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Dealing with uncertain times

Vet Advice with Dr. Ron Clarke

[UPDATED: June 13, 2019] Cattle producers across Western Canada grow weary of the relentless 2018-19 winter. For those of us living on the eastern slopes of the Rockies, it started with a record snowfall in October followed by record cold temperatures that extended across the central and northern Prairies. From mid-December to the end of February the cold broke 75-year records. By the first week of March, many producers looked at sparse feed supplies and thin cows with calving season at the gate. Winter seemed locked in.

Ranchers find themselves beyond the point of planning, the process that starts in summer and early fall when producers have a better handle on feed inventories. Then they consider options, guided by what sits in the feed yard, what can be purchased off the farm, cereal alternatives like baled greenfeed, straw and chaff collection, and extended grazing opportunities.

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This winter caught many by surprise. The deep freeze and snow depleted feed supplies more quickly than usual. Body condition scores plummeted in many herds. Getting calves on the ground and keeping them fed and healthy will be a crisis for some. Keeping brood cows lactating and getting them bred again as they are turned onto pastures — many overgrazed last fall — is going to be a nightmare.

Barry Yaremcio, beef and forage specialist with Alberta Agriculture and Forestry, provided his prognostications to veterinary staff attending the Western Canadian Association of Bovine Practitioners Annual Meeting in Saskatoon, January 2019:

  • Many cows will be turned out to pasture too early.
  • Cows will have low body condition scores this spring.
  • High open cow rates next fall.
  • Poor conception rates this spring.
  • Calving challenges (dystocia) due to inadequate nutrition.
  • Poor forage growth and production in areas experiencing two previous years of moisture deficiency.

Pre-calving nutrition and rebreeding potential is a particular concern. Previous studies comparing high versus low energy and protein intake showed days to estrus after calving varied from 66 days with optimum nutrition to as long as 87 days under poor nutrition. Conception rates varied from 78 per cent (optimum) to 60 per cent (inadequate levels of nutrition).

Body condition scores have an impact on milk yield. One body condition score equals approximately 200 pounds (91 kg) of body weight. One pound of fat (0.45 kg) produces enough energy to generate seven pounds (3.2 kg) of milk, which translates into an additional one pound of calf gain.

Short-term strategies

Overall, hay supplies are approaching record lows. Those who rely upon outside sources for feed, rather than growing their own, are particularly vulnerable. Those with hay to sell will do so at inflated prices, perhaps three times higher than in previous years. Long-term supply arrangements are often difficult. People buying hay are warned about rampant fraud activity and need to be cautious.

One option for individuals is to sell cattle they can’t afford to feed. Custom feeding is an option when available.

Byproducts of food production, normally considered waste, are suddenly in demand. Ammoniating (adding anhydrous ammonia to straw) doubles crude protein content and increases digestibility by 25 per cent, allowing greater use of straw and chaff in cattle feeding. Ammoniated wheat straw is about the same feed quality as prairie hay.

Liquid molasses can be added to straw bales when feed supplies are tight. Seventy to 100 pounds (45 kg) molasses added per 1,000-pound (450 kg) bale provides about two pounds (one kg) per 1,400-pound (630 kg) cow per day.

During drought, after hail, frost or herbicide application, plants accumulate nitrates. Discuss preventative measures regarding nitrate poisoning with your nutritionist and veterinarian. Legumes such as alfalfa rarely accumulate nitrates.

Ergot toxicity is another risk to be considered when feeding screenings. Hay produced from ergot-infested grass may also be toxic and should be inspected before feeding. Early symptoms include feed refusal, digestive upsets and pneumonia-like symptoms. Gangrene of ears, tail and feet happen in later stages of ergot poisoning. Discuss the potential of ergot toxicity with a veterinarian.

Swath and corn grazing is a viable option for some. Access control is key. Calcium and magnesium are deficient in cereal crops, therefore 2:1 Ca:P mineral mixes are inadequate. Use a feedlot-type mineral. Watch manure consistency. Peaked and lumpy manure may indicate a protein deficiency.

Hay stored unprotected outdoors deteriorates. Changes include:

  • 10 to 15 per cent loss of weight.
  • Up to a three per cent loss of protein and seven percent loss of energy (TDN).
  • 10 percent loss of digestibility.
  • 10 per cent increase in feed refusal.
  • Vitamin precursors are oxidized and unavailable.

Western Canadian feeds are deficient in selenium and vitamin E. Vitamin E plays an important role in immunity. Vitamin E requirements are 300 IU/day pre-calving and 500 IU/day post-partum. Present feed regulations limit selenium intake to three mg, which is too restrictive. Use a trace mineral fortified with selenium.

*Recommended magnesium levels are 0.23 to 0.27 per cent. Magnesium prevents downer cows, grass tetany and milk fever. When using salt, use only blue salt, which contains important micro-minerals like iodine and cobalt. Blue salt contains only cobalt and iodine, but does not contain the trace minerals copper, manganese, zinc or selenium, micronutrients deficient in most Western Canadian diets. Salt can be incorporated along with trace minerals in a total mixed ration or fed free choice when trace minerals are included in other formats.

Ionophores increase digestive efficiency five to seven per cent and provide a return on investment of six-to-one. When using ionophores, be careful about toxicity in non-target species.

Remember: colostrum is formed six to eight weeks prior to calving.

Paying attention to lower critical threshold temperature and the digestible energy of feedstuffs prevents one of the pregnant beef cow’s greatest enemies: abomasal impaction. Without wind, the low critical threshold temperature for most beef cattle on the Prairies is -20 C. During cold, windy or wet weather when temperatures fall below -20 C, heat production of the animal must increase immediately to prevent a drop in body temperature. This means eating more. Poor-quality roughage causes impaction.

*Update: Additional information regarding salt supplementation was added.

About the author

Columnist

Dr. Ron Clarke prepares this column on behalf of the Western Canadian Association of Bovine Practitioners. Suggestions for future articles can be sent to Canadian Cattlemen ([email protected]) or WCABP ([email protected]).

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