The incidence of hypocalcemia increases in high-parity dairy cows because resorption of bone Ca is delayed in these animals, and they appear to have a reduced ability to absorb Ca from the intestine during the early postpartum period. Difructose anhydride (DFA) III has been shown to promote the absorption of intestinal Ca via a paracellular pathway. However, past studies have not reported this effect in peripartum dairy cows. Therefore, we investigated the effect of DFA III supplementation on Ca metabolism during the peripartum period to determine whether DFA III promotes intestinal Ca absorption via this route. Seventy-four multiparous Holstein cows were separated into DFA and control groups based on their parity and body weight. The feed of the DFA group was supplemented with 40g/d of DFA III from -14 to 6d relative to calving. The control group did not receive DFA III. At calving (0h relative to calving), serum Ca declined below 9mg/dL in both groups. However, serum Ca concentrations were greater in the DFA group than in the control group at 6, 12, 24, and 48h relative to calving, and the time required for serum Ca to recover to 9mg/dL during the postpartum period was shorter in the high-parity cows in the DFA group than in those in the control group. Parathyroid hormone concentrations increased immediately after calving in both groups and were greater in the control group than in the DFA group at 12 and 24h relative to calving. Serum 1,25-dihydroxyvitamin D concentrations increased at 0 and 12h relative to calving in both groups and were higher in the control group than in the DFA group at 72h relative to calving. Serum concentrations of the bone-resorption marker cross-linked N-telopeptide of type I collagen (NTX) were not different between the groups during peripartum period, and serum NTX in all cows was lower at 0, 6, 12, 24, 48, and 72h relative to calving than at -21, 4, and 5d relative to calving. Thus, DFA treatment induced faster recovery of serum Ca, although bone resorption was restrained. In conclusion, DFA III promotes intestinal passive Ca absorption via the paracellular pathway during the early postpartum period; this absorption is unaffected by aging.

Requirements to control the large decrease in serum calcium (Ca) due to parturition and to increase the feed intake soon after parturition have been well accepted in dairy cows. This study was aimed to investigate the feed intake affected by serum Ca concentration with difructose anhydride (DFA) III supplement in dairy cows soon after parturition. Fourteen transition Holstein cows were divided into DFA and control (CONT) groups within 1 to 5 parity variations in each group. Measurement schedule for an individual cow was from 14 d before parturition to 7 d following parturition. The cows in DFA group were supplied 0.2 kg/head/d of DFA III feed containing 40 g of pure DFA III while the cows in CONT group received no DFA III. Other feeding procedures were the same for all cows in both groups. At parturition (d 0), serum Ca concentration sharply declined in both groups (p<0.05). Time interval for recovery from decreased serum Ca to its normal range (>9.0 mg/dL) tended to be faster in DFA group (12 h) than in the CONT group (48 h), but the differences were not significant. Active ruminal contraction was observed in DFA group at following parturition of d 1 (p<0.05), d 3 (p<0.05), and d 5 (p<0.01). Dry matter (DM) intake did not differ between the groups. However, positive correlations were observed between serum Ca concentration and ruminal contraction (p<0.001), and between ruminal contraction and DM intake (p<0.001) during following parturition. According to multiple regression analysis (R2 = 0.824, p<0.001), the DM intake was positively affected by serum Ca concentration and ruminal contraction. These results suggest that feed intake soon after parturition in dairy cows can be increased by improvement of serum Ca concentration and active ruminal contraction, but DFA III supplementation in this study did not improve the lower serum Ca concentration due to parturition.

The annual milk yield of dairy cows has been increasing, but the lifetime parity of dairy cows has been gradually decreasing (Essl, 1998; Hare, Norman, & Wright, 2006). Since the economic efficiency of dairy farming is mostly a result of achieved milk production and dairy cow longevity (Heins, Hansen, & Vries, 2012), a reduction in the lifetime parity number in dairy cows directly influences the profitability of dairy farming (Sewalem, Kistemaker, Ducrocq, & Doormaal, 2005). The main reasons for dairy cow culling in the United States of America were reproductive failure, mastitis and udder problems, lameness or injury, other diseases, and poor milk production (USDA, 2007), and reproductive disorders are the most common cause of dairy cow culling in Japan (Nakada, 2006). Most of the aforementioned problems are associated with the nutritive status of the cows around the time of calving. Lee and Kim (2006) reported that a milk yield increase and body condition loss during early lactation as well as periparturient disorders caused reproductive failure in dairy cows. Grohn and Rajala-Schultz (2000) reported that an improvement in milk yield resulted in high incidence rates of reproductive health problems. The extensive energy requirements of high-producing dairy cows result in a severe negative energy balance, which may adversely impact postpartum health and fertility during the early lactation period (Butler & Smith, 1989; Lucy, 2001). In general, the increase rate of dry matter intake (DMI) after

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