The lack of precipitation again has folks asking how to manage cattle on limited forage resources. In these challenging times, it does not hurt to discuss strategies to conserve precious inputs.

There are several strategies that can assist in reducing forage needs which include timely culling of open cows, selling calves early, feeding grains or co-products, proper bale storage, hay feeder type and limiting access to hay.

The following information provided to us by a new UK Beef Cattle Extension specialist, Dr. Jeff Lehmkuhler, will discuss how hay supplies may be stretched by limiting the time cows have access to hay as a conservation approach.

Having weaned calves in the fall from spring calving cows reduces nutrient needs of cows as milk production is eliminated and fetal growth during mid-gestation is slow. Therefore, production and nutrient needs are lowest during this time frame with nutrient needs increasing as cows advance to late gestation. This period of low nutrient demand is a key time frame to implement forage conserving strategies.

The following option assumes cows are in good condition and thin cows should not be managed under these strategies rather they should be separated from the herd. Thin cows will not regain body condition prior to calving needed, decreasing their odds of rebreeding the following season.

Researchers at Purdue investigated restricting cow access to hay. When mature cows were allowed access to hay for 4, 8, 12 or 24 hours, hay disappearance which includes both hay waste and consumption was decreased with reduced access time. Body weight change did not differ between 8, 12 or 24 hours of access while restricting access to only 4 hours resulted in decreased weight gain over the 50-day trial. For mature cows, to maintain body weight gain in this trial, restricting access to only 8 hours was adequate.

Restricting access time to hay resulted in a linear decrease in body weight gain in young, second calf cows. Keep in mind that these young cows are still growing to reach their mature size and have greater nutrient requirements during the dry period than older, mature cows.

In this work, restricting access to hay to 8 hours reduced hay disappearance by approximately 15 percent while not effecting weight change/gains. Restricting time further to only 4 hours resulted in reduced intakes but also impacted cow body weight gain. This is not ideal for thin, mature cows needing to regain body condition score or young, growing cows. Reducing time access to hay may restrict growth and body condition impacting future production and these younger and thinner cows should be sorted from the herd and managed separately if this strategy is to be employed.

Need more proof that this works? Recently, researchers at the University of Illinois reported findings from a similar trial involving restricting access time to hay. Two trials were conducted lasting 87 and 89 days using third trimester Simmental cows. Access to hay in this study was free-choice, 9, 6 or 3 hours.

Hay disappearance decreased from 34 pounds of dry matter for free choice cows to approximately 18 pounds for cows having only 3 hours of hay access.

Hay waste was similar and averaged 32 percent and calculated hay intake was reduced from 21 pounds of dry matter to 12 pounds. Cow body weight gains were 94, 87, 73 and 54 pounds for free-choice, 9, 6 and 3 hour access, respectively.

Body condition score changes followed similar trends to weight changes with cows maintaining body condition with an increase of 0.1 body condition score when cows had only 3 hours of access to hay.

In the second trial conducted by University of Illinois researchers, hay access was restricted to 6 or 9 hours. Again, hay disappearance decreased as access time was limited decreasing by 13 percent and 17 percent in comparison to free-choice for 9 and 6 hours of access. Hay waste was lower in this trial averaging 14 percent. Body weight and body condition score changes were not impacted by restricting hay access in this trial.

These trials indicate that when forage supplies are tight, or for producers looking to reduce annual cow costs associated with stored feeds, restricting the time cows have access to hay can reduce hay disappearance by approximately 15 percent with little impact on animal performance.

Depending upon forage quality, cow body condition score and environmental stress, hay savings may be even greater if time restriction is reduced to 3-4 hours. However, it is not recommended that access be restricted for developing replacement heifers, lactating females, young or thin cows as this may impact future productivity.