I give nursing beef cow diets a passing grade when they support beef cows to produce lots of milk for their newborn calves and promote growth in postpartum replacement heifers.
These diets must also retain their precious body condition (BCS of 2.5 -3.0, on a 5-point scale) so females can get rebred and conceive within the first few weeks of the breeding season. Not to mention the ‘next year’s’ calves from these properly fed cows and heifers tend to be born earlier in a shortened calving season, which also results in higher saleable weaning weights in the fall.
Research agrees, and confirms that postpartum beef cows in good BCS must consume a good level of dietary energy or 60-62 per cent TDN (total digestible nutrients) and a crude protein level of about 11-12 per cent in their daily diet, particularly when cows are milking at their highest levels which can be 10 to 15 litres per day.
First-calf heifers may not eat or milk as well as older cows but their dietary requirements are almost the same since they are still growing too. Moreover, regardless of age, all cows which calve in January to March might need 20-30 per cent more dietary energy just to keep warm, which is added on to their basic maintenance needs and supersede nutrients needed for milk production and reproduction.
Even with good forages, diets also must include minerals and vitamins such as calcium, phosphorus and other essential macro-minerals. In a similar fashion, respective bio-available sources of copper, zinc, manganese, iodine, cobalt, and selenium as well as fortified levels of vitamins A, D, an E should also be fed.
Well-planned diets for post-calving cows don’t have to be fancy or complex. Some of my best 80/90-day post-calving feeding programs follow these timeless traditional methods. Producers feed their early or mid-gestating cows on lower-nutrition forages such as straw or more grassy-types forages, as long as they meet the modest early- and mid-gestation nutrient requirements for most of the winter. Then they switch to a higher energy/protein diet encompassing higher-quality forages such as alfalfa-grass mixtures just before calving. This practice continues until the cows are moved onto green pastures and the breeding season is in sight.
A real herd feeding program
Case in point: I work with a beef producer on the southern Prairies who calves-out 150 commercial Angus/Simmental crossbred cows starting in the middle of March (re: replacement heifers freshen, three weeks earlier) during a 50-day calving season. The bulls are turned out about a couple months later.
His new post-calving diet (as well as nearly identical 30-day pre-calving feeding program) follows a modest overwintering program of allowing his early- and mid-gestation cow herd, right after fall weaning, to graze barley stubble supplemented with round bales of grass and cattle lick-tubs.
It goes something like this:
1. A morning feeding of a TMR mix is made up of 17 lbs. of alfalfa-brome grass bale and is chopped in a tub-grinder. It is mixed with four ounces of a fortified breeder cattle mineral and 10 lbs. of water.
As a result of his investment, my friend notices over the years that his cows clean within minutes after a 95 per cent calving rate and largely trouble-free calving season. Afterwards, these postpartum cows seem to milk well and later on return to active heats, are bred and conceive with a new calf.
Postscript: Last autumn, his weaned steers weighed 780 lbs. and heifers weighed 745 lbs.
In a nutshell, whether producers take the advice from me, my client or well-run university studies — we all advocate that a high plane of nutrition is necessary for beef cows after they calve. Again, it comes down to providing the cows’ essential nutrient requirements so they milk well and are ready for the upcoming breeding season. Such success is measured with spring calves that grow well and their mums get pregnant with another new calf.