Annual milk yield and reproductive performance of ketotic and non-ketotic dairy cows

Ketosis an Old Story Under a New Approach

Ketosis, characterized by high concentrations of ketone bodies in the blood, urine, and milk, affects a considerable number of cows immediately after calving. Although much is known about ketosis, dairy cows continue to be affected in every herd world-wide. Cows affected by ketosis are treated with palliative treatments after the disease is diagnosed. This is a very expensive approach and costs the dairy industry extra expenses, contributing to lower profitability of dairy herds. In this review article, we summarize the mainstream view on ketosis, classification of ketosis into three types, current diagnostic approaches to ketosis, and the economic impact of ketosis on dairy farms. Additionally, we discuss the most recent applications of the new ‘omics’ science of metabolomics in studying the etiopathology of ketosis as well as its contribution in identification of novel screening or diagnostic biomarkers of ketosis.

Prevalence of subclinical ketosis in dairy cattle in the Southwestern Iran and detection of cutoff point for NEFA and glucose concentrations for diagnosis of subclinical ketosis

Subclinical ketosis (SCK) is simply a condition marked by increased levels of circulating ketone bodies without the presence of the clinical signs of ketosis. Subclinical ketosis can cause economic losses through decreased milk production and association with preparturient diseases. Limited information is available regarding the prevalence of SCK in dairy herds in Southwestern Iran. The objectives of this study were (i) determination of the cutoff point of nonesterified fatty acids (NEFAs) and glucose concentrations for diagnosis of SCK using receiver operating characteristic (ROC) analysis, and (ii) determination of prevalence of subclinical ketosis in apparently healthy dairy cattle in Southwestern Iran. From October to December 2009, a total of 100 clinically healthy multiparous Holstein cows (3-8 years old) were randomly selected from 16 dairy herds around Kazerun, Fars Province, Iran. The cows had two-six lactations, with body weight ranging from 500 to 650 kg. Blood samples for each cow were taken at 2, 4 and 6 weeks post parturition and 3-4h after the morning feeding. The optimal cutoff point was set, by the ROC method, to >0.26 mmol/L for NEFA, and < 2.26 mmol/L for glucose with corresponding 82.54% sensitivity and 91.89% specificity for NEFA and 44.44% sensitivity and 78.38% specificity for glucose. Cows with BHB concentrations higher than 1200 μmol/L were classified as having SCK. In 2, 4 and 6 weeks post parturition 63%, 68% and 59% of the tested cows were subclinically ketotic. Overall, 97% of tested cows (97/100) were considered subclinically ketotic in at least one sample period. Thirty percent of tested cows (30/100) suffered from subclinical ketosis in all of the 2, 4 and 6 weeks postpartum. The results suggest that, a cut-off point of 0.26 mmol/L for NEFA concentrations can be used during early lactation for diagnosis of subclinical ketosis and making management decisions for prevention and treatment. Glucose cannot be a good criterion for diagnosis of SCK and it does not appear to be useful for monitoring subclinical ketosis.

Concentrations of ketones in milk in early lactation, and reproductive performance of dairy cows

Samples of blood and milk were taken from clinically ketotic cows at 12-hour intervals before and after treatment The concentration of beta-hydroxybutyrate was determined in plasma and milk, and the concentration of acetone was determined in milk. Measurement of milk acetone had the optimal combination of sensitivity, specificity and positive predictive value to identify ketotic cows and was subsequently used in a comparison of the fertility of ketotic and normal cows. Two samples of milk were taken approximately two weeks apart, between 12 and 60 days after calving, from 410 cows on three farms and the concentration of acetone in the milk was measured. Thirty cows with milk acetone concentrations of at least 0.4 mmol/litre were compared with paired control cows with milk acetone concentrations less than 0.3 mmol/litre. The ketotic cows had a significantly longer calving-to-conception interval and a significantly higher culling rate due to a failure to conceive (P<0.05).

Subclinical ketosis in lactating dairy cattle

Subclinical ketosis is an important and common condition of early-lactation dairy cattle. It is associated with losses in milk production and increased risk of periparturient disease. Prevention depends on several factors, including proper transition-cow nutrition, management of body condition, and the use of certain feed additives such as niacin, propylene glycol, and ionophores. All currently available cowside tests for subclinical ketosis have certain limitations in their use. Effective monitoring schemes for subclinical ketosis can be developed, however, and these may be useful in many herd health programs.

Effect of disease on reproduction in the dairy cow: a meta-analysis

Effects on reproduction of dystocia, stillbirth, abortion, milk fever, retained placenta, metritis, cystic ovaries, anestrus, ketosis, displaced abomasum, locomotor disorders, and mastitis were reviewed. Papers were considered if they provided quantitative estimates of diseases on days to first estrus, days to first service, conception rate at first service, days from first service to conception, days to conception or days open, calving interval, conception rates at various days post partum (dpp), and number of services per conception or per cow. Only papers in English in peer-reviewed journals were selected for analysis of post 1960 data from intensive dairy regions. Seventy papers fulfilled the selection criteria. Summary estimates of disease effects were calculated according to meta-analysis methods, and study designs were described in detail to identify possible heterogeneity of the results. Stillbirth, milk fever, displaced abomasum and mastitis had no effect on reproduction. Clinical ketosis, dystocia and retained placenta were associated with 2 to 3 more days to first service and with a 4 to 10% lower conception rate at first service, resulting in 6 to 12 more days to conception. Locomotor disorders were associated with an average increase of 12 d to conception, with wide variation depending on lesions and stage of occurrence. Metritis was associated with 7 more days to first service, 20% lower conception rate at first service, resulting in 19 more days to conception. Cystic ovaries were associated with 6 to 11 more days to first service and with 20 to 30 more days to conception. Anestrus was associated with 26 more days to first service and with an 18% lower conception rate at first service, resulting in 41 more days to conception. Abortion was associated with 70 to 80 more days to conception.

Effects of disease on milk production in the dairy cow: a review

Estimates of milk losses consequent to dystocia, stillbirth, milk fever, retained placenta, metritis, cystic ovaries, ketosis, displaced abomasum and locomotor disorders were reviewed. Papers were selected if they provided quantitative estimates of losses based on data collected after 1965, with a sample size resulting in a minimum number of disease cases of 25. Thirty-five papers fulfilled the selection criteria. Milk losses were expressed in kg/day over the period under study to allow comparison of results. Milk fever and cystic ovaries were not associated with yield losses (six studies for each disease). Less than half of the studies found losses associated with dystocia, retained placenta, and metritis, with, respectively, five studies out of 13 (0.3-2.3 kg/day across the lactation), five studies out of 13 (0.8 kg/day across the lactation to 2.5 kg/day across 100 days in milk), and two studies out of 10 (0.4 kg/day across the lactation, and 2.3 kg/day across 119 days in milk). More than half of the studies found losses associated with stillbirth, clinical ketosis, ketosis evidenced by a diagnostic test, and locomotor disorders, with, respectively, three studies out of five (0.7-1.3 kg/day across the lactation), seven studies out of 11 (2.6-5.7 kg/day short-term, and 1.2 kg/day across the lactation), five studies out of seven (1-7 kg/day on the day of diagnosis, and around 1 kg/day across 200 days in milk), and six studies out of 11 (0.3-3.3 kg/day across the lactation). All the five studies, investigating effects of displaced abomasum, found losses (3.5-10.9 kg/day across 80 days in milk, or 0.8-2.5 kg/day across the lactation).

Evaluation of a milk test for detection of subclinical ketosis

This study included 190 lactating cows from eight dairy farms and was designed to investigate the sensitivity and specificity of a milk test (Ketolac) for detecting subclinical ketosis in dairy cattle. Blood and milk samples were collected between 38 and 50 days post partum. At a beta-hydroxybutyric acid concentration in blood of 1.2 mmol/L, the prevalence of ketosis was 14%. A Response Operator Characteristic curve was drawn for two milk test values: 100 mumol/L and 200 mumol/L. Assessment of several beta-hydroxybutyric acid cut-off values in blood showed that when 100 mumol/L on the Ketolac milk test was defined positive, the most desirable sensitivity-specificity combination was achieved. This milk test can be routinely used to screen a herd for subclinical ketosis.

Prefeeding plasma acetoacetate and glucose in healthy, lactating heifers. Variations related to milk yield, metabolic balances and stage of lactation

When measured before morning feeding plasma acetoacetate (ACAC) increased and glucose (GL) decreased significantly with increasing milk yield (fat corrected, FCM) within 2 groups of half-sister related heifers which did not suffer from clinical ketosis. The groups received respectively A: 7 kg and B: 4 kg/d of concentrates in addition to grass silage ad libitum (each group 88 animals). Correlation coefficients of the same magnitude between the 3 variables mentioned were obtained in the 1st and 3rd month of lactation in spite of a narrowing of the ACAC range from 0.024-0.66 to 0.019-0.16 mmol/l. Reproducibility of differences between animals in milk yield and in the plasma components was evidenced by significant correlations between measurements in the 1st and 3rd month. The B-animals produced 2.4 kg/d less FCM than the better fed A group (A, 1st month of lactation 19.8 +/- 3.1 kg/d) while the mean values for ACAC and GL remained practically unaffected by the difference in feeding. B cows gave consistently 5-6% lower GL means (p < 0.01) than A animals with identical yields. Animals which showed marked ACAC increment during the first 5-6 weeks of lactation produced 3-4 kg more FCM/d than equally fed animals with constantly low ACAC levels. The estimated energy deficit of this ketonaemic, high-producing category corresponded to the production of 4.5-6 kg FCM/d from body reserves. Low ACAC values (< 0.05 mmol/l) were reproduced with a standard deviation of +/- 4% with the automated nitroprusside method described.

Correlation between energy balance and fertility in Finnish dairy cows

The effect of serum glucose, ASAT and urea on reproductive performance was studied in 45 Finnish dairy cows from 8 different herds. Blood samples were taken a month before calving as well as 2 weeks and 2 months after calving. Serum urea, ASAT and glucose were used as indicators of metabolic and energy balance. Glucose and ASAT concentrations were significantly correlated with fertility 2 weeks after calving, but not before calving or 2 months after calving. Antepartum, 60% of the cows had a low urea level; at 2 weeks and at 2 months postpartum 89% and 65%, respectively had low levels of urea. The cows were divided into groups as follows: low or high (greater than or equal to 2.9 mmol/l) glucose level and low or high (greater than or equal to 2.5 mmol/l) urea level. Low levels of glucose and/or urea in puerperium were associated with poor fertility. The intervals from calving to first insemination and conception were shorter in the group with high glucose and high urea than in the group with low values. The cows with the shortest intervals from calving to first insemination and conception showed adequate metabolic balance (high levels of urea and glucose). Clinical ketosis had an adverse affect on intervals from calving to first insemination and on conception. Intervals from calving to first insemination and to conception were significantly (p less than 0.01) longer in ketotic cows than in non-ketotic ones. Liver damage, reflected as elevated activity of ASAT, was associated with poor fertility. If shorter calving intervals are desired, adequate energy balance in puerperium is essential.

Effect of hyperketonaemia and feeding on fertility in dairy cows

Fertility in relation to acetone concentration in milk and level of nutrition was studied in 38,624 lactations from 474 herds over a 3-year period. Herd-related data on nutrition were collected once each year. Milk acetone concentrations higher than 0.40 mM were deemed to be hyperketonaemic. The interval from calving to first service was about 5 days longer in cows with acetone concentrations >2.00 mM, while the interval to the last service was shortest at 0.40 to 1.00 mM. The risk for cystic ovaries was severely increased in first calving heifers with acetone concentrations >2.00 mM (odds ratio; 8.7). In herds with a high frequency of hyperketonaemic cows, primiparous cows had a 6-day longer period from calving to the first service and a 12-day longer period from calving to the last service. Increased feeding frequency of concentrate (2 vs 4 times/day) was related to shorter intervals from calving to first service and from calving to last service of 5 and 6 days, respectively, in mature cows. Increased total intake of energy in early lactation was related to shorter intervals from calving to last service in both primiparous and multiparous cows, 0.3 and 0.1 days per megajoule metabolizable energy, respectively. However, increased amounts of concentrate at calving in multiparous cows, and 15 days after calving in primiparous cows, were related to longer intervals from calving to last service and from calving to first service, respectively. The negative effect on these intervals was estimated to be approximately 2 days per kilogram of concentrate.

Change of milk yield with clinical diseases for a high producing dairy herd

Changes in milk production associated with occurrence of clinical diseases (dystocia, stillbirth, twin births, milk fever, retained placenta, displaced abomasum, limping due to foot lesions, metritis, ketosis, and mastitis) were investigated. Data were collected daily on 388 lactation. Stepwise least squares regression was used to evaluate existence of associations between diseases and six yield measures that characterized milk production in the first 119 d postpartum. Logistic regression was used to investigate whether milk yield 1 to 5 d in milk might be of use to detect cows with early postpartum metritis (less than 21 d after calving). Lower milk production to 5 d postpartum was associated with an increased risk of early postpartum metritis in the logistic regression model. Yield to 5 and to 21 d postpartum was lower in cases of stillbirth, retained placenta, and early postpartum metritis. Yield from 22 to 49 d postpartum remained lower in cows diagnosed with early postpartum metritis. Milk yield losses occurred during diagnosis and treatment of displaced abomasum and mastitis. Ketosis was associated with yield losses prior to and at treatment. Ketosis to 21 d in milk was also associated with lower production after treatment. Limping diagnosed in the first 49 d postpartum coincided with higher yield to 5 d, to 21 d, and after 49 d postpartum.

Metabolic balance and reproductive performance in Finnish dairy cows

The relationships between energy level and reproductive performance were studied in 24 dairy cows, which were fed grass silage. Serum glucose and blood acetoacetate (AA) and beta-hydroxybutyrate (HB) were measured 10, 15, 30 and 50 days postpartum. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The time required for the complete uterine involution and the onset of ovarian activity were recorded. The pregnancy rate at the first insemination and the interval from calving to conception were obtained for each cow. The correlations between blood glucose and ketone bodies were negative, but they were significant only at days 15 and 30 for AA and at day 30 for HB. A low energy level in early puerperium caused a delay in uterine involution and in the onset of ovarian activity. The low energy balance in puerperium prolonged the interval from calving to the first insemination and the interval from calving to conception. The earlier the ovarian activity started the shorter was the interval from calving to conception. The energy level in early puerperium had a greater influence on the interval from calving to conception, whereas in late puerperium it was more important with regard to the interval from calving to the first insemination. Blood glucose had also a significant effect on the reproductive performance. The adverse influence of ketone bodies on fertility depended on duration and timing of their increased levels; the longer and later in puerperium the cow has elevated ketone bodies, the lower is the fertility.(ABSTRACT TRUNCATED AT 250 WORDS)

Subclinical ketosis in dairy cows

Subclinical ketosis is defined as a preclinical stage of ketosis. The peak prevalence of subclinical ketosis occurs during the fourth week of lactation. Herd-related factors, breed, parity, and season are other important determinants. Subclinical ketosis can be revealed by determining levels of plasma glucose, plasma NEFA and blood, and milk or urine ketone body concentration. There are theoretical and practical advantages of using milk ketone bodies. Most authors are agreed on approximate lower and upper borderlines for subclinical ketosis. The risk of an outbreak of clinical symptoms has been evaluated by some authors. Most authors have found significant negative relationships between energy balance and ketone body concentration. Some disagreement may be attributable to the fact that the diets used in different experiments can have different glucogenic potential, even if the energy content is the same. This affects the relationship between energy balance and ketone body concentration, as the ketone body level is influenced by both the energy balance and plasma glucose. Feeding silage with high butyric acid content increases the risk of subclinical ketosis. There are indications that cows with the highest milk yield directly after calving are at greatest risk for developing ketosis. Increased ketone body level secondarily reduces milk production, a decrease that has been quantified by some authors. Subclinical ketosis causes delayed reproductive functions return to normal after calving, increased intervals from calving to first and last service, and an increased frequency of ovarian cysts. The routine determination of milk acetone levels in control programs can be used to evaluate the status of individual cows, to indicate the energy feeding in early lactation at a herd level, and to evaluate sires for breeding. The heritability and the tendency toward a positive genetic correlation between milk acetone and milk yield have also been discussed, as have aspects of nutritional prevention. Factors such as energy- and protein-rich roughage, tasty high-energy concentrates, suitable feeding during the dry period, and division of the concentrates into at least four meals are considered to be important.