Effects of feeding a negative dietary cation and anion difference diet to twin-bearing Merino ewes in late gestation on parturition outcomes.

In Australia, dystocia is responsible for 53% of lamb mortalities, and calcium deficiencies may be a contributing factor. A negative dietary cation anion difference (DCAD) diet can increase calcium concentrations in sheep. Therefore, this study aimed to investigate the effects of a negative DCAD diet on metabolic state, mineral status and parturition duration in ewes compared with those fed a positive DCAD diet. At approximately day 130 of gestation (dG), 71 twin-bearing ewes were placed in the following treatment groups; ewes receiving a positive DCAD TMR (total mixed ration) (DCAD of total diet = 281.8 mEq/kg DM; n = 35) and twin-bearing ewes receiving a negative DCAD TMR (DCAD of total diet = -89.0 mEq/kg DM; n = 36). Urine and blood were sampled on dG 130, 140, and 145, and blood was also sampled at the onset of parturition and 4 h post-partum. Urine was analysed for pH and blood was analysed for metabolites, mineral concentration and acid-base balance. Lamb liveweight, rectal temperature, blood glucose and lactate, and body morphology were measured. Serum phosphate concentrations at dG 145 were significantly lower for negative DCAD ewes compared with positive DCAD ewes (1.9 ± 0.1 versus 2.1 ± 0.1 mmol/L, P = 0.047). Ionised calcium (P = 0.09) and serum magnesium (P = 0.09) pre-partum were marginally greater in the negative DCAD ewes (1.35 ± 0.06 and 1.06 ± 0.03 mmol/L respectively) compared with the positive DCAD ewes (1.18 ± 0.08 and 0.98 ± 0.04 mmol/L respectively). Urine pH was lower in the negative DCAD ewes compared with positive DCAD ewes at both dG 140 (7.38 ± 0.17 versus and 8.10 ± 0.19. P = 0.01) and dG 145 (and 7.20 ± 0.19 versus 8.25. P < 0.01). The birth interval between the first the second-born lamb was shorter in the negative DCAD ewes compared with the positive DCAD ewes (P = 0.02), but no differences in lamb survival or lamb viability (P > 0.05) were seen. The negative DCAD diet reduced parturition duration, most likely due to the marginally greater ionised calcium and magnesium concentrations. Despite this improvement, the negate DCAD ewes did not reach urinary acidification, indicating that the marginally significant greater ionised calcium and serum magnesium concentrations was due to the magnesium in the diets and not metabolic acidosis. Further research testing a negative DCAD diet that can achieve the target urine pH is required to determine whether this diet can decrease parturition duration and improve lamb viability.

Negative dietary cation and anion difference supplementation of twin-bearing Merino ewes grazing pasture in late gestation did not affect lamb growth or survival.

Each year in Australia, 53% of lamb mortalities are attributed to dystocia, with subclinical maternal calcium deficiencies likely contributing to dystocia rates. A negative dietary cation and anion difference (DCAD) diet has increased circulating calcium in sheep. Therefore, this study aimed to investigate the effects of supplementing twin-bearing, grazing ewes with a negative DCAD partial mixed ration (PMR) during late gestation on ewe calcium and magnesium concentrations and subsequent lamb growth and survival. On day 120 of gestation (dG), blood samples were collected from 115 twin-bearing Merino ewes and analyzed for glucose, ketone bodies, pH, ionized calcium, and serum calcium and magnesium. On dG 130, ewes were moved into lambing paddocks and placed in the following 2 treatment groups; ewes receiving a positive DCAD PMR (DCAD = 287 mEq/kg DM; n = 58) and ewes receiving a negative DCAD PMR (DCAD = -125 mEq/kg DM; n = 57) fed as a PMR. On dG 140, a blood and urine sample were collected. The urine was tested for pH. Pasture samples were taken on dG 133 and 149 and tested for DCAD and mineral content. When a lamb was 6 to 18 h old, survival, vigor score, liveweight (LW), rectal temperature, blood glucose, and body morphology were recorded. At 10 d of age, lamb LW and survival were recorded and a milk sample was collected from ewes. At 44 d of age, lamb LW and survival were recorded. The DCAD of the pastures across the 6 paddocks ranged from 598 to 893 mEq/kg DM. There were no differences in lamb survival, weight, or viability at any timepoint (P > 0.05). There were no differences in mineral status, metabolic state, or acid-base balance between the positive and negative DCAD-supplemented ewes (P > 0.05) during supplementation (dG 140). Supplementing a negative DCAD diet to ewes grazing pasture during late gestation did not improve lamb survival. The blood and urine pH of the negative DCAD-supplemented ewes indicated a mild metabolic acidosis was not reached due to the high DCAD of the pastures. Further research needs to take careful consideration of the DCAD of pasture when designing a negative DCAD supplement in order for it to be effective.

In Australia, 53% of lamb deaths annually are caused by birthing difficulties, otherwise known as dystocia. Calcium and magnesium deficiencies in ewes during late gestation are suspected to be causing cases of dystocia. We evaluated a supplement that provided a negative dietary cation and anion difference (DCAD) which can influence calcium metabolism, and in turn, may reduce lamb death rates. Grazing twin-bearing Merino ewes were provided either a positive DCAD supplement (n = 58) or a negative DCAD supplement (n = 57) at day 130 of gestation until 2.3 ±â€…0.2 d postpartum. Negative DCAD supplementation did not improve ewe calcium and magnesium concentrations or lamb survival, weight, or viability. The DCAD of the pastures was too high for the negative DCAD supplement to induce a metabolic acidosis as indicated by the urinary pH, which may explain the lack of improvement in mineral status.

Effects of negative dietary cation-anion difference and calcidiol supplementation in transition diets fed to sows on piglet survival, piglet weight, and sow metabolism.

Diets that provide a negative dietary anion cation difference (DCAD) and supplement with a vitamin D metabolite 25-OH-D3 (calcidiol) may increase calcium availability at parturition, and enhance piglet survival and performance. This factorial study assessed the effects of DCAD, calcidiol (50 µg/kg), and parity (parity 1 or >1) and their interactions. Large White and Landrace sows (n = 328), parity 1 to 8 were randomly allocated in blocks to treatment diets from day 103 of gestation until day 3 postfarrow: 1) negative DCAD without calcidiol (negative DCAD + no CA), n = 84, 2) negative DCAD with calcidiol (negative DCAD + CA) n = 84, 3) positive DCAD without calcidiol (negative DCAD + no CA), n = 81, and 4) positive DCAD with calcidiol (positive DCAD + CA), n = 79. Negative DCAD diets were acidified with an anionic feed (2 kg/t) and magnesium sulfate (2 kg/t). All treatment diets contained cholecalciferol at 1,000 IU/kg. Dry sow diets contained 14.8% crude protein (CP), 5.4% crude fiber (CF), 0.8% Ca, and 83 mEq/kg DCAD. Treatment diets 1 and 2 contained 17.5% CP, 7.3% CF, 0.8% Ca, and -2 mEq/kg DCAD. Treatment diets 3 and 4 contained 17.4% CP, 7.4% CF, 0.8% Ca, and 68 mEq/kg DCAD. Before farrowing, all negative DCAD sows had lower urine pH than all sows fed a positive DCAD (5.66 ± 0.05 and 6.29 ± 0.05, respectively; P < 0.01); urinary pH was acidified for both DCAD treatments indicating metabolic acidification. The percentage of sows with stillborn piglets was not affected by DCAD, calcidiol, or parity alone but sows fed the negative DCAD + CA diet had a 28% reduction in odds of stillbirth compared to the negative DCAD + no CA diet and even lesser odds to the positive DCAD + CA diet. At day 1 after farrowing, blood gas, and mineral and metabolite concentrations were consistent with feeding a negative DCAD diet and that negative DCAD diets influence energy metabolism, as indicated by increased glucose, cholesterol, and osteocalcin concentrations and reduced nonesterified free fatty acids and 3-hydroxybutyrate concentrations. In the subsequent litter, total piglets born and born alive (14.7 ± 0.3 and 13.8 ± 0.3 piglets, respectively; P = 0.029) was greater for positive DCAD diets compared to negative DCAD diets; and there was an interaction between DCAD, calcidiol, and parity (P = 0.002). Feeding a negative DCAD diet influenced stillbirth, subsequent litter size, and metabolic responses at farrowing. More studies are needed to define optimal diets prefarrowing for sows.

The transition period between late gestation and lactation is critical to farrowing and successful lactation; sows with higher blood calcium have less risk of dystocia. We evaluated transition diets that provided a negative dietary cation­anion difference (DCAD) and supplemented with calcidiol (CA), both of which influence calcium metabolism. Purebred Landrace or Large White sows (n = 328) were enrolled in the experiment and selected sows that were either primiparous (n = 99) or multiparous (n = 229; average parity = 2.59 ± 1.51; parity range = 1 to 8) were fed a dry sow ration until day 103 of gestation and were then fed transition diets until day 3 postfarrowing in a factorial study. The diets were formulated to include 1) negative DCAD + no CA, 2) negative DCAD + CA, 3) positive DCAD + no CA, or 4) positive DCAD + CA. All diets induced a metabolic acidosis as indicated by urinary pH. Sows fed the negative DCAD with added calcidiol had a >28% reduction in odds of stillbirth over negative DCAD + no CA and positive DCAD + CA diets. Following weaning and re-mating, there were 0.9 more piglets born in the subsequent litter for both positive DCAD diets compared to negative DCAD diets. Blood gas, and mineral and metabolite concentrations provided evidence that negative DCAD diets positively influenced energy metabolism.

Data on the effects of the anionic protein meal BioChlorⓇ on sows before and after farrowing.

Three hundred and two parity 3 and 4 sows were allocated to one of three treatment groups: A (n=106): Control group fed the standard lactation diet; B (n=94): Lactation diet supplemented with 10 kg BioChlor/T; C (n=102): Lactation diet supplemented with 20 kg BioChlor/T. The sows were randomly allocated to treatment on entry to the farrowing shed at 100 d of gestation. The numbers allocated to each treatment were not equal with fewer sows allocated to treatment B at the start of treatment feeding than originally intended. Six allocated sows were not pregnant at their due farrowing date and two control group sows died after treatment feeding commenced prior to farrowing. All sows were individually housed in sow stalls and were fed 3 kg of their treatment diet once a day from d 105 of gestation. At d 110 of gestation, sows were moved into farrowing crates and continued to be fed 3 kg of their treatment diet once a day until the day of farrowing followed by ad libitum feeding of the treatment diet during a 27-d lactation. Approximately 50 litters from each treatment were randomly weighed to determine treatment effects on piglet average daily gain from birth to weaning. Litters were standardized within treatment to 10 piglets per litter at d 3 of lactation by allocating piglets from sows within treatment that had more than 12 piglets. After weaning, all sows were transported to a commercial module and mated on the first display of estrus. Sows were offered a common boar shed diet (13.8 MJ DE/kg; 170 g protein/kg; 9 g lysine/kg) ad libitum from weaning to mating. Following mating, all animals were fed 2.5 kg of a gestation diet (13.0 MJ DE/kg; 125 g protein/kg; 6 g lysine/kg) until farrowing. All sows were stalled individually during the gestation period following treatment feeding. Measures included: date of birth, number of piglets stillborn, number of piglets born alive, total number of piglets born, number of mummified feti, litter weight and number of piglets weighed at birth, litter weight and number of piglets at d 3, 14, and 26, number of piglets stillborn (gestation 2), number of piglets born alive (gestation 2), and total number of piglets born (gestation 2). The number of piglets born alive, number of total piglets born, and all weight measures were analyzed with mixed models with treatment as a fixed effect and sow within farrowing house as a random effect. A negative binomial model was used to estimate the incidence of still birth with sow within farrowing house as a random effect. For the odds of being re-mated a logistic regression mixed model was used to evaluate differences among treatment groups. These data provide information on an individual animal basis that can be used to inform pig producers, nutritionists, veterinarians, and researchers for further investigation on the use of anionic feeds in gestation diets of pigs and is suitable for future meta-analyses.