Newborn calves are born with undeveloped rumens, yet they will spend more of their lives as fully functioning ruminants. The main objective is to assist the transition from pre-ruminant to ruminant by developing the rumen as much as possible before they are weaned off milk, so that they grow to be cost-effective forage consumers that are efficient at converting feed to milk or meat.

Rumen development begins within the first few days after birth and is advanced by exposure to healthy bacteria from the environment and the consumption of solid feeds – concentrates and straw (preferable to hay). Concentrates should be introduced from three days of age (an 18% crude protein calf starter ration/nut ideally) alongside free access to fresh clean water and high-quality clean straw ad-libitum (no haylage or silage).

Source: Penn State Extension

Considering Weaning 

Weaning on weight basis alone can leave a false sense of security with how ready calves are for the next stage of life/nutrition. The success of the weaning process and the weeks thereafter will hinge on how the rumen has developed over the first weeks of the calf-rearing period. Weaning should never be considered until calves are consuming at least 1.5kg of concentrates/hd/day in grouped pens – signalling that the calves dry matter intake can cope with the transition to a 100% solid feed diet.

Concentrates should be offered ad-lib while on milk but tracked closer to weaning to ensure the group is consuming adequate levels to allow weaning to commence.

Calf Rearing Advice: 

For further advice on calf rearing and calf milk replacer, contact your local Agritech Sales Advisor.

The efficiency of grass-based systems is hugely influenced by the calving pattern on farms, and subsequently requires excellent reproductive performance in a short-breeding season. Therefore, it is extremely important to navigate through the transition period of a spring calving herd, with nutrition being a top priority.

In the weeks post-calving, cows will produce more milk than their feed intake can provide, resulting in Body Condition Score (BCS) loss due to Negative Energy Balance (NEB). A cow typically reaches peak milk output 6-8 weeks post-calving but will only reach peak dry matter intake 10-12 weeks post-calving. The success of the breeding season is mainly dictated by the severity and duration of this period of NEB during the weeks post-calving.

When prolonged, NEB will firstly appear in the form of low milk protein % in the short term and in the more long-term have detrimental consequences on fertility during the breeding season. The overall objective is to have calved down the cow at a BCS of 3.25 and maintain an average herd BCS of 3.0 (with a range of 2.75-3.25) at the start of breeding to achieve optimal fertility. Keeping body condition loss to less than 0.5 BCS between calving and breeding has proven to significantly increase the likelihood of conception to first service, with cows that lost <0.5 body condition score between calving and breeding typically shown to ovulate 15 days sooner, than cows that lost ≥1 BCS.

In very practical terms, navigating the transition period means bridging the energy gap between the cow’s output relative to her intake. Forage quality and the proportion of high-quality grass in the diet will be the main dictating factors here. After this, most of the energy deficit will have to be filled with concentrates in the parlour, with milk output and silage analysis dictating feeding rates this spring.

Need help and advice?

For more information on the management of the transition cow, contact your local Agritech Sales Advisor.