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Our aim was to estimate the genetic parameters of residual energy intake (REI) and energy conversion efficiency (ECE), and their relationships with milk, feed intake and body weight (BW) and condition in Nordic Red dairy cattle with data from 400 animals. These data were analysed with repeatability and random regression models. The highest heritabilities for energy efficiency traits were obtained in the beginning and the end of the 30 week lactation period (0.21–0.40). The results suggest that the energy efficiencies in early- and mid-lactation periods are partially different traits. The genetic correlations of REI were moderate to high and positive with the other studied traits, and high and positive for ECE with milk, but moderate to low and negative with dry matter intake, BW and body condition score. Further improvements are still needed in modelling the energy efficiency traits of cows during lactation.

The relationship of milk fat–protein ratio (FP), body condition score (BCS), body weight (BW) and their changes (ΔBCS, ΔBW) to energy balance (EB) in early lactation, and usefulness of the traits for predicting of EB of primiparous Finnish Red Dairy Cattle were studied. BW on the first test-day after calving correlated negatively (r=−0.30; P

The differences in body weight (BW) and measurements between the cows of today and the early 70s was evaluated and the usefulness of heart girth (HG), wither height, body length (BL) and body condition score (BCS) as predictors of the BW of modern Finnish Ayrshire cows was estimated. During the last three decades, the BW, HG and BL has increased indicating change in body conformation. The BW prediction equation based on early 70s data underestimate the BW of modern Ayrshire cows. Based on current data it is recommended to use different models to predict BW for primiparous and multiparous cows. From single measurements, HG predicted BW most accurately. Inclusion of BL in model gave slight improve in BW prediction, especially for primiparous cows. An additional term of age or days in milk (DIM) for primiparous cows and BCS or DIM for multiparous cows along with HG increased slightly the accuracy of BW prediction.

Pre-pubertal (86-220 kg BW) Finnish Ayrshire heifers were used to study the effect of feeding level and nitrogen source on GH, IGF-I, and prolactin (PRL) receptors in mammary and liver parenchymal tissue. The heifers were fed a hay-barley diet supplemented with either urea or rapeseed meal. The treatments were: (1) LU, low feeding level+urea; (2) LR, low feeding level+rapeseed meal; (3) HU, high feeding+urea; (4) HR, high feeding level+rapeseed meal. The average daily gains of the heifers on LU, LR, HU and HR diets were 692, 655, 805 and 890 g. At slaughter, mammary and liver parenchymal tissue was collected for preparation of crude membranes, and ligand-binding assays were performed. Specific binding of bGH to mammary membranes could not be detected. Linear Scatchard plots were obtained showing the presence of a single class of high-affinity binding sites for IGF-I in mammary tissue. Specific binding of IGF-I to mammary membranes was unaffected by feeding level and nitrogen source. Furthermore, Scatchard...

The effect of feeding level and nitrogen source on mammary development and plasma hormone levels of pre-pubertal (86 to 220 kg) Finnish Ayrshire heifers was studied. The treatments were: (1) LU, low feeding level + urea; (2) LR, low feeding level + rapeseed meal; (3) HU, high feeding level + urea; (4) HR, high feeding level + rapeseed meal. The average daily gains of the heifers on LU, LR, HU and HR diets were 692, 655, 805 and 890 g, respectively. There was a significantly higher amount of mammary parenchymal tissue and parenchymal DNA at low (L) compared with high (H) feeding levels, but no difference in mammary weights between nitrogen sources was found. Plasma insulin concentration was greater at H compared with L feeding levels, but plasma growth hormone (GH), insulin-like growth factor-I (IGF-I) and prolactin concentrations were not significantly affected by the feeding level. The amount of mammary parenchymal tissue did not correlate with the mean plasma concentration of prolactin and insu...

The effects of feeding intensity and protein source on growth, feed intake, slaughter and body measurements of 24 pre-pubertal Finnish Ayrshire heifers were studied. The heifers were fed a hay-barley diet supplemented with either urea or rapeseed meal (RSM). The treatments were: (1) LU, low feeding level+urea; (2) LR, low feeding level+RSM; (3) HU, high feeding level+urea; (4) HR, high feeding level+RSM. Hay was fed ad libitum on HU and HR diets but was restricted on LU and LR diets. The average initial weight of the heifers was 87 kg, and the final weight 220 kg. There was a significant interaction between feeding level and protein source for growth and feed intake measurements, but not for slaughter quality. Protein source had no impact on the daily gain on low feeding intensity (692 vs. 655 g/d). On high feeding intensity the heifers grew 890 g/d and 805 g/d (P