The objectives of this study were to investigate different feeding strategies of high-yielding dairy cows during dry-off. With a 12- to 13-mo calving interval and increasing milk yield, metabolic and health problems during the dry-off period will increase. Twenty-two dairy primiparous and multiparous cows were randomly assigned to 2 feeding treatments. One group was fed straw ad libitum (straw), and the other group was fed silage (4 kg/d of dry matter) daily and straw ad libitum (silage). At the dry-off point (d 0), the cows had an average milk yield of 17.1 +/- 0.8 kg/d. All cows were milked in the morning on d 3 and 5 during the dry-off period. Rumen fluid was analyzed for volatile fatty acids (VFA), pH, NH3-N, and protozoa were counted from samples collected at d -3, 4, and 17. Total VFA concentration decreased at dry-off in both treatments and the drop was most pronounced among cows fed straw. Rumen pH increased significantly in both groups, and cows fed straw had significantly higher pH during dry-off. Ammonia N in rumen decreased significantly at dry-off and there was a tendency to lowered NH(3)-N in cows fed straw at dry-off. The plasma concentration of nonesterified fatty acids was markedly elevated during the dry-off period among cows in the straw treatment group, but was less pronounced among the cows fed silage with straw. The glucose level in plasma was not significantly affected during the dry-off period, and the insulin concentration was markedly reduced in both treatment groups. Plasma leptin concentration was lower in the lactating state than in the dry period. Both the beta-hydroxybutyrate and urea concentrations in plasma were significantly reduced during dry-off. Our results indicate that dry-off markedly affected the metabolism in the blood and in the rumen of the cows, and that the cows offered only straw during the dry-off were most affected.

The effects of milk yield at dry-off (DO), different calving intervals (CI; 12 and 15 mo) and breed on metabolism and udder health were studied in 56 primiparous and multiparous cows of the Swedish Red and White (SRB) and Swedish Holstein (SH) breeds. The cows were dried off 55 +/- 5 d prior to expected parturition. They were fed 4 kg of DM as silage and wheat straw ad libitum for 5 d, and were milked in the morning of d 2 and 5. Depending on their daily milk yield, the cows were divided into 3 numerically equal groups on 2 d during the week prior to DO: low (LY; 5.0 to 11.4 kg of milk/d, n = 19), medium (MY; 11.5 to 17.7 kg of milk/d, n = 19), and high (HY; 17.8 to 29.5 kg of milk/d, n = 18). The plasma cortisol concentration increased during DO only in MY and HY cows. Plasma nonesterified fatty acids increased during DO in all groups, but the maximum nonesterified fatty acid concentration was related to the milk yield prior to DO. The plasma glucose level during the DO period was not significantly affected by yield, but the insulin concentration decreased after DO, with a more pronounced drop in the HY group. The CI 15-mo group had a higher glucose level and tended to have a higher insulin level in plasma than the CI 12-mo group before DO. They also had a higher body condition than the CI 12-mo group. The results indicate that the CI 15-mo cows had a more positive nutrient balance. There were no effects of CI on milk production or composition during DO. The SRB and SH breeds did not differ in any of the measured plasma parameters or milk production. However, the lower somatic cell counts in SRB than in SH observed before and during DO, as well as after parturition, were attributed to being an effect of breed. The proportion of cows with intramammary infections (IMI) was significantly lower just after calving in the LY group than in the other yield groups. At 2 and 3 wk after DO, significantly fewer cows in the LY group had open teat canals compared with the HY and MY groups, respectively, but teat-end condition did not differ between yield groups. The yield before DO did not significantly influence the somatic cell counts during the first 4 wk after parturition or the presence of IMI 4 wk after parturition. We concluded that in the present study, higher milk yield prior to DO gave rise to a more pronounced metabolic response and a higher risk of contracting IMI during the dry period, at calving, or both, but yield at DO did not have any long-term effects on udder health. A prolonged CI did not facilitate a rapid decrease in milk production. The SRB and SH breeds responded equally in decreasing the milk production during DO, but the SRB breed had lower somatic cell counts.

With increasing milk production and short calving intervals, high daily milk yields at dry-off are rather common, making the dry-off procedure difficult and increasing the risk for health problems during the dry-off period. The objective of the following study was to compare the effects of 2 dry-off protocols, using different nutrient supplies, on health, as measured by clinical findings, intramammary infections, milk somatic cell count, and plasma concentrations of cortisol, serum amyloid A, haptoglobin, and Mg, in dairy cows. Twenty-one primi- and multiparous dairy cows were randomly assigned to 2 different feeding treatments. One group was fed ad libitum straw (straw), whereas the other group was fed 4 kg of DM silage daily and ad libitum straw (silage) during dry-off (i.e., for 5 d). All cows were milked in the morning of d 3 and 5 during this period. At the start of dry-off (d 0), the average daily milk yield was 17.1 +/- 0.8 kg. The plasma cortisol concentration increased during dry-off only in cows fed straw. There was no significant effect of treatment on plasma serum amyloid A, but the concentration increased during dry-off in both groups. The plasma Mg concentration decreased during dry-off, and the values tended to be lower in the straw group. The milk somatic cell count increased in both groups during dry-off but did not differ between groups. In both groups the heart rate decreased at dry-off, but the decrease was more pronounced in the straw group. Overall, this study (together with a previous report) shows that the common dry-off procedure of feeding straw only may give rise to metabolic disturbances. However, this might be avoided without any apparent negative effects on udder health if a limited amount of silage is added during dry-off.

In an experiment with 22 primi-and multiparious cows the effects of two different feeding strategies at dry-off were tested. One group was fed straw ad libitum, while the other group was fed silage (4 kg DM) and straw ad libitum. Plasma NEFA increased signifi cantly at dry-off, especially in the straw group. Plasma insulin and beta-hydroxybutyrate decreased in both groups. Milk fat percentage increased during dry-off as well as protein content. The metabolism of cows in the silage group were not as affected by the dry-off procedure as the cows in the straw group.