CALVING IS VERY IMPORTANT TIME IN PRODUCTION YEAR

by: Stephen Blezinger
Ph.D., PAS
For the cow-calf operation, the main goal is for each breeding female to produce a healthy calve once per year. That said, in the typical cow-calf operation, calving is, without a doubt one of the most important periods of the entire production year. While breeding must certainly occur for calving to take place, the delivery of a healthy calf is an equally important event. Without either, there is no calf to be sold for revenues to be generated.
I always find it remarkable when producers tell me they really do not have a “plan” for managing the cows and subsequent calves during this point in time. In reality, many producers do not have a program for “calving management,” and simply hope for the best during the periods when calves are scheduled to be born. For many producers who breed and calve year-round (not uncommon), their calving management program is an on-going process and requires constant attention. In these situations it is difficult to focus on the process and it becomes easy for the producer to be caught off-guard.
The shorter the calving period, the easier it is to monitor the process. Granted this also means that it is not uncommon to have more than one cow or heifer calving on a given day or even at or near the same time. However, by managing the breeding of a group or herd of females for a shortened period, the producers focus is increased and a management program can be better organized, specifically for the observation of females beginning the labor process.
Where to Start
Managing of the calving period may start at different periods depending on your perspective. For the purposes of this discussion let's say it starts at the beginning of the third trimester of pregnancy. At this point, the fetus enters a period when the greatest amount of growth occurs and is reflective of the nutritional plane the female is on. It is important for the cow or heifer to be on a proper nutritional program so that the cow's nutritional needs are met in order to maintain a proper level of body condition. This insures the cow will maintain an appropriate level of energy for the least stress delivery on both her and the calf. Secondly it will help promote a more optimal return to breeding condition so breed-back time is not extended.
An equally important component of third trimester is the growth of the fetus. Optimal fetal size or calf size at birth is not well defined. The calf needs to be neither too large (promotes calving difficulty) nor too small (promotes a weaker calf). Optimal calf size also is somewhat contingent on the frame size of the cow or heifer. Smaller framed females generally fare better with lower birth-weight calves. Larger framed cows and heifers normally will handle larger calf birth-weights more easily.
While this all seems fairly common-sense, many producers struggle with this concept and end up producing higher birth-weight calves on small females which can result in calving difficulty with may be problematic for the cow, the calf or both.
As mentioned, management during the last third of pregnancy is very critical, especially for the growing heifer and developing calf. The producer must keep in mind that the heifer must continue to grow structurally and gain body weight during this 90-day period. The weight of the fetus and fetal fluids and membranes will increase about .90 lb. per day. Therefore, the heifer needs to gain about 1 to 1.5 lbs. per day to sustain her growth and that of the fetus. However, a heifer should not gain excessive weight and become fat as this may increase the likelihood of calving difficulty since a significant amount of this fat may be deposited in and around the reproductive organs.
If the heifer is on a deficient nutritional level, she will draw nutrients from her body tissues to provide for the developing calf. The calf may lack vigor or energy at birth and need help nursing. These heifers may be short of colostrum, which is a component of the first milk given by the female that passes on crucial antibodies to the calf that helps to begin building the calf's immune system. In extreme cases, the calf may be born dead or die shortly after birth. Milk production will usually be decreased, which will reduce growth rate and weaning weight of the calf. Also, the heifer will tend to rebreed late or may fail to rebreed. All this said it is obvious that producers cannot afford to compromise the nutritional plane of bred heifers.
Some producers feel that reducing energy and/or protein intake prior to calving will reduce calf birth weights and, subsequently, calving difficulty and calf losses. Research does not agree with this. Restricting feed to heifers may reduce calf birth weights, but does not reduce calving difficulty. It may also decrease the percent of cows cycling and conceiving during the breeding season and it may reduce the weaning weight of the calves. Therefore, the practice of reducing feed to heifers in average or thin condition prior to calving is not advisable. However, feeding excess protein or energy to heifers should also be avoided.
Nutrient requirements for bred heifers are given in Table 1. These requirements and rations do not include extra energy needed during extremely cold, windy or wet weather. Provide cattle with all the roughage they will consume during severe cold periods.
At Calving Time - How to Determine if a Heifer or Cow Requires Assistance
In many situations it can be difficult to determine if or when to help a female in the calving process. The following steps can provide some clarification.
1. A COW OR HEIFER IS HAVING DIFFICULTY WHEN: • The cow actively strains for 40 to 60 minutes with no progress • 90 minutes have passed since the water bag first appeared • Feet and legs emerge with the surface of the hooves pointing up •Only the head or tail (bad sign) emerges
• A cow has demonstrated greater than 5-6 hours of anxiety, e.g. walking about, tail extended, apparently looking for something
2. TO EXAMINE A COW HAVING DIFFICULTY: • Restrain the cow either in a chute or in a safe and secure manner • Clean all manure away from around rectum and vulva. Washing is preferable to reduce contamination. • Use the plastic obstetrical sleeves with lubricant to improve sanitary conditions and reduce irritation of the vulva and birth canal.
• Explore the problem. A normally positioned calf will have both the front feet and head positioned as shown in Figure 1.
3. PULL CALF IF: 
• Two front legs and a nose OR two hind legs and the tail head can be guided into the bony part of the birth canal.
4. IF THE CALF IS INCORRECTLY POSITIONED: • Gently position the legs and head correctly. Gently push the calf back a little way to get some working room. Do not push against the cow's contractions - work with her, not against her. Cover the teeth and feet with your hand as you move them to reduce injury to the cow. • NOTE: If the position is too difficult to correct in 20 minutes, or two strong people cannot pull the calf - call your veterinarian. • Attach loops of soft nylon rope or surgical chain to the legs. By convention, place a loop above the fetlock joint as well as a half hitch below. A loop may also be placed around the head - over the poll behind the ears and under the mouth. NEVER attach a loop to the lower jaw. •Pull back and down on the ropes for a head-first calf, straight back for a tail-first calf. Pull alternately on either leg to angle the shoulders through the pelvis. Two strong people (pulling force of 250lbs. max.) should be able to pull a calf into the birth canal.
•Use calf pullers with caution. Remember to release tension periodically. Allow cow to push calf out.
5. WHEN TO CALL THE VETERINARIAN FOR A CAESARIAN SECTION:
A) If the calf is too large. This can be measured by the following: • If the front feet fill the pelvic opening and you can't get your hand beside them • If with gentle pulling, you cannot get the head and feet into the pelvis at the same time.
• If the heifer/cow has been actively straining for 30-40 minutes and hasn't been able to push the head and feet (or the tail head if coming backwards) into the bony part of the birth canal
B) If there are other complications, like: • Incomplete opening of soft tissues of the birth canal (incomplete dilation of the cervix) • twisted uterus
• misshapen pelvis
The Most Common Post-Calving Complications
In addition to problems a producer may see before and during calving, the post calving period can also produce a variety of problems in the cow or heifer. A couple of these include:
1) Prolapsed Uterus If the cow is straining badly and the uterus is very loose and soft, she may push the uterus out through the birth canal, inside-out. What you will see is a large solid mass of tissue with 2-3 inch long "buttons" on the surface where the membranes were attached. In these situations do the following: • Restrain the cow; the uterus is less likely to be damaged and is easier to be replaced in cows that are down • If there is a delay, cover the uterus with a wet towel or blanket to keep moist and protect from elements. Depending on the situation it may need to be washed off with warm water. • Keep other animals, including cows, away; they may eat or damage the uterus
• Call your veterinarian
2) Retained Placenta Normally the afterbirth will come away by 24 hours. There is no concern unless the cow is sick; example, with a high temperature and "off feed." In these cases you will need to provide: • Antibiotic injections as directed by your veterinarian; if there is no response in three days, call your veterinarian who may need to remove the retained placenta manually.
• Uterine boluses may also be used to help offset or reduce infection.
Conclusions
Having a proper calving management program can help reduce the problems and stresses of this very critical period in the operation's production calendar. Taking proper preemptive steps as well as keeping a close watch on cows and heifers about to calve can go a long way to simplify the calving event.
Copyright December 2016 – Stephen B. Blezinger, Ph.D., PAS. Dr. Steve Blezinger is and nutritional and management consultant with an office in Sulphur Springs Texas. He can be reached at (903) 352-3475 or by e-mail at sblez@verizon.net. For more information visit us on Facebook at Reveille Livestock Concepts.
Fuente:  http://cattletoday.com/archive/2016/December/CT3408.php

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