Effects of prepartum dietary cation-anion difference on aspects of peripartum mineral and energy metabolism and performance of multiparous Holstein cows

Abstract

The objectives of this study were to determine the effect of decreasing dietary cation-anion difference [DCAD; (Na + K) - (Cl + S)] of the prepartum diet on aspects of mineral metabolism, energy metabolism, and performance of peripartum dairy cows. Multiparous Holstein cows (n = 89) were enrolled between 38 and 31 d before expected parturition and randomized to treatments in a completely randomized design (restricted to balance for previous 305-d mature equivalent milk production, parity, and body condition score) at 24 d before expected parturition. Treatments consisted of a low-K ration without anion supplementation [CON; n = 30, DCAD = +18.3 mEq/100 g of dry matter (DM)]; partial anion supplementation to a low-K ration (MED; n = 30, DCAD = +5.9 mEq/100 g of DM); and anion supplementation to a low-K ration to reach a targeted average urine pH between 5.5 and 6.0 (LOW; n = 29, DCAD = -7.4 mEq/100 g of DM). Cows were fed a common postpartum diet and data collected through 63 d in milk. Urine pH (CON = 8.22, MED = 7.89, and LOW = 5.96) was affected quadratically by decreasing prepartum DCAD. A linear relationship between urine pH and urine Ca:creatinine ratio was observed (r = -0.81). Plasma Ca concentrations in the postpartum period (d 0 to 14; CON = 2.16, MED = 2.19, and LOW = 2.27 mmol/L) were increased linearly with decreasing prepartum DCAD. A treatment by parity (second vs. third and greater) interaction for postpartum plasma Ca concentration suggested that older cows had the greatest response to the low DCAD diet and older cows fed LOW had decreased prevalence of hypocalcemia after calving. A quadratic effect of decreasing DCAD on prepartum DMI was observed (CON = 13.6, MED = 14.0, and LOW = 13.2 kg/d). Milk production in the first 3 wk postpartum was increased linearly with decreasing DCAD (CON = 40.8, MED = 42.4, and LOW = 43.9 kg/d) and DMI in this period also tended to linearly increase (CON = 20.2, MED = 20.9, and LOW = 21.3 kg/d). Overall, effects on intake and milk yield analyzed over wk 1 to 9 postpartum were not significant. This study demonstrates that feeding lower DCAD diets prepartum improves plasma Ca status in the immediate postpartum period and results in increased DMI and milk production in the 3 wk after parturition. Compared with no anion supplementation or lower levels of anion supplementation, greater improvements were observed with the lower DCAD feeding strategy, in which an average urine pH of 5.5 to 6.0 was targeted.

Effects of feeding synthetic zeolite A during the prepartum period on serum mineral concentration, oxidant status, and performance of multiparous Holstein cows

“…The target study population was 50 cows and we assumed that 10 cows would be removed because of twinning or for health reasons. The sample size determination was based on biologically important differences in serum Ca concentrations between parturition and 2 DIM from previous work done by Leno et al (2017). The detectable difference in Ca concentration between the 2 treatments was at least 0.20 mmol/L, with α = 0.05 and β = 0.20.…”

“…Samples of TMR were then composited at 4-wk intervals and feed ingredients were composited over the course of the study. Composited samples were submitted to a commercial laboratory (Cumberland Valley Analytical Services, Waynesboro, PA) for wet chemistry analysis as described by Leno et al (2017). Results from analysis of composited forage samples were input into CNCPS v. 6.5 to determine predicted dietary MP concentrations.…”

Review: Endocrine pathways to regulate calcium homeostasis around parturition and the prevention of hypocalcemia in periparturient dairy cows

“…Metabolic acidosis level prepartum can be easily monitored by measuring either urinary calcium concentrations or urinary pH (Martin-Tereso and Martens, 2014). As described by Leno et al (2017) cows fed a negative DCAD diet prepartum (−74 mEq/kg DM) increased urinary calcium excretion (8.2 v. 0.7 g/ day, in negative DCAD diet and control cows, respectively) and maintained urine pH between 5.5 and 6.0 compared to the control cows (urine pH 7.89). Additionally, circulating calcium concentrations (2.27 v. 2.16 mmol/l), feed intake (3.07% v. 2.88% of BW) and milk yield (43.9 v. 40.8 kg/day) increased postpartum in cows fed a negative DCAD diet compared to control cows.…”

Reducing dietary cation–anion difference seldom affects rumen fermentation, cellulolytic bacteria populations, and microbiota in goats

“…Urine pH is a useful indicator to monitor the effect of a reduced DCAD diet on acid-base balance in goats and sheep [71,72], dairy cows [8,73,74], and buffalo [4]. This phenomenon can be explained using the strong ion difference theory of Stewart [75], who argued that with reductions of DCAD, the concentration of anions in blood would increase and cause the kidney to expel redundant H + in urine, resulting in lower urine pH.…”

“…The DCAD level has been an important parameter in the process of formulating diets in recent years [3][4][5][6][7]. Studies have shown that diets with a lower DCAD could enhance the health and extend the economic life of transition mammary animals [8][9][10].…”