Jaak Samarütel

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 glucose-induced insulin and metabolite responses in Estonian Holstein and Estonian Red dairy cows in two herds

BackgroundInsulin secretion and tissue sensitivity to insulin is considered to be one of the factors controlling lipid metabolism post partum. The objective of this study was to compare glucose-induced blood insulin and metabolite responses in Estonian Holstein (EH, n = 14) and Estonian Red (ER, n = 14) cows.MethodsThe study was carried out using the glucose tolerance test (GTT) performed at 31 ± 1.9 days post partum during negative energy balance. Blood samples were obtained at -15, -5, 5, 10, 20, 30, 40, 50 and 60 min relative to infusion of 0.15 g/kg BW glucose and analysed for glucose, insulin, triglycerides (TG), non-esterified fatty acids (NEFA), cholesterol and β-hydroxybutyrate (BHB). Applying the MIXED Procedure with the SAS System the basal concentration of cholesterol, and basal concentration and concentrations at post-infusion time points for other metabolites, area under the curve (AUC) for glucose and insulin, clearance rate (CR) for glucose, and maximum increase from basal concentration for glucose and insulin were compared between breeds.ResultsThere was a breed effect on blood NEFA (P < 0.05) and a time effect on all metabolites concentration (P < 0.01). The following differences were observed in EH compared to ER: lower blood insulin concentration 5 min after glucose infusion (P < 0.05), higher glucose concentration 20 (P < 0.01) and 30 min (P < 0.05) after infusion, and higher NEFA concentration before (P < 0.01) and 5 min after infusion (P < 0.05). Blood TG concentration in ER remained stable, while in EH there was a decrease from the basal level to the 40th min nadir (P < 0.01), followed by an increase to the 60th min postinfusion (P < 0.01).ConclusionOur results imply that glucose-induced changes in insulin concentration and metabolite responses to insulin differ between EH and ER dairy cows.

Relationships between luteal activity, fertility, blood metabolites and body condition score in multiparous Estonian Holstein dairy cows under different management.

The objective was to compare the relationships between luteal activity and fertility, and relate these parameters to metabolic indices and body condition changes in multiparous Estonian Holstein cows on two commercial dairy farms under different management and levels of production and nutrition (higher, H, n=54 (71 lactations) and lower, L, n=39 (39 lactations)). For statistical analysis cows were categorized according to their milk progesterone (P4) profiles as follows: normal ovarian function; delayed start of cyclicity (DC) (interval from calving to first luteal response (P45 ng/ml up to and more than 50 d respectively, followed by regular cyclicity); cessation of luteal activity (prolonged interluteal interval, P4<5 ng/ml, with a duration of 14 d between two adjacent luteal phases); prolonged luteal activity (P4 levels 5 ng/ml for 20 d without preceding insemination). The Mixed procedure of the SAS system was used to compare milk production traits, blood metabolites (ketone bodies, non-esterified fatty acids, total cholesterol) and aspartate aminotransferase, body condition scores (BCS) and fertility parameters between the two farms, and also fertility parameters between the farms within P4 categories. Differences in milk fat/protein ratio, ketone body levels and BCS indicated a deeper negative energy balance (NEB) during the first month after calving on farm L. On both farms nearly 50% of the recently calved dairy cows suffered from ovarian dysfunction during the post-partum period. Delayed start of cyclicity was the most prevalent abnormal P4 profile, 25% and 28% on farms H and L, respectively. Prolonged luteal activity accounted for one-third of atypical ovarian patterns on farm H, and cessation of luteal activity on farm L. On farm L, DC cows had lower BCS values from day 10 to day 90 after calving compared with normal cows (P<0.01) and cows lost more BCS (1.2 units) during the 40 d after calving than normal resumption cows (0.75 units; P<0.05). On farm H with moderate NEB the delayed start of ovulation post partum did not impair subsequent reproductive performance.