Understanding Transition Stress in Dairy Cattle and its Management
Devi Gopinath*1, Shruti Dehru1, Gauri Jairath1, Suma, N.1, Rinku Sharma1, Ajayta Rialch1, Birbal Singh1, Gorakh Mal1
1ICAR- Indian Veterinary Research Institute, Regional Station, Palampur, Kangra District., Himachal Pradesh- 176061
*Corresponding author: drdevigopinath@gmail.com; 8628909890
Introduction
Transition period is the crucial period in different physiological phases of dairy cattle because effective management strategies during this period is essential for maintaining proper health and productivity. The transition period refers to the period from 60 days prior to calving to 60 days after calving. During this period major metabolic transition takes place in animal body i.e the shift in demand from foetal growth to lactation. Physiological demands for energy, protein, fat, minerals and vitamins are markedly increased during this period and all these should be aquired through feed and homeostatic changes. The animal body is equipped for lactation during this phase and if there is greater imbalance in any of the nutritional components, it will be affecting the immunity, productivity and reproductive efficacy of the animal. There are reports that the transition stress in dairy cattle is directly associated with periparturient diseases like mastitis, hypocalcemia, ketosis and ruminal acidosis. All the periparturient diseases are economically significant and impacting the animal health and productivity adversely. They have the potential for long term impact on the production and reproductive traits also. So, effective management of transition stress is necessary to prevent various diseases and achieving optimum productivity of dairy cattle.
Physiology of transition period
Though the real transition period extends from 60 days prior to calving to 60 days post calving, the most crucial period is 21 days before calving to 21 days after calving. Numerous metabolic alterations happen during this period to address calving stress and negative energy balance. Physiologically transition period is characterized by reduced feed intake (fetus size reduces rumen volume) and increased energy demand (to equip for upcoming calving and initiation of lactation). The greater the energy deficit, the greater will be the transition stress. Negative Energy Balance stimulates body fat mobilization resulting in NEFA (Non-Esterified Fatty Acids) formation and its utilization as energy source. It further results in the loss of Body Condition Score (BCS). Gluconeogenesis by the liver will be utilized for glucose synthesis and the peripheral glucose utilization will be reduced. All these adaptations are aimed at directing more glucose towards the mammary gland. There is an increased requirement of metabolizable protein i.e methionine and lysine.
Hormonal adaptations
The hormones involved in these adaptations are progesterone, estrogens, prolactin, placental lactogens, insulin, glucagon, somatotropin, thyroid hormone and glucocorticoids. The hormonal adaptations are increased fat breakdown, decreased fat synthesis, increased gluconeogenesis, increased glycogenolysis, increased use of lipids as energy source, increased protein and mineral mobilization from their reserves, and increased mineral and nutrient absorption.
Management of transition period
Major strategies for transition period management involves
- Nutritional management
- Environmental management
Nutritional management:
Aimed at addressing Energy density, protein and mineral supplementation, preventing periparturient diseases. Recent concepts of precision feeding optimizes nutrient utilization and minimizes health issues during transition period. The mineral element of great significance is Calcium, whose optimal blood level is maintained through the hormonal interplay of calcitonin and parathormone. Calcitonin promotes the bone deposition of Calcium, when its blood level increases, while Parathormone enhances intestinal absorption of Ca through activating Vitamin D3 production when the blood levels fall. Vitamin D plays a dual role as vitamin and steroid hormone in Ca homeostasis.
Careful management of transition period diet positively impact the health and productivity of the animals.
Functional aminoacids like methionine, lysine serve as source of methyl group to GSH and taurine the extracellular antioxidant source. However it enhances immune function
Glucose metabolism
During lactation, a metabolic adaptation sets in to stimulate hepatic gluconeogenesis and mobilization of more glucose towards the mammary gland. Further the glicose will be utilized by the mammary gland for lactose synthesis. The major substrates of hepatic gluconeogenesis are propionate from ruminal fermentation, lactate from Cori cycle, amino acids from protein breakdown and glycerol from fat breakdown. Therefore, catabolism follows and loss of condition happens.
Lipid metabolism
For milk fat synthesis, adipose tissue will be broken down to release NEFA. In times of negative energy balance, NEFA will be utilized by skeletal tissue for energy. In early lactation, NEFA replaces glucose for energy demands. Sometimes, whole of NEFA could not be utilized by liver and it leads to accumulation of triglycerides i.e fatty liver. It adversely affect liver functions especially detoxification. Level of ammonia in circulation is an indicator of poor liver function. Therefore it is essential to maintain proper carbohydrate and protein levels in nutrition, otherwise the lipid metabolism will be detrimental to the animal’s health and productivity.
Calcium metabolism
The homeostatic mechanism to regulate Calcium balance involve parathormone, calcitonin and Vitamin D. The mechanisms to regulate Calcium and Phosphorus levels involve intestinal absortion, bone mineralization, bone demineralization and renal reabsorption. Hormones regulate these mechanisms to maintain normal calcium levels in circulation. The inclusion of Dietary Cationic Anionic Diet (DCAD) is controversial, therefore further studies are warranted to study the impact on Calcium metabolism.
Environmental management
It is aimed at reducing stress by managing temperature and humidity. Environmental stress by means of heat stress and elevated humidity, mainly impact through building up of oxidative stress in the animal. So by controlling the environment through proper ventilation, temperature and humidity control and cleanliness, oxidative stress could be reduced and the pathological changes could be minimized. Environmental management could be further achieved through provision of proper space and comfortable resting areas.
Conclusion
Transition animal health management is very important area in commercial livestock rearing, since it has devastating outcomes on the health and productivity. The transition from pregnancy to lactation should be as smooth as possible to minimize stress and complications. Periparturient diseases could be better controlled through proper transition stress management. As far as livestock economics is concerned, most of the economically significant dairy cattle diseases sets in and around parturition. Though number of researches are conducted aiming at better management of transition stress in dairy cattle from around the world, studies addressing local cross bred cattle breeds housed in villages are minimal. May be global solutions likely to fail in indigenous situations. So further studies are warranted to protect our local cross bred cattle from the devastating transition stress.
