comprises subsystems adaptable to the specific demands on the farm at a given moment and with a given problem. It indicates to what extent action is needed to solve the problem. Agricultural activities must be coupled to veterinary activities in order to provide the farmer with optimal advice. The farm checklist can be considered as a link between the two disciplines: the veterinarian can enlist the agricultural officer at the right moment. The frame-work of the basic system is introduced with emphasis on record keeping by the farmer, veterinary farm visits and the farm checklist.

Veterinary herd health and production control on dairy farms II. Index list on milk production and udder health.

In a previous paper an introduction was presented to a veterinary herd health and production control program. This program consists of a basic system and a flexible system. The basic system is built up from a standard on-farm and program registration system and from farm visit activities. In the registration system four index lists play a key role. These index lists comprise all relevant farm aspects with regard to the efficiency of milk production, calf production and cow replacement. Problem analysis is performed by means of the flexible system which indicates to what extent action for problem solving is needed. This paper presents index list 1 on milk production performance and udder health. Both aspects are of crucial importance to the economic results achieved on the farm. The index figures in list 1 serve to signalize unwanted situations or problems in relation to the aspects mentioned on the other lists. Index figures are built up from data collected on the farm by both the farmer and the veterinarian, and they serve as the basis for further analysis, solving and prevention of problems. The development, significance and implementation of the index figures in list 1 are presented. Reference values are given where applicable.