Having started my career in mainly large animal practice, admittedly in the last century, I tried (unsuccessfully) to remember what exactly the transition period is. Fortunately, Phil Elkins anticipated this possible gap in knowledge and defined the term in his first slide with an outline of what to expect in this veterinary webinar.
The transition period refers to the process of a late gestation cow becoming an early lactation cow. It is suggested that this is from 60 days pre-calving to 30 days post-calving and involves a number of physiological changes:
- Diet changes
- Doubling of energy requirements
- Massive alterations in mineral metabolism
- Socio-physiological effects
- Local and systemic immunological changes
A sobering statistic is that 75% of dairy cow disease is related to transition health, and a list of important diseases is given. These are: –
- Displaced abomasum
- Ovarian Dysfunction
- Retained Placenta
- Milk Fever
An incidence range is applied to each of these, followed by a very complicated diagram of relevant biochemistry that is, (fortunately), simplified in the next slide showing adaptations by adipose tissue, the rumen, liver, muscle and mammary gland to parturition and the onset of lactation. Two line diagrams summarise the interrelationship between immune suppression and a negative energy balance, with a detailed analysis of the effects of just one disease -milk fever.
A graph analyses the costs of four transition diseases (early mastitis, metritis, retained placenta and displaced abomasum) comparing heifers at first lactation and cows in subsequent lactations. As seen, these costs can be considerable, which brings in the suggested role of the vet in minimising these losses. This is: –
- To treat LDA/MF and advise if there are too many. But importantly also
- Monitor disease incidences (why wait until it is a problem?)
- Advise on measures to optimize health, welfare, production and economics
The suggestion made is that all transition diseases are interrelated so individual disease rates become less useful barometers for success. Vets should therefore be monitoring transition success rates. What does that imply?
Transition success. A cow is deemed to have successfully transitioned if she has: –
- Calved without dystocia
- Lasted 60 days in lactation in the absence of disease. These include metritis, purulent vaginal discharge, mastitis, high somatic cell count, displaced abomasum, retained placenta, milk fever, ketosis, and any cause for culling
- Returned to normal cyclicity defined as oestrus and absence of abnormal ovarian structures
- Suitable milk production
Graphs follow showing the potential effects on milk production with suggestions of how we might monitor transition success. For smaller herds a simple system recording cow ID, calving date, disease and date if they fail, tick, if they succeed, and tally over time, is adequate. For larger herds set up reporting functions on a herd management system. It takes some time to set up but makes the monitoring easy.
We are asked what percentage of cows should transition successfully –four possible answers to think about are 50%, 70%, 80%, and 90%. The suggested answer may surprise you.
Advised transition period goals are suggested: –
- Minimal risk dystocia
- Minimal risk of stillborn calves
- Minimal risk of metabolic diseases
- High milk production in early lactation
- Minimal loss of body condition
- Enhanced return to cyclicity and improved fertility
Factors influencing transitional goals are genetics, infectious diseases dry matter intake and nutritional competency.
Of these dry matter, intake is key and there is a selection of highly technical slides looking at this and nutritional competency. These need very careful scrutiny and there are some quite complicated graphs that I won’t attempt to summarise.
Phil recommends one very useful resource. It is called
‘Healthy Start Checklist’ This is an Elanco publication, which will supplement the information in the webinar.
Monitoring the transition success rate has some key things to keep an eye on. These are pre-calving dry matter intake, stocking density and nutritional competency. There are some supplementary methods of monitoring as described in detail in the webinar, including urine Ph., blood calcium, and blood beta-hydroxybutyrate (BHB). Phil suggests that there are lots more but makes the single most important point, which is that: –
‘The transition period is a key opportunity for veterinary involvement’.
Phil Elkins graduated from Edinburgh in 2005 and quickly moved to the far south-Cornwall, where he has spent the majority of his time in clinical practice. He gained his Certificate in Advanced Veterinary Practice in 2015 and has been a BCVA board member for the last 4 years. There is a huge amount of information in this veterinary webinar, which I am sure will be of value food for many cattle practitioners and students.