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Nutritional Requirements for a Heifer and a Calf to Three Years

Soijett BlueANSC 611Dr. PotterNovember 10, 2014

Animal diets fluctuate when they go through the period of gestation and lactation. As well as the young calves that are born, they also have a specialized diet once they are born so that they may maintain growth. More importantly, beef cattle have four phases, which are as follows: Pre-calving, Postpartum, Lactating and Pregnant, and Gestation (See Figure 1). This paper will focus on all four of these phases as well as go into depth on how to feed a calf up to age 3. For a farmer of beef cattle, it is mandatory that the knowledge of how to properly feed a heifer throughout all four phases and the calf is needed. Beginning with the Postpartum (after calving) phase, which is the 80-90 day period that begins at calving. During this period is when the most demand of nutrition is needed. The heifer will consume the most feed during this period. Also the cows undergo numerous processes to prepare their body to go through Lactation and Pregnancy and Gestation again. It is necessary that the cow meets the nutritional demand that she needs because if she doesnt, then she will be delayed in breeding and lose weight or not be able to breed during that period. There are various types of cows that can undergo the four phases stated above. The types of cows are Mature Cows, 1st Calf Heifers, and Pregnant Replacement Heifers; although all these types of cows require different nutritional demands, this paper will focus on Mature Cows only. Table 1 According to Table 1, it shows the nutritional requirements and Diet Nutrient Densities for Mature Cows. , Ffrom this table, it can be determined that the larger the heifer the more feed that they should intake. This table also shows the Calcium Phosphorous ratio, this ratio is important in all animals because if there is more than the other in the diet then it can be detrimental to the cow. As well as the Calcium Phosphorous ratio, it is also shown the amount of Crude Protein that is needed for the various weights of the cows. For example this paper will focus on a 1200 lb heifer, whom during the Post-Partum phase needs 27.6 lbs of Dry Matter Intake, 2.82 lbs Crude Protein, 0.08 lbs Calcium, and 0.06 lbs Phosphorous daily. (See Table 1) The next phase is Lactating & Pregnant, in which for 120-130 days, the nutritional requirements are still needed in high amounts. The reason that the nutritional requirements are still high at this point is because the cow is producing milk for the calf. The main things that vary from the post-partum phase is that the energy and protein requirement decrease to 13% and 8% respectively. During this period, cows reach peak lactation and decrease milk production. Referring to Table 1 for the Lactating & Pregnant phase for the 1200 lb cow, it shows that Dry Matter Intake has decreased a little from 27.6 lbs to 26.5 lbs. As well as the Crude Protein and Calcium Phosphorous ratio decreased to 2.28 lbs and 0.06:0.05 lbs respectively. Thirdly, Gestation period, which is the term of pregnancy for the heifer. The gestation period of a heifer is on average 285 days long. Heifers that are pregnant for the first time will typically be pregnant longer, than the more mature cows. This is because the young heifer is still growing herself. Also a cow with if the cow has poor fertility, overweight cows, and heifers that are more masculine will all have longer gestation periods. For this phase in the heifers life cycle, the nutritional requirements are lower because lactation has ended. As well as eEnergy needs are roughly 23% lower and as well as protein requirements drop by 36%. (See Table 1) This is when many farmers put weight onto the heifer to get them to a Body Condition Score (BCS) of 5 or 6. BCS of 6 is preferred because it ensures that there is meat to cover the ribs on the heifer. During this period the growth of the calf is slow and activity will decrease, however during this period heifers still need to gain a total of 1-1.5 lbs a day during this period. After the period of gestation, the heifer will go through one last phase before the calf is born. The heifer will go through the Pre-Calving Phase where they will also have nutritional changes to their diet. This is a phase that is directly before calving (birth of the calf), typically lasting sixty days, and is often called the dry period. This phase is the most critical for the heifer because they have to reach a BCS of either 5 or 6. This is important so that the heifers will be able to breed again without there being a lapse in breeding. In comparison to the gestation phase, energy and proteins requirements are increased by 20% or possibly greater than that. During the Pre-Calving phase, the growth of the fetus is rapid, with the calf gaining up to 60 lbs, as well as the placenta is growing. The heifer will need to gain at least 2-2.5 lbs per day, this is needed because along with the fetal and placenta growth the cow is preparing for lactation. During the latter part of this phase, the feed that in taken in by the heifer will decrease because the fetus is takingen up space that the rumen would normally occupy, therefore making the heifer eat lessnot eat as much. From this phase, calving then occurs and the calf is born, and with that it is necessary to make accommodations for both the heifer and the calf in their nutritional needs. Once the calf is born, they are fed 2 quarts of colostrum with another 2 quarts following within 12 hours. (See Table 2) The reason that the calf is fed 2 quarts of colostrum is because the ability of the calf to directly absorb immunoglobulins from the cows initial milk declines after the first 12 hours. When calves are first born, they have the digestive system of a non-ruminant, and therefore feeding them has to take this into account. After the colostrum is provided, it is necessary to provide milk or milk replacer for up to 60 days after birth because the rumen doesnt have the microbes that it needs yet. (See Table 2) There are two different milk feeding programs for the calf, they can either be placed on a whole milk or milk replacer diet. This paper will focus on a milk replacer, being that whole milk is great for the calf, but it is also expensive. A milk replacer is a high milk by-product feed that are sold as powder and reconstituted with water for feeding. (See Figure 2) (Handbook p. 486) For the first three weeks, a high-quality milk replacer should be used. For a typical milk replacer it contains, dried skim milk or whey with 10-30% animal fat for energy, along with supplemental vitamins, trace minerals, and antibiotics. Calves should then be placed onto a Calf Starter at about 1 week of age, this contains high energy and protein (16-20%) and low fiber grain mixes. Calcium, Phosphorous, Trace minerals, and Salt are typically added. Low doses of antibiotic (10 mg/lb) may improve the appetite, and therapeutic doses (100-500 mg/day) can combat scours from weaning. (See Figure 3) Elaborating more on the two different Milk Feeding Programs, the two general types are Liberal Milk System and Limited Milk System. Liberal Milk System is typically used for veal cows, the Limited Milk System is better fit for this paper. By utilizing the conventional method of the Limited Milk System, it will make it easier to wean the calf. During this method, the farmer/herder will need to feed the milk replacer that the calf is on at 8-10% of their body weight. (See Table 2) This will occur until the calf starts to consume 2-3 lbs of calf starter a day, at this point the milk replacer regime can be decreased and finally weaned by 4-7 weeks of age. Hay can also be fed but it isnt recommended that this occurs until 1 month of age to help encourage the consumption of the calf starter. The calf is weaned at either 6-8 weeks, before this occurs they are vaccinated, dehorned and will have extra teats removed. The farmer may also choose to wean the calf earlier than the 6-8 weeks that was previously stated. In this case, the farmer would be able to have the calf off the milk replacer entirely by the 1st month of life for the calf. This process would be completed by increasing the amount of milk that is consumed in a day in the beginning and slowly decreasing from there. As well as at the time of weaning, along with the consumption of milk the dry feed or calf starter should be fed at a rate of 1.5% of the calves body weight. (See Table 2) Lastly, silage for the calf may began to be consumed as early as 5-10 days old as long as the hay is of good quality. Also silage should be limited before three months of age because of the moisture content. As well as fiber must be included for proper health of the rumen papillae and to provide a rough texture in comparison to the silage. The calf that this paper focuses on is to make the calf into a replacement heifer so that breeding may occur again. From four to twelve months old the diet changes once again for the calf. If the replacement heifer (calf) was properly introduced to solid feeds before weaning, a growing ration can be changed gradually so that puberty is reached at 15 months and they can began to be bred. Since the calf described in this paper will be used as a replacement heifer there are many things to take into consideration. Items such as what type of free-choice mineral mix the famer sees as being the best one and that the feed will change during the year. The feed will change mainly in two portions of the year, Summer and Winter. During the summer months pasture, hay, and a grain mix preferably 3-7 lb/day would be vital for the growing calf. (See Figure 4) When winter comes, the diet regime changes slightly not in the amounts of food given but in what is given. In the winter hay, silage, and a grain mix will be given 3-7 lbs/day. (See Figure 4) (See Table 2) All the above stated amounts depend on the quality of the feed and the body weight of the calf. The free-choice mineral that should be included, should be a ratio of Calcium to Phosphorous since this will be a heifer. From twelve months to the age of calving which is roughly fifteen months, the replacement heifer should be gaining 1.5-1.8 lbs a day in order to prepare the heifers body for the process of pregnancy. (Handbook) As stated previously the two main parts of the year to be concerned with should be summer and winter because they are on different ends of the spectrum. Beginning with feeding in the summer instead of the 3-7 lbs/day that was fed while the calf was four-twelve months, the calf will now be fed 2-8 lbs/day. (See Table 2) Pasture or hay and hay and silage should be fed in the summer and winter respectively. Also the famer cannot forget about the free-choice minerals of calcium and phosphorous, salt and trace minerals if the forage will be of poor quality. In order to breed at 15 months, there should be quality heifer rearing to get the heifer cycling at 13 months, pregnant at 15 months, and calving by 24 months. (Laven) The heifer should weigh at least 550-800 lbs depending on the breed of heifer to begin the process stated above. The heifer that is still growing should utilize available nutrients in daily maintenance, growth, and ovulation and conception. From this point, the replacement heifer is newly bred and will follow the regimen that was stated in the beginning of the paper. (See Table 1) Some key factors to remember while the heifer is pregnant is that the feeding that takes place 60 days before the calving date, should aim for growth, but also not so much growth that there is an excess in fat. The last 60 days of gestation before the dry period a grain mix should began to be fed as well as increased gradually to adapt the heifer to the high grain intake that is needed for lactation after calving. This paper has thoroughly discussed the nutritional requirements of a heifer from the post-partum phase to calving and then taking that calf and making it a replacement heifer by the age of 15 months. This is all possible by the proper management on the farmers behalf. In order to ensure that the replacement heifer will be able to breed efficiently, a lot of time and dedication have to be put in for this to occur. The objective of this paper was to take the heifer and calf through gestation to calving to the calf reaching the age of 3 years. This paper thoroughly shows this because once the calf reaches the breeding age of 15 months, it is now a heifer and will continue the processes that were stated in the beginning of the paper. These processes were as follows: Post-Partum, Lactating & Pregnant, Gestation, Pre-Calving and Calving. This process can continue if there is proper management on the farmers behalf. Once the replacement heifer finishes out her first calving cycle she will be roughly 2 years and 3 months. (Refer to Figure 1) This replacement heifer will have to complete two successful calving cycles to reach the age of three that is required of this assignment. (Refer to Table 2) Thus making the objective of this paper completed and the replacement heifer to the age of three years old while calving twice.

Figures and Tables

Figure 1: Shows the production/calving cycle of a cow. This figure is fundamental in showing that the average cycle lasts roughly 365 days.

Table 1: Table 1 shows the diet that is necceary for a 1200 lb heifer while she is going through the four phases of production. Figures 2 and 3: shows the starting diet that the young calf will receive once they are born. It shows an example of the milk replacer and the calf starter that they will need.

Figure 4: shows the grower feed that the calves will need. This is essential in helping the calves to reach their maximum BCS or weight that the famer would like.

Table 2: shows the diet of a calf to when it becomes a replacement heifer, then it will follows the diet stated in Table 1.

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