Moderate overfeeding of different sources of metabolizable energy and protein. II: Effects on inflammatory status of sheep in late pregnancy and growth trajectory of the offspring.

Our objective was to evaluate the effects of moderate overfeeding of different sources of metabolizable energy (ME) and protein (MP) on inflammatory status of sheep in late gestation and short-term growth performance of the offspring. A total of 32 healthy pregnant Zell ewes (2.5 ± 1 years old, 42.19 ± 1.65 kg body weight [BW]) were selected 7 weeks before lambing. After receiving a ten-day adaptation diet, eight ewes were randomly allocated to each of the four treatments including: 1) The adaptation diet that fulfills ME and MP requirements, according to the National Research Council's (NRC, 2007) recommendations for late pregnant ewes (CON); 2) A diet with 10% higher levels of ME than CON, using corn grain for extra ME (HEC); 3) A diet with 10% higher level of ME compared to CON, using flaxseed for additional ME (HEF); and 4) A diet with a 10% higher level of MP than CON, using a rumen-protected lysin and methionine supplement (RP-Lys & Met) to supply extra MP (PRO). After lambing, ewes continued their dietary treatments until 30 days postpartum; however, the content of ingredients were proportionally increased to meet the recommended levels of energy and protein for lactating ewes (NRC, 2007). Blood samples from the ewes were taken on days -21, -14, and -7 before parturition. Colostrum yield and components were determined, and lamb's BW and milk intake (MI) were measured weekly until 28 days of age. Other growth performance indexes were computed accordingly. Blood samples from the offspring were taken on days 15 and 30 of life. The data was analyzed using SAS software (SAS Institute Inc., 9.4). Compared with the CON, HEF-fed ewes were the only group that had lower levels of oxidative stress and blood inflammatory markers at -7 d before parturition (P < 0.05). Concentrations of aminotransferases in CON-fed ewes were greater than other groups in late gestation (P ≤ 0.05). Offspring of HEF- and PRO-fed ewes had higher birth BW than lambs of the CON-fed group (3.71 and 4.11 vs. 3.01 ± 0.24, Kg for HEF, PRO, and CON, respectively). Except for week 2, lambs of CON-fed ewes had lower BW gain compared with the other offspring (P < 0.01). Lambs of PRO-fed ewes had greater levels of plasma immunoglobulin G (IgG, days 15 and 30 of life; P < 0.05) and MI (from week 2; P < 0.001) than other groups. In conclusion, regardless of the source, moderate overfeeding of ME/MP was more beneficial for the immune status of late pregnant dams and the offspring's performance than non-overfed ones.

Moderate over-feeding of different sources of metabolizable energy and protein improved gestational insulin resistance markers and maternal metabolic status of sheep around lambing.

The objective of this study was to determine the effect of moderate over-nutrition of energy (using flaxseed as a source of n-3 fatty acids) and protein (using rumen-protected lysine and methionine) around parturition on prepartal insulin resistance (IR) and periparturient metabolic status and performance of ewes. For this purpose, 32 apparently healthy ewes (2.5 ± 1 years old, 42.19 ± 1.65 kg body weight (BW)) were randomly selected out of 200 pregnant Zell ewes on d 50 before the expected lambing. After receiving a ten-day adaptation diet, eight ewes were randomly allocated to one of the following four dietary treatments: 1) the adaptation diet that meets the metabolizable energy (ME) and protein (MP) requirements of ewes during late pregnancy as recommended by National Research Council = NRC (2007) (Control = CON). 2) A diet with 10% higher levels of ME than NRC (2007) recommendations using corn grain as a source of extra ME (HEC). 3) A diet with 10% higher levels of ME compared to NRC (2007) recommendations using flaxseed for additional ME (HEF). 4) A diet with a 10% higher level of MP than NRC (2007) recommendations using rumen-protected lysine and methionine as a source of extra MP (PRO). While the dietary treatments did not affect animals' dry matter intake (DMI), the CON ewes lost more BW starting from d 10 to d 30 relative to parturition compared to others (P < 0.05). Milk protein and fat yield (g/d) were significantly higher for PRO and HEF compared to HEC and CON ewes (P < 0.05). Moderately over-fed ewes with MP and ME had an improved insulin sensitivity (IS) compared to CON ones. The source of additional ME also impacted IR indices because HEC showed an enhancement in IS than HEF animals (P < 0.05). A lower IS in CON ewes was parallel with higher concentrations of plasma urea at prepartum (P < 0.01), lower levels of plasma cholesterol, triglyceride (P < 0.01) and glucose post-partum (P < 0.05), and a tendency for higher levels of beta-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) in CON ewes during both pre- and post-partum periods. There were negative correlations between plasma urea, BHB, and NEFA with IR markers on d 7 prepartum in line with these results. Comparing data, we could not find a significant change in metabolic status among ewes fed with either PRO or HEF/HEC. In conclusion, the inclusion of 10% extra MP and ME could improve late gestation maternal IS and the metabolic status of dams around lambing.

Short- and long-term effects of postpartum oral bolus v. subcutaneous Ca supplements on blood metabolites and productivity of Holstein cows fed a prepartum anionic diet.

Little information is available regarding the calcium (Ca) dynamics and how its concentration is influenced following the Ca treatment (injection or bolus) after calving in dairy cows. To evaluate the short- and long-term effects of different sources of Ca supplement to animals fed anionic diets during the pre-partum period, 36 multiparous Holstein cows were randomly assigned to 1 of 3 treatments: (1) control group without Ca supplement (CON); (2) subcutaneous injection of 500 ml of 40% w/v Ca borogluconate immediately post-calving (SUB) and (3) oral supplement of Ca bolus containing 45 g Ca immediately and 24 h post-calving (BOL). Serum concentrations of Ca, P and Mg were measured. Serum concentration of Ca was affected by treatments at 48 h of post-calving (P < 0.01). The mean Ca at 6 h was greater in SUB compared to CON group (2.34 v. 2.01 mmol/l; P < 0.002). The lowest Ca concentration at 12 h was related to CON cows compared with BOL and SUB cows (1.90, 2.16 and 2.14 mmol/l, respectively; P < 0.02); a similar trend was observed 24 h post-calving (P < 0.02). Serum concentrations of P and Mg were not influenced by treatments. Yield of milk, milk protein and fat-corrected milk were lowest (P < 0.05) in SUB cows within 3 weeks of lactation in comparison with CON and BOL cows. However, milk yield and milk composition did not show any difference among treatments throughout the first 3 months post-calving. In general, under conditions of this experiment, Ca supplements to fresh cows as an oral bolus are recommended in comparison with subcutaneous injection.

Effect of oral calcium bolus administration on milk production, concentrations of minerals and metabolites in serum, early-lactation health status, and reproductive performance of Holstein dairy cows.

AIMS: To determine the effects of oral Ca bolus administration in the early postpartum period of cows on milk yield and composition, blood metabolites, early-lactation health status, and reproductive performance. METHODS: Multiparous Holstein dry cows (n=66) with a mean parity of 3.1 (SD 0.35) were fed a diet with a positive dietary cation-anion difference (DCAD) prior to calving. They were randomly assigned to receive no treatment (Control; n=33) or two oral Ca boluses (n=33, 45 g of Ca per bolus); one was administered immediately after calving (Day 0) and the second 24 hours (±30 minutes) later. Blood samples were collected at calving, and on Days 2 and 7 to determine concentrations in serum of Ca, P, Mg, glucose, non-esterified fatty acids (NEFA), and ß-hydroxybutyric acid (BHBA). Milk yield was recorded daily and milk composition was determined weekly from calving until 28 day postpartum. Health and outcomes were determined during the first 30 days postpartum and reproductive outcomes to 180 days postpartum. RESULTS: Mean milk yields and composition over the first month of lactation were similar between cows in the two treatment groups (p>0.1). Mean concentrations of Ca in serum were not different between treatment groups on Day 0, but were higher on Day 2 for cows that received oral Ca boluses (1.77 (SE 0.07)) compared with Control cows (1.54 (SE 0.08)) (p=0.04). Concentrations in serum of P, Mg, glucose, NEFA and ΒHBA did not differ between treatment groups on any day of measurement. Fewer cows that received oral Ca were diagnosed with hypocalcaemia (total concentrations of Ca in serum <1.5 mmol/L) by Day 2 (2/33; 6%) compared with Control cows (12/33; 36%) (p=0.01). There was no difference in the prevalence of other health outcomes between treatment groups. The proportion of cows conceiving to first insemination was greater in cows that received an oral Ca bolus (19/29; 65%) than Control cows (12/29; 41%) (p=0.01). CONCLUSIONS: Oral Ca bolus administration increased concentrations of Ca in serum on Day 2 postpartum, and increased first service conception rates, in cows fed a diet with a positive DCAD prior to calving compared to cows that received no oral Ca bolus supplementation. Because of the small number of cows used in this study, further studies in large-scale dairy farms should be carried out to confirm these findings.