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Effects of a low-energy diet followed by a compensatory diet on growth, puberty and milk production in dairy heifers
LIVESTOCK PR~~IUJ~IIN ELSEVIER
Livestock Production Science 39 ( 1994) 263-268
Effects of a low-energy diet followed by a compensatory diet on growth, puberty and milk production in dairy heifers H. Barash”,“, Y. Bar-Meirb, I. Bruckental” “Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel bKibutz A$qim 15148, Israel
Accepted 2 November 1993
Abstract Six-month-old Israeli Holstein heifers were fed on a low-energy (LE) diet with corn straw as the main feed component during the 4 months of summer, followed by a high-energy, high-protein diet for compensatory growth during the 2 months of autumn. During the same period a control group was fed to support an average daily gain of 0.65 kg. During the LE phase, the mean daily gains in heart girth, body weight and hip height were 51 to 67% lower than those of the control group. During the compensatory phase, mean daily gains in body weight, hip height and heart girth group were 197 to 225% times greater than in the control group. By the end of the compensatory phase the experimental group had the same mean body weight as the control group, but the mean hip height of the heifers was 2 cm shorter. Puberty was attained by the experimental group one month later than in the control group, but at the same body weight. Milk production was similar in the two groups. The efficiency of the metabolisable energy intake for body weight gain in both treatments was discussed. Keywords: Dairy heifer; Energy intake; Growth; Milk
1. Introduction The cost of raising heifers for the lactating dairy herd is significant. Food is a major component, accounting
for approximately 80% of the cost in the Israeli dairy herd. The use of low-cost food ingredients offers a potential saving, but any changes in food management must not be allowed to compromise the potential for milk production. Studies during the past two decades, as reviewed by Foldager and Sejrsen ( 1987, 1991), Johnson ( 1988) and Tucker ( 1987) show that the daily energy allowance of the growing heifer is a major deter*Corresponding author,Tel:972-8-470583, Fax: 972-8-475075. Contribution from the Agricultaral Research Organization, The Volcani Center, Bet Dagan, Israel. No. 1188-E, 1993 series. 0301-6226/94/$07.00 6 1994 Elsevier Science B.V. All rights reserved SSDI0301-6226(93) E0096-B
minant of the subsequent ability to express her inherited capacity for milk production. In the large dairy breeds the “critical period”, i.e., the time during which the heifer’s mammary development is sensitive to the energy allowance, appears to correspond to a liveweight range of 90 to 300 kg. This is also the period during which puberty is attained. It seems that there is also an optimal daily body weight (BW) gain during this period, which for large breeds is 0.7 kg. Heifers raised during the critical period with daily BW gains larger or smaller than the optimal are likely to exhibit subsequent impairment of milk production (Foldager and Sejrsen, 1987). Suboptimal daily BW gains seem to be less harmful to milk production than supra-optimal gains (Foldager and Sejrsen, 1991). However, a feeding regime in which the energy allowance was
264
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
initially restricted and then supplied ad lib. toward the end of the critical period, did not impair the milk production of dairy heifers (Park et al., 1987; Peri et al., 1993). In the dairy herds of the Jordan Valley in Israel, calving is synchronized to take place during October and November in order to avoid lactation during the hot summer months. The resulting production of agesynchronized dairy heifers offers an excellent opportunity to manipulate their feeding regimes at different times during their rearing period. In this study, Holstein dairy heifers were subjected toward the end of the critical period of growth to a two-phase feeding regime in which a low-energy, low-cost diet consisting mainly of corn straw was followed by a compensatory highenergy, high-protein diet. The aim of this study was to determine the effects of this feeding regime on the efficiency of metabolisable energy (ME) use for BW gain, as well as on growth, puberty and subsequent milk production.
2. Materials and methods Thirty Israeli Holstein heifers, with a mean age of 200 f 1.5 days and a mean (SW) of 173 f 4.1 kg, were divided into two groups of 15. An experimental feeding regime was applied for a total of 186 days, divided into two periods of 121 days in the summer (low-energy [LE] phase) and 65 days in the autumm (compcnsatory phase). During the first phase, heifers in the experimental group were fed an ad lib. LE diet. During the second phase, these heifers were fed an ad lib. compensatory diet. During both phases of the experiment, heifers in the control group were fed a ration calculated to support growth of 0.65 kg day-’ according to the National Research Council (NRC) ( 1989), The compositions of the diets given to the experimental and the control groups are described in Table 1. The heifers were group-fed total mixed rations. Feed was offered every day and residues were weighed every 2 days. After the end of the second phase and during lactation, all the heifers were fed rations calculated to provide the NRC ( 1989) recommendations. Heifer BW was recorded every week and heart girth was measured every month. Withers and hip heights were measured at the beginning and end of each phase of the experiment. The daily BW gain for each group
Table 1 Composition (g/kg DM) of diets Feed
Low-energy
Corn straw Oat hay Corn silage Wheat silage PM & T silage’ Corn cobs Cotton seeds Corn grain Protein sup.* Crude protein NDF3 ADF ME’, Meal
780 200 _
Compensatory
254 235
-
20 100 650 390 2.00
149 362 _ 185 320 185 2.83
Control
152 152 242 454 136 388 201 2.25
‘Poultry manure aad tomato peels silage. *Contains (% on DM basis): CP 50, Ca 0.34, P 0.85, Vitamin A 15000 iu, ME 2.9 Meal kg-‘. ‘Neutral detergent fiber. 4Acid detergant fiber. ‘Metabolisable energy, estimated from NRC ( 1989) tables.
calculated as a linear regression coefficient for the entire phase duration with omission of the first BW record for each phase. Puberty attainment was defined as the time when blood progesterone concentration reached 1 ng ml- ’ (Petitclerc et al., 1984). Blood samples for progesterone were taken weekly and for insulin and insulin-like growth factor 1 (IGFl) on the last day of each phase of the experiment. Blood was withdrawn from the jugular vein into heparinized vacutainers. Plasma was separated and stored at - 20°C until analysed. IGFl was determined by radioimmunoassay (RIA) as described by Daughaday et al. ( 1980) and Peri et al. ( 1993). Insulin was determined by RIA, with the aid of a commercial kit (INSIK-5, Sorin Biomedica, Italy). Progesterone was determined by RIA, with the aid of a commercial kit (Coat-A-Count DPC, Los Angeles, CA, USA) Analyses of variance were performed according to the procedure of the Statistical Analysis Systems Institute ( 1985).
was
3. Results The average, minimum and maximum ambient temperatures were 29.4,19.0 and 40.8”C, respectively dur-
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
ing the first phase and 18.7,5.3 and 30.0°C, respectively during the second phase. The average, minimum and maximum humidities were 53.5%, 35.0% and 64.0%, respectively, during the first phase and 65.0%, 49.0% and 8 1.O%, respectively, during the second phase. The effects of the experimental dietary regime on various growth parameters and on serum concentrations of insulin and IGFl by the end of the first and second phases are presented in Tables 2 and 3. At the end of the first (LE) phase, the mean increases in BW, heart girth, wither height and hip height were 41 .O%,48.4%, 29.2% and 33.1% lower, respectively, than those in the control group. Two months later, at the end of the second (compensatory) phase, the corresponding parameters were 198%, 225%, 156% and 216% greater on the average in the experimental group than in the control. Serum concentrations of IGFl and insulin at the end of each phase were higher in the group that had the higher daily ME intake. Two months after the end of the second phase, the two groups of heifers did not differ significantly in BW, Table 2 Growth parameters of heifers at the beginning and end of the lowenergy and compensatory phases of the experiment
Day 0’ BW, kg Heart girth, cm Withers ht, cm Hip ht, cm Day 121’ BW, kg Heart girth, cm Withers ht. cm Hip ht. cm hlean daily BWG, kg Day 1863 BW, kg Heart girth, cm Withers ht. cm Hip ht. cm Mean daily BWG, kg
P
Experimental
Control
Mean
*SE
Mean
173.6 127.0 98.3 107.2
5.0 1.2 0.8 1.1
172.1 127.0 98.2 107.0
6.4 1.5 0.8 0.8
228.7 136.5 107.5 116.9
5.8 1.4 0.9 1.1
266.6 145.4 111.2 121.5
7.7 1.6 0.6 0.8
0.02
0.46 299.4 155.4 114.5 121.0 1.09
0.01 6.3 1.0 0.8 0.9 0.4
0.78 302.5 153.8 115.7 123.4 0.55
265
Table 3 Serum concentration of IGFl (ng ml-‘) and insulin (pg ml-‘) at the end of the low-energy and compensatory phases P
Experimental
Control
Mean
&SE
Mean
*SE
Day 121’ IGFl Insulin
103.2 5.2
17.4 0.4
197.2 6.7
13.6 0.6
co.01
Day 186’ lGF1 Insulin
233.8 14.1
13.0 1.9
178.6 6.8
14.6 0.8
‘Day 121 -End of the low-energy phase of the experimental diet. ‘Day 186 - End of the compensatory phase of the experimental diet. Table 4 Actual and predicted metabolisable energy intake per unit body weight during the low-energy and compensatory phases of the diet Metabolisable energy intake, Meal kg-’ BWG Actual Experimental Phase 1 22.8 Phase 2 20.7 Phase 1 and Phase 2 21.6
Predicted Control
Experimental
Control
18.1 26.8 20.5
22.7 16.4 19.2
17.1 25.0 19.3
*SE
8.1
1.5 0.7 0.7
<0.05
0.03
‘Day 0 - Start of the experimental diet phase. *Day 121- End of the low-energy phase of the experimental diet. 3Day 186 - End of the compensatory phase of the experimental diet.
heart girth or withers and hip height. The effects of the experimental dietary regime on the ME intake kg-’ BW gain and the predicted ME intake kg-’ BW gain (NRC, 1989) during the first and second phases are presented in Table 4. During the first phase, the differences between the actual and predicted values in both the control and the experimental groups did not exceed 6%. During the second phase, however, the actual value in the experimental group was 1.26 times higher while in the control group the actual value exceeded the predicted value by only 7%. The average dry matter (DM) intake day - ’of the experimental and the control heifers during the first phase were 5.2 and 6.3 kg and during the second phase they were 8.0 and 6.6 kg, respectively. (The experimental group was fed ad lib. throughout the two experimental phases. The control group was fed ad lib. through the first phase and restricted amount throughout the second phase. The mean age and BW at puberty, insemination and calving, as well as the mean total milk production over
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
266
Table 5 Age and body weight at puberty, insemination and calving, and milk yield during first lactation
Puberty: Age (d) BW (kg) Insemination: Age (d) BW (kg) Calving: Age (d) BW (kg) Milk yield’ (kg) Milk fat (kg) Milk protein (kg)
Experimental
Control
Mean
Mean
&SE
P
*SE
348.0 264.4
6.0 6.3
318.0 210.7
6.9 8.8
405.0 316.3 690.0 446.0 7344 252 224
3.6 7.4 1.2 10.8 244 7.3 2.9
408.0 318.0 693.0 458.0 7478 255 231
3.9 7.6 9.6 10.1 293 5.2 3.7
co.01
‘Milk production during the first 300 days of the first lactation.
a period of 300 days, are presented in Table 5. In the experimental group, puberty occurred one month later than in the control group; this difference was significant (P < 0.01). There were no significant differences between the groups in BW at puberty attainment or at 4 weeks after calving. The total milk production and the contents of milk fat and protein were not affected by the different feeding regimes. Conception rates did not differ significantly in the two groups (data not shown) : 73.3% of the heifers in each group conceived after the first insemination, but one heifer from the experimental group did not conceive even after four inseminations and another heifer from this group aborted. Three cows from the experimental group and two from the control group were excluded from the milk production calculations because of severe mastitis.
4. Discussion During the 4 months of summer (the first phase of the experimental diet), heifers in the experimental group consumed less DM than those in the control group, although the diet of the control group was richer in ME per unit weight of DM. This lower consumption is probably attributable to the high neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of the corn straw diet. DM intake was inversely related to the NDF content of the diet. It has been reported that
the dietary ADF content has a linear effect on the rate of decrease in DM intake as environmental temperature increases (NRC., 1989; Cummins, 1992). Relative to the controls, heifers fed on the corn straw diet exhibited a lower ME intake and reduced gains in the BW, heart girth, withers height and hip height at the end of the first phase (LE). However, the percent reduction in gain differed amongst these parameters. The subsequent ad lib. feeding of the experimental animals on a diet rich in ME and crude protein (CP) resulted in their increased ME intake and accelerated gains in heart girth, BW, withers height and hip height, with the relative gains differing amongst these parameters. The overall effect of the non-proportional gain reduction and subsequent acceleration was that at the end of the second (compensatory) phase, the mean BW of heifers in the two groups did not differ significantly but the mean hip height of the experimental group was significantly lower than that of the control. The mean ME intake per mean BW gain in both groups during the first phase and in the control group during the second phase was as expected (NRC, 1989)) whereas in the experimental group during the second phase it was 1.26 times higher than expected (NRC, 1989). This relatively inefficient use of ME for BW gain by the experimental group during the second phase can probably be attributed to fattening. This notion is supported by the lower hip and withers height and the larger heart girth and higher serum insulin levels in the experimental animals than in the controls at the end of the second phase as shown in previous studies (Baile et al., 1983; Kertz et al., 1987). During the second phase the experimental group was fed on a rich CP, ME diet of 60 g CP per Meal ME. This CP: ME ratio is optimal for supporting maximum muscle protein deposition (Preston, 1972). However, it could be that in case of compensatory growth, a higher CP-to-ME ratio will increase muscle protein deposition. It should be taken in mind that the effects found during the compensatory phase might be attributed not only to dietary CP : ME ratio but also to dietary specific effect. Concentrations of serum IGFl in the experimental heifers and in the controls at the end of each experimental phase, were positively correlated to the ME intake and to the growth as shown in previous studies (Breier et al., 1986; Houseknecht et al., 1988; Peri et al., 1993). Puberty was attained in the two groups at the same mean BW of 270 kg, butat different ages. Similar find-
H. Barash et al. /Livestock
Production Science 39 (1994) 263-268
ings were reported by Waldo (1988) and Peri et al. (1993) in Holstein heifers raised on different nutritional regimes. In order to avoid the effect of age of calving on milk production (Foldeger and Sejrsen, 1987), the heifers were inseminated at the same age. The nutritional regime of the experimental group had no significant effect on reproduction, BW 4 weeks after calving, or milk production during the first lactation. High ME allowance during the critical period was expected to impair milk production (Foldager and Sejrsen, 1987). In our experiments the heifers were assigned a high ME allowance only at a BW of 229 kg, approximately 40 kg before puberty was attained, which could be too late to have a significant effect on milk production.
5. Conclusions ( 1) Feeding heifers on a corn straw diet during the hot summer months results in low DM intake and low ME intake. (2) The results of subsequent ad lib. feeding of a diet high in ME and protein, in order to compensate for the reduced BW gain, fall short of the predicted outcome (NRC, 1989), probably because of a fattening effect. (3) The low energy intake followed by a compensatory diet regime during the second part of the critical period of growth in Israeli Holstein heifers, which was tested in this experiment, had no effect on milk production during the first lactation.
References Baile, C.A.. Dela-Fern, M.A. and McLaughlin, C.L., 1983. Hormones and feed intake. Proc. Nutr. Sot., 42: 113-127. Breier, B.H., Bass, J.J., Butler, J.H. and Glukman, P.D., 1986. The somatotrophic axis in young steers: influence of nutritional status on pulsatile release of growth hormone and circulating concentrations of insulin-like growth factor-l. J. Endocrinol., 111: 209215. Cummins, K.A., 1992. Nutrition, feeding and calves. Effect of dietary acid detergent fiber on responses to high environmental temperature. J. Dairy Sci., 75: 1465-1471. Daughaday, W.H., Maritz, I.K. and Blethen, S.L., 1980. Inhibition of access of bound somatomedin to membrane receptor and immunobinding sites: a comparison of radioreceptor and radio-
261
immunoassay of somatomedin in native acid-ethanol-extracted serum. J. Clin. Endocrinol. Metab., 51: 781-790. Foldager, J. and Sejrsen, K., 1987. Mammary gland development and milk production in dairy cows in relation to feeding and hormone manipulation during rearing. In: B.B. Andersen, E. Andersen, B. Jensen, P.H. Petersen and V. Ostergaard (Editors), Research in Cattle Production: Danish Status and Perspectives. Danske Landhusholdingsselskab, Odensk, Denmark, pp. 102115. Foldager, J. and Sejrsen, K., 1991. Rearing intensity in dairy heifers and the effect on subsequent milk production. National Institute of Animal Science, Report No. 693. Research Center, Foulum, Denmark, 131 pp. Houseknecht, K.L., Boggs, D.L., Campion, D.R., Sartin, J.L., Kiser, T.E., Rampacek, G.B. and Amos, H.E., 1988. Effect of dietary energy source and level on serum growth hormone, insulin-like growth factor 1, growth and body composition in beef heifers. J. Anim. Sci., 66: 2916-2923. Johnson, I.D., 1988. The effect of prepubertal nutrition on lactation performance by dairy cows. In: P.C. Gusworthy (Editor), Nutrition and Lactation in the Dairy Cow. Butterworths, London. pp. 171-192. Kertz, A.F., Prewitt, L.R. and Ballam, J.M., 1987. Increased weight gain and effects on growth parameters of Holstein heifer calves from 3 to 12 months of age. J. Dairy Sci., 70: 1612-1622. National Research Council, 1989. Nutritional Requirements of Dairy Cattle: 6th rev. ed. National Academy of Sciences, Washington, DC. Park, C.S., Erickson, G.M., Choi, Y.J. and Marx, G.D., 1987. Effect of compensatory growth on regulation of growth and lactation: response of dairy heifers to a stair-step growth pattern. J. Anim. Sci., 64: 1751-1758. Peri, I., Gertler, A., BruckentaJ, I. and Barash, H., 1993. The effect of manipulation in energy allowance during the mating period on hormone levels and milk production in heifers. J. Dairy Sci., 16: 142-752. Petitclerc, D., Chapin, L.T. and Tucker, H.A., 1984. Carcass composition and mammary development responses to photoperiod and plane of nutrition in Holstein heifers. J. Anim. Sci., 58: 913919. Preston, R.L., 1972. Protein requirements for growing and lactating ruminants. In: H. Swan and D. Lewis (editors) Nutrition Conference for Feed Manufacturers, ~016, pp. 22-37. University of Nottingham, UK. Churchill Livingston Press, Edinburgh and London. SAS” User’s Guide: Statistics, Version 5.1985. SAS Institute, Gary, NC. Tucker, H.A., 1987. Quantitative estimates of mammary growth during various physiological states: a review. J. Dairy Sci., 70: 19581966. Waldo, D.R., 1988. Protein and energy deposition in growing Holstein heifers. In: Proc. 5th Symp. Protein Metabolism Nutrition, European Association of Animal Production, Publ. No. 35. Wilhelm Pieck, University of Restock, Germany, p. 111.
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R&urn6 Barash, H., Bar-Meir, Y. et Bruckental, I., 1994. Effets dune sequence ration pauvm-ration compensatrice sur la croissance, la pubert6 et la production laitiere de genisses laiti&res.Divest. Prod. Sci., 40: 263-268 (en anglais). Des g&rimes Holstein Israeliennes age.es de six mois ont re9u une ration pauvre en Bnergie (LE) pendant les 4 mois d’ete suivie dune ration de croissance compensatrice riche en Bnergie et en proteines pendant les 2 mois d’automne. Un lot mmoin recevait pendant ces memes p&odes un regime assurant des croissances joumaliems moyennes de 0.65 kg. Les gains joumaliers moyens de poids vif, de p&im&trethoracique, et de hauteur au garrot relias6s pendant la p&ode LE ont Bte de 51 a 67% plus faibles et ceux r&ah& pendant la phase compensatrice de 197 a 225% plus &e&s que ceux r&lids par le lot temoin. A la fin de la phase compensatrice le groupe experimental avait le &me poids vif que le lot temoin mais la hauteur au garrot moyenne des g6nisses emit de 2 cm inf&ieure. Le lot exp&imental a atteint la pubert6 un mois plus tard que le lot temoin mais au n&me poids vif. La production 1aitBre a et6 la meme pour les deux lots. L’effticacite de l’utilisation de l’energie metabolisable pour la croissance dam les deux traitements est discut&
Kurzfassung Barash, H., Bar-Meir, Y. und Bruckental, I., 1994. Auswirkungen auf Wachstum, Geschlechtsreife und Milchleistung von F&en, die nach einer Niedrigenergieration eine Ration mit hoher Energiedichte erhalten. Livesr. Prod. Sci., 263-268 (auf englisch), Israelische-Holstein-Fiirsen im Altervon sechs Monaten wurde w&rend der 4 Sommermonate eine Ration mit geringer Energiedichte (LE), die vorwiegend aus Maisstroh bestand, vorgelegt. In den anschlie5enden 2 Herbstmonaten erhielten sie eine sehr energie- und proteinmiche Ration, urn das kompensatorische Wachstum zu nutzen. W&end der gesamten Versuchsperiode wurde eine Kontrollgruppe so versorgt, da8 eine durchschnittliche tiigliche Zunahme von 0,65 kg erzielt werden konnte. W&end der LE-Periode war der mittlere Zuwachs bei Brustumfang, Korpergewicht und Kreuzbeinhiihe urn 5 1% bis 67% niedriger als in der Kontrollgmppe. In der Kompensationsphase hingegen lag der mittlere Tageszuwachs bei Korpergewicht, KreuzbeinhShe und Brustumfang mit 197% bis 225% rund doppelt so hoch wie in der Vergleichsgruppe. Am Ende der Kompensationsphase hatte die Versuchsgruppe zwar das gleiche Korpergewicht wie die Kontrollgruppe ermicht, wies jedoch eine urn 2 cm geringere Kreuzbeinhohe auf. Die Geschlechtsreife trat in der Versucbsgruppe urn ein Monat verzogert ein, aber bei etwa gleichem Korpergewicht. Die spatere Milchleistung war in beiden Gruppen gleich. Die Verwertung der aufgenommenen umsetzbaren Energie fth Kotpergewichtszuwachs in beiden Behandlungen wurde diskutiert.
Livestock Production Science 39 ( 1994) 263-268
Effects of a low-energy diet followed by a compensatory diet on growth, puberty and milk production in dairy heifers H. Barash”,“, Y. Bar-Meirb, I. Bruckental” “Institute of Animal Science, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel bKibutz A$qim 15148, Israel
Accepted 2 November 1993
Abstract Six-month-old Israeli Holstein heifers were fed on a low-energy (LE) diet with corn straw as the main feed component during the 4 months of summer, followed by a high-energy, high-protein diet for compensatory growth during the 2 months of autumn. During the same period a control group was fed to support an average daily gain of 0.65 kg. During the LE phase, the mean daily gains in heart girth, body weight and hip height were 51 to 67% lower than those of the control group. During the compensatory phase, mean daily gains in body weight, hip height and heart girth group were 197 to 225% times greater than in the control group. By the end of the compensatory phase the experimental group had the same mean body weight as the control group, but the mean hip height of the heifers was 2 cm shorter. Puberty was attained by the experimental group one month later than in the control group, but at the same body weight. Milk production was similar in the two groups. The efficiency of the metabolisable energy intake for body weight gain in both treatments was discussed. Keywords: Dairy heifer; Energy intake; Growth; Milk
1. Introduction The cost of raising heifers for the lactating dairy herd is significant. Food is a major component, accounting
for approximately 80% of the cost in the Israeli dairy herd. The use of low-cost food ingredients offers a potential saving, but any changes in food management must not be allowed to compromise the potential for milk production. Studies during the past two decades, as reviewed by Foldager and Sejrsen ( 1987, 1991), Johnson ( 1988) and Tucker ( 1987) show that the daily energy allowance of the growing heifer is a major deter*Corresponding author,Tel:972-8-470583, Fax: 972-8-475075. Contribution from the Agricultaral Research Organization, The Volcani Center, Bet Dagan, Israel. No. 1188-E, 1993 series. 0301-6226/94/$07.00 6 1994 Elsevier Science B.V. All rights reserved SSDI0301-6226(93) E0096-B
minant of the subsequent ability to express her inherited capacity for milk production. In the large dairy breeds the “critical period”, i.e., the time during which the heifer’s mammary development is sensitive to the energy allowance, appears to correspond to a liveweight range of 90 to 300 kg. This is also the period during which puberty is attained. It seems that there is also an optimal daily body weight (BW) gain during this period, which for large breeds is 0.7 kg. Heifers raised during the critical period with daily BW gains larger or smaller than the optimal are likely to exhibit subsequent impairment of milk production (Foldager and Sejrsen, 1987). Suboptimal daily BW gains seem to be less harmful to milk production than supra-optimal gains (Foldager and Sejrsen, 1991). However, a feeding regime in which the energy allowance was
264
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
initially restricted and then supplied ad lib. toward the end of the critical period, did not impair the milk production of dairy heifers (Park et al., 1987; Peri et al., 1993). In the dairy herds of the Jordan Valley in Israel, calving is synchronized to take place during October and November in order to avoid lactation during the hot summer months. The resulting production of agesynchronized dairy heifers offers an excellent opportunity to manipulate their feeding regimes at different times during their rearing period. In this study, Holstein dairy heifers were subjected toward the end of the critical period of growth to a two-phase feeding regime in which a low-energy, low-cost diet consisting mainly of corn straw was followed by a compensatory highenergy, high-protein diet. The aim of this study was to determine the effects of this feeding regime on the efficiency of metabolisable energy (ME) use for BW gain, as well as on growth, puberty and subsequent milk production.
2. Materials and methods Thirty Israeli Holstein heifers, with a mean age of 200 f 1.5 days and a mean (SW) of 173 f 4.1 kg, were divided into two groups of 15. An experimental feeding regime was applied for a total of 186 days, divided into two periods of 121 days in the summer (low-energy [LE] phase) and 65 days in the autumm (compcnsatory phase). During the first phase, heifers in the experimental group were fed an ad lib. LE diet. During the second phase, these heifers were fed an ad lib. compensatory diet. During both phases of the experiment, heifers in the control group were fed a ration calculated to support growth of 0.65 kg day-’ according to the National Research Council (NRC) ( 1989), The compositions of the diets given to the experimental and the control groups are described in Table 1. The heifers were group-fed total mixed rations. Feed was offered every day and residues were weighed every 2 days. After the end of the second phase and during lactation, all the heifers were fed rations calculated to provide the NRC ( 1989) recommendations. Heifer BW was recorded every week and heart girth was measured every month. Withers and hip heights were measured at the beginning and end of each phase of the experiment. The daily BW gain for each group
Table 1 Composition (g/kg DM) of diets Feed
Low-energy
Corn straw Oat hay Corn silage Wheat silage PM & T silage’ Corn cobs Cotton seeds Corn grain Protein sup.* Crude protein NDF3 ADF ME’, Meal
780 200 _
Compensatory
254 235
-
20 100 650 390 2.00
149 362 _ 185 320 185 2.83
Control
152 152 242 454 136 388 201 2.25
‘Poultry manure aad tomato peels silage. *Contains (% on DM basis): CP 50, Ca 0.34, P 0.85, Vitamin A 15000 iu, ME 2.9 Meal kg-‘. ‘Neutral detergent fiber. 4Acid detergant fiber. ‘Metabolisable energy, estimated from NRC ( 1989) tables.
calculated as a linear regression coefficient for the entire phase duration with omission of the first BW record for each phase. Puberty attainment was defined as the time when blood progesterone concentration reached 1 ng ml- ’ (Petitclerc et al., 1984). Blood samples for progesterone were taken weekly and for insulin and insulin-like growth factor 1 (IGFl) on the last day of each phase of the experiment. Blood was withdrawn from the jugular vein into heparinized vacutainers. Plasma was separated and stored at - 20°C until analysed. IGFl was determined by radioimmunoassay (RIA) as described by Daughaday et al. ( 1980) and Peri et al. ( 1993). Insulin was determined by RIA, with the aid of a commercial kit (INSIK-5, Sorin Biomedica, Italy). Progesterone was determined by RIA, with the aid of a commercial kit (Coat-A-Count DPC, Los Angeles, CA, USA) Analyses of variance were performed according to the procedure of the Statistical Analysis Systems Institute ( 1985).
was
3. Results The average, minimum and maximum ambient temperatures were 29.4,19.0 and 40.8”C, respectively dur-
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
ing the first phase and 18.7,5.3 and 30.0°C, respectively during the second phase. The average, minimum and maximum humidities were 53.5%, 35.0% and 64.0%, respectively, during the first phase and 65.0%, 49.0% and 8 1.O%, respectively, during the second phase. The effects of the experimental dietary regime on various growth parameters and on serum concentrations of insulin and IGFl by the end of the first and second phases are presented in Tables 2 and 3. At the end of the first (LE) phase, the mean increases in BW, heart girth, wither height and hip height were 41 .O%,48.4%, 29.2% and 33.1% lower, respectively, than those in the control group. Two months later, at the end of the second (compensatory) phase, the corresponding parameters were 198%, 225%, 156% and 216% greater on the average in the experimental group than in the control. Serum concentrations of IGFl and insulin at the end of each phase were higher in the group that had the higher daily ME intake. Two months after the end of the second phase, the two groups of heifers did not differ significantly in BW, Table 2 Growth parameters of heifers at the beginning and end of the lowenergy and compensatory phases of the experiment
Day 0’ BW, kg Heart girth, cm Withers ht, cm Hip ht, cm Day 121’ BW, kg Heart girth, cm Withers ht. cm Hip ht. cm hlean daily BWG, kg Day 1863 BW, kg Heart girth, cm Withers ht. cm Hip ht. cm Mean daily BWG, kg
P
Experimental
Control
Mean
*SE
Mean
173.6 127.0 98.3 107.2
5.0 1.2 0.8 1.1
172.1 127.0 98.2 107.0
6.4 1.5 0.8 0.8
228.7 136.5 107.5 116.9
5.8 1.4 0.9 1.1
266.6 145.4 111.2 121.5
7.7 1.6 0.6 0.8
0.02
0.46 299.4 155.4 114.5 121.0 1.09
0.01 6.3 1.0 0.8 0.9 0.4
0.78 302.5 153.8 115.7 123.4 0.55
265
Table 3 Serum concentration of IGFl (ng ml-‘) and insulin (pg ml-‘) at the end of the low-energy and compensatory phases P
Experimental
Control
Mean
&SE
Mean
*SE
Day 121’ IGFl Insulin
103.2 5.2
17.4 0.4
197.2 6.7
13.6 0.6
co.01
Day 186’ lGF1 Insulin
233.8 14.1
13.0 1.9
178.6 6.8
14.6 0.8
‘Day 121 -End of the low-energy phase of the experimental diet. ‘Day 186 - End of the compensatory phase of the experimental diet. Table 4 Actual and predicted metabolisable energy intake per unit body weight during the low-energy and compensatory phases of the diet Metabolisable energy intake, Meal kg-’ BWG Actual Experimental Phase 1 22.8 Phase 2 20.7 Phase 1 and Phase 2 21.6
Predicted Control
Experimental
Control
18.1 26.8 20.5
22.7 16.4 19.2
17.1 25.0 19.3
*SE
8.1
1.5 0.7 0.7
<0.05
0.03
‘Day 0 - Start of the experimental diet phase. *Day 121- End of the low-energy phase of the experimental diet. 3Day 186 - End of the compensatory phase of the experimental diet.
heart girth or withers and hip height. The effects of the experimental dietary regime on the ME intake kg-’ BW gain and the predicted ME intake kg-’ BW gain (NRC, 1989) during the first and second phases are presented in Table 4. During the first phase, the differences between the actual and predicted values in both the control and the experimental groups did not exceed 6%. During the second phase, however, the actual value in the experimental group was 1.26 times higher while in the control group the actual value exceeded the predicted value by only 7%. The average dry matter (DM) intake day - ’of the experimental and the control heifers during the first phase were 5.2 and 6.3 kg and during the second phase they were 8.0 and 6.6 kg, respectively. (The experimental group was fed ad lib. throughout the two experimental phases. The control group was fed ad lib. through the first phase and restricted amount throughout the second phase. The mean age and BW at puberty, insemination and calving, as well as the mean total milk production over
H. Barash et al. /Livestock Production Science 39 (1994) 263-268
266
Table 5 Age and body weight at puberty, insemination and calving, and milk yield during first lactation
Puberty: Age (d) BW (kg) Insemination: Age (d) BW (kg) Calving: Age (d) BW (kg) Milk yield’ (kg) Milk fat (kg) Milk protein (kg)
Experimental
Control
Mean
Mean
&SE
P
*SE
348.0 264.4
6.0 6.3
318.0 210.7
6.9 8.8
405.0 316.3 690.0 446.0 7344 252 224
3.6 7.4 1.2 10.8 244 7.3 2.9
408.0 318.0 693.0 458.0 7478 255 231
3.9 7.6 9.6 10.1 293 5.2 3.7
co.01
‘Milk production during the first 300 days of the first lactation.
a period of 300 days, are presented in Table 5. In the experimental group, puberty occurred one month later than in the control group; this difference was significant (P < 0.01). There were no significant differences between the groups in BW at puberty attainment or at 4 weeks after calving. The total milk production and the contents of milk fat and protein were not affected by the different feeding regimes. Conception rates did not differ significantly in the two groups (data not shown) : 73.3% of the heifers in each group conceived after the first insemination, but one heifer from the experimental group did not conceive even after four inseminations and another heifer from this group aborted. Three cows from the experimental group and two from the control group were excluded from the milk production calculations because of severe mastitis.
4. Discussion During the 4 months of summer (the first phase of the experimental diet), heifers in the experimental group consumed less DM than those in the control group, although the diet of the control group was richer in ME per unit weight of DM. This lower consumption is probably attributable to the high neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of the corn straw diet. DM intake was inversely related to the NDF content of the diet. It has been reported that
the dietary ADF content has a linear effect on the rate of decrease in DM intake as environmental temperature increases (NRC., 1989; Cummins, 1992). Relative to the controls, heifers fed on the corn straw diet exhibited a lower ME intake and reduced gains in the BW, heart girth, withers height and hip height at the end of the first phase (LE). However, the percent reduction in gain differed amongst these parameters. The subsequent ad lib. feeding of the experimental animals on a diet rich in ME and crude protein (CP) resulted in their increased ME intake and accelerated gains in heart girth, BW, withers height and hip height, with the relative gains differing amongst these parameters. The overall effect of the non-proportional gain reduction and subsequent acceleration was that at the end of the second (compensatory) phase, the mean BW of heifers in the two groups did not differ significantly but the mean hip height of the experimental group was significantly lower than that of the control. The mean ME intake per mean BW gain in both groups during the first phase and in the control group during the second phase was as expected (NRC, 1989)) whereas in the experimental group during the second phase it was 1.26 times higher than expected (NRC, 1989). This relatively inefficient use of ME for BW gain by the experimental group during the second phase can probably be attributed to fattening. This notion is supported by the lower hip and withers height and the larger heart girth and higher serum insulin levels in the experimental animals than in the controls at the end of the second phase as shown in previous studies (Baile et al., 1983; Kertz et al., 1987). During the second phase the experimental group was fed on a rich CP, ME diet of 60 g CP per Meal ME. This CP: ME ratio is optimal for supporting maximum muscle protein deposition (Preston, 1972). However, it could be that in case of compensatory growth, a higher CP-to-ME ratio will increase muscle protein deposition. It should be taken in mind that the effects found during the compensatory phase might be attributed not only to dietary CP : ME ratio but also to dietary specific effect. Concentrations of serum IGFl in the experimental heifers and in the controls at the end of each experimental phase, were positively correlated to the ME intake and to the growth as shown in previous studies (Breier et al., 1986; Houseknecht et al., 1988; Peri et al., 1993). Puberty was attained in the two groups at the same mean BW of 270 kg, butat different ages. Similar find-
H. Barash et al. /Livestock
Production Science 39 (1994) 263-268
ings were reported by Waldo (1988) and Peri et al. (1993) in Holstein heifers raised on different nutritional regimes. In order to avoid the effect of age of calving on milk production (Foldeger and Sejrsen, 1987), the heifers were inseminated at the same age. The nutritional regime of the experimental group had no significant effect on reproduction, BW 4 weeks after calving, or milk production during the first lactation. High ME allowance during the critical period was expected to impair milk production (Foldager and Sejrsen, 1987). In our experiments the heifers were assigned a high ME allowance only at a BW of 229 kg, approximately 40 kg before puberty was attained, which could be too late to have a significant effect on milk production.
5. Conclusions ( 1) Feeding heifers on a corn straw diet during the hot summer months results in low DM intake and low ME intake. (2) The results of subsequent ad lib. feeding of a diet high in ME and protein, in order to compensate for the reduced BW gain, fall short of the predicted outcome (NRC, 1989), probably because of a fattening effect. (3) The low energy intake followed by a compensatory diet regime during the second part of the critical period of growth in Israeli Holstein heifers, which was tested in this experiment, had no effect on milk production during the first lactation.
References Baile, C.A.. Dela-Fern, M.A. and McLaughlin, C.L., 1983. Hormones and feed intake. Proc. Nutr. Sot., 42: 113-127. Breier, B.H., Bass, J.J., Butler, J.H. and Glukman, P.D., 1986. The somatotrophic axis in young steers: influence of nutritional status on pulsatile release of growth hormone and circulating concentrations of insulin-like growth factor-l. J. Endocrinol., 111: 209215. Cummins, K.A., 1992. Nutrition, feeding and calves. Effect of dietary acid detergent fiber on responses to high environmental temperature. J. Dairy Sci., 75: 1465-1471. Daughaday, W.H., Maritz, I.K. and Blethen, S.L., 1980. Inhibition of access of bound somatomedin to membrane receptor and immunobinding sites: a comparison of radioreceptor and radio-
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immunoassay of somatomedin in native acid-ethanol-extracted serum. J. Clin. Endocrinol. Metab., 51: 781-790. Foldager, J. and Sejrsen, K., 1987. Mammary gland development and milk production in dairy cows in relation to feeding and hormone manipulation during rearing. In: B.B. Andersen, E. Andersen, B. Jensen, P.H. Petersen and V. Ostergaard (Editors), Research in Cattle Production: Danish Status and Perspectives. Danske Landhusholdingsselskab, Odensk, Denmark, pp. 102115. Foldager, J. and Sejrsen, K., 1991. Rearing intensity in dairy heifers and the effect on subsequent milk production. National Institute of Animal Science, Report No. 693. Research Center, Foulum, Denmark, 131 pp. Houseknecht, K.L., Boggs, D.L., Campion, D.R., Sartin, J.L., Kiser, T.E., Rampacek, G.B. and Amos, H.E., 1988. Effect of dietary energy source and level on serum growth hormone, insulin-like growth factor 1, growth and body composition in beef heifers. J. Anim. Sci., 66: 2916-2923. Johnson, I.D., 1988. The effect of prepubertal nutrition on lactation performance by dairy cows. In: P.C. Gusworthy (Editor), Nutrition and Lactation in the Dairy Cow. Butterworths, London. pp. 171-192. Kertz, A.F., Prewitt, L.R. and Ballam, J.M., 1987. Increased weight gain and effects on growth parameters of Holstein heifer calves from 3 to 12 months of age. J. Dairy Sci., 70: 1612-1622. National Research Council, 1989. Nutritional Requirements of Dairy Cattle: 6th rev. ed. National Academy of Sciences, Washington, DC. Park, C.S., Erickson, G.M., Choi, Y.J. and Marx, G.D., 1987. Effect of compensatory growth on regulation of growth and lactation: response of dairy heifers to a stair-step growth pattern. J. Anim. Sci., 64: 1751-1758. Peri, I., Gertler, A., BruckentaJ, I. and Barash, H., 1993. The effect of manipulation in energy allowance during the mating period on hormone levels and milk production in heifers. J. Dairy Sci., 16: 142-752. Petitclerc, D., Chapin, L.T. and Tucker, H.A., 1984. Carcass composition and mammary development responses to photoperiod and plane of nutrition in Holstein heifers. J. Anim. Sci., 58: 913919. Preston, R.L., 1972. Protein requirements for growing and lactating ruminants. In: H. Swan and D. Lewis (editors) Nutrition Conference for Feed Manufacturers, ~016, pp. 22-37. University of Nottingham, UK. Churchill Livingston Press, Edinburgh and London. SAS” User’s Guide: Statistics, Version 5.1985. SAS Institute, Gary, NC. Tucker, H.A., 1987. Quantitative estimates of mammary growth during various physiological states: a review. J. Dairy Sci., 70: 19581966. Waldo, D.R., 1988. Protein and energy deposition in growing Holstein heifers. In: Proc. 5th Symp. Protein Metabolism Nutrition, European Association of Animal Production, Publ. No. 35. Wilhelm Pieck, University of Restock, Germany, p. 111.
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R&urn6 Barash, H., Bar-Meir, Y. et Bruckental, I., 1994. Effets dune sequence ration pauvm-ration compensatrice sur la croissance, la pubert6 et la production laitiere de genisses laiti&res.Divest. Prod. Sci., 40: 263-268 (en anglais). Des g&rimes Holstein Israeliennes age.es de six mois ont re9u une ration pauvre en Bnergie (LE) pendant les 4 mois d’ete suivie dune ration de croissance compensatrice riche en Bnergie et en proteines pendant les 2 mois d’automne. Un lot mmoin recevait pendant ces memes p&odes un regime assurant des croissances joumaliems moyennes de 0.65 kg. Les gains joumaliers moyens de poids vif, de p&im&trethoracique, et de hauteur au garrot relias6s pendant la p&ode LE ont Bte de 51 a 67% plus faibles et ceux r&ah& pendant la phase compensatrice de 197 a 225% plus &e&s que ceux r&lids par le lot temoin. A la fin de la phase compensatrice le groupe experimental avait le &me poids vif que le lot temoin mais la hauteur au garrot moyenne des g6nisses emit de 2 cm inf&ieure. Le lot exp&imental a atteint la pubert6 un mois plus tard que le lot temoin mais au n&me poids vif. La production 1aitBre a et6 la meme pour les deux lots. L’effticacite de l’utilisation de l’energie metabolisable pour la croissance dam les deux traitements est discut&
Kurzfassung Barash, H., Bar-Meir, Y. und Bruckental, I., 1994. Auswirkungen auf Wachstum, Geschlechtsreife und Milchleistung von F&en, die nach einer Niedrigenergieration eine Ration mit hoher Energiedichte erhalten. Livesr. Prod. Sci., 263-268 (auf englisch), Israelische-Holstein-Fiirsen im Altervon sechs Monaten wurde w&rend der 4 Sommermonate eine Ration mit geringer Energiedichte (LE), die vorwiegend aus Maisstroh bestand, vorgelegt. In den anschlie5enden 2 Herbstmonaten erhielten sie eine sehr energie- und proteinmiche Ration, urn das kompensatorische Wachstum zu nutzen. W&end der gesamten Versuchsperiode wurde eine Kontrollgruppe so versorgt, da8 eine durchschnittliche tiigliche Zunahme von 0,65 kg erzielt werden konnte. W&end der LE-Periode war der mittlere Zuwachs bei Brustumfang, Korpergewicht und Kreuzbeinhiihe urn 5 1% bis 67% niedriger als in der Kontrollgmppe. In der Kompensationsphase hingegen lag der mittlere Tageszuwachs bei Korpergewicht, KreuzbeinhShe und Brustumfang mit 197% bis 225% rund doppelt so hoch wie in der Vergleichsgruppe. Am Ende der Kompensationsphase hatte die Versuchsgruppe zwar das gleiche Korpergewicht wie die Kontrollgruppe ermicht, wies jedoch eine urn 2 cm geringere Kreuzbeinhohe auf. Die Geschlechtsreife trat in der Versucbsgruppe urn ein Monat verzogert ein, aber bei etwa gleichem Korpergewicht. Die spatere Milchleistung war in beiden Gruppen gleich. Die Verwertung der aufgenommenen umsetzbaren Energie fth Kotpergewichtszuwachs in beiden Behandlungen wurde diskutiert.