Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Summer Phosphate Supplementation of Grazing Beef Cattle in Zimbabwe

878 views

Published on

This brief outlines results of some research carried out to show the impact of mineral supplementation for productivity of cattle grazing native pasture in Zimbabwe

Published in: Science

Summer Phosphate Supplementation of Grazing Beef Cattle in Zimbabwe

  1. 1. Phosphate supplementation for beef cattle on range 1 By Eddington Gororo Chinhoyi University of Technology, Zimbabwe E-mail: gororoeddington@yahoo.com Extensive areas of phosphorus-deficient soils occur throughout the world, especially in tropical and subtropical areas (Zimbabwe included), and a deficiency of phosphorus can be regarded as the most widespread and economically important of all the mineral disabilities affecting grazing livestock (McDonalds et al, 2010). Phosphorus is the most significant nutrient in short supply on green summer grazing. Summer phosphate supplementation of beef cattle offers a simple and relatively cheap means of increasing returns by a very considerable margin. Research in the sour-veld and mixed-veld (Agro-ecological Zones I-III) areas of the country has indicated that phosphorous supplementation in summer can result in increases in weight gains, in fertility and in calf viability (Gammon, 1993). However, cattle have shown little or no response to phosphorous supplementation in the sweetveld (mostly natural farming regions 4 and 5) of the low veld areas of Zimbabwe. The heavily leached soils of the high and middle veld areas and the resultant forages are low in phosphorous and have for a long time been held responsible for low production and reproduction problems in grazing cattle. For instance, in 1929, Bisschop and DuToit showed that phosphorous (steamed bone meal) supplementation increased weight gains of oxen by 30%, while supplemented cows weighed 20% more and produced 30% more calves (van Niekerk, 1978). Following extensive research on the subject at both Makoholi and Grasslands Research Stations, Ward (1968) and Grant (1976) reported that phosphorous supplementation of breeding stock increases summer gains by 18-45kg, calving rate by 4-5% and weaning weight by up to 10%. This converts to more than a 20% increase in total weaner production per cow per year. Table 1 below summarises the findings made by Grasslands Research Station when they supplememnted steers on veld in summer. The experimental group was given a 50/50 mixture of monocalcium phosphate (MCP) and common salt.
  2. 2. 2 Table 1 Summary of performance of steers given a phosphate supplement in summer at Grasslands Parameter Control (No P) Supplemented (P) Induction mass (6/11/1975) 186.5 184.0 Finishing mass (23/6/1976) 256.0 298.5 Total summer gain (kg) 69.5 114.5 Response to supplementation (extra LW, kg) - 45.0 Live mass into pens 256.0 298.5 Live mass at slaughter 409 441.5 LW Gain in pens 153.5 143.0 Days in pens 111 83 Feed Consumed (kg) Std pen diet 1070.8 878.8 Average Feed intake (kg/day) 9.647 10.587 LWG in pens (kg/day) 1.383 1.723 FCE (kg feed/kg LWG) 6.976 6.145 Carcass mass at slaughter (kg) 220.2 231.5 The supplemented group of steers gained 45kg more weight than the unsupplemented group and took less time to finish in pens. This would certainly reduce the farmer feed bill and increase turn over. Table 2 summarises the results of research on phosphorous supplementation carried out at Matopos, Makoholi and Grasslands research stations. The trials at Makoholi and Grasslands were conducted on granite sands while the Matopos trial was done on red clays. The increased weight gains due to phosphorous supplementation ranged from 14 to 18kg at the lower rainfall sites (Matopos and Makoholi) to 34-45kg at the higher rainfall site (Grasslands). In the trials the supplement was given free choice (ad lib) in mixtures containing monocalcium phosphate (MCP) and salt, or other carriers. Phosphorous intake per head ranged from 2.5g to 4.7g per day at the drier sites, and from 7.0g to 13.7g per day at the wetter site.
  3. 3. 3 Table 2 Summary of research on phosphate supplementation carried out in Zimbabwe Site Stock category Period (days) P. Intake (g/d) Extra LW (kg) Extra LW value $1.40/kg P. Cost ($8.00/kg) Net Value (P) ($/head) Makoholi Lactating Cows 210 6 26.2 36.68 10.08 +26.60 Makoholi Yearling steers 180 2.5 18 25.20 3.60 +21.60 Grasslands Yearling steers 179 11 44.8 62.72 15.75 +46.97 Grasslands Yearling steers 210 7 34 47.60 11.76 +35.84 Grasslands Yearling steers 210 10 38 53.20 16.80 +36.40 Grasslands Yearling steers 229 7.8 34 47.60 14.29 +33.31 Grasslands Yearling steers 229 13.7 45 63.00 25.10 +37.90 Matopos Yearling steers 167 3.4 16.1 22.54 4.54 +18.00 Matopos Yearling steers 167 4.7 14 19.60 6.28 +13.32 Matopos Yearling steers 155 3.4 12.1 16.94 4.22 +12.72 *Economic evaluation is based on a standard 15kg, 7% phosphate block, selling at $7.80 each In the Makoholi cow experiment, conducted over a six-year period, 26.2kg is the average increase in weaner weight produced per cow per year. This amounted to an increase of more than 20% per cow per year, made up by 7% increase in calving percentage, 16% increase in weaning weight and a small reduction in calf mortality. Products that can be used for phosphorous supplementation include monosodium phosphate, bone meal, monocalcium phosphate, and dicalcium phosphate, usually in combination with common salt for intake control. With ruminants, there appears to be no difference among the above substances as sources of phosphorous and the choice of supplement should be determined by the cost per kilo of phosphorous. However, use of steamed bone meal is restricted due to the BSE scare; although its use is still lawful when the beef product is not intended for export. In the medium rainfall areas (+/- 600mm) the optimum levels appear to be 2.5-4.0g/day for young stock and 6.0-9.0g/day for lactating cows. In the higher rainfall areas the optimum levels are probably in excess of 8g/day for young stock and 10g/day for older lactating cows.
  4. 4. The economics In spite of such overwhelming research evidence in favour of supplementation, a surprising number of farmers do not make use of phosphate to increase summer gains, conception rates and cow productivity. This may be due to a lack of awareness. But in most other cases it is due to the feeling that the difference between animals doing well in summer and those doing extremely well is not important. However, gaining extra weight in summer is as important as reducing weight loss in the drier season months. Many other farmers do not supplement phosphorous because they think that it is not profitable. It should therefore be beneficial to analyse the economics of phosphorous supplementation at present costs. The current cost and returns for supplementation in each of the experiments has been included in Table 2 above. A standard summer (7% phosphate) block on the market in Zimbabwe costs about $7.80 (which translates to approximately $8.00/kg P) and the increased live weight gain is valued at $1.40/kg live mass. It is then clear that a farmer could greatly increase profit per head by amounts ranging from $12.00 to over $37.00 through phosphorous supplementation. The lowest return per dollar invested would be 1:2.5 according to the analysis. At current beef and phosphate prices, supplementation during the growing season in the sour and mixed veld areas is highly profitable. The farmer will benefit superior animal performance on penning and a shorter fattening and production period. Conclusions  Supplemental phosphate is most critical during the wet season when animals are gaining weight rapidly and energy and protein supplies are adequate. Research has indicated little or no response to phosphate supplementation in the dry season when grazing cattle are in a negative protein and energy balance and are losing weight.  There is little or no response to phosphate supplementation of cattle grazing in the sweetveld of the lowveld areas of Zimbabwe. 4
  5. 5. 5  Consistently high conception rates in excess of 80%, high summer gains and minimal winter weight losses can be achieved by supplementing adequate protein in the dry season and adequate phosphorous in the growing season.  Phosphorous sources available to the farmer include monocalcium phosphate, dicalcium phosphate, monosodium phosphate, steamed bone meal and commercial phosphate products such as licks, blocks and meals.  Economic return on phosphate mineral supplementation is high. Reference Gammon D. M. 1993. Advice on summer phosphate supplementation. The Farmer, January 14 1993: 9. Gammon D. M. 1997. Phosphorous supplementation of beef cattle on veld. The Farmer November 6/13, 1997. Grant JL 1974/1975. Division of Livestock and Pastures. DR&SS Annual Reports 1974/1975. Department of Research & Specialist Services, Harare. McDowell L. R., Ellis G. L., and Conrad J. H. 1984. Mineral supplementation for grazing cattle in tropical regions. World Animal Review 52:2-12
  6. 6. 5  Consistently high conception rates in excess of 80%, high summer gains and minimal winter weight losses can be achieved by supplementing adequate protein in the dry season and adequate phosphorous in the growing season.  Phosphorous sources available to the farmer include monocalcium phosphate, dicalcium phosphate, monosodium phosphate, steamed bone meal and commercial phosphate products such as licks, blocks and meals.  Economic return on phosphate mineral supplementation is high. Reference Gammon D. M. 1993. Advice on summer phosphate supplementation. The Farmer, January 14 1993: 9. Gammon D. M. 1997. Phosphorous supplementation of beef cattle on veld. The Farmer November 6/13, 1997. Grant JL 1974/1975. Division of Livestock and Pastures. DR&SS Annual Reports 1974/1975. Department of Research & Specialist Services, Harare. McDowell L. R., Ellis G. L., and Conrad J. H. 1984. Mineral supplementation for grazing cattle in tropical regions. World Animal Review 52:2-12

×