Introduction to Fetal Programming Dr. Jeff Lehmkuhler Extension Beef Specialist Animal & Food Sciences ANR Update Fall 2013

Our Destination

Bovine Fetus Size 35 days 90 days 120 days 180 days 240 days

Barker Hypothesis Fetal Origins Hypothesis = Fetal Programming Traced back 1944 Nazi occupied Holland Calorie ration down to ~ 500 / d Offspring higher disease rates

Fetal Programming Maternal stimuli during pregnancy that can affect fetal development, as well as postnatal growth & health Maternal plane of nutrition influences / alters genetic expression of offspring In some species, lasts for several generations Provide opportunity of phenotypic variation in “Fixed” genotypes = Epigenetics

Epigenetics Heritable changes in gene expression resulting in alterations to chromatin structure – DNA methylation, Histone modification (acetylation), noncoding microRNAs

DNA Methylation Example Most DNA is methylated (CH3) – Regions not methylated are close to regulatory region Variation in methylation in different tissues S-adenosylmethionine = methyl donor influenced by diet Gestating Ewes restricted folate, vitamin B12, betaine, choline, methionine = obesity and impaired immune systems of progeny as adults

Estimated Net Energy Requirements for 2-, 3-, and 5-year old Cows Calving Months Since Calving 1996 Beef NRC Breeding Season Wean Mcal/d 75% Fetal Growth First Trimester

Past Thoughts Dry, mid-gestational cow lowest nutritional needs Best time to “cheat” nutritionally Little fetal development = low nutrient need High supplementation during late gestation = heavier Birth Weights

Placental Development Placentome = Cotyledons (Fetus) + Caruncles (Maternal) Growth occurs throughout gestation – First 2/3 of gestation primary growth Growth slows last trimester Blood flow 4.5-fold increase last ½ gestation

Nutrition & Placenta Nutrient restriction during early/mid-gestation – Lowered placentome weight – Altered Vascularity of placenta – Protein Supplementation on Day 190 = 2X blood flow – Restriction reduces number of cotyledons, not caruncles

Fetal Organ Development Restricted Cows from day of gestation – Fetuses had enlarged hearts & brains – Feeding cows back to same condition score by day 220 of gestation = No differences by d 245 – Vascular of intestines, size of liver, lungs, pancreas, kidney, perirenal fat have also been shown to be impacted by nutrition of the dam

Maternal Nutritional Restriction on Fetal Muscle Development Du et al., 2010 JAS Muscle Fiber Numbers SET No Increase after Birth

Muscle Development Animals born with set number of muscle fibers Hypertrophy occurs after birth = Muscle fiber size increases Low priority tissue = Susceptible to deficiency

Nutrient Restriction Skeletal Muscle Nutrition during pregnancy explained 20% of variation in birth weight (Robinson et al., 2013) Current research shows mixed results on muscle fiber number / diameter / carcass traits

What’s Been Reported – Few Examples Restriction Early preg negative impact on sow placenta, myogenesis = growth, carcass (Foxcroft 2006) Protein Deficiency last 100d in cows = delayed puberty (Corah 1975) Calf BW reduced protein deficiency 2 nd trimester (Micke 2010) Overfeeding Ewes overfed had progeny that were leptin resistant = obesity (Long 2010) Heifers had lower milk production when suppl 1st Trimester (Sullivan 2009) Supplementation Protein suppl lower morbidity (Mulliniks 2013) Suppl lower post- weaning morbidity (Larson 2009)

Timing of Cow Nutritional Plant & Impacts on Cattle Light = Time of nutrition Dark = When Impacts Progeny

So What = Theories We know – Birth weight, Colostrum, and placental development impacted We don’t know – Consistently what impact this will have on growth, fertility, health, etc… Add’l research in area will be forthcoming and help unravel

Recommendations? Manage diet to meet / slightly exceed nutritional requirements at various stages of production Critical points are late gestation / early lactation / early gestation – Often overlooked, hay quality ??, grass availability??, fescue toxicity?? Maintain BCS in 5-6 at critical points, Keeping Cows at Par / + Energy balance = Fertility

Mineral Update Matthews/Burris et al. Selenium Research – Support mix of organic / inorganic Se in mineral Grass tetany – Can occur in fall / winter – Lush pasture (N & K fertilizer) & cereal grain silage Spreadsheet comparison of IRM Rec to 4 oz

Forage Quality Going to be mixed = Recommend testing Late cuttings may be low quality Late Late cuttings may have vegetative regrowth to offset quality Second cuttings should be decent Silage quality likely quite good (high grain content)

Thoughts / Questions Underfed Cow?