Nutrition of Developing Beef Heifers

Nutrition of Developing Beef Heifers


Hi my name is Russ Euken, I’m an Iowa State University Extension Livestock Field Specialist. Through the Iowa Beef Center, we’re offering a series of videos on developing heifers. This one looks at nutrition for weaning through calving. If you’re looking for other topics on heifer development, check out the Iowa Beef Center and look for the other videos. So let’s get started on the nutrition section. When we look at developing a program for feeding heifers, it’s going to be driven by the target weights, and body condition scores, and meeting the nutritional needs to achieve those target weights and condition scores. Another video covers the target weights but just to mention it again, our goal is about sixty-five percent of mature weight at breeding, that’s what we’re trying to achieve and maintain the body condition score of five to six on these heifers as they go into breeding. This is going to require some moderately lower gains, it’s not a high-energy, we’re not trying to achieve a maximum gain by any means. It will be probably a forage based diet and a variety of feeds that we can use to successfully do that and we’ll look at some of those feeds and how they can be put together to achieve those gains. Certainly as on any feeding program, we want to manage the feed costs and waste as we deliver the feed to the heifers, and we certainly want to consider that these heifers, being smaller than the rest of the cow herd, are going to have lower intake and the energy requirement that they need for gains going to require that the ration is more energy dense than what the other cows, older cows, in the herd may be getting. We also want to consider mineral and vitamin supplementation. We’re not going to talk a lot about it in this video due to time, we’re going to primarily consider energy and protein requirements, but basically once we determine what kinds of feeds are going to be fed to meet the energy and protein requirements, then we can determine if we need minerals and vitamins as well. So in addition to the growth requirements, we need to make sure the ration is balanced, so we can achieve maturity, get good reproductive function, allowing the heifers to cycle and breed in a timely manner. This chart basically is just showing two ways of getting to a target weight. The solid blue line that goes kind of a gain of about point eight then ramps up to almost two pounds a day gain, looks at a kind of a two-phase program if you will, maybe not growing those heifers quite as fast for a period of time, then ramping up the nutrition and energy levels and protein levels to get to that higher gain, as opposed to the green line which shows a more consistent gain from weaning on up to breeding. The dotted lines then just represent the two programs and you can see we want to arrive at the same point and we can use both programs successfully just need to look at our own situation: what feeds we have, and making sure we do arrive at that target weight that we’re trying to achieve. So if we’re looking at some gains of maybe one point three to two pounds a day that’s shown on this slide, what kind of energy levels do we need then? It’d probably be an energy level of in mega Cal’s of about point four eight, all up to about up to point five three, or TDN of 73 up to 77, crude protein requirements from 13 up to 15, and these would be rations that wouldn’t have any increased maintenance requirements, no weather stress, those sorts of things that we sometimes run into and need to adapt to. Obviously the higher gains need more energy and more protein. We can also look at it in terms of stage of the heifer and time of year for our spring calving herds. Typically we’d have that weaned heifer trying to grow her up to breeding in the fall and winter to achieve that 1.7 to 1.8 gain, going to need of 75-76% TDN ration, fourteen to fifteen percent crude protein. We get around to the next fall when we might be feeding stored feeds again, hopefully that heifers bred and she’s going into second/third trimester. A little bit lower gains required at that time even though she is carrying a calf, we might have a little lower TDN, lower protein requirements. And you can oppose both of those or compare both of those to a mature cow that’s in good body condition score and just need to maintain her weight and doesn’t really need to gain anything over the pregnancy weight gain, you can see those energy needs and protein needs are quite a bit lower for that mature cow in second or third trimester. So the main point here is that we need to manage these groups differently. When we look at feeds that are available, certainly there’s others that we’re not listing here, but the forages that we mainly have available. Most of them with the exception of corn silage, would be below seventy percent TDN and we’d probably have to be supplementing those to achieve the gains that we’re talking about and trying to achieve. Certainly in grazing programs, whether that’s corn stocks or pasture, they’ll do some selective grazing and might be able to achieve a little bit better ration than what we’re showing here, but in general we’re probably going to need to do some supplementation, primarily on energy and some cases protein. And here’s our feeds that we typically use and again we can do this quite effectively with these feeds as well as others and we’ll look at how to put those together here in some example rations. And here are some examples for a 6-700 or 800 pound heifer that we’d be targeting to gain about 1.7 to 1.8. Again these would be rations looking at no waste, we’ve increased maintenance so if we did have some bad weather or wasting quite a bit of feed, these levels of feed would be increased. We certainly would encourage you to sample and analyze those feedstuffs, particularly forages, so we know that we’re delivering the nutrients that we’re planning on delivering in these rations. So with the prices we’re using, you can see the costs go up as the heifer gets bigger, intake gets more, a $1.10 up to a $1.50 in this case. Looking at some other example feedstuffs combined into a ration, here using some corn stocks in addition to hay along with some distillers grains, you can see we can reduce the cost a little bit, but we might have to do some processing of the corn stalks, maybe you want to deliver this as a total mixed ration, that would increase our costs as well a little bit in some cases. So we can save some money on the feed, but it might be a little bit more expensive to actually deliver it. And again one other example here looking at some corn silage rations, again if you remember from a previous slide, the corn silage is about seventy percent TDN, so that provides most of the energy that we need. We can use a little bit of distillers with that to supply the protein needs and a little bit of energy that we need and works quite well. And in our examples, here is the cheapest rations that we can do with the cost again that we’re assuming. A couple other points, there’s been lots of popular press and also research looking at adding fat, on increasing the number of heifers of cycling and getting pregnant, that increase in conception rate appears to be dependent on length of exposure probably wanted in there 45 to 60 days ahead of breeding, and we’re talking about it at five percent additional fat added to a standard kind of conventional ration. The other thing in a lot of these cases, the increased percentage on cattle getting bred or cycling certainly is a benefit for some thin heifers. If we got those heifers in good condition going into the breeding season, we might not expect those kinds of increases by adding fat. Ionophores like rumensin, bovatech, we can save some feed on forage diets as well as in typical feedlot diets. With higher cost feeds, this may be important, we can also improve gain on those developing heifers. There’s been some reports and actually it’s been mixed research on results on improvement and percent cycling or pregnant when rumensin was in the ration, so I wouldn’t necessarily say that feeding an ionophore is going to improve percent cycling or pregnant, but again in some research projects they have seen that. Might mention to you rumensin is the one ionophore that’s approved for mature beef cows as well as for heifers. So a summary of what we’ve been discussing here on developing heifer nutrition. Our target weights are going to be driving what kind of nutrition program we need. Again sixty-five percent of mature weight is the goal, so we determine the gain needed to meet that target weight. We need to assess the available feedstuffs, the cost of those feedstuffs, and how we’re going to meet the gain requirement and supplement those effectively with the minerals and vitamins that we need, in addition to the energy and protein that we’re going to consider first. We need to plan and implement a feeding program for heifers versus mature cows, basically handling the heifers separately. We might be able to do the developing heifers, the first calf heifers, maybe some thin cows that need extra energy together, but we need to look at that in your own program and see what’s going to work best. Again make sure the intakes that we’re actually seeing are close to what we’re expecting to make sure they’re getting the nutrition needed. A good way to monitor whether we’re getting the nutrition into the cows we need is to assess the body condition scores and making sure we’re keeping those heifers at a five to six and supplementing additional energy as weather conditions might get more adverse with cold weather, damp cool weather, or mud, those sorts of things. Hopefully this has been helpful. If you need more assistance on developing rations, contact your local beef field specialist and they can help you put those rations together. And for other topics on heifer development, look at the Iowa Beef Center website and find the other information at that location. Thank you!

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