The following trial information was presented:
- Trial compared heifers with high or low BV (+5 or -5) found that fertility BV is a good predictor of fertility; puberty is an early predictor of fertility. Larger trial will be carried out.
- Found greatest conception loss occurred in the first week after pregnancy (day 4), when the embryo is reliant on follicular fluid. We know what is in the blood is taken up into follicular fluid; can we feed to impact this?
- Research (Nottingham University, Garnsworthy) shows starch helps improve fertility. DNZ trialled fibre vs. starch diets and found the 6-week in calf rate was higher with the fibre diet. Suggested there is need for energy, not a specific type.
- Zeolite trial; attracts cations, can mimic low calcium pre calving. 25 cows per treatment. Dosed 500 g/cow for 2 weeks pre-calving. Plasma calcium didn’t drop so far at Day 0 (vs. control). Phosphrous plummets; risky in cows with boarderline P. Next steps:
- larger trial
- different intakes
- different length of time
- Reviewed cut off for subclinical and clinical ketosis. Higher basal butyrate in NZ cows vs. cows; some absorbed through the rumen wall. In our systems, at 1.2 mM cows don’t have an issue. Possibly needs to be a matrix review to include glucose and NEFA levels.
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