Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 18 COPRA MEAL AS A SUPPLEMENT FOR GRAZING DAIRY COWS W.K. EHRLICH*, P.C. UPTON**, R.T. COWAN* and R.J. MOSS* Copra meal temperate were given 3 kg copra was evaluated as a supplement for dairy cows grazing tropical and Twenty Holstein Friesian cows in early to mid lactation pastures. supplements once per day of either nil, 3 kg cracked sorghum grain, meal or 6 kg copra meal over a 12 week period. Cows consumed all the sorghum supplement but found copra meal unpalatable to a degree. The intakes of copra meal averaged 2.5 and 3.1 kg/d for cows offered 3 and 6 kg daily respectively. Milk yields averaged 12.4 kg/day for unsupplemented cows and 13.0 kg/d for supplemented cows. Copra meal increased the butterfat content of milk (P<O.OS) and reduced liveweight loss (P<O.OS). We conclude that copra meal can partly replace sorghum grain as a supplement and increase butterfat percentage. INTRODUC!l!ION There is potential for copra meal to be imported from Papua New Guinea and used as a supplementary feed for cattle in northern Australia. In this environment pastures grazed by dairy cows have a relatively low energy content, and substantial amounts of grain and molasses are fed to increase production. Coconut meal has been shown to be a suitable supplement for cows grazing tropical pastures in Fiji (McIntyre 1973). In this experiment copra meal was compared with sorghum grain as a supplement for dairy cows grazing tropical and temperate pastures. MATERIALS AND WETaoDS The experiment was carried out on Mutdapilly Research Station in south-east Queensland (lat. 27O46'S; long- 152�40'E). It was done in two 12 week periods, from January to March 1988 and June to August 1988, During the first period, cows grazed irrigated pangola grass (Digitaria decumbens); during the second period they grazed irrigated oats (Avena sativa), Cows grazed as one group at a stocking rate of approximately 5 cows/ha on each pasture type. Copra meal obtained from a single batch was used during both periods. Eight multiparous Holstein Friesian cows calving date and yield during two weeks then randomly allocated to treatments. Friesian cows were similarly allocated to were selected on the basis of similar prior to the first period; they were Twelve separate multiparous Holstein treatments during winter. All cows received 3 kg cracked sorghum daily from calving until entering the experiment. Cows were adapted to copra by gradually increasing the copra content of supplement until all grain was removed after two weeks. Supplements were then offered at nil, 3 kg cracked sorghum/d, 3 kg copra meal/d and 6 kg copra meal/day. Cows were individually fed after morning milking and reject feed was weighed each day. Analyses of grain and copra meal are shown in Table 1. Supplement degradability was measured in sacco (Mehrez and Orskov 1977), using three rumen-fistulated Holstein Friesian cows on a basal diet of Rhodes grass (Chloris gayana) pasture and supplemented with lucerne (Xedicago sativa) ay (Table 1). Qld Dept Primary Industries, Mutdapilly Research Station, MS.825, Ipswich, Qld. 4305. ** Qld Dept Primary Industries, AB Centre, Wacol, Qld. 4076. 196 * Proc. Aust. Soc. Anim. Prod. Vol. 18 Table 1 Chemical analyses and degradability of supplements Cows were milked twice daily, and yield recorded on two consecutive milkings each week. A composite sample of evening and morning milk was analysed for butterfat, protein and lactose content (Milkotester Mk III - Foss Electric). During the last week of each period a composite milk sample was taken for analyses of fatty acid composition of milk fat (Aston 1977). During the last week of the first period samples of jugular blood and rumen liquor (stomach tube) were taken before and four hours after feeding supplements. Cows grazed pasture during these four hours. Blood serum was analysed for urea (Talke and Schubert 1965). Rumen liquor was analysed for pH and ammonia content (Bolleter et al. 1961). Live weights were recorded fortnightly after morning milking. RESULTS Voluntary intake of copra varied from 1.9 to 6.0 kg/day. Milk yields were similar for cows given grain or copra, and tended to be lower in unsupplemented animals (Table 2). Copra meal increased fat content of milk, but did not alter the protein or lactose content (Table 2). Feeding copra meal caused smaller changes in Cl8 fatty acids in milk fat than did feeding grain (Table 2). Rumen ammonia concentration tended to increase with supplementation, and in the four hours after feeding increased slightly for cows given pasture only and decreased for cows given grain. The decline for cows given copra meal was small (Table 2). Rumen pH was reduced with grain feeding but maintained with copra feeding (Table 2). Serum urea content tended to increase with the crude protein content of the total diet (Table 2). Liveweight change was reduced with copra meal feeding (Table 2). 197 Proc. Aust. Soc. Anim. Prod. Vol. 18 Table 2 Intakes of supplement and effects on milk yield, composition, ammonia, rumen pH, serum urea and live weight rumen DISCUSSION Copra meal was effective in maintaining milk yield at a level similar to that of cows given grain. McIntyre (1973) measured a 60% increase in milk yield when coconut meal substituted for molasses. We did not include molasses in our experiment but Cowan and Davison (1978) demonstrated that for cows grazing tropical pastures plus grain, milk yield increased 30% when compared with molasses. Possible reasons for the high response measured by McIntyre (1973) were that he continued the experiment for the full lactation, which has been shown to enhance the response to supplementary feeding (Cowan 1983). Also levels of protein in the pastures used by McXntrye (1973) were likely to be considerably less than those in the present experiment and the copra meal may have been acting as a protein and energy supplement. The pasture consumed in our experiment would have had a protein content in the order of 17% in the dry matter, and it is unlikely a response would have been measured to the extra protein contained in copra meal (T-M. Davison unpublished). A third difference is the relatively high fibre content of the copra meal we used compared to that used by McIntyre (1973). The increase in fat percentage of milk may have been due to either the high fibre content of copra meal or its relatively high oil content. Feeding saturated fats may increase fat content of milk relative to grain feeding and can change the fatty acid composition of milk fat (Palmguist and Jenkins 1980). The advantage to copra meal in liveweight change may be brought about by a reduction in demand for body lipids for milk fat synthesis. Copra meal was not palatable initially and required about two weeks training to achieve satisfactory intakes. After 12 weeks only one cow ate 6 kg/d and intake Ey other cows was not increasing. During the second period of the experiment it was observed that palatability of copra meal was lower than in the first period, and intake was 1 kg/cow/day less. This may reflect a problem with rancidity of copra meal after prolonged storage, though no obvious signs of rancidity were noticed. In addition cows grazed temperate pasture during 198 Proc. Aust. Soc. Anim. Prod. Vol. 18 winter, compared with less digestible tropical pastures during summer , and this may have reduced their appetite for supplement (Phipps et al. 1 987). Copra meal was found to be an effective supplement for dairy cows. Despite not being highly palatable, milk fat content increased. Its acceptance as a supplement in comparison to cereal grains would depend on availability and cost. We thank Mr I. Buchanan and Mr D. Kerr for technical support and Mutdapilly staff for care of the animals. Mr P. Martin and Mr H. Kramer carried out the analyses of serum, rumen liquor and feed, and Mr A. Reid the analyses of milk fatty acids. Australian Agricultural Technology provided the meal and support for this experiment. ASTON, J.W. (1977). J. Chromatog. 131: 121. BOLLETER, W-T., BUCHMAN, C. J. and TIDWELL, P.W. (1961). Anim. An. Chem. 33: 592. COWAN, R.T. (1983). In 'Efficient Dairy Production', p.109, Aust. and N.Z. SAP, Albury Wodonga, March 1983. COWAN, R.T. and DAVISON, T.M. (1978). Aust. J. Exp. Agric. Anim. Husb. 18: 12. COWAN, R-T., DAVISON, T.M. and O'GRADY, P. (1977). Aust. J. Exp. Agric. Anim. Hush. 17: 373. MEHREZ, A-2. and ORSKOV, E.R. (1977). J. Agric. Sci., Camb. 88: 645. MCINTYRE, K.H. (1973). Trop. Agric. (Trinidad) 50: 17. PALMQUIST, D-L., and JENKINS, T.C. (1982). J. Dairy Sci. 63: 1. PHIPPS, R.H., WELLER, R.F. and BINES, J.A. (1987). Grass Forage Sci. 42:49. TALKE, H. and SCHUBERT, G.F. (1965). Klin. Wochensch. 43: 174.