1 Introduction to Milk Fever – Parturient Paresis

Transcript

Hello! greetings to all,

I welcome all the vets to the agMOOCs program on ‘Metabolic Disorders in Cattle’, jointly organized by commonwealth learning Canada and the director of extension TANVAS. Milk production is the main source for rural farmers and dairy cattle nowadays, they are going for high yielders, and crossbreeding of a non-descript breed with Holstein Friesian and Jersey cattle breed predisposes them to go for various disorders. So Metabolic disorders or production diseases are ones that mainly occur due to high yielders, deficiency of trace elements, major/ measure minerals, and energy imbalance. and this occurs mainly during periparturient cows during a transition period.

And the occurrence of subclinical metabolic disorders causes it’s a silent killer, we can say it causes severe economic loss to the dairy industry. So, this program is designed in such a way to cover all the important metabolic disorders under a Program.

My topic is on a Milk fever or Parturient Paresis in dairy cattle and this program is designed into different lessons that are a compressing of five lessons starting from 1,2,3,4, and 5.

In this Lesson-1, first I will be covering the Importance of Parturient Paresis or Milk fever in dairy cattle. How does it occur? and the Predisposing factors, risk factors involved, and the Economic importance of Milk fever in cattle. and

Lesson-2; mainly includes how it occurs, that is the effect of hypocalcemia on various systems and the Clinical signs manifested in stage-1, stage-2, stage-3, and the outcome of the disease.

Lesson-3; it’s mainly involved in the Complications and the Outcome of Hypocalcemia, and the concurrent ailment and it also covers the how-to diagnose the disease, Differential Diagnosis, and all.

Lesson-4; is an important part of the Program, it is how to Manage Hypocalcemia either with a Calcium treatment like Intravenous therapy or the subcutaneous or oral preparation and then how the animals respond to the treatment for both the unfavorable response and the favorable response the treatment will be covered in lesson-4. And,

Finally, the Lesson-5 is comprised of how to prevent the Hypocalcemia because causes it’s subclinical is a major part of a Metabolic disorder, so how to prevent the disease during the dry calf period as well as a post-calving. This is about the full module on Hypocalcemia in Cattle.

Hello! Welcome to Lesson-1 on Introduction of Parturient Paresis in Cattle.

So, in this lesson, we are having a different components like

• Introduction,
• How the Hypercalcemia occurs and
• what are all the risk factors involved and
• the Etiology for Hypocalcemia and
• the economic importance.

Commonly called a Parturient Paresis or Milk fever Hypocalcemia all are synonyms.

• This is an important Metabolic disorder; it constitutes about 10% of a dairy cattle recently calved animals or prone to Hypocalcemia
• In sub-clinical Hypocalcemia that is silent there, it will not be any overt clinical signs, only a reduction in milk yield. so, this clinical hypercalcemia constitutes about 50% of multiparous periparturient dairy cattle, so that is why it forms a greater impact on the economy of the dairy industry, and
• Among the dairy cattle so due to the cross-breeding of our indigenous cattle with Jersey and Holstein Friesian to increase the milk yield, actually, these Jersey breeds are highly prone to Hypocalcemia, they are genetically predisposed, and the intestinal absorption of calcium is less when compared to other breeds of cattle, so that is why it is highly prone to Hypocalcemia. When does it occur? Usually, Hypocalcemia occurs in a transition period, which is 3 weeks prior to calving and 3 weeks after calving is the transition period. During that period, the majority of cases occur immediately after calving, that is within 24 hours of calving there is a high influx of calcium into the milk and rest of the cases occur 24 to 48 hours and in some cases even occur before calving also, and

How does it occur?

In high yielders because it is nothing but there is an imbalance between the input of dietary calcium and the output of calcium in the form of milk. so that is why it occurs immediately after calving and also there is increased loss of calcium in the milk, and

What is the main reason for Hypercalcemia; is there is a reduction in ionized calcium in the blood, so usually the blood calcium is serum calcium is total calcium in that protein-bound form and free forms are there, so ionized calcium is the part of total calcium that exerts its physiological function.

How the level of calcium is maintained in the bloodstream:

Actually, there are two hormones are involved:

• one is a Parathamron and
• another is a 1-5 dihydroxycholicals for all vitamin d3

And there are 3 systems, involved in the maintenance of Calcium in cattle that is ;

1. Kidney and
2. Intestine and
3. Bone

So normally the calcium is that is ingested through the diet, and it is it’s called calcium homeostasis. So normal level is maintained by the influence of Parathamron and vitamin D3 through this organ, so normally it is absorbed through the intestine and excess calcium is excreted through kidneys and in the production animal, the calcium is in addition to the physiological function, the additional calcium is excreted in milk also, that is why there is a high demand for calcium in a post parturient animal.

What is Calcium Homeostasis?

That means, there is a feedback mechanism, that is physiologically the animal is going for excess calcium or low calcium in the blood, then there is a hormonal influence, that is a Parathamron hormone, so once the blood level of calcium decreases, then it stimulates the parathyroid gland to secrete a Parathamron. We know the calcium level decreases, it stimulates the parathyroid gland, so to secrete the Parathamron this Parathamron has an effect on the kidney, and it catalyzed that is a 25 hydroxycholef calciferol into 125 hydroxycholesterols, that is colic calciferol, that is a vitamin D3 and it directly increases the reabsorption of calcium from the renal tubules and this vitamin D3 it exerts its function on bone and intestine. So in the bone, it stimulates the osteoclastic activity, thereby there is a mobilization of calcium from the one to the bloodstream in addition in the intestine it stimulates the absorption of calcium from the intestine so the excess calcium from the bone and bone reception intestinal absorption and the kidney reabsorption is considered by both Parathamron and vitamin D3. Ultimately the calcium level in the blood increases. This adaptive mechanism is a fails in a recently covered animal due to increased demand for calcium more than the input, so this adaptive mechanism is insufficient to meet the demand for calcium in the form of milk or cholesterol leading to Hypocalcemia.

So, what are the Risk Factors Involved in Hypocalcemia, how the animals are predisposed to go for a Parturient Paresis?

So mainly it’s

• an Animal factor as well as:
• a Dietary and environmental risk factors:

What is the Animal factor; excessive loss of calcium in the colostrum, so the animal usually in the first calving, second calving as the number of calving increases in multiparous animal third lactation or fourth lactation the yield increases, so during the transition period from that is a dry period to post-calving there is a sudden surge of calcium into the colostrum. So, this dramatic increase in the loss of calcium occurs at a faster rate so the influx of calcium to the bloodstream rate is unable to meet the loss in the colostrum and the second thing even though the Parathamron hormone and vitamin D3 functions, due to some reason like there is the occurrence of diarrhea, so the intestinal absorption decreases, there also the calcium level decreases. and then the marked reduction in the mobilization of calcium, for example as the animal age advances the number of receptors that are an osteoclastic activity decreases. So, the response, the rate of mobilization is less in the multiparous animals when compared to a primiparous animal. So, these are all the major animal component that predisposes the animal to go for Hypocalcemia. and another important factor that plays a major role in causing Hypocalcemia is: The Dietary and Environmental factors like the amount of Calcium, Phosphorus, and Potassium and the Dietary Cat-ion, An-ion balance, play a major role.

How the Dietary and Environmental factors causing Hypocalcemia, for example, if the animal during the dry period, the owner may be supplementing high Calcium in the diet with the aim of to prevent Hypocalcemia before calving but it is not that way it causes the less stimulation for Parathamron hormone secretion, so excess calcium decreases the Parathamron need, thereby it is causing Hypocalcemia, and less green pressure, usually potassium-rich fodder that is fed during the transition period or a recently calved animal, this excess potassium causes reduced calcium absorption in the intestine due to an increased level of cat-ion in the feed, and Dietary Magnesium; actually, most of the time Hypocalcemia occurs concurrently with the hyper magnesium, what happens is, that magnesium is an important factor for the secretion of Parathamron so whenever there is decreased magnesium secretion, the parathyroid secretion also decreases that’s thus predisposing to Hypocalcemia.

Then a dietary excess Phosphorus supplementation during a dry calf period; so, for example the animals are fed with excess wheat bran or rice bran, which is rich in Phosphorus and this may cause a reduced calcium level in the blood through Parathamron activity.

Okay, all these factors how affect the Calcium Homeostasis is the excess loss of calcium in the colostrum, that is there is a demand for calcium but the mobilization of calcium from the storage skeleton may not be sufficient to meet the demand for excess calcium in the milk and dietary cat[1]ion and an-ion difference, so this plays a major role. The increase in the cat-ion salts like Sodium and Potassium in the diet may decrease the that is a calcium availability to the animal and apart from that, there is an impairment of absorption of calcium from the intestine as I said earlier due to some compromise in the Intestine like diarrhea and then increase Dietary Phosphorus and the Calcium during the dry period all those factors that it causes reduced Parathamron secretion and absorption of calcium from the gut and predispose them to go for Hypercalcemia. It is so important because our Indian economy is mainly based on rural industry, especially the dairy industry and this occurrence of Hypocalcemia cannot be prevented by vaccination or any other medication, so it is a metabolic disorder due to there is an impairment of input and output of calcium in the diet in the system.

So, this Milk fever in some cases in multiparous dairy cattle, high yielders the incident occurrence of Milk fever will be again and again it occurs within for example after calving within 10 days, it occurs 3 times or 4 times, it’s called as Calcium cycles or Relapse. So relapse of this disease causes severe economic loss and the untreated cases or delays in the management of Hypercalcemia especially if the cow goes for sternal recumbency then it becomes downer cow and the success of management of downer cow is very very limited, even in western countries and this Hypocalcemia may produce for the animal to go for Dystocia and all other reproductive disorders like Retained placenta, Metritis and subsequently it decreases the general systemic state and there will be reduced intake and followed with reduced milk yield and apart from that most of the time it decreases the immune system also and most of the time recumbent cows they are highly predisposed for Mastitis. So once Mastitis is there occurs then also there is a severe loss of milk due to Mastitis and apart from that there is in high illness in will maintained form, usually the Hypocalcemia may predispose them to go for Abomasum displacement and concurrently there will be energy in a negative energy balance it will have Ketosis and finally, all these disorders may force the farmer to Cull the animal. So, it is an economically important disease.

So, in this Lesson-1, we have seen about

• What is Hypocalcemia and which breeds it is so common and usually, it occurs in a multiparous dairy cattle and
• How the Calcium Homeostasis is maintained, mainly the Parathamron and vitamin D3 role and then
• The 3 systems involved Kidney, Intestine, Bone and
• What all are the Risk Factors like the Reduced mobilization of Calcium from bone or reduced intestinal absorption or else the Environmental factor like increased dietary Calcium, Phosphorus and Dietary Cat-ion and An-ion difference, that is increased Cat-ion in the diet and
• How it causes severe economic loss to the farmer and

With this, we are completing the class and we will see in the next class.

Thank you!