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Shortening the dry period improves postpartum energy balance, which has potential positive effects on metabolic health. This concept has been mainly studied in Holstein cows. The aim of this study was to assess the effect of a short dry period of 4 wk, compared with a standard dry period of 8 wk, on the metabolic status, progesterone profiles, health, and colostrum quality of dairy cows of 2 breeds, Swedish Red (SR) and Swedish Holstein (SH), not treated with antibiotics at dry off. The IgG uptake in calves was also studied to reflect the colostrum quality when shortening the dry period. Cows of both SH and SR were blocked by breed and parity and then randomly allocated to a short dry period of 4 wk (4W, n = 43) or a conventional dry period of 8 wk (8W, n = 34). Blood samples were collected wk −8, −4, −2, −1 and 1, 2, 3, 4, 6, 9, and 12 relative to calving. Prepartum, cows with a 4-wk dry period had higher concentrations of nonesterified fatty acids and lower concentrations of insulin-like growth factor-1 and insulin than 8W cows. Postpartum, plasma concentration of nonesterified fatty acids was lower, whereas plasma insulin and insulin-like growth factor-1 tended to be higher for 4W cows than for 8W cows. Plasma concentration of β-hydroxybutyrate did not differ between dry period lengths. Swedish Holstein cows with a 4W dry period responded with a lower concentration of insulin prepartum than SR and SH on an 8W dry period. The dry period length had no effect on the proportion of disturbed progesterone profiles; disturbed progesterone profiles occurred in 30% of the 4W cows and 47% of the 8W cows. In this trial, only 48.8% of the SR cows had a normal progesterone profile, which differed from the SH where 76.5% had a normal profile. Fertility-related diseases (endometritis, pyometra, anestrus, ovarian cyst) did not differ between the 2 dry period groups: 21% in the 8W group versus 12% in the 4W group, whereas mastitis tended to be more common: 26% of the 4W cows versus 9% of the 8W cows. A short dry period resulted in less colostrum but with a higher content of protein and somatic cell count. Calves were fed colostrum from their dam, and the IgG and total protein in plasma did not differ between calves to mothers with different a dry period length. Shortening the dry period could improve metabolic status in cows of both SH and SR breed postpartum, without compromising the colostrum quality. Health and progesterone profiles were not affected by the dry period length for SH or SR in this study. [ABSTRACT FROM AUTHOR]

We evaluated the effect of shortening the dry period (DP) on milk and energy-corrected milk (ECM) yields, milk components, colostrum quality, metabolic status, and reproductive parameters. Primiparous (n = 372) and multiparous (n = 400) Israeli Holstein cows from 5 commercial dairy herds were subjected to a 60-d or 40-d DP. Cows within each herd were paired according to milk production, age, days in milk, and expected calving. Analysis of the data from all cows, irrespective of age, revealed significant differences in milk and ECM yields that favored the 60-d DP, with a prominent effect in 2 of 5 examined herds. In primiparous cows, milk and ECM yields were similar between groups in 4 of 5 farms. In multiparous cows undergoing a 60-d (vs. 40-d) DP, milk and ECM yields were higher in 3 herds. These differences could not be explained by milk and ECM yields in cows diagnosed with metritis, ketosis, and mastitis (defined by a somatic cell count threshold of 250,000 cell/mL), distribution of infected and non- infected cows, or new infections during DP and after calving. Including the milk and ECM yields from an average of 19.55 d from the previous lactation revealed higher milk and ECM yields for 40-d (vs. 60-d) DP cows in all herds. Analyzing 2 consecutive lactations revealed similar milk and ECM yields between groups in 4 out of 5 herds. In 1 herd, yields were higher in the 40-d compared with the 60-d DP group. One week after calving, the nonesterified fatty acid concentrations of 40-d DP cows were significantly lower than those of 60-d DP cows, indicating better postpartum energy balance. Colostrum quality, measured as IgG concentration, did not differ between the 2 DP groups. Cows assigned to 40-d DP had better reproductive performance, as reflected by fewer days to first insemination, a lower proportion with >90 d to first insemination, and fewer days to pregnancy. With respect to primiparous cows, a short DP increased conception rate after first artificial insemination and decreased the proportion of nonpregnant cows after 150 d in milk. In light of these findings, we suggest that a short DP be applied for its economic and physiological benefits. This is highly relevant to dairy herds located in regions such as Israel, Spain, and Florida that suffer from reduced milk production during the hot season. [ABSTRACT FROM AUTHOR]

Shortening the dry period (DP) has been proposed as a management strategy to improve energy balance in early lactation. It is well known that both shortening and complete omission of the DP reduces milk production in the subsequent lactations. In most of these studies milk production data were obtained from planned animal experiments where cows were randomly assigned to DP length treatments, and cow management and diet composition did not differ among treatments. It may therefore be hypothesized that cows on commercial herds which apply a no-DP or short-DP-strategy, and support this by management adjustments, will have a less dramatic reduction in milk production. In this study, milk production and somatic cell count (SCC) following different DP lengths was investigated under commercial circumstances. Milk production of 342 cows (2,077 test-day records) was available from 5 Dutch commercial dairy herds which started a no DP-strategy for all cows. Test days of the year before applying the no-DP strategy are used as control (323 cows, 1,717 test-day records). Six other herds applied an individual cow approach and have different preplanned DP lengths within one herd. From these herds, information on 81 cows (482 test-day records) with a DP length between 0 and 20 d, 127 cows (925 test-day records) with a DP length between 21 and 35 d, and 143 cows (1,075 test-day records) with a DP length of more than 35 d was available. A generalized linear model incorporating an autoregressive covariance structure accounting for repeated test-day yields within cow was developed to estimate the daily yield (milk, fat and protein) and SCC of all cows. Applying no DP for all cows in the herd resulted in a reduction in postpartum milk production compared with within-herd control lactations (until 305 DIM) between 3.2 and 9.1 kg/d, which was a reduction of 12 and 32%, respectively. For the 6 herds that applied an individual cow approach with different preplanned DP lengths, the cow-specific DP strategy was based on milk production and SCC approximately 2 mo before calving. Cows with a preplanned DP length ranging between 0 and 20 d had a reduction in postpartum milk production between 5.7 and 13 kg/d compared with cows with a DP length of >35 d. Cows with a preplanned DP length ranging from 21 to 35 d had a numerically lower milk production (between 0.6 and 5.3 kg/d) than cows with a preplanned DP length of >35 d, but this difference was significant in only one herd. When corrected for milk yield, no difference in postpartum SCC for cows with different DP lengths was found. [ABSTRACT FROM AUTHOR]