To maintain a highly successful, healthy, and productive dairy herd, good youngstock management is key. The fundamentals of a strong, healthy dairy cow are established within the first 24 hours of a calf’s life. From birth to approximately four weeks of age, calves do not have a functioning rumen. To ensure successful digestion, milk production, fertility, and ultimately herd longevity, efficient rumen development is vital.
Feeding good quality colostrum quickly and efficiently is imperative to producing a strong calf. Within the first four hours post-birth, four litres of clean, antibody-rich colostrum should be fed. This should then be followed up by a further two litres within 12 hours of birth. The efficiency of antibody absorption from colostrum declines rapidly after birth; therefore, feeding colostrum as soon as possible is crucial for passive transfer. When feeding colostrum, the temperature must be around 38-40°C.
What is rumen development?
Rumen development is the process by which a calf transitions from solely using the abomasum to efficiently utilising all four stomachs to successfully digest food. The length of this process is highly dependent on the feeding regime. If milk or milk replacer is exclusively available for extended periods, concentrate feed intake will reduce, and rumen development will be slow. By offering quality concentrates early on, rumen development is enhanced, and a fully functional rumen will develop between 8-12 weeks. To enable the successful growth of rumen papillae and the thickening of the rumen wall, starter concentrates should be introduced from seven days old.
When feed enters the rumen, it enters an anaerobic environment. In combination with the intake of unlimited fresh drinking water, the bacteria in the rumen will ferment the feed, producing fatty acids. The rumen bacteria digest starch and crude fibre, which produce propionic and acetic acids that are absorbed into the bloodstream and directly used as an energy source for the young calf.
It is also important to offer a source of ad-lib structural fibre, such as clean chopped straw or hay, from the third week of life. For optimum intake, the concentrate and forage should not be mixed. To avoid sorting, the forage should be chopped to at least 5 to 6 cm. Feeding a structural source has important functions, such as stabilising the rumen pH and stimulating the rumen wall, causing rumen wall contractions, and encouraging the calf to ruminate. At this point, starter/concentrated feed will be the calf’s main source of nutrition, and the rumen will have expanded to 70% of the total digestive tract. The rumen should be able to digest feeds similar to that of adult cattle. This is dependent on the age of weaning and the type of compound feed consumed. This is crucial at weaning; the animal must compensate for the nutritional value lost by ceasing milk or milk replacer. By increasing concentrate feed intake during the weaning period, the calf should maintain the same daily live weight gain (DLWG) pre- and post-weaning.
For further information on maximising your youngstock enterprise, get in touch with the NWF Youngstock team HERE.
