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Effects of protein source and level on performance of lactating Damascus goats in negative energy balance
Small Ruminant
Research ELSEVIER
Small Ruminant Research
15 (1995)
257-263
Effects of protein source and level on performance of lactating Damascus goats in negative energy balance M. Hadjipanayiotou*,
A. Photiou
Agricultural Research Institute, Nicosia. Cyprus Accepted 20 April 1994
Abstract Effect of protein source (untreated soybean meal vs. formaldehyde-treated soybean meal) at three levels (13, 15 and 18% CP in the concentrate mixture, DM basis) on milk yield, milk composition, body weight (BW) change and rumen metabolites of 48 lactating Damascus goats was studied. Animals were fed to meet maintenance energy requirements and 60% of milk production energy requirements. Animals were housed and fed concentrates in groups of two animals, whereas roughage was offered to a single group per treatment. Goats consumed 0.175 kg barley hay and 0.269 kg barley straw/d. There were no significant effects of protein concentration or source on milk yield, milk composition, BW change and rumen metabolites. Protein source did not affect rumen NH3-N and total VFA concentration, but dietary protein level had a significant effect (P < 0.00 1) on rumen NH,-N concentration. When all animals were changed to a higher feeding level at the end of the 42-d trial, milk yield was increased slightly; most of the extra feed allowance was directed towards weight gain. Formaldehyde (HCHO) treatment of soybean meal reduced degradability of DM (21 percentage units) and CP (19.2 percentage units) in the rumen. It was concluded that reduction in energy supply below requirements will result in considerably reduced milk yield, and that supply of a protein supplement of low degradability will not alleviate reduction in milk yield through greater mobilization of body reserves and subsequent use for milk production. Keywords: Damascus
goat; Protein source; Protein level; Milk yield; Milk composition;
1. Introduction
Energy requirements of dairy animals of high production potential cannot be fully met in early lactation, and animals compensate for the resulting energy deficit by mobilizing body tissue primarily from body fat (Morand-Fehr, 1981; Chestnutt, 1987). On the other hand, very limited amounts of body protein reserves can be drawn upon when dietary protein supply is inadequate (Orskov et al., 1981). *Corresponding
author.
0921~4488/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO921-4488(94)00034-5
Rumen metabolite
Efficient use of mobiIised fat for milk production is likely to depend on the availability of adequate supplies of essential amino acids to the mammary gland. Orskov et al. (1977) reported that cows in early lactation responded by increasing their milk yield when cows were given protein supplements which escaped rumen degradation. Ewes have also responded in the same way (Gonzalez et al., 1982) when animals were in negative energy balance. Orskov and Hovel1 ( i986) postulated that the greatest application of protected protein sources in periods of limited feed resources availability was the greater use of fat reserves for milk production. Dual purpose breeds (milk and meat) of small ruminants
258
M. Hadjipanayiotou,
A. Photiou /Small Ruminant Research 15 (1995) 257-263
produce considerable quantities of milk during the postweaning period and they may also rely on body reserves mobilization in periods of limited feed resources availability. An increase in CP intake increased BW loss and milk yield in lactating ewes (Robinson et al., 1974) and the increases in milk yield were shown to be associated with increases in the amount of non-ammonia N reaching the abomasum (Robinson et al,, 1979). Contrary, in studies of Cowan et al. (1981) there was no effect of level of protein intake on the rate of loss of body fat. The present studies were undertaken to study the effects of protein source (unprotected vs. protected soybean meal) at three levels each on BW change, milk yield, milk composition and rumen metabolites in Damascus goats offered 60% of their energy requirements for milk production.
2. Materials and methods Production study
A trial with 48 lactating Damascus goats (9lk3.6 d in milk, range 83 to 98) was conducted to study the effect of protein source (untreated soybean meal vs. formaldehyde-treated soybean meal) and level ( 13, 15 or 18% CP in the concentrate mixture, DM basis) on lactation performance and rumen metabolites of goats in negative energy balance. Animals were loosing weight ( -3.75f4.791 kg/head) from kidding to weaning of kids (49 d in milk), but they were gaining weight (3.5 + 12.58 kg/head) from weaning to the commencement of the experiment (9 1 + 3.6 d in milk). Goats were divided into six uniform groups based on their fat-corrected milk yield. Groups were allocated to treatments at random. The experiment was laid out in a completely random design with a 2 X3 factorial arrangement of the treatments. The two types of protein source (untreated, formaldehyde-treated soybean meal) comprised the two levels of one factor and the three levels of protein ( 13, 15 and 18% in the concentrate mixture) the three levels of the other factor. Percentage composition of the concentrate mixtures is in Table 1. The solution of formaldehyde (3 1 of 40% formaldehyde diluted in 77 1 of water/t of soybean meal) was sprayed onto soybean meal, while it was fed into a vertical mixer. After further mixing for approx. 10 min, the sprayed soybean meal was packed into
Table I Composition
(g/kg)
of concentratesa
Barley grain Barley spike awns Corn grain Untreated soya Wheat bran Limestone Sodium chloride Vitamin-trace elements
C13
C1s
C18
728 100 70 40 50 7 3 2
648 100 70 120 50 7 3 2
568 100 70 200 50 7 3 2
a In this and subsequent tables and figures: C and F represent concentrate mixtures with untreated or formaldehyde-treated soybean meal, respectively; subscripts denote 13, 15 and 18% CP in the concentrate mixture. In the F mixtures the untreated soya was completely replaced by formaldehyde-treated soya ( 1: 1 ratio).
sealed polyethylene bags. Bags were opened after 48 h and the soybean meal was poured onto a plastic sheet to a depth of 3-5 cm and allowed to air equilibrate for 72 h. Formaldehyde-treated soybean meal was then processed in the concentrate mixture like the untreated protein soybean meal at the rate of 1: 1. A vitamin-trace element mixture (Vita 6, Vita-Trace Nutrition, Cyprus) added in all mixtures supplied 6000 IU vitamin A, 1000 ILJ vitamin D,, 8.5 IU vitamin E, 23 mg Mn, 1.75 mg I, 45 mg Zn, 30 mg Fe, 2 mg Co and 60 mg Mg per kg concentrate mixture (as fed basis). Concentrate mixtures (9-mm cubes) were given along with roughage (approx. 0.7 : 0.3 ratio) from separate feed containers. Roughage was barley hay, harvested at the milk stage of rain maturity, and barley straw (0.2 : 0.1) . Animals were housed and fed concentrates in groups of two animals each. Pens were of 2.7 X 1.5 m with concrete floor bedded with wood shavings. Roughage was offered to a single group per treatment. Animals had access to concentrates 2 h daily (one in the morning and one in the afternoon) and to roughage during the rest of the day. Goats were fed to meet their total maintenance (0.4 MJ, ME X kg weight0.73) and 60% of their milk production energy requirements. Feed allowance was adjusted weekly based on fat-corrected milk yield and BW in the previous week. The dietary energy requirements (MJ ME) for production were estimated according to Economides (1986) from the energy value in milk ( Y= 1.64+0.42X) divided by 0.62 (where X= fat percentage and 0.62 is the efficiency of utilization of dietary ME for milk production). Animals
259
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263 Table 2 Chemical composition to goats
Barley hay Barley straw C,? C,, C,X F II F 15 F IR
(% DM) of hay, straw and concentrates
fed
DM
CP
Ash
ADF
NDF
ADL”
87.2 88.0 89.4 89.2 88.3 89.3 89.0 88.7
9.9 4.5 13.0 15.0 18.1 12.6 14.8 18.3
9.9 7.0 4.7 5.3 5.1 4.9 6.6 5.0
33.5 46.4 1.9 9.3 9.1 8.9 8.1 8.9
63.5 76.1 19.5 21.8 19.6 19.9 19.9 20.3
3.8 5.0 0.9 0.9 0.9 1.0 1.0 1.2
’ ADL. acid detergent lignin.
were weighed prior to the morning feeding at the beginning, end and once a week during the course of the 42d trial. Milk yield was recorded twice a week. Animals were milked by machine twice daily (07 : 00 and 14 : 00 h) on non-milk recording days, and by hand, due to lack of measuring cylinders, on milk recording days. Representative samples from morning and afternoon milking were taken on one recording day and analyzed for protein, fat, ash and total solids (MAFF, 1973). It is assumed that changes in milk yield or milk composition associated with method of milking are similar for all six treatments. All concentrate mixtures were prepared from the same batch of basic ingredients. Soybean meal was bought from the market and its previous processing, if any, was unknown. Proximate constituents and other analyses were made on bulk, ground (1 mm) samples of feed as outlined by Harris ( 1970). Large quantities (0.4-0.6 l/goat, to reduce contamination from saliva) of rumen liquor samples were taken from all goats 3 h after the morning feeding at the end of the experiment. Rumen liquor samples were obtained by means of a tube passed into the reticulorumen via the oesophagus and suction created by a vacuum pump. Samples were strained immediately after collection through two layers of fine muslin; the pH was measured immediately, and the samples then processed and analyzed for rumen ammonia nitrogen (NH,-N) and volatile fatty acid (VFA) concentration as outlined by Hadjipanayiotou et al. (1988b). The mean concentrate intake of each pair per treatment was used as a single observation in statistical analyses. Data were analyzed using a General Linear Model procedure (SAS, 1989) that accounted for pro-
tein source (untreated soybean meal, formaldehydetreated soybean meal), level of protein ( 13, 15 and 18% CP in the concentrate mixture, DM basis) and their interaction. Mean separation/comparison was performed using Duncan’s multiple range test. On completion of the 42-d experimental period, during which goats were on negative energy balance, they changed over gradually (5 d) to a high level of energy intake. Animals were daily on 1610 g concentrate, 580 g barley hay, 170 g straw and 450 g fresh berseem (Trifolium alexandrinum) . Goats were weighed at the beginning and at the end of the 28-d post-experimental period.
Rumen degradation study Three mature Damascus goats fitted with a perrnanent rumen cannulae, weighing on average 67 kg, were used to measure rumen degradability of dry matter and CP of untreated and formaldehyde-treated soybean meal. Animals were kept in individual pens with concrete floors bedded with wood shavings. Goats were fed on 500 g concentrate (14% CP) and 500 g barley hay. The two samples were incubated (5, 8 and 24 h) in nylon bags (three bags/incubation interval) in the rumen of the animals as outlined by Hadjipanayiotou et al. ( 1988a) for determination of their degradability. Samples were analyzed for DM and CP before and after incubation. The mean of the three bags per incubation interval was used for calculations. Processing of samples after withdrawal of bags from the rumen was as outlined by Hadjipanayiotou et al. ( 1988a). Data on rumen degradability were analyzed using a General Linear Model procedure (SAS, 1989) that accounted for protein source (2), incubation interval (3) and their interaction, Table 3 DM and CP degradability values of untreated and formaldehydetreated soybean meal incubated in the rumen of Damascus goats Degradability
( W)
DM Incubation interval (h) Untreated soybean meal Treated soybean meal SD
5 54.5 34.0
CP 8 67.5 43.0 6.14
24 89.4 71.4
5 30.0 12.8
8 40.0 16.5 4.73
24 57.8 40.9
260
M. Hadjipanayiotou,
Table 4 Performance
of Damascus
goats on different
A. Photiou /Small Ruminant Research 15 (1995) 257-263
levels ( 13, 15, 18% CP mix.) and sources (untreated, formaldehydetreated soybean meal) of
dietary protein C13 No. of animals Milk yield (kg/d) FCM (4%) (kg/d)
C,,
C18
F13
F1S
F18
SD
8
8
8
8
8
8
_
1.31 1.60
1.35 1.54
1s2 1.81
1.28 1.56
1.31 1.68
1.52 1.I6
0.39 0.41
Milk composition (%) Fat CP (Nx6.38) Ash Total solids Concentrate intake (g/d)a Initial weight (kg) Final weight (kg) Weight loss (g/d) a Four individual
observations
5.5 4.2 0.9 14.4 979
5.0 4.1 0.9 13.8 1007
5.2 4.2 0.9 14.0 1067
5.4 4.3 0.9 14.4 916
5.5 4.1 0.9 14.3 984
5.2 4.0 0.9 13.8 1048
0.65 0.36 0.04 0.88 57
66.9 59.3 183
71.2 63.8 177
68.2 61.6 156
68.4 60.9 177
66.9 58.4 202
69.2 62.1 168
3.43 3.25 22.3
per treatment.
Performance data are in Table 4. There were no differences between protein source or level for milk yield, fat-corrected milk yield, milk composition and BW change. In all six treatment diets animals were suffering a decline in milk yield (Fig. 1) and BW loss (Fig. 2) throughout the 42-d experimental period. Dietary ME (MJ/head/d) intake of goats over the last week on trial (estimated to meet the total mainte-
..\ 0
,
,
,
(
,
,
,
,
,
1
2
3
4
5
6
7
B
9
r 10
Wdt
Fig. 1. Fat-corrected milk yield (kg/h/d) of goats on two sources of protein (untreated, - --formaldehyde-treated soybean meal) at three levels each (0 I3%, X 15%. * 18% CP in the concentrate mixture). Last 4 weeks, post-experimental period, all animals on a similar diet.
3. Results 55
Treatment of soybean meal with formaldehyde resulted in a significant reduction (P < 0.001) of DM and CP degradability in the rumen (Table 3). The degradability of both sources was increased with advanced incubation interval.
Fig. 2. Weight changes of goats on two sources of protein (treated, - - - - formaldehyde-treated soybean meal) at three levels each (0 13%, X 15%. * 18% CP in the concentrate mixture). Last 4 weeks, post-experimental period, all animals on a similar diet.
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263 Table 5 Rumen metabolites of dietary protein
in Damascus
goats on different levels ( 13, 15, 18% CP mix.) and sources (untreated,
C,, No. of animals Total VFA (mmol/ 100 ml) Molar proportion of Acetic acid Propionic acid Butyric acid Valerie acid NH,-N (mg/ 100 ml) Rumen pH
C,,
CI,
261
formaldehyde-treated
F 13
F 15
F IR
SD _
8 8.8
8 7.5
8 8.6
8 1.1
8 8.3
8 8.2
57.4 28.9 11.0 2.3 38 5.9
61.3 26.2 10.7 2.0 48 5.8
62.0 24.6 12.0 1.7 67 6.1
60.0 28.9 9.6 1.9 36 6.0
61.1 25.6 11.9
62.1 25.1 11.1 1.5 57 6.2
nance and 60% of the production requirements) was 12.25; during this period animals were loosing weight ( 105 ? 34 g/d) and producing 1.06 +0.38 kg milk of 5.55 + 0.7% butterfat. Increasing the daily feed allowance to 23.85 MJ ME/d resulted in an increase of milk (1.35 kg/head/d) produced over the 4-week postexperimental period (Fig. 1) Although the daily milk energy output was increased (last week on test 4.22 vs. 4.88 MJ GE/head/d) as a result of higher feed allowance, most of the energy input went on BW gain (daily BW gain 206 k 85 g/head). Effect of protein source and level on rumen metabolites is shown in Table 5. Overall, protein source did not affect rumen NH,-N concentration, ruminal pH and molar proportion of VFA. Goats on the 13% CP mixture had significantly lower (P< 0.001) rumen NH,N concentration than those on the 15 and 18% CP mixture. Differences among diets for other metabolites were not significant (Table 5).
4. Discussion Formaldehyde treatment of soybean meal reduced degradability of DM and CP in the rumen, which is broadly in agreement with the results obtained by Rooke et al. ( 1982)) Morgan ( 1985) and Hadjipanayiotou ( 1992a). The amount of formaldehyde and the general processing procedure applied in the present study was similar to the one used by Hadjipanayiotou (1992b) where formaldehyde treatment reduced the degradability of CP in the rumen, but not in the entire digestive tract of Chios growing lambs, implying that soybean meal was not overprotected, and could show
soybean meal)
1.5 52 6.2
1.60 3.92 4.08 2.17 0.85 18.0 0.36
positive effects associated with undegradable protein as outlined by Orskov et al. (1981). Although the animals used in the present study were in a more advanced stage of lactation than those used by Robinson et al. (1974) and Orskov et al. (1987), this is not expected to affect the response to different sources and levels of dietary protein, since in all studies animals were in negative energy balance. Goats used in the present study were gaining BW (83 g/d) from weaning to the commencement (50-91 d in milk) of the trial, implying that there were body reserves that could be mobilized as a result to protein supplements. Klopfenstein ( 1985) reported that responses to slowly degradable protein are more evident when they are fed with feedstuffs of low protein content. The fact that goats were on dietary protein levels below the NRC ( 198 1) recommended levels, therefore, would facilitate the appearance of response to supplements. According to NRC ( 1981) the CP requirements of goats (minimal activity), based on their mean BW and FCM yields (Table 4), were 204, 205, 22 1, 203, 210 and 219 g CPlheadld. The actual CP intakes were below requirements by 71, 53, 34, 65, 57 and 38 gl head/d for diets C,,, C,,, Ci8, F,,, F,, and F,s, respectively, and increases in milk yield would be expected as a result of increments of dietary CP intakes. Fat-corrected milk yield of animals was declining (Fig. 1) and feed intake was decreasing with time (Fig. 3) because the animals were rationed to meet only 60% of the production requirements of the previous week. Due to the fact that animals were fed below requirements they were loosing weight throughout the 6-week experimental period (Fig. 2). When they changed to a higher feed allowance (post-experimental period,
262
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263
1300-
1200.
p11ws i glO-
900-
0
12
3
4
5
6
7
6
9
10
Fig. 3. Concentrate intake by goats on two sources of protein (untreated, - - - - formaldehyde-treated soybean meal) at three levels each (0 13%. x 15%, * 18% CP in the concentrate mixture).
week 7 to 10) milk yield was increased slightly (Fig. 1) ; the extra feed allowance was mainly directed towards weight gain, demonstrating that, when milk yield is adversely affected due to undernutrition, the later is not compensated via greater weight loss for the production of milk. Any decline in milk yield due to undernutrition can only be partially alleviated (Fig. 1) by a higher level of intake, the later directed mainly towards weight gain (Fig. 2). The lack of effect of protein intake on the rate of loss of BW appears to conflict with the findings of Robinson et al. (1974), Sparrow et al. (1973), Orskov et al. (1977) and Orskov et al. (1987), but it is in line with those of Cowan et al. ( 198 1) and Kaim et al. ( 1987). Similarly, the results obtained from formaldehydetreated (protected, less rumen degradable protein) soybean meal in the present study are in line with Sheehan and Hanrahan ( 1989), but differ from Orskov et al. (1987) where it appeared possible to increase milk yield by stimulating BW loss through giving protein supplements of low degradability to underfed cows. In line with previous studies with ewes and goats (Hadjipanayiotou, 1992a), there was no difference in milk composition of goats on untreated or formaldehydetreated soybean meal. In line with Kaim et al. ( 1987), protein concentration and source, did not affect significantly the molar proportion of VFA. Rumen ammonia-N increased with
increasing dietary protein concentration, but there was no difference between the two sources of protein. The non-significant effect of treatment on rumen NH,-N concentration is at variance with the data of Crooker et al. ( 1983) and Folman et al. ( 1981), but in line with a previous study carried out in our Institute (Hadjipanayiotou, 1992a). It must be emphasized, however, that rumen NH,-N concentration is variable during the day. In the study of Crooker et al. (1983), formaldehydetreated soybean meal resulted in less rumen NH,-N accumulation 2-3 h postfeeding than untreated soybean meal, but 6-7 h postfeeding formaldehyde treatment did not reduce NH,-N, presumably because other sources of nitrogen contributed proportionally more NH,-N to the rumen fluid ammonia pool than that contributed by the degradable soybean meal still in the rumen. Regression analysis of milk yield, fat-corrected milk yield, milk components, rumen NH,-N concentration and daily BW loss (I’) on dietary CP level (X) (within protein source) confirmed the findings of the analysis of variance. Increasing the level of dietary CP resulted in a significant increase of NH,-N in the untreated soya (b = 1.73, P < 0.007). A similar trend, although statistically non-significant, was observed in the untreated soya (b=0.87, PcO.1). The findings demonstrated that any reduction in energy supply below requirements will result in considerable reduction in milk yield, and that supply of a protein supplement of low degradability will not alleviate reduction in milk yield through greater mobilization of body reserves and subsequent use for milk production.
Acknowledgements The authors are grateful to M. Theodoridou, M. Karavia, Ch. Spanos and the staff of the Central Chemistry Laboratory of the Agricultural Research Institute for skilled technical assistance. This study was supported partly by FAO/IAEA, Vienna.
References Chestnutt, D.M., 1987. Effect of high-protein supplements on the utilization of body reserves by single-suckling cows. Anim. Prod., 45: 15-22.
M. Hadjipanayiotou,
A. Photiou /Small Ruminant Research
Cowan, R.T., Robinson, J.J., McHattie, I. and Pennie, K., 1981. Effects of protein concentration in the diet on milk yield, change in body composition and the efficiency of utilization of body tissue for milk production in ewes. Anim. Prod., 33: 11 l-120. Crooker, B.A., Clark, J.H. and Shanks, R.D., 1983. Effects of formaldehyde treated soybean meal on milk yield, milk composition, and nutrient digestibility in the dairy cow. J. Dairy Sci., 66: 492-504. Economides, S., 1986. Comparative studies of sheep and goats: milk yield and composition and growth rate of lambs and kids. J. Agric. Sci., 106: 477484. Folman, Y., Neumark, H., Kaim, M. and Kaufmann, W., 1981. Performance, rumen and blood metabolites in high yielding cows fed varying protein percents and protected soybean. J. Dairy Sci., 64: 759-768. Gonzalez, J.S., Robinson, J.J.. McHattie, I. and Fraser, C., 1982. The effect in ewes of source and level of dietary protein on milk yield, and the relationship between the intestinal supply of non ammonia nitrogen and the production of milk protein. Anim. Prod., 34: 3140. Hadjipanayiotou, M., 1992a. Effect of protein source and formaldehyde treatment on lactation performance of Chios ewes and Damascus goats, Small Rumin. Res., 8: 185-197. Hadjipanayiotou, M., 1992b. The influence of fish meal and of formaldehyde-treated soybean meal on the performance of early weaned Chios lambs and Damascus kids. Technical Bulletin 145, Agricultural Research Institute, Nicosia, pp. 8. Hadjipanayiotou, M., Georghiades, E. and Koumas, A., l988a. The effect of protein source on the performance of suckling Chios ewes and Damascus goats. Anim. Prod., 46: 249-255. Hadjipanayiotou, M., Papachristoforou, C. and Economides, S., 1988b. Effects of lasalocid on growth, nutrient digestibility and rumen characteristics in Chios lambs and Damascus kids. Small Rumin. Res., I: 217-227. Harris, L.E., 1970. Nutrition Research Techniques for Domestic and Wild Animals, An International Record System and Procedures for Analyzing Samples. Logan, UT, USA. Vol. 1. Kaim, M., Neumark. H., Folman, Y. and Kaufmann, W., 1987. The effect of two concentrations of dietary protein and of formaldehyde-treated soya-bean meal on the performance of high-yielding dairy cows. Anim. Prod., 44: 333-345. Klopfenstein, T.J., 1985. Animal protein products fed as bypass protein for ruminants. Feedstuffs, February 25, 1985, Vol. 5, 31 PP. MAFF. 1973. The Analysis 27, HMSO, London.
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Morand-Fehr, P., 198 1.Nutrition and feeding of goats: Application to temperate climatic conditions. In: C.G. Gall (Editor), Goat Production, Academic Press, New York, pp. 193-232. Morgan, D.J., 1985. The effect of formalin-treated soyabean meal upon the performance of lactating cows. Anim. Prod., 4 1: 3342. NRC, 1981. Nutrient Requirements of Domestic Animals. No. 15, Nutrient Requirements of Goats, National Academy Press, Washington, DC, pp. 9 1. Orskov, E.R., Grubb, D.A. and Kay, R.N.B., 1977. Effect of postruminal glucose or protein supplementation on milk yield and composition in Friesian cows in early lactation and negative energy balance. Br. J. Nutr., 38: 397-405. Orskov, E.R. and Hovell, F.D.DeB., 1986. Protein metabolism and utilization during undernutrition in ruminants. In: Proc. of an Intern. Symp. on the Use of Nuclear Techniques in Studies of Animal Production and Health in Different Environments, Vienna, 17-2 1 March, IAEA, Vienna, 1986, pp. 429-438. Orskov, E.R., Reid, G.W. and McDonald, I., 1981. The effects of protein degradability and food intake on milk yield and composition in cows in early lactation. Br. J. Nutr., 45: 547-555. Orskov,E.R.,Reid,G.W.andTait,C.A.G., 1987,Effectoffishmeal on the mobilization of body energy in dairy cows. Anim. Prod., 45: 345-348. Robinson, J.J., Fraser, C., Gill, J.C. and McHattie, I., 1974. The effect of dietary crude protein concentration and time of weaning on milk production and body-weight change in the ewe. Anim. Prod., 19: 331-339. Robinson, J.J., McHattie, I. and Calderon Cottes, J.F., 1979. Further studies on the response of lactating ewes to dietary protein. Anim. Prod., 29: 257-269. Rooke, J.J., Norton, B.W. and Armstrong,
D.G., 1982. The digestion
of untreated and formaldehyde treated soybean meals and estimation of their rumen degradabilities by different methods. J. Agric. Sci., 99: 441452. SAS, 1989. SAS/STAT
User’s Guide, Version 6, fourth edition.
SAS Institute Inc., Gary, NC, USA, Vol. 2, pp. 891-996. Sheehan, W. and Hanrahan, J.P., 1989. A comparison of soybean meal and fish meal as supplement for the lactating ewe. Irish J. Agric. Res., 28: 133-140. Sparrow, R.C., Hemken, R.W., Jacobson, D.R., Button, F.S. and Enlow, C.M.. 1973. Three protein percents on nitrogen balance, body weight change, milk production and composition of lactating cows during early lactation. J. Dairy Sci., 56: 664 (Abstr.).
Research ELSEVIER
Small Ruminant Research
15 (1995)
257-263
Effects of protein source and level on performance of lactating Damascus goats in negative energy balance M. Hadjipanayiotou*,
A. Photiou
Agricultural Research Institute, Nicosia. Cyprus Accepted 20 April 1994
Abstract Effect of protein source (untreated soybean meal vs. formaldehyde-treated soybean meal) at three levels (13, 15 and 18% CP in the concentrate mixture, DM basis) on milk yield, milk composition, body weight (BW) change and rumen metabolites of 48 lactating Damascus goats was studied. Animals were fed to meet maintenance energy requirements and 60% of milk production energy requirements. Animals were housed and fed concentrates in groups of two animals, whereas roughage was offered to a single group per treatment. Goats consumed 0.175 kg barley hay and 0.269 kg barley straw/d. There were no significant effects of protein concentration or source on milk yield, milk composition, BW change and rumen metabolites. Protein source did not affect rumen NH3-N and total VFA concentration, but dietary protein level had a significant effect (P < 0.00 1) on rumen NH,-N concentration. When all animals were changed to a higher feeding level at the end of the 42-d trial, milk yield was increased slightly; most of the extra feed allowance was directed towards weight gain. Formaldehyde (HCHO) treatment of soybean meal reduced degradability of DM (21 percentage units) and CP (19.2 percentage units) in the rumen. It was concluded that reduction in energy supply below requirements will result in considerably reduced milk yield, and that supply of a protein supplement of low degradability will not alleviate reduction in milk yield through greater mobilization of body reserves and subsequent use for milk production. Keywords: Damascus
goat; Protein source; Protein level; Milk yield; Milk composition;
1. Introduction
Energy requirements of dairy animals of high production potential cannot be fully met in early lactation, and animals compensate for the resulting energy deficit by mobilizing body tissue primarily from body fat (Morand-Fehr, 1981; Chestnutt, 1987). On the other hand, very limited amounts of body protein reserves can be drawn upon when dietary protein supply is inadequate (Orskov et al., 1981). *Corresponding
author.
0921~4488/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO921-4488(94)00034-5
Rumen metabolite
Efficient use of mobiIised fat for milk production is likely to depend on the availability of adequate supplies of essential amino acids to the mammary gland. Orskov et al. (1977) reported that cows in early lactation responded by increasing their milk yield when cows were given protein supplements which escaped rumen degradation. Ewes have also responded in the same way (Gonzalez et al., 1982) when animals were in negative energy balance. Orskov and Hovel1 ( i986) postulated that the greatest application of protected protein sources in periods of limited feed resources availability was the greater use of fat reserves for milk production. Dual purpose breeds (milk and meat) of small ruminants
258
M. Hadjipanayiotou,
A. Photiou /Small Ruminant Research 15 (1995) 257-263
produce considerable quantities of milk during the postweaning period and they may also rely on body reserves mobilization in periods of limited feed resources availability. An increase in CP intake increased BW loss and milk yield in lactating ewes (Robinson et al., 1974) and the increases in milk yield were shown to be associated with increases in the amount of non-ammonia N reaching the abomasum (Robinson et al,, 1979). Contrary, in studies of Cowan et al. (1981) there was no effect of level of protein intake on the rate of loss of body fat. The present studies were undertaken to study the effects of protein source (unprotected vs. protected soybean meal) at three levels each on BW change, milk yield, milk composition and rumen metabolites in Damascus goats offered 60% of their energy requirements for milk production.
2. Materials and methods Production study
A trial with 48 lactating Damascus goats (9lk3.6 d in milk, range 83 to 98) was conducted to study the effect of protein source (untreated soybean meal vs. formaldehyde-treated soybean meal) and level ( 13, 15 or 18% CP in the concentrate mixture, DM basis) on lactation performance and rumen metabolites of goats in negative energy balance. Animals were loosing weight ( -3.75f4.791 kg/head) from kidding to weaning of kids (49 d in milk), but they were gaining weight (3.5 + 12.58 kg/head) from weaning to the commencement of the experiment (9 1 + 3.6 d in milk). Goats were divided into six uniform groups based on their fat-corrected milk yield. Groups were allocated to treatments at random. The experiment was laid out in a completely random design with a 2 X3 factorial arrangement of the treatments. The two types of protein source (untreated, formaldehyde-treated soybean meal) comprised the two levels of one factor and the three levels of protein ( 13, 15 and 18% in the concentrate mixture) the three levels of the other factor. Percentage composition of the concentrate mixtures is in Table 1. The solution of formaldehyde (3 1 of 40% formaldehyde diluted in 77 1 of water/t of soybean meal) was sprayed onto soybean meal, while it was fed into a vertical mixer. After further mixing for approx. 10 min, the sprayed soybean meal was packed into
Table I Composition
(g/kg)
of concentratesa
Barley grain Barley spike awns Corn grain Untreated soya Wheat bran Limestone Sodium chloride Vitamin-trace elements
C13
C1s
C18
728 100 70 40 50 7 3 2
648 100 70 120 50 7 3 2
568 100 70 200 50 7 3 2
a In this and subsequent tables and figures: C and F represent concentrate mixtures with untreated or formaldehyde-treated soybean meal, respectively; subscripts denote 13, 15 and 18% CP in the concentrate mixture. In the F mixtures the untreated soya was completely replaced by formaldehyde-treated soya ( 1: 1 ratio).
sealed polyethylene bags. Bags were opened after 48 h and the soybean meal was poured onto a plastic sheet to a depth of 3-5 cm and allowed to air equilibrate for 72 h. Formaldehyde-treated soybean meal was then processed in the concentrate mixture like the untreated protein soybean meal at the rate of 1: 1. A vitamin-trace element mixture (Vita 6, Vita-Trace Nutrition, Cyprus) added in all mixtures supplied 6000 IU vitamin A, 1000 ILJ vitamin D,, 8.5 IU vitamin E, 23 mg Mn, 1.75 mg I, 45 mg Zn, 30 mg Fe, 2 mg Co and 60 mg Mg per kg concentrate mixture (as fed basis). Concentrate mixtures (9-mm cubes) were given along with roughage (approx. 0.7 : 0.3 ratio) from separate feed containers. Roughage was barley hay, harvested at the milk stage of rain maturity, and barley straw (0.2 : 0.1) . Animals were housed and fed concentrates in groups of two animals each. Pens were of 2.7 X 1.5 m with concrete floor bedded with wood shavings. Roughage was offered to a single group per treatment. Animals had access to concentrates 2 h daily (one in the morning and one in the afternoon) and to roughage during the rest of the day. Goats were fed to meet their total maintenance (0.4 MJ, ME X kg weight0.73) and 60% of their milk production energy requirements. Feed allowance was adjusted weekly based on fat-corrected milk yield and BW in the previous week. The dietary energy requirements (MJ ME) for production were estimated according to Economides (1986) from the energy value in milk ( Y= 1.64+0.42X) divided by 0.62 (where X= fat percentage and 0.62 is the efficiency of utilization of dietary ME for milk production). Animals
259
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263 Table 2 Chemical composition to goats
Barley hay Barley straw C,? C,, C,X F II F 15 F IR
(% DM) of hay, straw and concentrates
fed
DM
CP
Ash
ADF
NDF
ADL”
87.2 88.0 89.4 89.2 88.3 89.3 89.0 88.7
9.9 4.5 13.0 15.0 18.1 12.6 14.8 18.3
9.9 7.0 4.7 5.3 5.1 4.9 6.6 5.0
33.5 46.4 1.9 9.3 9.1 8.9 8.1 8.9
63.5 76.1 19.5 21.8 19.6 19.9 19.9 20.3
3.8 5.0 0.9 0.9 0.9 1.0 1.0 1.2
’ ADL. acid detergent lignin.
were weighed prior to the morning feeding at the beginning, end and once a week during the course of the 42d trial. Milk yield was recorded twice a week. Animals were milked by machine twice daily (07 : 00 and 14 : 00 h) on non-milk recording days, and by hand, due to lack of measuring cylinders, on milk recording days. Representative samples from morning and afternoon milking were taken on one recording day and analyzed for protein, fat, ash and total solids (MAFF, 1973). It is assumed that changes in milk yield or milk composition associated with method of milking are similar for all six treatments. All concentrate mixtures were prepared from the same batch of basic ingredients. Soybean meal was bought from the market and its previous processing, if any, was unknown. Proximate constituents and other analyses were made on bulk, ground (1 mm) samples of feed as outlined by Harris ( 1970). Large quantities (0.4-0.6 l/goat, to reduce contamination from saliva) of rumen liquor samples were taken from all goats 3 h after the morning feeding at the end of the experiment. Rumen liquor samples were obtained by means of a tube passed into the reticulorumen via the oesophagus and suction created by a vacuum pump. Samples were strained immediately after collection through two layers of fine muslin; the pH was measured immediately, and the samples then processed and analyzed for rumen ammonia nitrogen (NH,-N) and volatile fatty acid (VFA) concentration as outlined by Hadjipanayiotou et al. (1988b). The mean concentrate intake of each pair per treatment was used as a single observation in statistical analyses. Data were analyzed using a General Linear Model procedure (SAS, 1989) that accounted for pro-
tein source (untreated soybean meal, formaldehydetreated soybean meal), level of protein ( 13, 15 and 18% CP in the concentrate mixture, DM basis) and their interaction. Mean separation/comparison was performed using Duncan’s multiple range test. On completion of the 42-d experimental period, during which goats were on negative energy balance, they changed over gradually (5 d) to a high level of energy intake. Animals were daily on 1610 g concentrate, 580 g barley hay, 170 g straw and 450 g fresh berseem (Trifolium alexandrinum) . Goats were weighed at the beginning and at the end of the 28-d post-experimental period.
Rumen degradation study Three mature Damascus goats fitted with a perrnanent rumen cannulae, weighing on average 67 kg, were used to measure rumen degradability of dry matter and CP of untreated and formaldehyde-treated soybean meal. Animals were kept in individual pens with concrete floors bedded with wood shavings. Goats were fed on 500 g concentrate (14% CP) and 500 g barley hay. The two samples were incubated (5, 8 and 24 h) in nylon bags (three bags/incubation interval) in the rumen of the animals as outlined by Hadjipanayiotou et al. ( 1988a) for determination of their degradability. Samples were analyzed for DM and CP before and after incubation. The mean of the three bags per incubation interval was used for calculations. Processing of samples after withdrawal of bags from the rumen was as outlined by Hadjipanayiotou et al. ( 1988a). Data on rumen degradability were analyzed using a General Linear Model procedure (SAS, 1989) that accounted for protein source (2), incubation interval (3) and their interaction, Table 3 DM and CP degradability values of untreated and formaldehydetreated soybean meal incubated in the rumen of Damascus goats Degradability
( W)
DM Incubation interval (h) Untreated soybean meal Treated soybean meal SD
5 54.5 34.0
CP 8 67.5 43.0 6.14
24 89.4 71.4
5 30.0 12.8
8 40.0 16.5 4.73
24 57.8 40.9
260
M. Hadjipanayiotou,
Table 4 Performance
of Damascus
goats on different
A. Photiou /Small Ruminant Research 15 (1995) 257-263
levels ( 13, 15, 18% CP mix.) and sources (untreated, formaldehydetreated soybean meal) of
dietary protein C13 No. of animals Milk yield (kg/d) FCM (4%) (kg/d)
C,,
C18
F13
F1S
F18
SD
8
8
8
8
8
8
_
1.31 1.60
1.35 1.54
1s2 1.81
1.28 1.56
1.31 1.68
1.52 1.I6
0.39 0.41
Milk composition (%) Fat CP (Nx6.38) Ash Total solids Concentrate intake (g/d)a Initial weight (kg) Final weight (kg) Weight loss (g/d) a Four individual
observations
5.5 4.2 0.9 14.4 979
5.0 4.1 0.9 13.8 1007
5.2 4.2 0.9 14.0 1067
5.4 4.3 0.9 14.4 916
5.5 4.1 0.9 14.3 984
5.2 4.0 0.9 13.8 1048
0.65 0.36 0.04 0.88 57
66.9 59.3 183
71.2 63.8 177
68.2 61.6 156
68.4 60.9 177
66.9 58.4 202
69.2 62.1 168
3.43 3.25 22.3
per treatment.
Performance data are in Table 4. There were no differences between protein source or level for milk yield, fat-corrected milk yield, milk composition and BW change. In all six treatment diets animals were suffering a decline in milk yield (Fig. 1) and BW loss (Fig. 2) throughout the 42-d experimental period. Dietary ME (MJ/head/d) intake of goats over the last week on trial (estimated to meet the total mainte-
..\ 0
,
,
,
(
,
,
,
,
,
1
2
3
4
5
6
7
B
9
r 10
Wdt
Fig. 1. Fat-corrected milk yield (kg/h/d) of goats on two sources of protein (untreated, - --formaldehyde-treated soybean meal) at three levels each (0 I3%, X 15%. * 18% CP in the concentrate mixture). Last 4 weeks, post-experimental period, all animals on a similar diet.
3. Results 55
Treatment of soybean meal with formaldehyde resulted in a significant reduction (P < 0.001) of DM and CP degradability in the rumen (Table 3). The degradability of both sources was increased with advanced incubation interval.
Fig. 2. Weight changes of goats on two sources of protein (treated, - - - - formaldehyde-treated soybean meal) at three levels each (0 13%, X 15%. * 18% CP in the concentrate mixture). Last 4 weeks, post-experimental period, all animals on a similar diet.
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263 Table 5 Rumen metabolites of dietary protein
in Damascus
goats on different levels ( 13, 15, 18% CP mix.) and sources (untreated,
C,, No. of animals Total VFA (mmol/ 100 ml) Molar proportion of Acetic acid Propionic acid Butyric acid Valerie acid NH,-N (mg/ 100 ml) Rumen pH
C,,
CI,
261
formaldehyde-treated
F 13
F 15
F IR
SD _
8 8.8
8 7.5
8 8.6
8 1.1
8 8.3
8 8.2
57.4 28.9 11.0 2.3 38 5.9
61.3 26.2 10.7 2.0 48 5.8
62.0 24.6 12.0 1.7 67 6.1
60.0 28.9 9.6 1.9 36 6.0
61.1 25.6 11.9
62.1 25.1 11.1 1.5 57 6.2
nance and 60% of the production requirements) was 12.25; during this period animals were loosing weight ( 105 ? 34 g/d) and producing 1.06 +0.38 kg milk of 5.55 + 0.7% butterfat. Increasing the daily feed allowance to 23.85 MJ ME/d resulted in an increase of milk (1.35 kg/head/d) produced over the 4-week postexperimental period (Fig. 1) Although the daily milk energy output was increased (last week on test 4.22 vs. 4.88 MJ GE/head/d) as a result of higher feed allowance, most of the energy input went on BW gain (daily BW gain 206 k 85 g/head). Effect of protein source and level on rumen metabolites is shown in Table 5. Overall, protein source did not affect rumen NH,-N concentration, ruminal pH and molar proportion of VFA. Goats on the 13% CP mixture had significantly lower (P< 0.001) rumen NH,N concentration than those on the 15 and 18% CP mixture. Differences among diets for other metabolites were not significant (Table 5).
4. Discussion Formaldehyde treatment of soybean meal reduced degradability of DM and CP in the rumen, which is broadly in agreement with the results obtained by Rooke et al. ( 1982)) Morgan ( 1985) and Hadjipanayiotou ( 1992a). The amount of formaldehyde and the general processing procedure applied in the present study was similar to the one used by Hadjipanayiotou (1992b) where formaldehyde treatment reduced the degradability of CP in the rumen, but not in the entire digestive tract of Chios growing lambs, implying that soybean meal was not overprotected, and could show
soybean meal)
1.5 52 6.2
1.60 3.92 4.08 2.17 0.85 18.0 0.36
positive effects associated with undegradable protein as outlined by Orskov et al. (1981). Although the animals used in the present study were in a more advanced stage of lactation than those used by Robinson et al. (1974) and Orskov et al. (1987), this is not expected to affect the response to different sources and levels of dietary protein, since in all studies animals were in negative energy balance. Goats used in the present study were gaining BW (83 g/d) from weaning to the commencement (50-91 d in milk) of the trial, implying that there were body reserves that could be mobilized as a result to protein supplements. Klopfenstein ( 1985) reported that responses to slowly degradable protein are more evident when they are fed with feedstuffs of low protein content. The fact that goats were on dietary protein levels below the NRC ( 198 1) recommended levels, therefore, would facilitate the appearance of response to supplements. According to NRC ( 1981) the CP requirements of goats (minimal activity), based on their mean BW and FCM yields (Table 4), were 204, 205, 22 1, 203, 210 and 219 g CPlheadld. The actual CP intakes were below requirements by 71, 53, 34, 65, 57 and 38 gl head/d for diets C,,, C,,, Ci8, F,,, F,, and F,s, respectively, and increases in milk yield would be expected as a result of increments of dietary CP intakes. Fat-corrected milk yield of animals was declining (Fig. 1) and feed intake was decreasing with time (Fig. 3) because the animals were rationed to meet only 60% of the production requirements of the previous week. Due to the fact that animals were fed below requirements they were loosing weight throughout the 6-week experimental period (Fig. 2). When they changed to a higher feed allowance (post-experimental period,
262
M. Hadjipanayiotou, A. Photiou /Small Ruminant Research 15 (1995) 257-263
1300-
1200.
p11ws i glO-
900-
0
12
3
4
5
6
7
6
9
10
Fig. 3. Concentrate intake by goats on two sources of protein (untreated, - - - - formaldehyde-treated soybean meal) at three levels each (0 13%. x 15%, * 18% CP in the concentrate mixture).
week 7 to 10) milk yield was increased slightly (Fig. 1) ; the extra feed allowance was mainly directed towards weight gain, demonstrating that, when milk yield is adversely affected due to undernutrition, the later is not compensated via greater weight loss for the production of milk. Any decline in milk yield due to undernutrition can only be partially alleviated (Fig. 1) by a higher level of intake, the later directed mainly towards weight gain (Fig. 2). The lack of effect of protein intake on the rate of loss of BW appears to conflict with the findings of Robinson et al. (1974), Sparrow et al. (1973), Orskov et al. (1977) and Orskov et al. (1987), but it is in line with those of Cowan et al. ( 198 1) and Kaim et al. ( 1987). Similarly, the results obtained from formaldehydetreated (protected, less rumen degradable protein) soybean meal in the present study are in line with Sheehan and Hanrahan ( 1989), but differ from Orskov et al. (1987) where it appeared possible to increase milk yield by stimulating BW loss through giving protein supplements of low degradability to underfed cows. In line with previous studies with ewes and goats (Hadjipanayiotou, 1992a), there was no difference in milk composition of goats on untreated or formaldehydetreated soybean meal. In line with Kaim et al. ( 1987), protein concentration and source, did not affect significantly the molar proportion of VFA. Rumen ammonia-N increased with
increasing dietary protein concentration, but there was no difference between the two sources of protein. The non-significant effect of treatment on rumen NH,-N concentration is at variance with the data of Crooker et al. ( 1983) and Folman et al. ( 1981), but in line with a previous study carried out in our Institute (Hadjipanayiotou, 1992a). It must be emphasized, however, that rumen NH,-N concentration is variable during the day. In the study of Crooker et al. (1983), formaldehydetreated soybean meal resulted in less rumen NH,-N accumulation 2-3 h postfeeding than untreated soybean meal, but 6-7 h postfeeding formaldehyde treatment did not reduce NH,-N, presumably because other sources of nitrogen contributed proportionally more NH,-N to the rumen fluid ammonia pool than that contributed by the degradable soybean meal still in the rumen. Regression analysis of milk yield, fat-corrected milk yield, milk components, rumen NH,-N concentration and daily BW loss (I’) on dietary CP level (X) (within protein source) confirmed the findings of the analysis of variance. Increasing the level of dietary CP resulted in a significant increase of NH,-N in the untreated soya (b = 1.73, P < 0.007). A similar trend, although statistically non-significant, was observed in the untreated soya (b=0.87, PcO.1). The findings demonstrated that any reduction in energy supply below requirements will result in considerable reduction in milk yield, and that supply of a protein supplement of low degradability will not alleviate reduction in milk yield through greater mobilization of body reserves and subsequent use for milk production.
Acknowledgements The authors are grateful to M. Theodoridou, M. Karavia, Ch. Spanos and the staff of the Central Chemistry Laboratory of the Agricultural Research Institute for skilled technical assistance. This study was supported partly by FAO/IAEA, Vienna.
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M. Hadjipanayiotou,
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