Effect of monensin on milk fatty acid profile in dairy cows and on the use of fatty acids for early diagnosis of elevated blood plasma concentrations of nonesterified fatty acids and hyperketonemia.

This work examined the effects of precalving administration of continuous-release monensin capsule on postcalving milk fatty acid (FA) profile and on the accuracy of FA as a biomarker in the early identification of cows with elevated blood plasma nonesterified fatty acids (NEFA) and ß-hydroxybutyrate (BHB) concentrations. Approximately 3 wk before expected calving, 203 multiparous Estonian Holstein cows were randomly divided into control (CO; n = 116) and experimental (MO; n = 87) groups, and a continuous-release capsule of monensin was administered to the MO cows. Blood samples were taken daily in the first 4 d postpartum, then on the sixth or seventh day in milk, twice in the second week, and thenceforth once per week until the end of the sixth week. Milk samples were taken once from 4 to 7 d in milk, twice in the second week, and thenceforth once per week. Blood samples were analyzed for NEFA and BHB, and milk was analyzed for FA concentrations. Cows with postpartum BHB concentrations ≥1.2 mmol/L at least once during the 6 wk were classified as hyperketonemic (HYK), and cows with NEFA concentrations ≥1.0 mmol/L as having elevated concentration of NEFA (NEFAH). The ability of FA to predict NEFAH and HYK cows was studied with logistic regression and receiver operating characteristic curve analysis and the identification accuracy was estimated by area under the receiver operating characteristic curve. For these analyses, we used FA measured on the ninth day after calving. Monensin administration affected FA mobilization and metabolism of the animals as blood NEFA were lower in the MO group on wk 1 and wk 3, and BHB values were considerably lower from wk 1 to wk 4 compared with the CO group. The FA dynamics were generally similar for MO and CO groups. Monensin administration resulted in higher concentrations of C15:0, C16:0, iso C17:0, anteiso C15:0, anteiso C17:0, total trans monounsaturated FA, and C18:2 cis-9,trans-11, and lower proportions of C18:0, C18:1 cis-9, and most of the iso FA. The identification accuracy of NEFAH and HYK cows was higher in the CO compared with the MO group and for the identification of HYK compared with NEFAH cows (0.75-0.77 vs. 0.78-0.80 in the CO group, and 0.61-0.66 vs. 0.68-0.75 in the MO group for NEFAH vs. HYK, respectively). For all FA, the threshold values to identify NEFAH and HYK cows were different in the CO and MO groups. Results suggest that specific threshold values for the identification of NEFAH and HYK cows could be applicable only within similar feeding conditions and rumen environment.

Bovine colostrum whey: Postpartum changes of particle size distribution and immunoglobulin G concentration at different filtration pore sizes.

Bovine colostrum, as vital as it is for calves, is also a valuable source of functional components with rich health benefits for humans. Bovine colostrum whey consists of a large number of bioactive proteins and peptides. The most abundant of these is IgG. Particle size distribution (PSD) is an important feature of many of the processes in the dairy food industries. Despite this, scientific literature on PSD of colostrum whey is scarce. The goal of this research was to describe bovine colostrum whey PSD with an emphasis on postpartum milking time, filtration (pore size 450, 100, and 20 nm), IgG concentration, and lactation number. For this purpose, 4 postpartum milking colostrum samples were sequentially milked from 46 Holstein cows at 12 ± 1 h intervals. Colostrum whey was prepared by renneting and diluted (1:200) for PSD analyses by a Malvern Zetasizer Nano ZS (Malvern Instruments Ltd., Malvern, UK). Immunoglobulin G concentration of these diluted colostrum whey samples were analyzed by an Octet K2 (Molecular Devices LLC, San Jose, CA) system. Linear mixed model analysis revealed significant effects of filter pore size, postpartum milking, and lactation on colostrum whey IgG concentrations. The percentage of particles in the size interval 5 to 15 nm (the hydrodynamic diameter of IgG is around 10 nm) had an intermediate positive correlation (r = 0.50) with IgG concentration. Furthermore, we showed that PSD was associated with IgG concentration, postpartum milking time, and lactation number. The PSD measurement results showed the mean hydrodynamic diameter of 100 nm pore size filtered colostrum whey to be around 10 nm. This, with the IgG concentration results, suggests that even though the size of IgG is around 10 nm, a 100 nm pore size is adequate for membrane-involved IgG separations. In terms of energy efficiency of the filtration process, the use of a larger filter pore size can make a remarkable difference, for example, in pressurizing and cooling costs. Our work contributes to the development of sustainable and widely available colostrum-derived food and feed supplements.

Body condition and insulin resistance interactions with periparturient gene expression in adipose tissue and lipid metabolism in dairy cows.

Adipose tissue plays an important role in a cow's ability to adapt to the metabolic demands of lactation, because of its central involvement in energy metabolism and immunity. High adiposity and adipose tissue resistance to insulin are associated with excessive lipid mobilization. We hypothesized that the response to a glucose challenge differs between cows of different body condition 21 d before and after calving and that the responses are explainable by gene expression in subcutaneous adipose tissue (SAT). In addition, we aimed to investigate insulin resistance with gene expression in SAT and lipid mobilization around parturition. Multiparous Holstein cows were grouped according to body conditions score (BCS) 4 wk before calving, as follows: BCS ≤ 3.0 = thin (T, n = 14); BCS 3.25 to 3.5 = optimal (O, n = 14); BCS ≥ 3.75 = over-conditioned (OC, n = 14). We collected SAT on d -21 and d 21 relative to calving. A reverse-transcriptase quantitative (RT-q)PCR was used to measure gene expression related to lipid metabolism. One hour after the collection of adipose tissue, an intravenous glucose tolerance test was carried out, with administration of 0.15 g of glucose per kg of body weight (with a 40% glucose solution). Once weekly from the first week before calving to the third week after calving, a blood sample was taken. The transition to lactation was associated with intensified release of energy stored in adipose tissue, a decrease in the lipogenic genes lipoprotein lipase (LPL) and diacylglycerol O-acyltransferase 2 (DGAT2), and an increase in the lipolytic gene hormone-sensitive lipase (LIPE). On d -21, compared with T cows, OC cows had lower mRNA abundance of LPL and DGAT2, and the latency of fatty acid response after glucose infusion was also longer (8.5 vs. 23.3 min) in OC cows. Cows with higher insulin area under the curve on d -21 had concurrently lower LPL and DGAT2 gene expression and greater concentration of fatty acids on d -7, d 7, and d 14. In conclusion, high adiposity prepartum lowers the whole-body lipid metabolism response to insulin and causes reduced expression of lipogenic genes in SAT 3 weeks before calving. In addition, more pronounced insulin release after glucose infusion on d -21 is related to higher lipid mobilization around calving, indicating an insulin-resistant state, and is associated with lower expression of lipogenic genes in SAT.

Maternal and paternal genetic variation in Estonian local horse breeds in the context of geographically adjacent and distant Eurasian breeds.

The maternal and paternal genetic variation of horse breeds from the Baltic Sea region, including three local Estonian breeds, was assessed and compared with that of Altai and Yakutian horses. In the mtDNA D-loop region, 72 haplotypes assigned to 20 haplogroups in the nine breeds were detected. In Estonian local breeds, 38 mtDNA haplotypes were found, and five of them were shared by the three breeds. More than 60% of all identified haplotypes were rare. Compared with the Estonian Native and Estonian Heavy Draught breeds, a higher haplotypic diversity was found in the Tori breed (h = 0.969). Moreover, four haplotypes shared among Finnish and Estonian local horse breeds indicated ancient ancestry, and of these, H30 (haplogroup D3) showed global sharing and genetic links between modern Baltic Sea region and Siberian horses, specifically. The studied breed set showed high variability in maternal inheritance and mixed patterns of the international and native breeds of the Siberian and Baltic regions. No variation was found in paternally inherited markers among horse breeds in the Baltic Sea region.

Fatty acid profile of milk from Saanen and Swedish Landrace goats.

Recent years have had an increased demand for goat milk and its products. The quality of goat milk is determined, in part, by the fatty acid (FA) profile, but there is little information about breed influence on the FA profile of goat milk. The aim of this study was to describe and compare FA profiles of goat milk produced by Saanen and Swedish Landrace breeds. FA profiles were analysed by gas chromatography with a flame ionisation detector using 100 m capillary column coated with ionic liquids of extreme polarity (SLB-IL111). The amounts of 19 FAs were measured. Analyses indicated that FA profile in the milk of Saanen goats differs from that of Swedish Landrace goats with the first having higher proportions of most SFA-s and the second having lower proportions of C16:0, C16:1 and C18:1. This knowledge enables the improvement of the quality of goat milk and goat milk-derived products.

Adipose tissue insulin receptor and glucose transporter 4 expression, and blood glucose and insulin responses during glucose tolerance tests in transition Holstein cows with different body condition.

Glucose uptake in tissues is mediated by insulin receptor (INSR) and glucose transporter 4 (GLUT4). The aim of this study was to examine the effect of body condition during the dry period on adipose tissue mRNA and protein expression of INSR and GLUT4, and on the dynamics of glucose and insulin following the i.v. glucose tolerance test in Holstein cows 21 d before (d -21) and after (d 21) calving. Cows were grouped as body condition score (BCS) ≤3.0 (thin, T; n = 14), BCS = 3.25 to 3.5 (optimal, O; n = 14), and BCS ≥3.75 (overconditioned, OC; n = 14). Blood was analyzed for glucose, insulin, fatty acids, and ß-hydroxybutyrate concentrations. Adipose tissue was analyzed for INSR and GLUT4 mRNA and protein concentrations. During the glucose tolerance test 0.15 g/kg of body weight glucose was infused; blood was collected at -5, 5, 10, 20, 30, 40, 50, and 60 min, and analyzed for glucose and insulin. On d -21 the area under the curve (AUC) of glucose was smallest in group T (1,512 ± 33.9 mg/dL × min) and largest in group OC (1,783 ± 33.9 mg/dL × min), and different between all groups. Basal insulin on d -21 was lowest in group T (13.9 ± 2.32 µU/mL), which was different from group OC (24.9 ± 2.32 µU/mL. On d -21 the smallest AUC 5-60 of insulin in group T (5,308 ± 1,214 µU/mL × min) differed from the largest AUC in group OC (10,867 ± 1,215 µU/mL × min). Time to reach basal concentration of insulin in group OC (113 ± 14.1 min) was longer compared with group T (45 ± 14.1). The INSR mRNA abundance on d 21 was higher compared with d -21 in groups T (d -21: 3.3 ± 0.44; d 21: 5.9 ± 0.44) and O (d -21: 3.7 ± 0.45; d 21: 4.7 ± 0.45). The extent of INSR protein expression on d -21 was highest in group T (7.3 ± 0.74 ng/mL), differing from group O (4.6 ± 0.73 ng/mL), which had the lowest expression. The amount of GLUT4 protein on d -21 was lowest in group OC (1.2 ± 0.14 ng/mL), different from group O (1.8 ± 0.14 ng/mL), which had the highest amount, and from group T (1.5 ± 0.14 ng/mL). From d -21 to 21, a decrease occurred in the GLUT4 protein levels in both groups T (d -21: 1.5 ± 0.14 ng/mL; d 21: 0.8 ± 0.14 ng/mL) and O (d -21: 1.8 ± 0.14 ng/mL; d 21: 0.8 ± 0.14 ng/mL). These results demonstrate that in obese cows adipose tissue insulin resistance develops prepartum and is related to reduced GLUT4 protein synthesis. Regarding glucose metabolism, body condition did not affect adipose tissue insulin resistance postpartum.

Short communication: Genetic correlation and heritability of milk coagulation traits within and across lactations in Holstein cows using multiple-lactation random regression animal models.

Genetic parameters of milk rennet coagulation time (RCT) and curd firmness (a30) among the first 3 lactations in Holstein cows were estimated. The data set included 39,960 test-day records from 5,216 Estonian Holstein cows (the progeny of 306 sires), which were recorded from April 2005 to May 2010 in 98 herds across the country. A multiple-lactation random regression animal model was used. Individual milk samples from each cow were collected during routine milk recording. These samples were analyzed for milk composition and coagulation traits with intervals of 2 to 3 mo in each lactation (7 to 305 DIM) and from first to third lactation. Mean heritabilities were 0.36, 0.32, and 0.28 for log-transformed RCT [ln(RCT)] and 0.47, 0.40, and 0.62 for a30 for parities 1, 2, and 3, respectively. Mean repeatabilities for ln(RCT) were 0.53, 0.55, and 0.56, but 0.59, 0.61, and 0.68 for a30 for parities 1, 2 and 3, respectively. Mean genetic correlations between ln(RCT) and a30 were -0.19, -0.14, and 0.02 for parities 1, 2, and 3, respectively. Mean genetic correlations were 0.91, 0.79, and 0.99 for ln(RCT), and 0.95, 0.94, and 0.94 for a30 between parities 1 and 2, 1 and 3, and 2 and 3, respectively. Due to these high genetic correlations, we concluded that for a proper genetic evaluation of milk coagulation properties it is sufficient to record RCT and a30 only in the first lactation.

Alterations in milk metabolome and coagulation ability during the lactation of dairy cows.

Milk composition has been known to change during lactation. To help understand the changes in metabolic profile throughout the whole lactation, liquid chromatography mass-spectrometry was used to analyze 306 milk samples from 82 primi- and multiparous dairy cows. Changes in metabolic profile common to all cows throughout lactation were ascertained based on principal component and general linear model analysis. Sets of specific markers; for instance, 225, 397, and 641-642 m/z (positive mode), and 186, 241, and 601-604 (negative mode), with at least a 1.5-fold higher intensity during the first 60 d compared with the last 60 d of lactation were observed. The metabolome was affected by parity and milking time. Markers, identified as peptides differentiating parity, were observed. A significant increase for citrate was observed in evening milk. Milk coagulation traits were strongly animal specific. The curd firmness values were influenced by milking time. Sets of markers were associated with curd firmness in positive (197 m/z) and negative (612, 737, 835, 836, 902, 1000, 1038, and 1079 m/z) ion mode.

Composite ß-κ-casein genotypes and their effect on composition and coagulation of milk from Estonian Holstein cows.

The objective of this study was to estimate the effect of composite ß-κ-CN genotypes on milk coagulation and composition traits, and on the additive genetic variation of these traits in Estonian Holstein dairy cattle. A total of 23,970 milk samples, repeated measurements from the first to third lactation from 2,859 Estonian Holstein cows from 78 herds across the country, were analyzed for milk yield, milk fat and protein percentages, somatic cell count, and milk coagulation properties (milk coagulation time and curd firmness). Each cow had at least 3 measurements per lactation. Two single-trait random regression animal models were fitted for the traits studied. The first model considered fixed effects of year-season of sampling and year-season of calving, calving age (nested within lactation), sample age (only for milk coagulation traits) and days in milk, and random herd, additive genetic, and permanent environmental effects. The animal and permanent environmental effects were modeled over the lactation period by using Legendre polynomials. The second model had the additional fixed ß-κ-casein effect in the form of a third-order Legendre polynomial. The 2 most frequent ß-κ-casein composite genotypes were A2A2AA and A1A2AA, both with prevalence greater than 20%. Percentages of the remaining 31 genotypes were less than 8%, including 20 genotypes with percentages less than 1%. The ß-κ-casein genotype-specific lactation curves were significantly different for milk coagulation traits and milk protein percentage. The B variant of κ-casein showed a favorable effect on both milk coagulation traits, whereas the IB haplotype had an increasing effect on curd firmness and protein percentage. Inclusion of the ß-κ-casein genotype effects in the model resulted in decreases in the mean additive genetic variations for milk coagulation time and curd firmness of 12.9 and 51.1%, respectively.

Relationships between milk coagulation property traits analyzed with different methodologies.

Milk coagulation properties (MCP) analysis is performed using a wide range of methodologies in different countries and laboratories, using different instruments, coagulant activity in the milk, and type of coagulant. This makes it difficult to compare results and data from different research. The aims of this study were to propose a method for the transformation of values of rennet coagulation time (RCT) and curd firmness (a(30)) and to predict the noncoagulation (NC) probability of milk samples analyzed using different methodologies. Individual milk samples were collected during the morning milking in October 2010 from each of 165 Holstein-Friesian dairy cows in 2 freestall barns in Italy, and sent to 3 laboratories for MCP analysis. For each laboratory, MCP analysis was performed using a different methodology: A, with a computerized renneting meter instrument using 0.051 international milk clotting units (IMCU)/mL of coagulant activity; B, with a Lattodinamografo (Foss-Italia, Padova, Italy) using 0.051 IMCU/mL of coagulant activity; and C, with an Optigraph (Ysebaert, Frépillon, France) using 0.120 IMCU/mL of coagulant activity. The relationships between MCP traits were analyzed with correlation and regression analyses for each pair of methodologies. For each MCP trait, 2 regression models were applied: model 1 was a single regression model, where the dependent and independent variables were the same MCP trait determined by 2 different methodologies; in model 2, both a(30) and RCT were included as independent variables. The NC probabilities for laboratories with the highest number of NC samples were predicted based on the RCT and a(30) values measured in the laboratories with lower number of NC samples using logistic regression and receiver operating characteristic analysis. The percentages of NC samples were 4.2, 11.5, and 0.6% for A, B, and C, respectively. The transformation of MCP traits was more precise with model 1 for RCT (R(2): 0.77-0.82) than for a(30) (R(2): 0.28-0.63). The application of model 2 was needed when the C measurements were transformed into the other scales. The analyses of NC probabilities of milk samples showed that NC samples from one methodology were well distinguishable (with an accuracy of 0.972-0.996) based on the rennet coagulation time measured with the other methodology. A standard definition for MCP traits analysis is needed to enable reliable comparisons between MCP traits recorded in different laboratories and in different animal populations and breeds.

Folate-metabolizing gene variants and pregnancy outcome of IVF.

There is growing evidence that folate status and variation in folate-metabolizing genes are involved in female reproductive functions. This study evaluated the influence of maternal blood folate, vitamin B(12), homocysteine and 10 folate pathway gene variants on IVF outcome. Also, the prevalence of these polymorphisms was compared in 439 female IVF patients and 225 fertile controls. MTHFR 677 CT heterozygotes had a higher proportion of good-quality embryos and an increased chance of pregnancy. MTHFR 1793 GA heterozygosity was associated with a lower percentage of previously failed IVF treatments. Heterozygosity for FOLR1 1816 C/delC and 1841 G/A was associated with a raised risk of pregnancy loss. The CTH 1208 GT genotype was associated with an increased chance of pregnancy and a smaller number of previously failed IVF cycles and the genotype frequency was lower in IVF patients with three or more previously failed IVF treatments compared with fertile controls. SLC19A1 80 GA heterozygotes had a decreased number of previously failed IVF treatments and were more prevalent among fertile controls. In conclusion, polymorphisms in folate-metabolizing genes may affect ovarian stimulation and pregnancy outcome of IVF, and heterozygous individuals, rather than the wild-type homozygotes, appeared to have more favourable outcomes.

Influence of digital dermatitis and sole ulcer on dairy cow behaviour and milk production.

The aim of the study was to investigate whether the presence of digital dermatitis (DD) and sole ulcer (SU) in dairy cows was associated with changes in behaviour and milk production. Swedish Red and Swedish Holstein cows (mostly in the first to second lactation) were housed in a cubicle system with automatically scraped passageways. After maintenance claw trimming of all the cows in the herd, 10 cows with DD and 10 cows with SU were selected. For each DD- or SU-affected cow, a healthy control cow, matched according to breed, age, parity and lactation stage, was selected. The behaviour of each of the 20 focal cows was observed for 1 h during 2 to 3 weeks after claw trimming (WACT; period 1) and for 1 h during 5 to 6 WACT (period 2). Milk production parameters: energy-corrected milk (ECM), fat and protein percentages and somatic cell counts (SCCs) were recorded once monthly. Lameness was scored once at the start of the study and cows with SU and DD showed more score 2 lameness (42% v. 31%) than the healthy cows (12%). Most differences in behaviour were found during 2 to 3 WACT when DD- and SU-affected cows were lying less (P = 0.001 and P = 0.012, respectively) than healthy cows. Ruminating while standing was performed more in DD-affected cows (P < 0.001) and tended to be performed more in SU-affected cows (P = 0.079) than their controls. Vigilance was performed more in DD- and SU-affected cows than in healthy cows (P < 0.001 and P = 0.047). Cows with DD produced approximately 5.5 kg less ECM per day both at 2 to 3 WACT (P = 0.022) and at 5 to 6 WACT (P = 0.017) than healthy cows, whereas SU-affected cows tended to produce less ECM at 5 to 6 WACT (P = 0.059). No differences in milk fat and protein or SCC were found. It may be concluded that DD-affected cows showed a stronger behavioural response to the claw disease than the SU-affected cows. This shows the importance of regular claw checking and claw trimming of the cows in order to avoid the negative effects on behaviour and milk production.

Morphological quality of oocytes and blood plasma metabolites in repeat breeding and early lactation dairy cows.

The objectives of the study were to evaluate the morphological quality of oocytes in repeat breeder and early lactation cows and to determine the possible associations between the quality of oocytes and a range of blood metabolites. Oocyte quality and a range of metabolites were compared between 29 repeat breeder and 13 early lactation cows. The yield of oocytes from the repeat breeders was lower than that from the early lactation cows (4.4 ± 0.2 vs 5.4 ± 0.6, p < 0.05). Percentages of abnormal oocytes for the repeat breeders and the early lactation cows were 52.5% and 37.9%, respectively (p < 0.001). An excess of abnormal oocytes to normal was found in 55.2% of the studied repeat breeders (65.8% vs 34.2%, p < 0.05). Total protein, glucose and aspartate aminotransferase did not differ (p > 0.05) between the repeat breeders with an excess of abnormal oocytes (81 ± 1.0 g/l, 3.5 ± 1.0 mmol/l and 68.5 ± 3.7 U/l), those with the prevalence of normal oocytes (84 ± 1.0 g/l, 3.6 ± 0.1 mmol/l and 73.2 ± 3.5 U/l) and the early lactation cows (83 ± 2.0 g/l, 3.7 ± 0.1 mmol/l and 74.5 ± 3.6 U/I). The repeat breeders with an excess of abnormal oocytes had higher (p < 0.05) urea (5.2 ± 0.2 mmol/l) level than in those with the prevalence of normal oocytes (4.8 ± 0.2 mmol/l) and the early lactation cows (4.7 ± 0.2 mmol/l). A trend for higher total cholesterol and lactate dehydrogenase activity was found in the repeat breeders with an excess of abnormal oocytes. In conclusion, it is suggested that possible causes of repeat breeding in dairy cows may include impaired oocytes. An excess of abnormal oocytes in the repeat breeder cows was associated with elevated blood plasma levels of urea.

Genetic parameters for milk coagulation properties in Estonian Holstein cows.

The objective of this study was to estimate heritabilities and repeatabilities for milk coagulation traits [milk coagulation time (RCT) and curd firmness (E(30))] and genetic and phenotypic correlations between milk yield and composition traits (milk fat percentage and protein percentage, urea, somatic cell count, pH) in first-lactation Estonian Holstein dairy cattle. A total of 17,577 test-day records from 4,191 Estonian Holstein cows in 73 herds across the country were collected during routine milk recordings. Measurements of RCT and E(30) determined with the Optigraph (Ysebaert, Frepillon, France) are based on an optical signal in the near-infrared region. The cows had at least 3 measurements taken during the period from April 2005 to January 2009. Data were analyzed using a repeatability animal model. There was substantial variation in milk coagulation traits with a coefficient of variation of 27% for E(30) and 9% for the log-transformed RCT. The percentage of variation explained by herd was 3% for E(30) and 4% for RCT, suggesting that milk coagulation traits are not strongly affected by herd conditions (e.g., feeding). Heritability was 0.28 for RCT and 0.41 for E(30), and repeatability estimates were 0.45 and 0.50, respectively. Genetic correlation between both milk coagulation traits was negligible, suggesting that RCT and E(30) have genetically different foundations. Milk coagulation time had a moderately high positive genetic (0.69) and phenotypic (0.61) correlation with milk pH indicating that a high pH is related to a less favorable RCT. Curd firmness had a moderate positive genetic (0.48) and phenotypic (0.45) correlation with the protein percentage. Therefore, a high protein percentage is associated with favorable curd firmness. All reported genetic parameters were statistically significantly different from zero. Additional univariate random regression analysis for milk coagulation traits yielded slightly higher average heritabilities of 0.38 and 0.47 for RCT and E(30) compared with the heritabilities of the repeatability model.

Field trial on progesterone cycles, metabolic profiles, body condition score and their relation to fertility in Estonian Holstein dairy cows.

Resumption of luteal activity postpartum and fertility were investigated in an Estonian Holstein high milk production and good fertility dairy herd. Body condition was scored after every 10 days in 54 multiparous dairy cows (71 lactations) calving inside from December to March during 4-year period. Blood samples were taken 1-14 days before calving and 1-14, 28-42 and 63-77 days after calving: analytes estimated were serum aspartate aminotransferase (AST), glucose, ketone bodies, total cholesterol, non-esterified fatty acids and triglycerides. The general linear mixed model was used to compare the data for cows with different characteristics in luteal activity postpartum based on their milk progesterone profiles. Forty-five per cent of cases had abnormal profiles; delayed resumption of ovarian cyclicity postpartum (DC) was the most prevalent abnormality. There was no difference in body condition scores between the groups. The DC and prolonged luteal phase groups had higher serum AST activity (p < 0.01) 1-14 days postpartum compared with normal group. The DC group also had higher cholesterol and triglyceride values (p < 0.05) 28-42 days postpartum and higher milk fat/protein ratio (p < 0.01) on the first month of lactation compared with normal profile group. Despite long post-calving anoestrous period (71 +/- 5.0 days; mean +/- SEM) DC group had 64.7% first service pregnancy rate (normal group 48.6% and PLP group 37.5%). This study did not find any detrimental effect of prolonged anovulatory period postpartum on subsequent fertility.

Field trial on the relationship of blood metabolites and body condition score with the recurrence of luteal activity in Estonian Holstein cows.

Associations of body condition scores and blood metabolites, measured before calving and at different periods during early lactation, with recurrence of luteal activity were investigated in a 250-head commercial dairy farm during a 4-year period (1999-2002). The study was conducted on 48 dairy cows (60 lactations) with average 305-day milk yield of 8149 kg per cow. Blood samples taken 1-14 days before calving and 1-14, 28-42 and 63-77 days after calving were analysed for aspartate aminotransferase, glucose, ketone bodies, triglycerides, non-esterified fatty acids and cholesterol. Milk progesterone (P(4)) profiles (samples collected twice a week, P(4) levels measured in whole milk by enzyme immunoassay) were used to evaluate the interval from calving to first luteal response, P(4) >5 ng/ml, and the interval from calving to first normal cycle. The MIXED procedure of the sas system was used to study the association of investigated parameters. A higher concentration of ketone bodies before calving was associated with shorter interval to recurrence of first normal cycle (P = 0.007) and tended to be related to shorter interval from calving to first luteal response (P = 0.071). A lower prepartum aminotransferase activity showed a tendency to be associated with shorter interval from calving to first luteal response (P = 0.084). Results suggest metabolic status up to 2 weeks prepartum to be related to the resumption of postpartum luteal activity in Estonian Holstein dairy cows.

Incidence of multifactorial diseases in Estonian dairy herds--a survey.

An important precondition of a well-functioning dairy production is knowledge about the incidence of environmentally evoked non-infectious diseases in a particular herd, in the region and in the country as a whole. The aim of this study was to determine the incidence rate of environmentally evoked multifactorial diseases in Estonian dairy herds, and to compare the disease incidence in small (< or = 100 cows) and large herds (101-300 cows). The disease incidence was recorded by local veterinarians in twelve production units with a total of 33 cowsheds and about 5000 dairy cows. Fourteen disease groups were formed. In order to describe the range of disease incidence, the relative frequency of each group of diseases was determined, as well as the incidence rate. The 95 % confidence interval was applied in order to assess the reliability of the incidence rates. The most common disorders of Estonian dairy cows are udder diseases, followed by uterine infection, metabolic diseases and retained placenta. The disease incidence in Estonian dairy herds is similar to that of other European countries. Most of the diseases occur more often in small herds than in large herds.