Pregnancy Toxemia in sheep

This presentation was prepared for the annual meeting of the Leicester Longwool Sheep Breeders Association, October 28, 2023.

1. Pregnancy toxemia SUSAN SCHOENIAN Sheep & Goat Specialist Emeritus University of Maryland Extension [email protected] | sheepandgoat.com sheep101.info | wormx.info Facebook @ MDSmallRuminant

2. Pregnancy toxemia Very well-known disease. One of the most common diseases of sheep (#7 NAHMS 2021) A metabolic disease that occurs in late gestation (last 6 weeks). Most common metabolic disorder in pregnant ewes. Usually caused by mismanagement (nutrition) during gestation.

3. Other names for pregnancy toxemia Twin lamb disease Pregnancy disease Gestational toxemia Lambing sickness Lambing paralysis Ketosis H ypoglycemia Hyperketonemia Fatty liver syndrome

4. Late gestation 75% of fetal growth occurs during the last trimester of pregnancy. Ewe starts to put nutrients towards milk production. Rumen capacity is decreasing. The ewe may be slower and less active foraging. Greatest nutritional demands, especially for energy (also calcium).

5. What causes pregnancy toxemia? Negative energy balance resulting from increased energy demands for rapid fetal growth during late gestation. Insufficient nutrition during late pregnancy. Inadequate intake of energy. Decreased rumen capacity due to fetal growth. Rumen capacity can also be decreased by large intra-abdominal fat deposits.

6. How does she get pregnancy toxemia? NEGATIVE ENERGY BALANCE Insufficient glucose due to inadequate nutrition (propionate). She begins to mobilize body fat. The liver processes all the body fat. The increased mobilization of fat overwhelms the liver’s capacity to break it down. When it can’t break down all the fat, the liver makes toxic “ketone bodies.” She’s ultimately unable to clear ketone bodies in time, and pregnancy toxemia results.

7. Risk factors for pregnancy toxemia Any age or breed; some breeds are more prone to developing pregnancy toxemia. Being in late pregnancy Carrying multiple fetuses Being under or over-conditioned Receiving a diet that fails to meet energy (TDN) requirements Low quality forage (can’t eat enough) Having other diseases or conditions that limit intake. Breed and genetics     Triggered by stress

8. What is Stress? A change in diet Change in feeding time Weather changes/extremes Moving to new pens Changing of pen mates Transportation Handling Dogs

9. Diagnosis of pregnancy toxemia History Clinical signs Low blood glucose (early stages) Increased urine ketone concentrations. Increased serum BHBA ( β- hydroxybutyrate) concentrations. Pregnancy toxemia should be suspected any time a late-pregnant ewe lags behind the rest of the flock or goes off-feed.

10. Signs of pregnancy toxemia Symptoms can be different. Lags behind, separation from flock Anorexia (off-feed) Depression, head down Nervous system signs: tremors and blindness Teeth grinding (pain) Recumbency -> death 

11. What else can it be? Some differential diagnoses Pregnancy toxemia Low blood sugar. Ketones in breath, blood, and urine. Caused by inadequate energy intake in late pregnancy. Only seen in late pregnancy Slow disease course (many days) Separation from other sheep. Low blood calcium Caused by sudden increase in calcium demand. Usually occurs late pregnancy but can occur after (dairy females). Moderate disease course (< 1 day). Characteristic pose. Low blood magnesium Caused by low magnesium or salt intake Usually seen during lactation Rapid disease course (hours) Twitchy gait Hypomagnesemia “grass staggers” Milk fever Hypocalcemia More common ~20% of ewes that have pregnancy toxemia also have milk fever.

12. Treatment options Individual penning of affected ewes with access to palatable and energy-dense feeds. Oral administration of energy products Subcutaneous (SQ) injection of glucose products Intravenous (IV) administration of glucose Induction of parturition or abortion (+ birthing assistance) Caesarian section to remove lambs. Euthanasia when ewe is too far gone. Still eating

13. Quick sources of energy to treat early stages of pregnancy toxemia Propylene glycol 60 ml every 6-12 hours Glycerol Corn syrup Molasses Apple Cider Vinegar Homemade sugar solutions table sugar + water yogurt + water ~$40 now

14. Other medicines given to support ewe and lambs Calcium borogluconate (to simultaneously treat milk fever) NSAID (Rx) (to improve ewe survival) Vitamin B12 (role in gluconeogenesis) Electrolytes (to restore hydration) Sodium bicarbonate (to counteract acidosis) Dexamethasone (Rx, to induce lung maturation in pre-term lambs )

15. Treatment of pregnancy toxemia Identify early signs of disease Treatment is much more successful if it is initiated early. Up to 90% ewes will die if left untreated If caesarian section (Vx) is done more than five days before the ewe’s due date, then lamb survival is likely to be very low.

16. Pregnancy toxemia is usually a flock problem. Need to evaluate your nutritional program to make sure ewes are getting enough energy in their diet. If necessary, divide ewes into groups based on BCS, fetal number, and expected lambing dates – and feed accordingly. If ewes are strictly grass-fed, special emphasis should be place on feeding high quality roughage to ewes in late gestation. Aim for body condition score of 3 to 3.5 (at least 2.5) at the time of lambing. Balance rations to make sure pregnant ewes are getting proper nutrition.

17. Balancing rations for pregnant ewes What you need to know Age and weight of ewes Stage of gestation (early, mid, late) Fetal number (1, 2, 3 or more). Nutritive value of feeds “book” values are usually adequate for grain, but not for forages or by-product feeds. How much feed your ewes are consuming (how much you feed minus how much they are WASTING!)

18. Balancing a ration for pregnant ewes Example 4-year-old ewe 154 lbs. Late gestation Twin lambs Stage of Production BW, lb DMI, lb % BW TDN, lb CP, lb Ca, lb P, lb   88 2.33 2.66 1.87 0.271 0.0139 0.0075 Late gestation 110 3.23 2.93 2.13 0.326 0.0161 0.0095 Twins lambs 132 3.63 2.75 2.40 0.363 0.0178 0.0106   154 4.03 2.61 2.66 0.403 0.0194 0.0117   176 4.38 2.48 2.90 0.436 0.0207 0.0128   198 5.90 2.97 3.12 0.506 0.0235 0.0158   220 6.31 2.87 3.34 0.541 0.0249 0.0169   264 7.13 2.70 3.78 0.612 0.0275 0.0189 According to the NRC, she needs to consume 2.66 lbs. of energy (TDN) per day. Her dry matter intake is estimated to be about ~2.6% of her body weight. This is equivalent to ~4.0 lbs. -- or ~4.5 lbs. of feed (AS FED – what you feed her). What about a ewe carrying triplets? She needs 3.01 lbs. of TDN, with an estimated DMI of ~4.6 lbs. (~3% of her body weight). A single-bearing ewe only needs 2.1 lbs. TDN. UME Sheep Ration Evaluator – uses 2007 NRC requirements https://www.sheepandgoat.com/spreadsheets (scroll down)

19. How much is 2.66 lbs. of TDN (energy)? *sheep are ruminants; can’t feed exclusively grain diet to ewes **excluding waste Feedstuff Lbs. (as fed) % DM %TDN Corn* 3.36 90 88 Barley* 3.52 90 84 Commercial feed* 4.10 90 72 Soyhull pellets 4.60 89 65 Alfalfa pellets 4.74 92 61 Good quality hay** 4.62 90 64 Average quality hay** 5.1 90 58 Low quality hay** 5.9 90 50 Corn silage 10.9 34 72 Mature orchardgrass pasture 11.4 44 53 Early fresh orchardgrass 17.1 24 65 Hydroponic fodder 23.6 15 75 ~88% TDN ~58% TDN

20. Good nutrition relies on accurate appraisal of forage. Species Legume hays are typically higher in protein, calcium, and other minerals and vitamins than grass hays. Not necessarily energy. Stage of maturity Biggest factor affecting quality (grass or legume) Leafiness - leaf to stem ratio Most of the nutrients are found in the leaves. Color While you like a bright green color, color can be deceiving. Softness Sheep prefer soft hay. Odor and condition Mold or dust - sheep may refuse to eat. Foreign material Weeds and foreign objects can affect quality and safety.

21. Importance of forage testing Forage usually compromises the majority of the diet of pregnant ewes. Forages vary considerably in their nutritive content. You could be underfeeding or overfeeding nutrients. Visual appraisal is only an estimate of forage quality. Sample CP, % TDN, % Ca, % Second cut 12.1 64.1 0.50 Second cut 12.7 64.1 0.52 Second cut 12.9 59.0 0.51 First cut 7.2 55.2 0.38 Mix with alfalfa 18.8 58.4 0.94 Mostly alfalfa 18.1 54.9 1.02

22. Let’s go back to our 4-year-old, 180-lb. ewe pregnant with twins. What should you feed her?

23. Strictly grass hay (4 lbs./day) Not enough of anything

24. 4 lbs. hay + 2 lbs. of pellets Too much grain = too much energy and protein

25. A balanced ration 0.75 lb. corn + 4 lbs. of mixed hay (75% orchardgrass 25% alfalfa)

26. Okay, so you’re not going to balance rations for your ewes… Then, estimate forage quality and feed: Free choice hay + ½ to 1 lb. of grain Gradual introduce and increase amount of grain in diet. May need more grain if hay quality is poor (stemmy, a lot of waste). More grain for prolific ewes (lots of triplets expected) Add protein to grain ration if hay is deficient (grass, stemmy, mature). Add calcium to grain diet if hay is deficient (not part legume). Free choice minerals don’t ensure adequate intake.

27. Prevention of pregnancy toxemia Adequate energy in diet during last 4-6 weeks of pregnancy. Good quality hay with some grain (energy) supplementation Adequate feeder space for hay and grain Feed yearlings and mature females separately. Avoid abrupt feed changes Avoid stressors Monitor and control parasitism and other diseases.

28. Thank you. Comments? Questions? SUSAN SCHOENIAN Sheep & Goat Specialist Emeritus University of Maryland Extension [email protected] www.sheepandgoat.com www.sheep101.info (/201) www.wormx.info Facebook @ MDSmallRuminant Flickr @ / baalands