Possibility to Estimate Same Day Energy Status of Dairy Cows during First Half of Lactation by Non-Invasive Markers with Emphasis to Milk Fatty Acids.

Postpartum negative energy balance (NEB) is detrimental to cows and decreases profitability in dairy farming. The two origins of milk fatty acids (FA), de novo synthesized in the mammary gland and plasma lipids initially originating from feed, rumen microbes and the animal's adipose tissue, make milk FA candidates as possible NEB biomarkers. The aim of this study was to assess the possibility to predict EB in cows in the first 150 days of lactation with BCS, milk traits and selected individual milk FA and the ratios of blood-derived and de novo synthesized FA.

The fatty acid composition of Estonian and Latvian retail milk; implications for human nutrition compared with a designer milk.

The study reported in this Research Communication compared retail milks' FA profiles from two neighbouring countries, estimated the potential contributions of these milks and a designer milk (achieved by changing the diet of the dairy cow) to the recommended human dietary intake of FA, and predicted (based on the milk FA profile) methane emission from dairy cows. Retail milks in Estonia and Latvia were purchased from supermarkets monthly for one year. To compare the FA composition of retail milk with designer milk with an increased PUFA content, the bulk milk FA profile from a separate field trial was used.

Field trial on glucose-induced insulin and metabolite responses in Estonian Holstein and Estonian Red dairy cows in two herds.

Background: Insulin 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.

Methods: The study was carried out using the glucose tolerance test (GTT) performed at 31 +/- 1.

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.