Some component of the suckling process inhibits LH secretion and delays postpartum ovulation in beef cows. To investigate a possible role for maternal behavior in suckling-mediated anovulation, 27 crossbred beef cows were randomly allotted to 1 of 3 groups: 1) alien (dam suckled by alien calf; n = 11); 2) own (dam suckled by own calf; n = 8); and 3) weaned (calf removed for 6 days; n = 8). Beginning 14-17 days after parturition (experimental Day 0), cows were control suckled (10 min every 6 h) in stanchions for 6 days by either their own calf or by an alien calf or were weaned. Mean LH pulse frequencies in the alien and weaned groups were similar but were elevated (p < 0.02) on experimental Days 2 and 4 compared to those in the own group. The incidence of luteal activity by experimental Day 10 was greater (p < 0.01) for the alien (72.2%) and weaned groups (75.0%) than for the own group (12.5%). Frequency of oxytocin release following suckling was greater (p < 0.01) in the own group than in the alien group (Day 2: 100% vs. 36.4%; Day 4: 100% vs. 54.6%), whereas suckling-induced release of prolactin was similar for both groups. Data provide evidence that the mother-offspring bond is an important link in suckling-mediated inhibition of LH secretion and ovulation.

The aim of this study was to determine the effect of butaphosphan and cyanocobalamin (BTPC) supplementation on plasma metabolites and milk production in postpartum dairy cows. A total of fifty-two Holstein cows were randomly assigned to receive either: (1) 10 ml of saline (NaCl 0.9%, control group); (2) 1000 mg of butaphosphan and 0.5 mg of cyanocobalamin (BTPC1 group); and (3) 2000 mg of butaphosphan and 1.0 mg of cyanocobalamin (BTPC2 group). All cows received injections every 5 days from calving to 20 days in milk (DIM). Blood samples were collected every 15 days from calving until 75 DIM to determine serum concentration of glucose, non-esterified fatty acids (NEFA), b-hydroxybutyrate (BHB), cholesterol, urea, calcium (Ca), phosphorus (P), magnesium (Mg), aminotransferase aspartate (AST) and g-glutamyltransferase (GGT). The body condition score (BCS) and milk production were evaluated from calving until 90 DIM. Increasing doses of BTPC caused a linear reduction in plasma concentrations of NEFA and cholesterol. Supplementation of BTPC also reduced concentrations of BHB but it did not differ between the two treatment doses. Milk yield and milk protein had a linear increase with increasing doses of BTPC. A quadratic effect was detected for milk fat and total milk solids according to treatment dose, and BTPC1 had the lowest mean values. Concentrations of glucose, urea, P, Mg, AST, GGT, milk lactose and BCS were not affected by treatment. These results indicate that injections of BTPC during the early postpartum period can reduce NEFA and BHB concentrations and increase milk production in Holstein cows.Keywords: butaphosphan, cyanocobalamin, postpartum dairy cows, non-esterified fatty acid ImplicationsThis study presents a new metaphylactic strategy aimed to reduce the intensity of negative energy balance (NEB) in postpartum dairy cows. Unlike previous studies, the current protocol consists of five injections of cyanocobalamin and butaphosphan at 5 days interval during the first 20 days in milk (DIM), the period of greatest metabolic challenge for dairy cows. The results of this experiment indicate that this protocol can improve metabolic adaptation in the early postpartum period, by reducing adipose tissue mobilization and increasing milk production.

This work aimed to describe the activity of paraoxonase 1 (PON1) in serum, follicular fluid and seminal plasma of sheep. Average serum PON1 activity was 286.8 ± 96.2 U/ml in females and 237.6 ± 18.9 U/ml in males. There was a positive correlation between PON1 activity in serum and follicular fluid in females, being twice higher in serum than in follicular fluid (148.8 ± 15.7 U/ml). PON1 activity in males' serum was 10-fold higher than in seminal plasma (21.18 ± 14.2 U/ml), and there was no correlation between PON1 activity in both compartments. Finally, this work suggests that PON1 activity of in sheep is higher compared to other mammalian species, and there is an association between PON1 in serum and follicular fluid only.