Many livestock, particularly those making a living on rangelands, encounter poor-quality forages at some point in the grazing season or during the winter, (less than 7% crude protein and 50% TDN). But that doesn’t have to be a problem. We’ve found that introducing them to poor-quality roughage early in life with their mothers actually makes them more productive over their lifetimes. And, not giving them this early experience, but instead feeding replacement females high-quality diets, may actually make it harder for them to maintain weight and reproduce on poor-quality rangeland or on forages high in toxins.
Here are some examples of what our research has demonstrated about how exposure to poor-quality or high-toxin forages early in life can increase intake and preference for certain forages and improve productivity of your livestock.
Increasing How Much of a Poor-Quality Forage Animals Will Eat
In this example we looked at goat kids who learned to eat poor-quality forages from their mothers before they were weaned. We used Blackbrush, a low-quality, high-tannin forage that grows in southern Utah. Goat kids foraged on blackbrush with their mothers for 3 months when they were 1 to 4 months of age. Another group of kids were not fed blackbrush until after they were weaned at 4 months of age. As yearlings, goats that had learned to eat blackbrush with their mothers ate 20% more blackbrush than yearling goats who hadn’t extent the shrub until 4 months of age (Distel and Provenza, 1991).
Increased Preference for Poor-Quality Forage Too
Being introduced to Blackbrush with their mom turned into a long-term preference for it as well. When the yearling goats were given a choice of alfalfa pellets and blackbrush, the goats who learned early with mom ate 30% more blackbrush than goats exposed later without mom (Distel and Provenza 1991). Similar results have been reported for sheep eating poor-quality grass hay (Distel et al. 1994).
Improved Performance on Poor Quality Forage
Early experience in life can affect how animals perform on a feed much later in life. Five-year-old cows wintered on two-thirds ammoniated straw and one-third alfalfa hay gained 81 pounds from December to March provided they had been exposed to ammoniated straw with their mothers early in life. Cows without exposure lost 48 pounds during the same period. Interestingly, weight differences between the two groups persisted over the summer. The following November, cows experienced at eating ammoniated straw still weighed 48 pounds more than inexperienced cows. Differences in weight for the two groups of cows persisted for at least three years (Wiedmeier et al. 2002).
A little exposure to ammoniated straw can go a long way. Half the cows in this study were exposed as calves to ammoniated straw during late gestation and early lactation. After weaning, all cows were fed high-quality diets until they were 2 1⁄2 years of age. They were not fed ammoniated straw again until 5 years of age. When both groups of cows were wintered on ammoniated straw and alfalfa, those who had brief exposure to straw in utero and soon after birth enabled them to out-perform cows without exposure to ammoniated straw as calves.
In this same study, cows with prior exposure to ammoniated straw bred back 9 days sooner and produced 20% more milk than cows without exposure (Wiedmeier et al. 2002).
Early Exposure = Physical Changes
Exposure to foods early in life can even change how the body works. For example, lambs fed poor- quality roughage with their mothers when they were 1 to 4 months of age digested poor-quality forages to a greater extent (55.1% vs. 50.6%) than lambs without exposure to poor-quality forages. Lambs experienced with poor-quality roughage also recycled nitrogen more efficiently than lambs without experience (Distel et al. 1994, 1996).
As an example, let’s look at animals grazing saltbush (Atriplex nummularia). One group of pregnant ewes grazed saltbush from the 60th day of pregnancy until 3 weeks after lambing. The other group of ewes grazed pasture during and after pregnancy. When lambs from both groups were 10 months of age, they grazed saltbush for 8 weeks. Lambs from ewes that had eaten saltbush during and after pregnancy gained more weight, had heavier fleece weights, and increased excretion of salt from the body than lambs from ewes that grazed pasture during and after pregnancy (Chadwick et al. 2009). (Note: There are several saltbushes that grow in Utah including fourwing, mat, Gardner, and shadescale. All are palatable to livestock.)
Better Adaptations to Plants High in Toxins
Since there are plants out there that carry high toxin loads, preparing your livestock early helps them make better forage choices. What we learned is that animals are more likely to eat plants high in toxins, like sagebrush, if their first experience with the plant is positive. In this case, one group of lambs was fed an alfalfa-grain mix immediately before and after eating an unfamiliar, poor-quality, high-toxin feed. The other group was fed the same alfalfa-grain mix and the unfamiliar, poor-quality, high-toxin feed at different times of the day. Lambs fed the high-quality feed and high-toxin feed closely in time, ate more of the toxin-containing feed and spent less time searching for other feeds than lambs fed the two feeds at different times of the day (Baraza et al. 2005). In addition, lambs eating a tannin-containing feed and a high-quality feed in the same meal showed greater preference for the tannin-containing feed than animals that ate the two feeds in separate meals (Villalba et al. 2006). This is useful for those of us who’d like to help our animals eat forages that contain toxins to help them deal with parasites.
What Should You Do With This?
Feed young animals and their mothers unlimited poor-quality forages. For young animals, milk will supplement poor-quality forage. If forages don’t provide adequate nutrition for mom during lactation, providing limited amounts of high-quality supplements will boost nutrition and encourage and enable mom and her offspring to eat poor-quality feeds and still provide benefits when animals eat poor-quality foods later in life.
And here are the references if you’d like to read more:
Baraza, E., J.J. Villalba, and F.D. Provenza. 2005. Nutritional context influences preferences of lambs for foods with different plant secondary metabolites. Applied Animal Behavior Science 92:293–305.
Catanese F., R.A. Distel, R.M. Rodrı ́guez Iglesias, and J.J. Villalba. 2010. Role of early experience in the development of preference for low-quality food in sheep. Animal 4:784–791.
Chadwick, M.A., I.H. Williams, P.E. Vercoe, and D.K. Revell. 2009. Feeding pregnant ewes a
high-salt diet or saltbush suppresses their offspring’s postnatal renin activity. Animal 3:972–979.
Distel, R.A., and F.D. Provenza. 1991. Experience early in life affects voluntary intake of blackbrush by goats. Journal of Chemical Ecology 17:431-450.
Distel, R.A., J.J. Villalba, and H.E. Laborde. 1994. Effects of early experience on voluntary intake of low-quality roughage by sheep. Journal of Animal Science 72:1191-1195.
Distel, R.A., J.J. Villalba, H.E. Laborde, and M.A. Burgos. 1996. Persistence of the effects of early experience on consumption of low- quality roughage by sheep. Journal of Animal Science 74:964-968.
Villalba, J.J., F.D. Provenza, and R. Shaw. 2006. Initial conditions and temporal delays influence preference for foods high in tannins and for foraging locations with and without foods high in tannins by sheep. Applied Animal Behavior Science 97:190– 205.
Wiedmeier, R.D., F.D. Provenza, and E.A. Burritt. 2002. Exposure to ammoniated wheat straw as suckling calves improves performance of mature beef cows wintered on ammoniated wheat straw. Journal of Animal Science 80:2340-2348.