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Title:The effects of feeding a negative dietary cation-anion difference diet at two dietary calcium inclusion rates to close up dry cows on the subsequent lactation uterine health and fertility
Author(s):Ryan, Kelly Thomas
Advisor(s):Cardoso, Felipe C.
Contributor(s):Drackley, James K.; Lima, Fabio S.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Transition Cow
Uterine Health
Abstract:Feeding a negative dietary cation-anion difference (DCAD) diet in the prepartum phase been associated with increased biological active blood Ca levels (ionized Calcium; iCa) in the first days postpartum, linked with decrease incidences of hypocalcemia (HC) and subclinical hypocalcemia (SCH), as well as a host of other periparturient disorders. This is achieved by altering the mineral composition of the prepartum diet to induce a slight metabolic acidosis environment to attenuating PTH sensitivity to circulating Ca levels. While this concept has been established in literature, the rate of inclusion of dietary Ca in a negative DCAD diet has not. The objective of this study was to determine at what concentration of dietary Ca to feed with a close-up dry cow negative DCAD diet and the effects on the subsequent uterine health, circulating inflammatory blood metabolites, ovulation dynamics, and fertility. Multiparous Holstein cows (n = 76) were enrolled at 50 days before expected calving date and followed until 75 days in milk (DIM). Treatments began at 28 days before expected calving and were: CON (n = 24), a positive DCAD diet with low dietary Ca (DCAD = 9.46 mEq/ 100 g DM; 0.4% DM); LOW (n = 26), a fully acidified DCAD diet (DCAD = -24.13 mEq/ 100 g DM; urine pH = 5.7) with low dietary Ca (0.4% DM); HIGH (n = 24), a fully acidified DCAD diet (DCAD = -23.97 mEq/ 100 g DM; urine pH = 5.7) with high dietary Ca (2.0% DM). Vaginal discharge was evaluated was at 4, 7, 10, 13, 15, 17, and 30 DIM via Metricheck (MC; 0-3 scale: 0 = clear mucus; 1 = mucus containing non-purulent material; 2 = mucus containing ≤ 50% purulent material; 3 = mucus containing > 50 % purulent material). Polymorponuclear (PMN) cell concentration in the uterus was evaluated at 15 and 30 DIM, and endometrial tissue samples were harvested at 30 DIM for glandular morphology and assessment of superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity as markers of oxidative stress. Blood plasma and serum samples were harvested at -28, -21, -14, -7, 15 and 30 DIM and were assessed for concentrations of lipopolysaccharide binding protein (LBP), serum amyloid A (SAA) and haptoglobin (HP). Ovarian dynamics was assessed at 7, 9, 11-17, 20, 30, 55, 62, and 69 DIM. Data collected were analyzed using PROC MIXED in SAS. Contrasts were CONT1 (CON vs the average of cows fed LOW and HIGH diets) and CONT2 (LOW vs HIGH). Cows fed CON tended to have a lower MC score (P = 0.06) than the average of cows fed LOW and cows fed HIGH. Cows fed LOW tended to have a higher MC score than cows fed HIGH. There were differences in uterine gland epithelial height where cows fed HIGH had greater epithelial height (P = 0.02) than cows fed LOW and cows fed CON tended to have shorter epithelial height (P = 0.06) than the average of cows fed LOW and cows fed HIGH. Cows fed HIGH also had a greater number of epithelial cells per gland (P = 0.05) than cows fed LOW. Anti-oxidative enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) relive oxidative stress in cells. Cows fed HIGH had increased activity of SOD (P = 0.05) decreased activity of GPX (P < 0.001) than cows fed LOW calcium diet. Cows fed LOW had higher HP concentrations than cows fed HIGH in the prepartum (P = 0.01) and post-partum (P = 0.03) periods. Cows fed CON diet had higher (P = 0.01) HP concentration than the average of cows fed LOW and cows fed HIGH (contrast CON vs. LOW and HIGH) postpartum. Cows fed HIGH tended to have an increased likelihood of being pregnant at the first timed artificial insemination. Cows fed HIGH seemed to have an improved uterine environment due to alleviation of oxidative stress, an enhanced immune response to parturition and uterine discharge comparable to cows fed CON. In conclusion, the periparturient period is a challenging time to the dairy cow with numerous metabolic changes that affects lactation and reproductive performance. Calcium metabolism and homeostasis is an important factor and can be influenced by prepartum feeding management. Strategies such as feeding a negative DCAD diet to close-up dry cows has been credited with decreasing incidences of HC and SCH and improving reproductive performance. Additionally, feeding a negative DCAD diet with 2% dietary Ca inclusion seems to attenuate the reproductive health and fertility of the dairy cow.
Issue Date:2019-01-16
Rights Information:Copyright 2018 Kelly Ryan
Date Available in IDEALS:2019-08-23
Date Deposited:2019-05

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