Developing urea-molasses feed blocks in the Falkland Islands

S M Miller and R P Thompson ^*

Department of Agriculture, Goose Green, Falkland Islands
Struan Agricultural Centre, PO Box 618, Naracoorte, South Australia, Australia 5271
^* DPIWE, Scottsdale, Tasmania, Australia 7260
miller.sean@saugov.sa.gov.au

Abstract

This paper details the development of urea-molasses feed blocks for use by the sheep and cattle industries in the Falklands Islands. Protein-poor native pastures restrict growth and survival rates of ruminants in the Falklands, and an opportunity exists to improve animal productivity by supplementing animals with nitrogen. Due to the high cost of imported feed blocks, systems to manufacture blocks locally with both local and imported ingredients were developed. In addition, variations in feed block composition were identified that may be used to manipulate the quantity of the feed block consumed daily by animals. The two key steps to make stable feed blocks were the use of calcium hydroxide as the setting agent, and pressure to form the block.

The home-made feed blocks were successfully consumed by both sheep and cattle grazing Falklands’ pastures. Further work is underway to determine the economic benefits of these supplements for the wool and meat industries.

Keywords: Cattle, home-made feed blocks, molasses, sheep, urea

Introduction 

Lying between latitudes 51 and 53 degrees south and approximately 600km west of Argentina, the Falkland Islands have historically been reliant upon income from the export and sale of wool and development assistance from the Overseas Development Administration, London. Following the conflict with Argentina in 1982, considerable financial and infrastructure development has occurred in the Islands. The Islands no longer receive financial assistance from the United Kingdom as income from the sale of offshore fishing licences generates revenue totalling approximately £23 million per annum for the Falkland Islands Government. By contrast, revenue generated from wool is now less than £1million per annum. For the wool farmers in the Falklands, these low returns have resulted in the Falklands’ Government subsidising farm production by as much as 50% to 75% of farm income for the past decade. 

Falklands’ agriculture 

Agricultural production in the Falklands is unsophisticated. Wool harvested from the Islands’ 650,000 sheep is the mainstay of farm income, and the Islands’ population of 4,800 cattle are kept to provide milk and meat for farm owners, and to supply a small domestic meat industry with less than 250 carcasses per year. Sheep and cattle are typically grazed on the same pasture year round, chemicals are not used to treat disease, nutritional supplements are not used, and male stock are often retained with females from the joining period until progeny are weaned. This production system has been effective for more than 100 years, however the dramatic slump in wool prices over the last decade, a shift from large farms owned by foreign companies to small, family owned farms, and reliance on wool as the sole commodity have exposed the inefficiencies of the traditional farming system. For the wool industry, these weaknesses stem from the low survival rates of lambs and weaner sheep. Survival rates are frequently less than 50%. Consequently, flock integrity and an ability to select genetically superior animals for improved productivity are compromised by high mortality. Beef cattle have not been treated as a serious industry but rather as a resource that is annually harvested in winter as a variance in the diet from the traditional mutton. Consequently there has been little management and the animals killed are generally at least four years old at slaughter. Economic and social pressure is being exerted on farmers to diversify farming to reduce the reliance upon Government subsidy to sustain agricultural production. A European Union accredited export abattoir has recently been constructed in the Falklands and opportunities now exist to develop sheep and cattle meat industries in addition to wool. 

Ruminant nutrition in the Falklands 

Sheep and cattle in the Falklands rely upon low quality native pastures for their nutriment. These pastures are characterised by their poor protein and energy content for as much as nine months of the year (Davies 1988), with quality increasing rapidly for only a short period during summer (Miller 2002). Consequently, low stocking rates typical of many of the World’s other rangelands pastures prevail in the Falklands (Thompson and Miller 2000). Recent studies have identified that insufficient protein, phosphorus and energy intake during the autumn, winter and early spring seasons are the cause of poor growth rates of weaner sheep and cattle (Miller 2002; Miller and Thompson 2002). In addition, poor winter nutrition of pregnant ewes causes foetal restriction during pregnancy that affects wool follicle development in their offspring (Baughan et al 1993). Consequently, whole-of-life wool production is significantly reduced (Kelly et al 1996). 

Sheep and cattle grazing Falklands’ native pasture consume insufficient protein to maintain optimal rumen fermentation for much of the year (Figures 1a and 1b).

Figure 1a. Ammonia concentrations in rumen fluid from cattle grazing native Falkland Islands pastures	Figure 1b. Ammonia concentrations in rumen fluid from sheep grazing native Falkland Islands pastures

Ammonia concentrations in rumen fluid fall below the 5mg/100ml to 8mg/100ml range generally recommended as the minimum for efficient rumen function (Satter and Slyter 1974; Pisulewski et al 1981; SCA 1990). Urea-molasses feed blocks have been widely advocated as supplements to increase the intake and digestibility of low quality native pastures and roughages (Leng 1984). Moreover, sheep consuming similar natural pastures to those in the Falklands, and suffering similar productivity problems in the neighbouring Patagonia region in Argentina have benefited from the use of these supplements (Golluscio et al 1998). In anticipation that Falklands’ ruminants could similarly benefit from these supplements, and in recognition that imported feed blocks were too expensive to be used by local farmers to improve animal survival and production, a project was undertaken to develop and test home-made feed blocks using a combination of imported and local ingredients. 
 

Methodology 

A review of methods to produce feed blocks was conducted, and the two methods chosen for further investigation were i) poured feed blocks, and ii) pressure-based feed blocks. For the poured feed blocks, moulds were made from timber. To make pressure-based feed blocks, two presses were made that differed in cost and complexity. Both presses were made from scrap materials found on-farm. To evaluate the setting characteristics of the feed blocks, small volumes of the ingredients were mixed by hand in plastic buckets. When successful mixtures were identified, 50kg to 100kg batches of the feed blocks were prepared in either small, motorised cement mixers or a larger tractor-driven cement mixer. 

To test the palatability and preference of animals for the various feed blocks, groups of five to ten sheep and cattle were housed in indoor pens and fed mature pasture hay. Feed blocks were placed in the pens for three days with the groups of animals and the weight of the blocks was recorded daily. 

Results 

Feed block setting 

Initially a recipe was chosen based on feed blocks that used cement as the setting agent (Blackwood 1998). This recipe called for moulds into which the mixture could be poured and allowed to set before use. Our experience was that the blocks would not set sufficiently well for paddock use despite including cement at higher rates than recommended (up to 25%). The authors presumed this to be related to the low temperatures experienced during winter whilst the blocks were being poured. As a consequence, a wider review of block production methods in commercial use was conducted and a pressure-based feed block was developed using calcium hydroxide as the setting agent. Calcium hydroxide proved to be an effective setting agent and it was included in all subsequent blocks. 

Home-made pressing devices 

Two feed block presses were designed for use on-farm. The first press was a simple design. The mixture was placed in a four-sided mould without a top or bottom (Figure 2). The mould was seated on a solid surface and a plastic bag was placed in the mould. The feed block mixture was then placed in the mould and a square plate was placed on the filled bag. Using a motor vehicle jack with a lever action, the steel plate was pressed down into the mould until no more pressure could be applied. The whole mould was then removed from the press and the block was removed by pressing it through the mould. The blocks were then sealed in the plastic bags and stored until required.

 

Figure 2. Simple press to manufacture feed blocks

The second press was more sophisticated and required a tractor with hydraulic outlets to operate (Plate 1). The principal was the same as the simple press, however larger blocks can be produced and more pressure can be applied to the block to improve its consistency. The press used an hydraulic ram positioned horizontally along a frame extending to a pressing chamber. This chamber was filled from the top, and a sliding plate was used to seal the chamber before pressing. To remove the pressed block from the chamber, the vertical chamber wall at the opposite end to the ram was unbolted from the chamber and removed. The block was then pushed through and out of the chamber as the hydraulic ram is extended. 

Plate 1. Hydraulically operated feed block press

 Factors affecting feed block intake 

Whilst evaluating the palatability of various feed block formulations, three specific ingredients were of interest; salt, calcium hydroxide, and fish-meal. Increasing the concentration of salt from 5% to 20% in the feed block decreased intake in a linear response (Figure 3).  

 Figure 3. Effect of salt concentration in the feed block on consumption of the block by cattle

Hardness of the block also affected its consumption by cattle. Blocks containing 15% calcium hydroxide were consumed less readily than softer blocks containing 7.5% (Figure 4).  

 Figure 4. Effect of block hardness on intake of block by cattle 

Fish-meal is a locally available by-product of the extensive offshore fishery. Both white fish-meal, produced from squid, and yellow fish-meal, produced from fin fish are available. Fish-meal offers advantages over urea as a protein source as it is a source of  by-pass protein, and of essential vitamins and minerals.

 Figure 5. Effect of prior experience of fish-meal on consumption of fish-meal feed blocks by sheep

Prior consumption of fish-meal was important to the acceptability of the block to the sheep. If the animals had previously consumed fish-meal, they consumed more of the feed blocks when they were subsequently exposed to them (Figure 5). This trend was particularly evident for feed blocks containing high concentrations of fish-meal. Once adapted to these high fish-meal blocks, sheep consumed blocks at a rate of 350g/head/d (Figure 6). 

Figure 6. Rate of consumption of a 30% fish-meal feed block by sheep 

On-farm use of feed blocks 

A preliminary evaluation of the feed blocks was conducted with the Falkland Islands’ National Beef Herd over a 12-month period (Plate 2).  

Plate 2. Falkland Islands’ cattle consuming a home-made feed block 

A block with 30% fish-meal and 10% urea was used (Table 1). During the evaluation period we observed that the feed blocks retained their integrity for up to 12 weeks in the paddock if not consumed by cattle. Also, as a novel feed, acceptance of the feed blocks was a problem when the animals first encountered them. This was overcome by training a few animals within the herd to accept and consume the supplement. The trained animals then acted as tutors for the remainder of the herd and their offspring. Without these trained animals, feed blocks were ignored. 

 

Discussion 

The value of supplementation in modern farming systems is predominantly measured in economic terms. If the supplements described here are to be adopted locally then they too must pass this test. Several variations of the basic feed block have been developed (Table 2) and fed to sheep and cattle, however the effects on animal production and economic return have yet to be evaluated. 

Supplementing mature, wool sheep breeds with non-protein nitrogen supplements under field conditions has elicited variable results elsewhere, and cattle generally respond better to these supplements than sheep (SCA 1990). Consequently, in the Falklands it is likely that the most economic use of these supplements would be confined to young, growing sheep and cattle, and late-pregnant and lactating animals. The benefits of supplementing these groups are likely to come from increased survival of young animals, increased lifetime wool production, and improved wool quality if the effects of dietary restriction during pregnancy can be overcome by the supplements. 

In addition to protein deficiencies, cattle and young sheep also experience periods of phosphorus, calcium and vitamin D₃ insufficiency (Miller et al 1998; Miller 2002), and in some regions young sheep suffer cobalt and selenium deficiencies (Whitley 1983). For cattle, mineral deficiencies have not been investigated in the same detail as sheep, however evidence of low fertility rates and pica such as bone chewing are indications that phosphorus in particular is deficient in cattle diets. Feed blocks would be effective agents to supplement Falklands’ ruminants with these nutrients. 

Local ingredients 

For the feed blocks to be economic, a further requirement is for the ingredients to be low cost. Freight is a large component of the cost of goods imported to the Falklands due to their distance from mainland suppliers. A number of local resources may be used to lower the cost of the blocks. In particular, fish-meal, calcified seaweed, and kelp may be incorporated into the blocks to aid specific nutrient deficiencies. Calcified seaweed contains at least 30% calcium carbonate and when ground is an effective source of calcium and a range of trace elements. There is a concurrent effort by farmers to move Falklands’ agriculture towards an organic footing. In the event of this move, supplements such as urea would not be an acceptable nitrogen source, consequently locally available, high protein kelps (Miller 2002) may be useful substitutes. Furthermore, the alginates in the kelp may help to ‘set’ the blocks and lower the requirement for imported calcium hydroxide. Blocks using these ingredients have not yet been tested. 

Conclusions 

Feed blocks can be easily manufactured by farmers on-farm in the Falklands for a cost less than one third of imported, commercial feed blocks. Calcium hydroxide and pressure proved to be the two most important factors to produce well formed, stable blocks. Consumption of the blocks can be manipulated by changing the amount of salt, calcium hydroxide and fish-meal in the blocks, and would enable the farmer to match the nutrients supplied by the supplement to the nutrient requirement of the animals being supplemented. 

Acknowledgements 

We’d like to thank Gordon Lennie (Department of Agriculture, Falkland Islands), Colin Coleman (Coleman Stockfeeds, Charters Towers, Australia), and Stuart Wallace (Fortuna Limited, Falkland Islands) for their assistance with this work. 

References 

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