Effects of calcium salts of polyunsaturated fatty acids on productive and reproductive parameters of lactating Holstein cows

Abstract

Two experiments evaluated milk production, serum progesterone and insulin, and reproductive performance of lactating Holstein cows receiving or not receiving Ca salts of polyunsaturated fatty acids (PUFA), or receiving Ca salts of PUFA at different daily frequencies. In experiment 1, 1,125 cows randomly distributed in 10 freestall barns were enrolled. Barns were assigned randomly to receive a high-concentrate diet containing (PF) or not containing (control, CON) 1.1% (dry matter basis) Ca salts of PUFA. Diets were offered 6 times daily, whereas the Ca salts of PUFA were included in the PF treatment in the first feeding of the day. In experiment 2, 1,572 cows were randomly distributed in 10 freestall barns, which were assigned randomly to receive a diet similar to PF, but with Ca salts of PUFA included only in the first feeding of the day (PF1X), or equally distributed across all 6 feedings (PF6X). During both experiments, cows were artificially inseminated 12 h after the onset of estrus. Once per month, cows that did not conceive to artificial insemination were assigned to a fixed-time embryo transfer protocol. Pregnancy was determined via transrectal ultrasonography 28 and 60 d after expected ovulation. Pregnancy loss was considered in cows that were pregnant on d 28 but nonpregnant on d 60. During both experiments, feed intake, milk yield, and milk protein and fat content were recorded weekly. Blood samples were collected concurrently with embryo transfer. During experiment 1, feed intake was similar between treatments. Compared with CON, PF cows had greater milk yield (37.8 vs. 35.3 kg/d), and reduced milk fat content (3.41 vs. 3.55%). However, PF cows had reduced pregnancy losses per service compared with CON (12.6 vs. 18.3%). Serum progesterone was greater and serum insulin tended to be greater in primiparous cows receiving PF compared with CON cohorts (4.50 vs. 3.67 ng of progesterone/mL, and 10.4 vs. 7.5 µUI of insulin/mL). During experiment 2, no treatment effects were detected for feed intake, milk yield, or milk fat, whereas PF1X cows tended to have reduced pregnancy losses per service compared with PF6X (14.4 vs. 18.4%). In summary, feeding Ca salts of PUFA to dairy cows increased milk production, did not alter feed intake, and reduced pregnancy losses per service. Further, the total daily amount of Ca salts of PUFA should be fed during the first feeding of the day to optimize its benefits on pregnancy maintenance of dairy cows.

Effects of supplementation of calcium salts of polyunsaturated fatty acids on serum concentrations of progesterone and insulin of pregnant dairy cows

“…Fouladi-Nashta et al (2007) only observed a tendency for greater P 4 concentrations when lactating dairy cows were fed 0.80 kg/d of calcium salts of FA compared with 0.20 kg/d. The results of the present study are in agreement with Lopes et al (2009) and Reis et al (2012), who did not observe increase in serum P 4 concentrations by adding calcium salts of PUFA at approximately 0.20 kg/cow daily. Taking these results together, it is possible that adding 0.22 kg of PF did not result in sufficient amounts of PUFA to decrease the hepatic clearance of P 4 .…”

“…Although there is evidence that feeding fatty acids improved the energy status of lactating dairy cows (Staples et al, 1998), an enhanced reproductive performance may occur apart from an improved energy status of the animals (Sklan et al, 1991). In agreement, Reis et al (2012) reported that feeding calcium salts of polyunsaturated fatty acids (PUFA) at 1.1% of diet DM to lactating dairy cows did not affect DM or energy intake, but decreased pregnancy losses compared with control cows that did not receive PUFA supplementation.…”

“…Likewise, Lopes et al (2009) did not observe differences in serum concentrations of insulin in beef cows supplemented with up to 0.20 kg/d rumen-inert PUFA. Reis et al (2012) reported that adding calcium salts of PUFA (1.1% of diet DM) increased serum P 4 concentrations, and tended to increase serum insulin concentrations in primiparous, but not multiparous cows, which suggests that the outcome of fat supplementation is dependent on the category of animal being used. Thus, it is possible that the lack of differences detected in serum insulin concentrations may be a result of the animal category used in the present study.…”

“…The effects of fat supplementation on insulin concentrations are varied, showing increase (Blum et al, 1985;Reis et al, 2012), no effect (Fouladi-Nashta et al, 2007;Reis et al, 2012), and decrease in concentrations of insulin after fat supplementation (Relling and Reynolds, 2007). Insulin concentrations reflect energy intake, and therefore, differences in insulin concentrations can be due to differences in energy status (Lucy et al, 1991).…”

“…Also, PUFA supplementation may decrease the hepatic metabolism of P 4 (Hawkins et al, 1995). However, limited information exists regarding the effects of relatively small amounts of PUFA supplementation on circulating concentrations of P 4 in dairy cows (Reis et al, 2012). Polyunsaturated fatty acids may be partitioned into different locations (e.g.…”