Birthing in Sync with Your Forage Supply By Jim Gerrish

MAY, Idaho: 

This is the second installment in a series looking at changes that need to be made on the livestock side of your operation to help facilitate year-around grazing.

Last month the theme was stocking breeding female enterprises to your winter grazing capacity rather than your summer grazing capacity. Now we will look at the importance of calving and lambing in sync with your forage supply.

Note I did not say ‘calving in sync with nature’ as this mantra is often presented. The reason for that is human beings in some areas have modified the predominant pasture plants away from native species towards something ‘unnatural.’ More about that later.

In a large swath of the country, calving in sync with nature is absolutely the right thing to do. The basic gist of calving or lambing in sync with nature is to have your domesticated calves, lambs, and kids born in the same window of time that wild ruminants like deer, antelope, and bison are giving birth. In the absence of human intervention, almost all grazing herbivores start having their babies a few weeks after spring forage growth has begun. This ‘nature-based’ strategy makes sense in almost all native range environments.

A ewe or nanny goat comes to peak lactation in just a few weeks after birthing while a cow may take six to eight weeks to reach her peak. For ewes and nannies, their daily nutrient demand can increase 2-3X at peak lactation compared to maintenance.

A beef cow will typically have 30-80% increase in nutrient demand at peak lactation while a dairy cow can eas- ily have 2-3X increase in nutrient demand.

As you can see, we need a lot more feed from birthing to peak lactation than we need from mid-gestation to birth. When calves, lambs,and kids are born in the winter months in most areas, all that added nutrition must come from either stockpiled dormant-season forage or stored feed. The problem with most stockpiled forage is it is not adequate energy and/or protein content to meet the demands of lactation. There are a few exceptions we will discuss below. The problem with stored forage is it is typically much more expensive than green, growing pasture. Hence, calving in winter can be very expensive.

Throw in the fact that all ruminant animals are born with a summer hair coat and the lethality of winter can be a major impediment to profitability. The main argument for calving in winter is to have bigger calves in the fall. Unfortunately, weaning weight is a very small contributor to whole ranch profitability. Almost every financial analysis I have seen in the last 30 years shows feed cost is the main driver of profitability. Every additional pound of weaning weight created by having calves, lambs, and kids being born in the winter months comes at a disproportionately high cost.

Where does calving in sync with your forage supply rather than in sync with nature come into play?

The first example is endophyte-infected tall fescue. This plant is not native to North America but is now the dominant pasture across most of the Lower Midwest and Upper South. The toxicity of the endophyte occurs mainly in spring and summer when the grass seed heads can be present. Seed is the most toxic part of the plant while leaves are the least toxic. Tall fescue also has the beneficial characteristic of being the very best cool-season grass for stockpiling as winter feed. Winter is also the season when the grass is the least toxic.

We ran fall-calving cows at the Forage Systems Research Center in north central Missouri through the entire winter on nothing but stockpiled pastures with a strong
tall fescue component. This is the cheapest way I know to grow calves over the winter months. I have long said the five best reasons for growing tall fescue are November, December, January, February, and March.

This is a clear example of calving in sync with your forage supply rather than calving in sync with nature.

Another example is when cool-season annuals like annual ryegrass, oats, triticale, brassicas, or winter annual legumes like crimson or arrowleaf clover are interseeded into non-native warm-season pastures. None of the cool-season plants listed are native to North America. This is another example of humans modifying nature to the extent that the highest quality forage supply is in winter or early spring. In much of the South where cool-season annuals are the best forage opportunity, fall or even winter calving can make sense.

One of the great advantages of fall calving is it puts your calf crop count- er-cyclical in terms of the seasonal price patterns, which are driven by the preponderance of calves being born February-April. However, too many people attempt to implement fall calving in environments with way too much winter or really poor winter grazing resources. If you incur even greater costs because you are feeding lactating cows throughout the win- ter, all of the marketing advantages with fall-calving vanish and may be replaced by even greater financial loss.

Making fall or winter calving work depends on a couple of critical factors. One is having a mild enough climate where calving outside of the normal late spring or early summer season is not a death trap for newborns. The second is having the resources and grazier skill set neces- sary for providing and managing mod- erate to high quality forage throughout the normal dormant season.

If you can’t meet these last two criteria, then calving in sync with nature is going to be your best option in moving towards year-around grazing.

Jim Gerrish is a practitioner, researcher, and educator in the realm of grazing management on pasture and range. You can learn more about implementation of and tools for Management-intensive Grazing at www.americangrazinglands.com. His books are available from the SGF Bookshelf