You’ve invested in feeding your cows properly throughout the winter, so they’ll calve out in the right body condition and reward you with a healthy newborn calf.
Once, your sleepless calving season nights ends, it’s a good idea to continue feeding your beef cows, a good post-calving ration for the next couple of months. Adequate nutrition during this time helps them retain good body condition, which in turn helps them produce lots of milk for their calves and within time, quickly return to strong heats to get re-bred and become pregnant with next years’ income.
Well-designed post-calving rations don’t need to be particularly fancy or contain alot of complex or specific feeds. They only need to supply the following four nutrients in adequate amounts recommended for milking beef cows:
Energy — This is the single largest requirement of all animals. There is a hierarchy as to how dietary energy is used in the cow’s body. After its basic body function and growth requirements are taken care of, whatever energy is leftover, is spent on milk production and finally on reproduction. Laid-down body fat, as estimated by visual beef cow body condition scores, is essentially the storage of excess dietary feed energy.
A postpartum cow maintained in good body condition and is milking about 10 litres per day requires about 58 to 60 per cent total digestible nutrients (TDN) of energy in her diet. It is also important to keep in mind that cows that calve out in February to April may need 20 to 30 per cent more dietary energy just to keep warm.
Protein — A protein shortage in the post-partum diet will likely depress beef cow milk production. Dietary protein is not only involved in actual milk synthesis, but is a basic constituent of milk (re: 3.0 per cent protein, dm basis). Furthermore, a lack of protein in the ration can lead to: decreased rumen microbial activity (decreased fermentation and digestibility of forages and other feeds), reduced total feed intake, poor body growth in replacement heifers and visible weight loss. A post-partum cow with a 2.5-3.0 BCS and is milking well should receive about 10 to 11 per cent protein in her diet.
Minerals and vitamins — Macro-minerals, trace-minerals and Vitamins A, D and E play a wide range of metabolic roles in the beef cow body from basic physiochemical reactions to stimulation of healthy ovarian follicles and the fertilization process. After calving, the requirement for both mineral and vitamins tends to skyrocket. For example, calcium (re: milk contains about 0.12 per cent Ca) increases by 80 to 90 per cent, while associated phosphorus and trace mineral usage grows by 50 to 60 per cent. Vitamin requirements (re: Vitamin E is sometimes called the “fertility” vitamin) tend to double.
Water — This is the “forgotten” nutrient. A milking cow can easily drink 45 to 50 litres from a waterer per day, up from her normal 25 to 30 litres on any given day before calving. After all, milk contains about 87 per cent water. It’s important to remember that a couple of days without water (i. e.: broken or frozen water line) can irreversibly reduce or stop a beef cow from producing milk for her calf for rest of the post-calving season.
Most of these essential nutrients provided to post-partum beef cows should be supplied by a solid foundation of mid-to high-quality forages. Subsequently, whatever nutrients that cannot be achieved by a mouthful of palatable forages are often supplemented with a single choice or combination of respective feed concentrates (i. e.: energy and protein supplements or even a commercial beef mineral/ vitamin premix).
Here are a few feeding strategies that are based on such prairie forage and home-grown supplements for post-partum beef cows:
Free-choice, good quality alfalfa-mixed grass hay supplemented with one to 2.5 kg of barley grain. 100 g of a 2:1 mineral and provide salt blocks.
Free-choice mixed grass hay (53 to 58 per cent TDN) supplemented with either two to three kg of distillers’ grain or a 14 to 16 per cent cow-calf pellet. Free choice 2:1 loose mineral option and provide salt blocks.
Free-choice alfalfa mixed grass hay mixed with five to six kg of barley or corn silage, supplemented with one to two kg of barley grain. Free choice 2:1 loose mineral and provide salt.
12 to 15 kg of barley or corn silage, five kg of mixed hay supplemented with one to two kg of barley grain. Feed 100 g of a 3:1 beef cow premix and provide salt.
These few beef diets are just a tip of the hundreds of good post-calving rations that can be formulated and put in front of a herd of nursing beef cows. Given today’s forage and ingredient prices, the above examples should cost about $1.50 -$1.75 to feed each cow per day (re: costs will vary from farm to farm). Their respective nutritional value should keep freshened cows in a good calving body condition of 2.5 to 3.0 (one = thin and five = fat) until the breeding season, so they can produce lots of milk for their calves and return quickly to active heat-cycles after calving.
University and extension research seems to agree that milk production of most cow herds will become depressed, if milking beef cows are underfed, which in turn affects their calves’ overall growth rates. For example, a group of University of Nebraska spring calves suckling beef cows with high milk production weighed almost 17 kg more at weaning time than pen-mates suckling cows of low milk production. Furthermore, nursing calves from low milk production cows relied earlier and to a greater extent on alternative dry feed sources.
Likewise, Oklahoma State University (OSU) has spearheaded a number of excellent studies, which illustrates a clear relationship between body condition score and fertility. In a two-year field trial, their data proved the importance of adequate post-partum BCS in nursing beef cows, namely; those experimental cows that were fed to maintain an optimum BCS of 2.7 until breeding averaged 94 per cent pregnant compared to counterparts (which calved in similar body condition), which were fed to lose one-point of BCS averaged a 73 per cent rebreeding rate.
Not only did their research confirm that one major “secret to success” for high beef cow pregnancy rates is to assure mature cows calve out in a BCS of at least 2.5, but in other OSU studies, first-calf replacement heifers should calve in a BCS of 3.0 or slightly better body condition, since they need an extra allowance for body growth. These researchers also recommended that producers avoid calving out any beef herd in thin condition, because it is very difficult to get them back into optimum BCS right after calving and for a couple of months afterwards, due to a high nutrient shift toward milk production.
Peter Vitti is an independent livestock nutritionist and consultant based in Winnipeg. To reach him call 204-254-7497 or by email at [email protected]