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Inclusion of feed efficiency traits into the dairy cattle breeding programmes will require considering early lactation energy status to avoid deterioration in health and fertility of dairy cows. In this regard, energy status indicator (ESI) traits, for example, blood metabolites or milk fatty acids (FAs), are of interest. These indicators can be predicted from routine milk samples by mid-IR reflectance spectroscopy (MIR). In this study, we estimated genetic variation in ESI traits and their genetic correlation with female fertility in early lactation. The data consisted of 37 424 primiparous Nordic Red Dairy cows with milk test-day records between 8 and 91 days in milk (DIM). Routine test-day milk samples were analysed by MIR using previously developed calibration equations for blood plasma non-esterified FA (NEFA), milk FAs, milk beta-hydroxybutyrate (BHB) and milk acetone concentrations. Six ESI traits were considered and included: plasma NEFA concentration (mmol/l) either predicted by multiple linear regression including DIM, milk fat to protein ratio (FPR) and FAs C10:0, C14:0, C18:1 cis-9, C14:0 * C18:1 cis-9 (NEFAFA) or directly from milk MIR spectra (NEFAMIR), C18:1 cis-9 (g/100 ml milk), FPR, BHB (mmol/l milk) and acetone (mmol/l milk). The interval from calving to first insemination (ICF) was considered as the fertility trait. Data were analysed using linear mixed models. Heritability estimates varied during the first three lactation months from 0.13 to 0.19, 0.10 to 0.17, 0.09 to 0.14, 0.07 to 0.10, 0.13 to 0.17 and 0.13 to 0.18 for NEFAMIR, NEFAFA, C18:1 cis-9, FPR, milk BHB and acetone, respectively. Genetic correlations between all ESI traits and ICF were from 0.18 to 0.40 in the first lactation period (8 to 35 DIM), in general somewhat lower (0.03 to 0.43) in the second period (36 to 63 DIM) and decreased clearly (−0.02 to 0.19) in the third period (64 to 91 DIM). Our results indicate that genetic variation in energy status of cows in early lactation can be determined using MIR-predicted indicators. In addition, the markedly lower genetic correlation between ESI traits and fertility in the third lactation month indicated that energy status should be determined from the first test-day milk samples during the first 2 months of lactation.

Dairy cows have intense fluctuations in digestive, metabolic and hormonal systems around calving which predispose them to various disorders and health problems. The aim of the current experiment was to investigate feed and nutrient intake, rumen fermentation, rumen bacterial communities, milk production, milk fatty acid composition and plasma biomarker profiles of dairy cows to assess the modulation of these functions by in-feed resin acid inclusion. Thirty-six Nordic Red cows were used in a continuous feeding trial starting 3 weeks prepartum and lasting for 10 weeks into the lactation. The cows were fed grass silage ad libitum and the dietary treatments were 1) control with basal concentrate (CON), 2) CON supplemented with tall oil fatty acids (TOFA; 90 % fatty acids and 9% resin acids) at 7.0 g/cow/day and 3) CON supplemented with resin acid concentrate (RAC; 37.5% resin acids) at 1.7 g/cow/day. The mixture of resin acids in TOFA and RAC, consisting mostly of abietic and dehydroabietic acids, originated from coniferous tree species Pinus sylvestris L. and Picea abies L. Feed intake and milk production were measured throughout the experimental period. Milk and blood samples were collected at weeks 2, 3, 6 and 10, and rumen fluid was sampled at weeks 2 and 10 of lactation to analyse rumen fermentation and rumen bacterial communities. The dynamics in feed intake and milk production with progressing lactation showed typical curvilinear trends (P for time

Green biorefineries provide novel opportunities to use the green biomass efficiently and utilize the ecosystem services provided by grasslands more widely. The effects of the inclusion of fractionated grass silage solid fraction (pulp) on feed intake, rumen fermentation, diet digestion and milk production in dairy cows were investigated. Pulp was separated from grass silage using a screw press simulating a green biorefinery. Partial removal of liquid from forage increased DM concentration from 220 to 432 g/kg and NDF from 589 to 709 g/kg DM while CP decreased from 144 to 107 g/kg DM. A feeding trial using an incomplete changeover design with 24 Nordic Red cows and two 3-week periods was conducted. The pulp replaced grass silage in the diet at 0 (P0), 25 (P25) and 50 (P50) percentage of total forage, which was fed ad libitum with 13 kg of concentrate for all treatments. The forage DM intake was highest on P25 (14.1 kg/day) while P0 and P50 did not differ from each other (13.2 and 13.0 kg/day, respectively). There were no differences between the treatments in rumen pH or ammonia N, but the proportion of acetate increased with increasing pulp inclusion. The digestibility was measured using acid insoluble ash and indigestible NDF (iNDF) as internal markers. Neither of the markers detected differences in NDF digestibility, but according to iNDF, apparent total tract organic matter digestibility decreased with increasing pulp inclusion. The cows maintained milk production at P25, but it showed some decline at P50 (energy-corrected milk at P0 and P25 was 39.8 kg/day while for P50, it was 38.5 kg/day, P = 0.056) and the milk protein yield significantly declined with higher pulp inclusion. Simultaneously, the nitrogen use efficiency in milk production increased. It seems that the fibrous grass-based fraction from a biorefinery process has potential to be used as a feed for ruminants.

The inclusion of feed intake and efficiency traits in dairy cow breeding goals can lead to increased risk of metabolic stress. An easy and inexpensive way to monitor postpartum energy status (ES) of cows is therefore needed. Cows' ES can be estimated by calculating the energy balance from energy intake and output and predicted by indicator traits such as change in body weight (Delta BW), change in body condition score (Delta BCS), milk fat:protein ratio (FPR), or milk fatty acid (FA) composition. In this study, we used blood plasma nonesterified fatty acids (NEFA) concentration as a biomarker for ES. We determined associations between NEFA concentration and ES indicators and evaluated the usefulness of body and milk traits alone, or together, in predicting ES of the cow. Data were collected from 2 research herds during 2013 to 2016 and included 137 Nordic Red dairy cows, all of which had a first lactation and 59 of which also had a second lactation. The data included daily body weight, milk yield, and feed intake and monthly BCS. Plasma samples for NEFA were collected twice in lactation wk 2 and 3 and once in wk 20. Milk samples for analysis of fat, protein, lactose, and FA concentrations were taken on the blood sampling days. Plasma NEFA concentration was higher in lactation wk 2 and 3 than in wk 20 (0.56 +/- 0.30, 0.43 +/- 0.22, and 0.13 +/- 0.06 mmol/L, respectively; all means +/- standard deviation). Among individual indicators, C18:1 cis-9 and the sum of C18:1 in milk had the highest correlations (r = 0.73) with NEFA. Seven multiple linear regression models for NEFA prediction were developed using stepwise selection. Of the models that included milk traits (other than milk FA) as well as body traits, the best fit was achieved by a model with milk yield, FPR, Delta BW, Delta BCS, FPR x Delta BW, and days in milk. The model resulted in a cross-validation coefficient of determination (R(2)cv) of 0.51 and a root mean squared error (RMSE) of 0.196 mmol/L. When only milk FA concentrations were considered in the model, NEFA prediction was more accurate using measurements from evening milk than from morning milk (R(2)cv = 0.61 vs. 0.53). The best model with milk traits contained FPR, C10:0, C14:0, C18:1 cis-9, C18:1 cis-9 x C14:0, and days in milk (R(2)cv = 0.62; RMSE = 0.177 mmol/L). The most advanced model using both milk and body traits gave a slightly better fit than the model with only milk traits (R(2)cv = 0.63; RMSE = 0.176 mmol/L). Our findings indicate that ES of cows in early lactation can be monitored with moderately high accuracy by routine milk measurements.

Residual feed intake (RFI) is a candidate trait for feed efficiency in dairy cattle. We investigated the influence of lactation stage on the effect of energy sinks in defining RFI and the genetic parameters for RFI across lactation stages for primiparous dairy cattle. Our analysis included 747 primiparous Holstein cows, each with recordings on dry matter intake (DMI), milk yield, milk composition, and body weight (BW) over 44 lactation weeks. For each individual cow, energy-corrected milk (ECM), metabolic BW (MBW), and change in BW (∆BW) were calculated in each week of lactation and were taken as energy sinks when defining RFI. Two RFI models were considered in the analyses; RFI model [1] was a 1-step RFI model with constant partial regression coefficients of DMI on energy sinks (ECM, MBW, and ∆BW) over lactation. In RFI model [2], data from 44 lactation weeks were divided into 11 consecutive lactation periods of 4 wk in length. The RFI model [2] was identical to model [1] except that period-specific partial regressions of DMI on ECM, MBW, and ∆BW in each lactation period were allowed across lactation. We estimated genetic parameters for RFI across lactation by both models using a random regression method. Using RFI model [2], we estimated the period-specific effects of ECM, MBW, and ∆BW on DMI in all lactation periods. Based on results from RFI model [2], the partial regression coefficients of DMI on ECM, MBW, and ∆BW differed across lactation in RFI. Constant partial regression coefficients of DMI on energy sinks over lactation was not always sufficient to account for the effects across lactation and tended to give roughly average information from all period-specific effects. Heritability for RFI over 44 lactation weeks ranged from 0.10 to 0.29 in model [1] and from 0.10 to 0.23 in model [2]. Genetic variance and heritability estimates for RFI from model [2] tended to be slightly lower and more stable across lactation than those from model [1]. In both models, RFI was genetically different over lactation, especially between early and later lactation stages. Genetic correlation estimates for RFI between early and later lactation tended to be higher when using model [2] compared with model [1]. In conclusion, partial regression coefficients of DMI on energy sinks differed across lactation when modeling RFI. Neglect of lactation stage when defining RFI could affect the assessment of RFI and the estimation of genetic parameters for RFI across lactation. Key words: residual feed intake, dairy cattle, energy sink, lactation stage, genetic parameter

Digestibility traits included in this study were dry matter digestibility (DMD, g/kg), which was calculated based on the indigestible neutral detergent fibre (iNDF, g/kg of dry matter) content in faeces (iNDFf) and in diet (iNDFd), and iNDFf predicted directly from faecal samples by near infrared reflectance spectroscopy (NIRS). The data set was collected at three research herds in Finland and one in Norway including in total 931 records from 328 lactating Nordic Red Cattle and Holstein cows. Observations were associated with different accuracy, due to the differences in sampling protocols used for collecting faecal samples. Heritability estimates varied between different sampling protocols and ranged from 0.14 ± 0.06 to 0.51 ± 0.24 for DMD and from 0.13 ± 0.05 to 0.48 ± 0.18 for iNDFf. Estimated genetic standard deviations were 10.5 g/kg and 6.2 g/kg dry matter for DMD and iNDFf, respectively. Results of our study indicated that recording only the iNDF content in the faeces is sufficient to determine genetic variation in cows’ ability to digest feed. The coefficient of genetic variation for DMD was rather small (1.7%), but could be utilized if it is supported by a positive analysis of benefits over costs. Genetic parameters for cow-specific digestibility predicted by near infrared reflectance spectroscopy

In this study, we aimed to estimate and compare the genetic parameters of dry matter intake (DMI), energy-corrected milk (ECM), and body weight (BW) as 3 feed efficiency-related traits across lactation in 3 dairy cattle breeds (Holstein, Nordic Red, and Jersey). The analyses were based on weekly records of DMI, ECM, and BW per cow across lactation for 842 primiparous Holstein cows, 746 primiparous Nordic Red cows, and 378 primiparous Jersey cows. A random regression model was applied to estimate variance components and genetic parameters for DMI, ECM, and BW in each lactation week within each breed. Phenotypic means of DMI, ECM, and BW observations across lactation showed to be in very similar patterns between breeds, whereas breed differences lay in the average level of DMI, ECM, and BW. Generally, for all studied breeds, the heritability for DMI ranged from 0.2 to 0.4 across lactation and was in a range similar to the heritability for ECM. The heritability for BW ranged from 0.4 to 0.6 across lactation, higher than the heritability for DMI or ECM. Among the studied breeds, the heritability estimates for DMI shared a very similar range between breeds, whereas the heritability estimates for ECM tended to be different between breeds. For BW, the heritability estimates also tended to follow a similar range between breeds. Among the studied traits, the genetic variance and heritability for DMI varied across lactation, and the genetic correlations between DMI at different lactation stages were less than unity, indicating a genetic heterogeneity of feed intake across lactation in dairy cattle. In contrast, BW was the most genetically consistent trait across lactation, where BW among all lactation weeks was highly correlated. Genetic correlations between DMI, ECM, and BW changed across lactation, especially in early lactation. Energy-corrected milk had a low genetic correlation with both DMI and BW at the beginning of lactation, whereas ECM was highly correlated with DMI in mid and late lactation. Based on our results, genetic heterogeneity of DMI, ECM, and BW across lactation generally was observed in all studied dairy breeds, especially for DMI, which should be carefully considered for the recording strategy of these traits. The genetic correlations between DMI, ECM, and BW changed across lactation and followed similar patterns between breeds.

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.

In a search for novel sustainable feed resources for ruminant livestock, interest towards wood-based feed materials such as bark has risen. To evaluate the feed potential of ground bark, a dairy cow feeding experiment was conducted using 24 high yielding (average milk yield in the beginning of the experiment 38.0 ± 4.53 kg/d) Nordic Red cows in a 3 × 3 Latin square design using 21-day periods. The cows were offered grass silage-based diets supplemented with 3 different concentrate feeds; a control concentrate containing no additional bark meal (C) or two different concentrate feeds containing low (LB, 87 g/kg of dry matter (DM)) or high (HB, 173 g/kg DM) level of dried ground pine bark meal supplement. Experimental concentrates were fed at a level of 12.4 kg per day resulting in feeding of ca. 1 and 2 kg of bark meal per day at low and high levels, respectively. The good quality grass silage used as the basal feed elicited high total daily feed DM intake which was on average 25.6 kg. The palatability of all experimental concentrates was good. Dietary bark meal increased the intakes of silage DM and total DM, but decreased yields of milk, energy-corrected milk, milk fat and protein, and concentrations of milk constituents although numerical differences between treatments were small. Bark meal supplements decreased linearly metabolizable energy intake, but had no significant effect on the estimated intake of amino acids absorbed from the small intestine as the concentrate feeds were balanced by rapeseed meal. Dietary bark meal decreased linearly the feed efficiency. Milk from all treatments had good sensory properties. This study demonstrated that the energy value of bark meal was very low compared to the traditional feeds as demonstrated by the decreased production results. The economic output of bark meal inclusion depends on the savings in replacing traditional feeds with bark meal, and the losses as reduced milk sales. In long term, other aspects may be considered such as potential shortage and elevated prices of traditional feeds and need to use non-human edible feed components in animal production, but under current conditions, it cannot be recommended as a feed component for high producing dairy cows.

Dry matter intake (DMI) is a key component of feed efficiency in dairy cattle. In this study, we estimated genetic parameters of DMI over the first 24 lactation weeks in 3 dairy cattle breeds: Holstein, Nordic Red, and Jersey. In total, 1,656 primiparous cows (717 Holstein, 663 Nordic Red, and 276 Jersey) from Denmark, Finland, and Sweden were studied. For each breed, variance components, heritability, and repeatability for weekly DMI were estimated in 6 consecutive periods of the first 24 lactation weeks based on a repeatability animal model. Genetic correlations for DMI between different lactation periods were estimated using bivariate models. Based on our results, Holstein and Nordic Red cows had similar DMI at the beginning of lactation, but later in lactation Holstein cows had a slightly higher DMI than Nordic Red cows. In comparison, Jersey cows had a significantly lower DMI than the other 2 breeds within the first 24 lactation weeks. Heritability estimates for DMI ranged from 0.20 to 0.40 in Holsteins, 0.25 to 0.41 in Nordic Red, and 0.17 to 0.42 in Jerseys within the first 24 lactation weeks. Genetic and phenotypic variances for DMI varied along lactation within each breed and tended to be higher in the middle of lactation than at the beginning of the lactation. High genetic correlations were noted for DMI in lactation wk 5 to 24 in all 3 breeds, whereas DMI at early lactation (lactation wk 1 to 4) tended to be genetically different from DMI in the middle of lactation. The 3 breeds in this study might differ in their genetic variances for DMI, but the differences were not statistically significant in most of the studied periods. Breed differences for the genetic variance tended to be more obvious than for heritability. The potential breed differences in genetic variation for DMI should be considered in a future study using feed intake information from multiple breeds.

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 experiment was conducted to study use of barley fibre and wet distillers’ solubles (WDS), by-products from integrated starch–ethanol production, as feed in dairy cows’ diet. Barley fibre is a fibrous by-product with high content of neutral detergent fibre and low content of starch. Wet distillers’ solubles is the non-fermentable residue after distillation of ethanol. It has a high crude protein content with a high rumen degradability. Ayrshire cows, 12 multiparous and 12 primiparous, were divided into 6 blocks of 4 cows according to parity and calving date. Cows in each block were fed four different total mixed rations (TMR) according to a balanced 4 × 4 Latin Square design within a 2 × 2 factorial arrangement of the treatments. Treatments were two different energy sources (barley (B) or barley + barley fibre (BF, 1:1)) with two protein sources (rapeseed meal (RSM) or RSM + WDS). Thus, the treatments were B, B + WDS, BF and BF + WDS. Grass silage was the forage (400 g/kg diet dry matter). On the B + WDS and BF + WDS diets, the amount of WDS in TMR was 120 g/kg dry matter (DM). The crude protein content of the diets was 180 g/kg DM. Replacing half of the barley grain with barley fibre increased (P versus 33.0 kg/day) but had no effect on DM intake (DMI) (21.5 kg/day versus 21.7 kg/day). Replacement caused a small, but significant (P versus 34.2 g/kg) with no change in protein yield. Inclusion of barley fibre in the diet had no effect on milk fat content but changed (P versus 22.1 kg/day), milk yield (31.7 kg/day versus 33.6 kg/day) and yields of milk components. Inclusion of WDS in the diet decreased efficiency of N utilization. Barley fibre was a good fibrous component in concentrates for dairy cows’ TMR, but WDS was an inferior protein feed to RSM as a feed for lactating Ayrshire dairy cows.

Forty Finnish Ayrshire cows, 16 primiparous and 24 multiparous, were randomly assigned to 1 of 2 treatments (FF1 or FF5). Total mixed ration (TMR) was fed once a day on the FF1 treatment and 5 times a day on the FF5 treatment. The experiment began at calving and continued to wk 28 of lactation. The TMR consisted of a grass silage and concentrate mix. The amount of concentrate in the TMR was 51% on a DM basis. The feeding frequency had no effect on milk or energy-corrected milk yields or on milk composition. The average energy-corrected milk yield was 32.8 kg/d on the FF1 treatment and 32.5 kg/d on the FF5 treatment. The less frequent feeding increased the dry matter intake (DMI) of cows. The average DMI during the experiment was 20.9 kg/d on the FF1 treatment and 19.9 kg/d on the FF5 treatment. The difference in DMI was due to the differences in DMI of the mature cows. Energy and protein conversion tended to be lower with feeding once a day compared with feeding 5 times a day. The cows' feeding behavior was also observed. Cows fed 5 times a day tended to eat quite evenly after each delivery, whereas on the FF1 treatment there were 2 clear feeding peaks in the evening after the feed delivery. The time spent eating during the observation period was longer on FF5 than on FF1. The cows fed once a day spent more time lying than the cows fed 5 times a day. Based on the observations of feeding behavior, feeding a TMR 5 times a day seemed to be too frequent based on the increased restlessness and decreased lying time of the cows.

Fifty primiparous Finnish Ayrshire cows were used in 2×2 factorial study. The factors were the protein-feeding strategy: constant (cCP) or variable (vCP) protein content in concentrate during lactation and the use of a commercial health product from 2 weeks pre- to 8 weeks postpartum. On treatment cCP, the CP content of the concentrate was 180 g/kg in dry matter (DM) throughout the lactation, and on vCP treatment, the CP content was 210, 180 and 150 g/kg DM during lactation days 0–100, 101–200 and 201–305, respectively. The concentrate blends included barley, oats, rapeseed meal, molassed sugar beet pulp and minerals and vitamins. Grass silage and ensiled wet sugar beet pulp (100 g/kg DM in TMR) were used as forage. The forage-to-concentrate ratio in TMR was 55:45 on both treatments. The experimental period was 305 days of the first lactation. The average daily milk yield (cCP: 26.3 kg/day vs. vCP: 27.5 kg/day) was higher (P

The performance of 45 primiparous Ayrshire cows fed total mixed ration (TMR) with constant (TMR1) or variable (TMR3) proportion of concentrate in dry matter was studied. On TMR1 treatment the forage to concentrate ratio of TMR was 53:47 in dry matter (DM) throughout the lactation. On TMR3 the forage to concentrate ratio increased during the lactation being 43:57, 53:47 and 63:37 on 0–100, 101–200 and 201–305 days post partum, respectively. The experimental period was 305 days of the first lactation. The feeding strategy had no significant effect on average milk yield. The energy corrected milk yield was 24.4 kg/day on TMR1 and 24.3 kg/day on TMR3 treatment. Also milk protein content was not affected by the treatment, but the milk fat content tended (P

A field study was conducted to study the relationships between average daily gain (ADG) of heifers and their first lactation milk yield. To predict the body weight (BW) the heart girth of 4058 heifers was measured by AI-technicians. Based on these measurements and national milk recording data, the ADGs before and after breeding were calculated. Other variables collected were after calving BW, calving age, and milk production yields on first lactation. After edits the final data included 2194 Ayrshire (Ay) and 738 Friesian (Fr) heifers and their 7215 relatives. Data used for calving BW and ADGs after breeding was 43% smaller because of missing information. The average BW and age at breeding were 356 kg and 483 days for Ay and 376 kg and 484 days for Fr, respectively. The after calving BW for Ay was 502 kg and for Fr 520 kg. The weights correspond to ADGs of 660 g (S.D. 99 g) and 695 g (S.D. 114 g) before breeding, and 497 g (S.D. 190 g) and 492 g (S.D. 196 g) after breeding for Ay and Fr breeds, respectively. The average 305-day milk yield for Ay was 6198 kg and for Fr 6440 kg. Positive genetic correlations between growth rate before (0.13±0.11) and after (0.34±0.17) breeding and milk yield as well as calving BW and milk yield (0.26±0.13) were found. The environmental correlation between ADG before breeding and milk yield was positive (0.13±0.04), while the ADG after breeding and milk yield was uncorrelated (−0.01±0.04). Based on the feeding trials a negative environmental correlation between ADG before breeding and milk yield could have been expected. It was concluded that the negative effect could not be estimated, because of the disturbance caused by herd effect. Also, the fact that most of the heifers had been reared within recommended limits of ADG could have affected the results.

The effect of different feeding intensity at two stages of gestation on performance of primiparous cows was studied in 40 pregnant Ayrshire cows. The feeding intensity was either medium (M) or high (H) in period 1 (2–6 months of pregnancy) or period 2 (7–9 months of pregnancy) resulting in treatments MM, MH, HM and HH. Before pregnancy all heifers were reared to gain 650 g/day. In period 1, heifers on H feeding intensity, grew significantly faster than heifers on M (844 vs. 638 g/day; SEM=18.9). Daily gains in period 2 were affected by feeding intensity in period 1 and were 710, 1042, 636 and 874 g on MM, MH, HM, and HH diets, respectively. The body weights at calving were 462, 498, 480 and 499 kg on MM, MH, HM and HH diet, respectively. Feeding intensity in period 1 had no effect on milk production, but H plane of nutrition in period 2 increased milk yield by approximately 11% (22.6 vs. 20.3 kg/day, P

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 effect of the rate of increase in concentrate allowance after calving with two concentrate mixes (A and B) differing in composition was evaluated using 64 Finnish Ayrshire cows during the first 100 days of lactation. After calving, the concentrate allowance of multiparous cows was increased stepwise from 4 to 17 kg/day, and of primiparous cows from 3 to 13.5 kg/day over 12 days (F rate of increase; multiparous 1.08 kg/day, primiparous 0.88 kg/day) or 24 days (S rate of increase; mutiparous 0.54 kg/day, primiparous 0.44 kg/day). The concentrates were formulated to have similar crude protein and metabolizable energy concentrations but differing starch and NDF concentrations. For concentrate A the starch and NDF concentrations were 421 and 167 g/kg dry matter (DM) and for concentrate B 258 and 251 g/kg DM. All cows received grass silage ad libitum. The higher concentrate intake during weeks 1 to 4 of lactation with F compared with the S rate of increase caused higher DM, energy and protein intake. The higher concentrate intake for F than for S treatment in early lactation did not cause a large decrease in silage intake (8.8 v. 8.3 kg DM/day). The intake of concentrate A and B after calving did not differ for S treatment. However, for F treatment the intake of fibrous concentrate B increased faster than starch-rich concentrate A during weeks 1 to 4 of lactation. The concentrate composition had no effect on energy-corrected milk (ECM) yield during weeks 1 to 4 of lactation for S treatments, but with F treatments the cows fed B concentrate produced more milk. The F rate of increase in concentrate allowance compared with the S rate increased the calculated energy balance after calving. The rate of increase in concentrate feeding post partum or concentrate composition had no effect on DM, energy or protein intake during the whole 100-day experiment. The average ECM yield over days 1 to 100 of lactation was higher for S than for F treatments and tended to be higher with concentrate B than A. Results of this study showed that by the fast rate of increase in concentrate allowance after calving on a grass silage diet, it was possible to improve the energy status of the cows in early lactation. This had, however, no effect on production later in lactation.

The aim of this paper was to study the genetic parameters for feed intake, milk production, and energy balance in Nordic Red dairy cattle from an experimental data set. The data were collected at the MTT Agrifood Research Finland Rehtijarvi experimental farm in 4 feeding trials between 1998 and 2008, and included lactation wk 2 to 30 for 291 Nordic Red nucleus heifers descending from 72 different sires. The studied traits included weekly averages for energy-corrected milk yield (ECM, kg/d), dry matter intake (kg/d), body weight (BW, kg), body condition score (BCS, score 1 to 5), and energy balance (EB, MJ of metabolizable energy/d). The data were analyzed with both fixed and random regression models. The heritabilities of ECM and BCS were moderate to high and remained fairly constant over the entire lactation period, whereas the heritabilities of BW and EB were the highest in early lactation (0.47 and 0.37, respectively) and declined later on. The heritabilities of DMI were highest (0.33) around lactation wk 5 and again at lactation wk 30, and were somewhat lower at the beginning of the lactation and in the middle period. The genetic correlations between the traits differed considerably between early and later lactation periods, especially for the trait pairs ECM-dry matter intake, ECM-EB, BW-EB, and BCS-EB, being negative or close to zero in lactation wk 2 to 5 but turning moderate to strong and positive by lactation wk 10. The results suggest that the lactating cows express their genetic potential for feed intake and energy utilization most clearly between lactation wk 2 to 10. The best candidate trait for selection might be EB in lactation wk 2 to 5 because it has a moderate heritability and is not genetically correlated with BW or BCS in that period.

Existing variation in energy efficiency and its relationship with milk yield and milk composition, body weight and body condition, feed intake, and energy status was studied in primiparous Nordic Red dairy cattle with data including 3,752 weekly records from 145 cows. Energy efficiency was defined as energy conversion efficiency (ECE) and as residual energy intake (REI) estimated based on Finnish feeding standards (REI₁) or from the current data (REI₂). The results indicated true phenotypic variation in energy efficiency of the cows. The proportion of total variance due to the animal was 0.35 for REI₁, 0.30 for REI₂, and 0.50 for ECE. The high efficiency based on ECE was associated with increased mobilization of body reserves (r = -0.50) and decreased dry matter intake (r = -0.51). With REI as an energy efficiency measure, the increased efficiency was associated with a large decrease in feed intake (REI₁: r = 0.60; REI2: r = 0.74) without any effect on body weight change (REI₁: r = 0.13; REI2: r = 0.00). Increased efficiency based on ECE and REI₁ was associated with increased milk yield (ECE: r = 0.58; REI₁: r = -0.41). A clear effect of stage of lactation on REI was found, which could be caused by true differences in utilization of metabolizable energy during lactation. However, it might also be related, in part, to the lack of knowledge of the composition of body weight change in the beginning of lactation.

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

For almost 3 decades, superovulation and embryo transfer have been used in cattle breeding to increase the number of offspring from genetically superior female animals. Several factors including nutrition affect the number of transferable embryos recovered. We compared the effects of two different dietary protein levels easily achieved in practical conditions on embryo number and quality in superovulated heifers. Finnish Ayrshire heifers ( n = 37) were allocated to isoenergic diets containing either 14% (D14) or 18% (D18) crude protein (CP). Estruses were synchronized, and the heifers were subsequently superovulated and inseminated using a standard FSH-protocol. Embryos were collected 7 days after inseminations (71–72 days after the beginning of the treatment period) by uterine flushing. The number of corpora lutea, and the number and quality of embryos were determined. Protein feeding did not affect superovulatory response, the number of embryos or the number of transferable embryos recovered. Proportionally more poor-quality embryos were found in group D14 than in group D18 (20.2% versus 13.2%, respectively, P = 0.053). It is concluded that a long-term moderate increase in the content of crude protein fed to energy-adequate heifers does not seem to affect superovulatory response and the number of embryos recovered, but it may be advantageous to the quality of embryos.

Soybean meal, fish meal, meat and bone meal, and two animal by-product blends (A, B) were compared as nitrogen sources for corn silage diets for growing dairy heifers of different ages. Supplement A (62% CP) was a blend of meat and bone, meat, poultry, blood, and feather meals. Supplement B (71% CP) included the same ingredients as A but had a higher amount of blood meal and also a low concentration of fish meal. Holstein heifers were divided into five age groups with initial age of 210, 263, 314, 462, and 524 d in age groups 1, 2, 3, 4, and 5, respectively. Animals were fed a corn silage-based diet for ad libitum intake. Average intakes and gains (kg/d) were 5.66, 1.10; 6.76, 1.04; 7.45, .93; 8.51, .83; and 8.68, .80 for age groups 1, 2, 3, 4, and 5, respectively. No significant interactions among protein meal and age group were found for any measurement. Among protein sources no significant differences in growth, DM intake, or feed efficiency were found. However, the DM intake tended to be lower for heifers fed fish meal diets than for heifers fed other diets.

Eighty primiparous cows were assigned to either soybean meal, fish meal, or A and B treatments. Commercial supplement A was a blend of meat and bone, meat, poultry, blood, and feather meals. Commercial supplement B included the same ingredients as A but had a higher amount of blood meal and also a low concentration of fish meal. In vitro undegradabilities of protein were 32.0, 37.8, 38.8, and 42.4% for soybean meal, fish meal, A, and B rations, respectively. Milk yields and body weight changes were not significantly affected by treatments. Because of the lower milk fat content on fish meal diet, FCM yield was lower for cows fed fish meal than soybean meal or B supplements. Milk protein content was 3.19, 3.19, 3.03, and 3.09% on soybean meal, fish meal, A, and B diets, respectively. The calculated protein efficiency (100* output/input) on soybean meal, fish meal, A, and B diets were 47.8, 51.6, 45.9, and 48.7, respectively. The undegraded protein in the fish meal after an 18-h in vitro incubation with protease enzyme (Streptomyces griseus, type V) had a higher concentration of methionine and lysine than the undegraded protein of other supplements. Flavor of milk produced on the soybean and fish meal diets was evaluated. No flavor differences were detected.