The transition period is defined as the last three weeks prior to calving, and the first three weeks into lactation. Over 80% of health issues experienced by the cow during lactation will occur or are caused by events during this six-week transition period.
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The main targets for this period are to have a live healthy calf and sufficient colostrum produced that has high immunoglobulin content. This is vital for providing passive immunity to the new-born calf. It is also critically important for the productivity and profitability of the farm, that the cow has a smooth transition, calves down easily and goes back in calf giving the farmer more options around breeding and herd management. The following key management decisions and dietary components are essential for a successful transition period.
BODY CONDITION SCORE (BCS)
Body condition scoring is subjective but yet a very reliable way of assessing the fat cover of your animals. BCS ranges from 1-5 where 1 is extremely low (very thin) and 5 is over fat.
Ideally cows should be dried off with a BCS between 2.75 and 3. Target body condition score at calving is 3 to 3.5 for first calving heifers, and 3 to 3.25 for cows. Primiparous animals calving with a BCS in excess of 3.5 will have depressed appetites and lose more body weight in early lactation. This leads to increased incidences of metabolic disorders which will have a negative impact on animal health and milk production. Ideally, cows should lose no more than 0.5 of BCS between calving down and reaching peak yield.
Cows that are over conditioned at calving are four times more likely to have milk fever with increased chances of fatty liver, ketosis, retained placenta and displaced abomasum. These cows will have significantly lower feed intake in early lactation and are already in a period of negative energy balance which is exasperated. There is also evidence of a link between the condition of cows, reduced fertility and longer calving intervals.
Concentrate feeding should be tailored to support BCS in late lactation to correct body condition of animals outside the optimal range highlighted above.
As the calving period approaches, it is vitally important that cows get the correct balance of energy and protein to meet the increasing nutritional demands of the animal in the onset of lactation. It is recommended to analyse forages available on farm to assess mineral content as well as energy and protein levels. This will assist balancing a feeding regime for the energy, protein, and mineral requirements of the cow.
Animals in transition have a supressed appetite and reduced dry matter intake. It is critical that intake levels are maximised by feeding an energy dense ration. Furthermore, it is vital to incorporate high quality protein to animals during the transition period helping ensure sufficient quality and quantity of colostrum is produced for the calf at parturition. Excess dietary protein pre-calving can increase the risk of gorging udders and may increase the risk of mastitis. A 14% protein diet is targeted on many farms, but this can only be done if the forages are analysed. ByPro is a unique cost effective, highly digestible bypass protein and rumen protected blend of essential amino acids, which can be incorporated into transition cow diets to help meet protein requirements and help boost colostrum quality and quantity.
In the close-up period, it is crucial to control the dietary cation-anion balance (DCAB). High DCAB silages with high potassium and/or high sodium content, need careful management and supplementation to ensure the prevention of milk fever. The target forage DCAB level for dry cows is < 150 mEq/kg.
Diets can be formulated to partial or full DCAB status depending on the cow type, production level and previous history of calving difficulties. Ideally high DCAB forages should not be fed to cows near calving. On problematic farms, close up transition cows should be fed a DCAB mineral diet that can be monitored by measuring urine pH.
One of the main concerns with DCAB diets is that some of the products used may be unpalatable and could depress dry matter intake before calving. This can be problematic and stressful for the cow. Soychlor is a DCAB product specially designed to maximise dry matter intake as it’s more palatable than traditional anionic salts and supplements. SoyChlor improves calcium release from bone reserves and increases absorption in the gastrointestinal tract by acidifying the blood. It works to prevent potential metabolic disorders in early lactation by reducing blood pH. It also uses amino acids to boost the immune system and colostrum quality. Producing a partial anionic state, SoyChlor also provides high levels of rumen undegradable protein. It is designed to be fed in the close-up transition cow period at an intake of 0.75 - 1.5 kg per head per day (level adjusted to match the DCAB of the diet).
Metabolic problems arise when cows are fed high DCAB diets. The cow becomes alkalotic and fails to respond to parathyroid hormone stimulation. This causes a decrease in blood calcium and production of 1,25 di hydroxy vitamin D which leads to severe hypocalcaemia. On average, a case of hypocalcaemia costs €298. 8% of cases die, 12% of affected cows are culled due to the other metabolic diseases that can arise and on average 500L of milk is lost. This highlights the importance of correct nutrition during the transition period as failure to do so can lead to reduced cow health and on farm profitability.
Devenish offer a Transition Cow Blend, a product specifically formulated for this period. It helps cows replenish body reserves, prepare intestines for the lactating ration, maximise post calving appetite and yield potential as well as milk income per unit feed cost. The transition Cow Blend can enhance rumen fermentation whilst reduces rumen ammonia and help the cow avoid metabolic and infectious diseases. The Transition Cow Blend should be used at a rate of 1kg/cow/day throughout the transition period.
Furthermore, it is important to note that postpartum intake is not correlated with milk yield, it is correlated with DMI. Maximising DMI in the transition period is critical for reducing negative energy balance of the cow during early lactation which helps mitigate metabolic disorders that can occur.
Careful balancing of key major minerals and trace elements is crucial to ensuring transition is stress free for the animal, and metabolic disorders are prevented. The following table outlines why these key minerals are so important for your animals.
It is important to note that calcium is not normally added to dry cow diets but in partial or full DCAB diets, supplementation is controlled. Magnesium cannot be stored by ruminants for longer than 10-12 hours. A rumen soluble source is recommended for including in DCAB close-up diets and when potassium levels are high. MAG12 is a highly rumen soluble magnesium source which prevents scouring occurring compared to other traditional sources of magnesium supplementation. Finally, vitamin E supplementation is required in close up pre calvers as straw-based diets can be deficient.
A number of management strategies can be employed and should be aimed at minimising stress to the animal. Overcrowding, inadequate feeding space 75-80cm, mixing of animals and uncomfortable lying conditions are the main stressors in the transition period. The best herds aim for 80% occupancy of cubicles in the transition period i.e. 80 animals with 100 cubicles and 100 feed spaces.
Try and move cows no later than ten days prior to calving. Cows and in calf heifers reduce DMI by 30-40 percent in the week leading to parturition. Moving them no later than ten days before allows the animal to acclimatise herself to the new environment which will help reduce stress, and a further drop in DMI. It is important any lameness issues are rectified at drying off as failure to do so will lead to animals having reduced DMI and potential problems with metabolic disease postpartum.
Feed presentation is crucial to maximise DMI during the transition period. Always ensure that feed is fresh, clean, pushed up regularly and that water supplies are clean and fresh. If you are feeding a total mixed rations (TMR) then ensure that particle length is approximately two inches and ensure cows are not sorting the diet.
Overall animal health has an important part of any management strategy. Always ensure that cows are treated for worms and fluke as per veterinary instructions and that all vaccination programmes are carried out at appropriate times to match the farm vaccination protocols.
The metabolic diseases outlined in the table below can be minimised by implementing a strategic action plan at drying off, in advance of the transition period. Key management decisions taken combined with appropriate nutrition will help to ensure a reduction of stress for animals during the transition period helping achieve the targets below.