Suckler cow nutrition pre-calving stage 1

Results:

It can be concluded that literature sources have not been able to give a clear picture of the need for, or responses to, higher levels of metabolisable protein fed to dry cows in their last trimester than are currently used by many suckler cow ration programs employed in England. Better calf survival outcomes or enhanced weaning weights from the average cow in adequate condition are unlikely to be found given the literature reviewed. The most likely effect of protein supplementation is increased weight of cow at calving.

There are legitimate concerns that the current recommendations for protein based on AFRC (1993) are too low and do not take into account changes in the genetics that have occurred since they were formulated or colostrum production in the last two weeks of pregnancy. However, many organisations already recognise this and have amended their advice in regard to protein supply.

Table 6 below summarises results from suckler cow and dairy experimental data where metabolisable protein supply in the late pregnancy/dry period diets has been enhanced either by increased microbial protein supply from energy and rumen degradable protein sources or from supplementary DUP  in relation to components of cow and calf survival.

There are severe limitations to the data, most of the information gathered has come from North America. Some of the trial work was in similar systems to the UK and some was not, for example extreme winter grazing systems which are not applicable in the UK.

In relation to colostrum production and quality, experimental data sets were often too small to produce significant results and overall there was little statistically significant evidence for responses to protein supplementation of cows pre-calving. Similar lack of response from sheep experiments where ewes were in good condition have recently been presented at BSAS (Houdijk, 2016 and Wilkinson, 2016). Given that suckler cows with a single calf produce much less birth weight in relation to maternal bodyweight than sheep, and are thus under less nutritional pressure, such a result is not unexpected. There is clearly a danger of overfeeding suckler cows resulting in dystocia which is a common problem, especially in autumn calving herds. Also, compared to sheep, cows tend to calve over longer periods of time thus there are cost issues and potential dystocia risks from potentially long periods of supplementary soya feeding for colostrum. As Wright and Russell’s work showed, it is likely cow size, condition and protein reserves will determine the effect of supplementary feeding on cow condition, milk production and weaning weight of calves.

With increasing mature size of suckler cows in the UK common place – for example up to 900kg LW at calving –  such cows have huge body reserves to potentially mobilise, and consequently may be even less likely to show responses to supplementary feeding of protein. However, large cows that are in good body condition which are mobilising body tissue are likely to be out of balance between protein and energy as the tissue contains a relatively low amount of protein to energy and they may be deficient in MP as a result (Wright and Russell). In these situations additional DUP might be beneficial. Knowing the quality and quantity of the forage to be fed is an absolutely vital part of managing the cow and the ration.

Farmer Messages

• It is essential to analyse your forage, if the basal forage is poor and there is not enough energy and protein for the cow to make enough microbial protein, then supplementing with a high protein source may be advisable to make better use of the forage given. The main source of protein to the cow should first come from protein made by the rumen bugs so ensuring adequate energy and rumen available protein to feed the rumen is essential
• If cows are thin and have lack of their own reserves they may benefit from additional protein, but it does depend on the quality of the forage available to them. Feed according to condition and start planning in plenty time before calving.
• Heifers, especially those calving at two, need to have adequate protein and energy for growth as well as pregnancy. Heifers tend to have lower quantity and quality of colostrum. There is an argument to supplement heifers that are under nutritional strain with additional protein and look after them as a separate group
• Cows that are in good condition have reserves to use and need to have feed  restricted to avoid them becoming too fat. Adequate rumen available protein should always be fed – research shows that severely undersupplying protein by feeding straw alone in the last few weeks pre-calving reduces colostrum immunoglobulins and thus preventing the calf getting sufficient immunity via colostrum. Also there could be an issue with cows’ rumens not being able to function adequately
• Getting rations worked out based on your forage quality and the condition of your cows will not only utilise your forage efficiently but it will ensure cows are in the correct condition to calve down well and prevent problems with dysotocia or lack of colostrum

The Problem:

Traditionally spring calving suckler cows are fed a flat rate ration during the dry period which restricts their energy and protein intake prior to calving and may fall short of meeting their protein requirements, especially if the production of colostrum is to be taken into account. The nutritional recommendations in the UK used for formulating suckler cow rations are taken from AFRC (1993) which is based on work carried out in the 1970s. Since then there have been significant developments in beef genetics and commercial suckler beef cows have changed considerably. At a meeting of beef cattle nutritionists, organised by EBLEX in 2014, it was concluded that the nutrient requirements published by the AFRC underestimate metabolisable protein (MP) requirements of beef cows and these requirements for MP are lower than in other published systems (e.g. France and the United States).

Anecdotal evidence from farmers that have increased the MP supply to dry cows by feeding soya bean meal in the last month prior to calving has found improvements in ease of calving, calf vigour and health but there is no documented evidence to support this practice. This work will review the information available on pre-calving nutrition of beef cows, with particular emphasis on protein supply, and its affect on the cow and the survival and subsequent performance of the calf.

Aims and Objectives:

To establish if there is evidence for a benefit in increasing the metabolisable protein (MP) supply to pregnant beef cows in terms of calf survival, vitality and performance and to identify gaps in current knowledge. This topic is of direct relevance to the AHDB Beef & Lamb R&D research priority 2015-2020: increased weight of suckled calf per ha.

Approach:

A review has been conducted of published information on the effects of metabolisable protein supply to pregnant suckler cows in the last trimester of pregnancy. This review has informed messages to suckler producers via KE activity and suggested some potential areas for further investigation in relation to pre-calving nutrition that may have a positive effect on calf survival and performance.