AGRICULTURAL AND FOOD SCIENCE IN FINLAND vol 10, no. 1 p. 3-18 Influence of pre partum and post partum plane of nutrition on the performance of crossbred suckler cows and their progeny AGRICULTURAL AND FOOD SCIENCE IN FINLAND Merja Manninen Harri Huhta Photos: Merja Manninen International journal of agriculture and food science Vol. 10, No. 1, p. 3–18 ISSN 1457-3806 Agricultural and Food Science in Finland http://www.mtt.fi/afsf 3 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. © Agricultural and Food Science in Finland Manuscript received August 2000 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. Influence of pre partum and post partum plane of nutrition on the performance of crossbred suckler cows and their progeny Merja Manninen Agricultural Research Centre of Finland, Animal Production Research, FIN-31600 Jokioinen, Finland, e-mail: merja.manninen@mtt.fi Harri Huhta Agricultural Research Centre of Finland, Karelia Research Station, FIN-82600 Tohmajärvi, Finland. Current address: Agricultural Research Centre of Finland, Resource Management Research, Ecological Production, FIN-50100 Mikkeli, Finland The objective of the experiment was to study the effects of two pre partum and four post partum feeding levels on the performance of 28 Hereford-Ayrshire and 30 Limousine-Ayrshire spring-calv- ing mature cows in calf to Limousin and their calves from the beginning of indoor feeding until the end of grazing under Finnish climatic conditions. A 2 × 2 factorial design experiment consisted of a low (L) and moderate (M) pre partum feeding levels based on hay and straw and two post partum concentrate feeding levels, 1.5 and 3.5 kg/d (1 and 2, respectively). The treatments were replicated across the genotypes. For feeding level L the amount of roughage offered was restricted to propor- tionately 0.7 on a dry matter (DM) basis of feeding level M. Milled barley was offered at 1.3 kg DM/ d to all cows 72 days pre calving. The experiment was divided into two parts, an indoor feeding (215 days) and grazing period (114 days). The indoor feeding period included three periods, from start of the study to the beginning of additional concentrate feeding (P1) and feeding additional concentrate supplements both pre (P2) and post calving (P3). On feeding level M cows had a daily intake of 9.1 and 10.4 kg DM during periods P1 and P2, respectively. During period P3 intake was 10.4 and 12.0 kg DM for 1 and 2. Corresponding values for feeding level L were 6.7, 8.0, 8.0 and 9.7 kg DM, respectively. At the onset of grazing, cows on feeding level M were 47 kg heavier (P<0.05) than those on feeding level L. At pasture, cows fed feeding level L had a higher (P<0.001) live weight gain (LWG) than those on feeding level M. Cows fed less concentrate lost more (P<0.001) live weight from calving to grazing than those receiving higher amounts (–1241 vs. –588 g/d) but compensated for these losses (P<0.05) at pasture. Post partum concentrate feeding did not affect cow condition. During indoor feeding cows receiving a lower level of feeding lost more (P<0.05) condition (–0.67 vs.–0.09 for L and M, respectively). Pre partum treatments did not lead to calving difficulties. Treatments had no effect on calf LWG pre weaning. Cows had a mean milk production of 11.8 kg/d and an average conception rate of 86.8%. Cows on diet L1 appeared to receive enough energy for satisfactory cow and calf performance. The mailto:merja.manninen@mtt.fi 4 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows current data indicates that feeding levels pre calving have a greater significance on cow and calf performance than the plane of nutrition post calving. Key words: beef cows, calves, conception rate, condition score, milk production, plane of nutrition Introduction Approximately half of the total energy required for beef production is a result of energy costs for maintenance (Ferrell and Jenkins 1984). Two thirds of the annual energy and protein require- ments of the beef cow are necessary for mainte- nance, requirements that are closely related to animal live weight. In fact, the efficiency of en- ergy utilization for beef production is known to be poor. Approximately 65% of the total feed consumed in the typical life time of a beef cow, is needed to get calves to the age of weaning (Gregory 1972). For these reasons restriction on intake is often recommended in order to reduce feeding costs, especially in marginal areas such as Finland with long indoor feeding periods and short grazing periods. However, reducing intake may have a detri- mental effect on cow and calf performance, since during late pregnancy severe undernutrition may compromise calf survival and subsequent per- formance. Immature, young cows fed reduced levels of feeding tended to produce lighter calves than mature cows (Smithson et al. 1966) due to both direct intake effects and due to partitioning of energy towards growth rather than pregnan- cy. Undernutrition may also result in lower calf birth weights (Hight 1966, Houghton et al. 1990, Spitzer et al. 1995). Calf survival rates and growth are reduced due to greater calving diffi- culties, reduced quality and quantity of colos- trum milk and reduced maternal properties. A low level of feeding may also affect suckler cow milk yield as well as calf growth rate (Hodgson et al. 1980, Bartle et al. 1984). However, the most important and immediate effect of undernutri- tion in the beef cow is a delay in cycling and ovulation and thus, depressed pregnancy rates (Holness et al. 1978, Somerville et al. 1979). Body condition at calving has a major role in reproductive performance of suckler cows, since it regulates the duration of post partum anoe- strus (Wiltbank et al. 1962, Selk et al. 1988). A low level of feeding in marginal climatic areas did not affect cow or calf health but depressed reproductive performance (Manninen et al. 2000). However, cows replenished live weight losses during the grazing period on sufficiently good quality pasture. The objective of the present experiment was to study under suckled-calf production in Fin- land and regions with similar climatic conditions the effects of two pre partum feeding levels based on hay and straw and four post partum feeding levels on the performance of Hereford- Ayrshire and Limousine-Ayrshire crossbred ma- ture cows and their Limousin calves from the beginning of November until the end of grazing on September. Material and methods Animals and experimental design The experiment was carried out at Tohmajärvi research station located in eastern Finland (62°14’N, 30°21’E). The temperatures recorded inside and outside the cowhouse are presented in Figure 1. Average growth period at Tohma- järvi is 155 days (base temperature +5°C) and grazing period 100–120 days. Twenty-eight Hereford-Ayrshire (HfAy)- cows, initial live weight (LW) 613 kg and 30 Limousine-Ayrshire (LiAy)-cows, initial LW 577 kg were selected for the current experiment. Animals of both breeds were mature, four-year- old and in calf to a Limousin (Li) bull. A 2 × 2 5 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. factorial arranged experiment consisted of two pre partum treatments of a low (L) and moder- ate (M) level of feeding based on hay and straw and two post partum concentrate feeding levels, (1.5 and 3.5 kg/animal/d, 1 and 2, respectively), subsequently refered as L1, L2, M1 and M2. Predicted calving date (= stage of gestation based on the ultrasonic scanning) and initial LW were used in order to allocate animals to experimen- tal treatments. Animals were group-fed, once daily in the morning, six to eight animals per pen, four pens per treatment pre calving and two pens per treatment post calving. Each pen includ- ed one breed (Table 1). The treatments were rep- licated across the genotypes. The experiment commenced on 31 October and consisted of two main parts, an indoor feeding averaging 215 days and a grazing period averaging 114 days which commenced on 2 June. The indoor feeding was comprised of three periods: from the start to the beginning of extra concentrate feeding (P1 mean 97 days), additional concentrate feeding pre calv- ing (P2 mean 72 days) and post calving (P3 mean 46 days). The grazing season ended and calves were weaned on 24 September. Details of the animal housing facilities have been documented previously (Manninen et al. 1998). Feeds, feeding and feed sampling During feeding at 0730, cows were tied for 2–3 hours to allow an equal opportunity to consume offered feed. The amount of feed offered and refused was recorded for each group daily. For feeding level M, feed was offered to cows ac- cording to Finnish recommendations (Ojala 1987) which are based on those for dry dairy cows (Salo et al. 1982) documented as LW0.75/ 5000.75 × 4.0 fattening feed units (FFU) for main- tenance and 0.4 FFU/kg fat corrected milk for milk production. The feed evaluation system Fig. 1. Daily temperature (°C) inside and outside the barn during indoor feeding. 6 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows changed in Finland from net energy based sys- tem into metabolizable energy (ME) based sys- tem after the present experiment was planned and thus, the results are calculated and reported in the present ME based system. In the present feed evaluation system (Tuori et al. 1996) energy re- quirement for maintenance for dry dairy cow is documented as 8.31 MJ ME + 0.0078 × LW and 5.15 MJ ME × kg energy corrected milk for milk production. Forage consisted of hay and straw offered as proportionately 0.75 and 0.25 on a dry matter (DM) basis. Cows received the same amount of roughage during the entire indoor feeding period. For feeding level L, the amount of roughage offered was restricted to proportion- ately 0.7 of feeding level M. The extent of re- striction was based on initial animal liveweights and the protein and energy values of the experi- mental feeds. Milled barley was offered individ- ually to all cows at 1.3 kg DM/d during period P2. After calving during period P3 cows received individually either 1.28 (diet 1) or 2.94 (diet 2) kg DM barley/d for both feeding levels. During indoor feeding, cows had free access to a miner- al mixture rich in phosphorus (Suomen Rehu Ltd.: Fosfori-Hertta, Ca:P = 1.2:1; Ca 145 g/kg, P 115 g/kg, NaCl 110 g/kg, Na 65 g/kg, Mg 35 g/kg), salt lick and water. A vitamin mixture (Karja-Vitan and Karjan Teho-Vitan; A 2 000 000 I.U./kg, D 3 200 000 I.U./kg, E 2 000 mg/kg, Se 10 mg/kg) was given to cows at 200 g/week. During the indoor period feed samples for chemical analyses were taken at every feeding and pooled over a four week period. Calculated energy values of hay, oats straw and barley are based on determined chemical composition and averaged digestibility coefficients reported by Tuori et al. (1996). ME values of feeds were cal- culated according to MAFF (1975, 1984). Hay ME content was calculated as 0.169 × digestible organic matter in the DM (DOMD) –1.05 and ME content of straw as 0.14 × DOMD. Published value was used for barley (Tuori et al. 1996). Amino acids absorbed in the small intestine (AAT) and protein balance in the rumen (PBV) were calculated using determined chemical com- position of the feeds and published constant val- ues according to Tuori et al. (1996). Pasture comprised of a meadow fescue-tim- othy (Festuca pratensis-Phleum pratense) sward was continuously grazed, with an area of 49.5 hectares at the beginning and 58.0 hectares at the end of grazing season. Cows had free access to water with no additional feeds, except for a Table 1. Length of feeding periods at each treatment. Pen 1 3 2 4 5 7 6 8 Number of animals 6 6 7 7 8 6 6 7 Breed1 HfAy LiAy HfAy LiAy HfAy LiAy HfAy LiAy Pre partum feeding2 L L L L M M M M Post partum feeding3 1 1 2 2 1 1 2 2 Feeding period, days P1, from start to the onset of concentrate feeding 93 100 97 96 P2, concentrate feeding pre calving 78 69 72 70 P3, post calving 45 45 45 48 Indoor period 216 214 214 214 Grazing period 113 115 115 115 1 HfAy=Hereford-Ayrshire, LiAy=Limousine-Ayrshire. 2 L=Low, M=Moderate. 3 1=1.5 kg/d, 2=3.5 kg/d. 7 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. magnesium rich mineral supplement. Calves were creep-fed on pasture milled barley from 13 August until weaning in order to facilitate adap- tation to the post weaning diet. Live-weight, condition scoring and calving difficulties Cows were weighed at the beginning of the ex- periment, 60 days prior to the estimated calving date, 1–7 days pre partum, within 48 hours after parturition and at the beginning and end of graz- ing. Cows were condition scored (Lowman et al. 1976) at the beginning of the experiment, 60 days before estimated calving, at calving and at the beginning and end of grazing. Data from one LiAy cow offered diet M1 was omitted due to an aborted pregnancy two months into the experi- ment, and that from another LiAy cow, fed diet L2 was omitted due to a fatal uterine torsion. Furthermore, data from a HfAy cow (diet M2) and two LiAy cows (diet L1) were omitted due to still-born calvings. Calves were weighed immediately after birth, at 14 and 100 days of age, at the beginning and end of grazing, the latter also representing weight at weaning. One Li × HfAy-calf died due to bloat- ing on pasture in September two weeks prior to weaning. Only birth weights are available of still-born calves. All calvings were monitored and assistance was provided as described by Manninen et al. (2000). Milk production and rebreeding Milk production was measured for six cows from each treatment group using the machine-milk- ing technique. Milk yield was measured on 10, 20, 35, 50, 70, 100 and 130 days of lactation. Cows selected for assessing milk production were primarily the first six cows on a calving date basis per treatment, taking into account the sex of the calf. The cow and progeny were re- moved from the main group and the calf was separated from the dam. Cows were milked at 1200, 1800, 0600 and at 1200 hours, respective- ly. The aim of the first milking was to empty the udder and use the sum of the last three milkings as an estimate of milk production. At every milk- ing, an intramuscular injection 3 ml of SYNOX- solution (oxytosin, 5 I.U./ml) was used to en- sure complete emptying of the udder. Milking was started five minutes post injection. During milking the calf was in front of the dam. After milking, collected milk was given to the calf. Milk samples were collected during the last three milkings and pooled according to yield and ana- lysed for fat, protein and lactose at the laborato- ry of Valio Ltd. using a Milcoscan 605 infrared analyser (Foss electric, 69 Slangerupgade, DK 3400 Hillerød, Danmark). A Charolais-bull (Ch) ran with the cows from 2 June to 27 August. Pregnancy diagnosis was performed by ultrason- ic scanning. Interval from calving to conception was calculated on the basis of ultrasonic scan- ning results. Statistical analysis Data was subjected to Analysis of Variance us- ing the MIXED procedure of the Statistical Anal- ysis System (SAS 1989). Satterthwaite’s formu- la was used to correct degrees of freedom when estimated variance of block (breed) or pen was non-positive. Animals were in pens, six to eight animals per pen, four pens per treatment pre calv- ing and two pens per treatment post calving, and therefore pen was used as an experimental unit (Gill 1989). Breed was used as block effect. In- dividual cow and calf data was used for testing cow and calf performance, milk production and milk composition. Feed intake data was not sta- tistically evaluated due to fixed experimental feeding regimens. Milk production and cow performance data was analysed according to the following model (Morris 1999): y l(ijk) = µ + p k + b i + d j + bd ij + pbd ijk + ε l(ijk) where y l(ijk) is the observed value, µ is the general mean, b i is the pre partum feeding level, 8 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows d j is the post partum concentrate feeding level, bd ij is their interaction, p k is a random effect due to block (breed), pbd ijk is a random effect due to pen and ε l(ijk) is the residual error term. In the analysis, the pbd ijk term with four degrees of free- dom has been used as an error term. Post par- tum concentrate feeding level was not included in the model when interpreting initial LW and condition score, LW and condition score 60 days pre partum, pre calving LW and live weight gain (LWG) and condition score changes from the start of the study to calving. Data for calves was analysed using the same model in addition that the effect of sex (s m ) and interactions between sex and pre partum feed- ing level, sex and post partum concentrate feed- ing level, sex, pre partum feeding level and post partum concentrate feeding level were includ- ed. In this analysis, the pbds ijkm term with eight degrees of freedom has been used as an error term for comparisions related to sex. Calf birth date was used as a covariate in the analysis when interpreting calf performance data. Results Chemical composition of feeds and feed intake Mean chemical composition of experimental feeds is given in Table 2. In general, only small amounts offered feeds were refused on some days. On feeding level L, hay comprised of 80.4% and straw 19.6% of the total amount of roughage offered during the indoor feeding pe- riod. The corresponding value for feeding level M was 84.4% and 15.6%, respectively. Average daily nutrient intakes during the indoor feeding periods P1–P3 are summarized in Table 3. Dur- ing period P1 cows on feeding levels L and M consumed on an average 6.7 and 9.1 kg DM, re- spectively. For period P2, DM intakes were 1.3 kg higher for both levels due to barley supple- mentation. After calving cows on the M1- and M2-diets consumed 10.4 and 12.0 kg DM, re- spectively. Corresponding values for feeding lev- el L during P3 were 8.0 and 9.7 kg DM, respec- tively. At pasture, the creep-fed barley intake of calves was on average 0.24 kg/d. Live weight, condition score and calving difficulties of cows No interactions in maternal LW, LWG, condi- tion score (CS) and changes of condition score between pre partum and post partum feeding level were observed and therefore, only least squares means of the main effects are presented in Tables 4 and 5. The initial LW of cows aver- aged 590 kg. Sixty days before estimated calv- ing there were no differences in LW between the pre partum feeding levels, but pre calving cows on feeding level M tended to be heavier (P<0.10) than those on feeding level L. At the onset of grazing, cows on feeding level M were 47 kg heavier (P<0.05) than those on feeding level L. Cows fed 1-diets lost more (P<0.001) LW from calving to grazing than those on 2-diets (–1241 vs. –588 g/d). At pasture cows overwintered on feeding level L had a higher 477 g (P<0.001) LWG than those on feeding level M. In addition, LWG was 157 g higher (P<0.05) on diet 1 than on diet 2 at pasture. At the end of grazing, cows had a mean 23 kg increase in LW compared to the beginning of the experiment and no differ- ences were observed between treatments. At the beginning of the experiment the aver- age condition score of cows was 2.64. At calv- ing cows on feeding level M had a better (P<0.01) condition score than those on feeding level L (2.72 vs. 2.36). In fact, cows on feeding level M were in better condition at calving than at the onset of the experiment. Post partum con- centrate feeding did not affect the condition at the onset of grazing, but cows on feeding level M were in better (P<0.05) condition than those on feeding level L (2.47 vs. 2.03). During in- door feeding cows on feeding level L lost more (P<0.05) condition than those on feeding level M (–0.67 vs.–0.09), but compensated for these 9 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. Table 2. Mean chemical composition of experimental feeds. Hay Oats Barley straw Number of samples 10 8 6 Chemical composition Dry matter (DM),(g/kg) 860 849 867 In DM, Ash 47 57 23 Crude protein 91 37 135 Ether extract 19 16 22 Crude fibre 361 438 53 Nitrogen free extract 482 452 767 Feed value, (/kg DM) ME, MJ 8.8 6.1 13.1 AAT, g 75 54 105 PBV, g –37 –55 –36 ME, metabolizable energy. AAT, amino acids absorbed in the small intestine. PBV, protein balance in the rumen. Table 3. Mean daily intake of dry matter (DM), energy (metabolizable energy, ME), amino acids absorbed in the small intestine (AAT) and protein balance in the rumen (PBV) of cows during indoor feeding, peri- ods P11, P22 and P33. Pre partum feeding Low Moderate Post partum feeding 1 2 1 2 Number of groups 2 2 2 2 DM, kg Hay, P1-P3 5.29 5.29 7.54 7.56 Oats straw, P1-P3 1.29 1.29 1.42 1.37 Mineral mixture, P1-P3 0.15 0.15 0.15 0.15 Barley, P2 1.30 1.30 1.30 1.30 Barley, P3 1.28 2.94 1.28 2.94 Total P1 6.73 6.73 9.11 9.08 Total P2 8.03 8.03 10.41 10.38 Total P3 8.01 9.67 10.39 12.02 ME, MJ Total P1 54.2 54.1 74.6 74.5 Total P2 71.2 71.1 91.6 91.5 Total P3 70.9 92.5 91.3 113.0 AAT, g Total P1 465 465 640 639 Total P2 601 601 776 775 Total P3 598 771 773 945 PBV, g Total P1 –265 –264 –352 –351 Total P2 –312 –311 –399 –398 Total P3 –315 –378 –402 –466 1 P1 = from start to beginning of feeding with barley, mean 97 days. 2 P2 = feeding with barley pre calving, mean 72 days. 3 P3 = post partum feeding, mean 46 days. 10 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows Table 4. Live weight (LW) and live weight gain (LWG) of cows during indoor feeding and grazing. Pre partum Post partum SEM2 Significance1 feeding feeding min – max Low Moderate 1 2 Pre partum Post partum feeding feeding Number of cows 26 27 26 27 LW, kg Initial 592 588 21.8–22.0 NS 60 days pre partum 594 620 18.7–18.9 NS Pre calving 628 661 18.3–18.5 o Post calving 568 607 596 579 21.2–21.4 * NS Onset of grazing 523 570 543 550 13.9–14.2 * NS End of grazing 617 609 618 608 16.2–16.4 NS NS LWG, g/d Start → calving 205 435 28.9–29.5 *** Calving → grazing –1086 –744 –1241 –588 124.8–126.6 * *** During indoor –321 –87 –260 –147 48.3–48.9 * NS At pasture 826 349 666 509 45.8–46.8 *** * Entire experiment 76 64 59 82 24.3–24.8 NS NS 1 o P<0.10; * P<0.05; ** P<0.01; *** P<0.001; NS not significant. 2 SEM=Standard Error of the Mean. Table 5. Condition, change at condition score of cows during indoor feeding and grazing and interval from calving to conception. Pre partum Post partum SEM2 Significance1 feeding feeding min – max Low Moderate 1 2 Pre partum Post partum feeding feeding Number of cows 26 27 26 27 Condition score Initial 2.71 2.56 0.186–0.187 NS 60 days pre partum 2.49 2.68 0.128–0.129 NS Calving 2.36 2.72 2.58 2.50 0.116–0.117 ** NS Onset of grazing 2.03 2.47 2.21 2.29 0.102–0.103 * NS End of grazing 3.16 3.07 3.16 3.08 0.180–0.181 NS NS Change at condition score Start → calving –0.35 0.16 0.098–0.099 *** Calving → grazing –0.33 –0.25 –0.38 –0.20 0.070–0.071 NS o During indoor –0.67 –0.09 –0.48 –0.29 0.147–0.149 * NS At pasture 1.13 0.58 0.94 0.78 0.176–0.177 o NS Entire experiment 0.46 0.51 0.47 0.50 0.113–0.115 NS NS Interval from calving to conception, days3 67 71 69 68 5.5–5.9 NS NS 1 o P<0.10; * P<0.05; ** P<0.01; *** P<0.001; NS not significant. 2 SEM=Standard Error of the Mean. 3 Number of cows: low = 25, moderate = 21, 1 = 23, 2 = 23. 11 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. losses (P<0.10) at pasture (1.13 vs. 0.58). At the end of the grazing season all cows were in good condition, mean condition score 3.12, and no between-treatment differences were observed. Most calvings were easy, with only six requir- ing slight assistance. Live weight of calves No interactions between treatments in calf LW and LWG were observed and therefore, only least squares means of the main effects are presented in Table 6. Post partum concentrate feeding had no effect on calf performance. The pre partum feeding level had no effect on calf birth weight, but male calves were heavier (P<0.05) at birth than females (44.8 vs. 41.1 kg). At weaning only sex affected calf LW, with male calves being 24 kg heavier (P<0.001) than females. Pre grazing, calves born to dams on feeding level M grew better (P<0.05) than those born to dams on feed- ing level L (1356 vs. 1226 g/d). Pre weaning calves born to dams fed feeding levels L and M, and diets 1 and 2 had a LWG of 1278, 1332, 1311 and 1299 g/d, respectively. Prior to weaning male calves grew better (P<0.001) than females (1369 vs. 1241 g/d). Milk production, milk composition and conception rate No interactions between treatments in milk pro- duction and milk composition were observed and therefore, only least squares means of the main effects are presented in Table 7. Treatments had no effect on mean milk production and milk pro- tein content. Only on days 35 and 50 of lacta- tion, did cows on the diet 2 tend to produce more (P<0.10) milk than those on diet 1 (12.1 vs. 10.4 kg/d and 12.5 vs. 10.8 kg/d). Milk fat con- tent was higher (P<0.10) for cows on feeding level M than L (46.9 vs. 43.1 g/kg). In contrast, mean milk lactose content tended to be higher (P<0.10) for cows on feeding level L than M (50.1 vs. 48.9 g/kg). During the mating period 86.8% of cows conceived. All cows on diet L1 become pregnant, 13 out of 14 cows on diet L2 (92.9%), 11 out of 14 cows on diet M1 (78.6%) and 10 out of 13 cows on diet M2-diet (76.9%). However, conception rates were not statistically tested. Treatments had no effect on the interval from calving to conception averaging 69 days (Table 5). Discussion Feed value and feed intake In general, the health of cows and calves was satisfactory during the experiment. One calf died in the present experiment due to bloating, and rather than directly due to experimental treat- ments. Two LiAy cows calved on the same night on 21 April in the outdoor exercise area and lost their calves due to unfavourable climatic condi- tions. Experimental hay had a low crude protein and high fibre content and therefore, calculated energy content (8.8 MJ ME/kg DM) was typical for late harvested hay. ME-based feed evalua- tion system was introduced in Finland after the experiment was done and thus, the results are expressed on ME-basis. During period P1, cows on feeding levels L and M consumed on average 54.2 and 74.6 MJ ME/d, respectively. For dry, non-lactating dairy cows of LW 600 kg, an energy intake of 63.2 MJ ME/d is recommended (Tuori et al. 1996), which exceed the feeding level L by 9 MJ ME. Based on this value, feeding level M appeared to ex- ceed maintenance recommendations for dry dairy cows by 11.4 MJ ME. For period P2 cows had an energy intake of 71.2 and 91.6 MJ ME/d for feeding levels L and M. For dairy cows in the last trimester of pregnancy respective (8th and 9th month of pregnancy) intakes of 81.9 and 97.1 MJ ME/d are recommended by Tuori et al. (1996), which is in good accordance with the energy level cows received on feeding level M pre calving. During period P3 cows on diet L1 12 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows Table 6. Mean treatment and sex effects on calf performance. Pre partum Post partum SEM2 Significance1 feeding feeding Sex min–max Low Moderate 1 2 Male Female partum partum feeding feeding Number of calves 28a 28b 28a 28b 32c 24d Average calving date3 107 105 107 105 110 102 5.3–5.6 NS NS * Live weight, kg Birth 43.4 42.5 42.6 43.3 44.8 41.1 1.04–1.20 NS NS * 14-day 60.8 60.1 60.8 60.0 62.9 58.0 1.34–1.51 NS NS * 100-day 173 182 178 176 185 170 3.1–3.6 o NS ** 160-day4 248 255 252 251 264 240 4.1–4.7 NS NS *** Onset of grazing 101 104 103 102 105 100 2.2–2.5 NS NS NS Weaning = End of grazing 249 255 253 251 264 240 4.0–4.6 NS NS *** Weaning age, d 159 163 160 162 156 166 6.1–6.3 NS NS * Live weight gain, g/d Birth → grazing 1226 1356 1292 1290 1313 1269 40.4–45.8 * NS NS At pasture 1299 1317 1317 1298 1390 1225 26.5–29.1 NS NS *** Birth → weaning 1278 1332 1311 1299 1369 1241 22.0–25.5 NS NS *** 1 o P<0.10; * P<0.05; ** P<0.01; *** P<0.001; NS not significant. 2 Standard Error of the Mean. 3 Day 1=1 January. 4 Average weaning age of the calves. a n=28 for calving difficulty and birth weight then n=26. b n=28 for calving difficulty and birth weight, n=27 for calving difficulty, birth weight, 14-day and 100-day weight then n=26. c n=32 for calving difficulty and birth weight then n=29. d n=24 for calving difficulty, birth weight, 14-day and 100-day weight then n=23. Pre Post Sex maintained their energy intake as that during period P2. Post-calving cows on the diets L2 and M1 had practically the same energy intakes (92.5 vs. 91.3 MJ ME/d). Post-calving cows on the diet M2 had a mean calculated energy intake of 113 MJ ME/d, a value consistent for lactating dairy cows with a mean daily milk yield of 10 kg (114.7 MJ ME) recommended by Tuori et al. (1996). Calculated AAT intakes exceeded rec- ommended levels (Tuori et al. 1996) for dairy cows pre calving for all experimental diets. How- ever, only diet M2 theoretically provided suffi- cient AAT for cows post calving based on Finn- ish recommendations. Comparisions between recommendations for dairy cows and measured ME and AAT intakes of suckler cows in the present experiment is po- tentially compromised due to differences in housing conditions. Loose housing can increase the maintenance energy requirements of suckler cows by between 10 and 20% (Petit and Agabri- el 1989) depending on shelter type during win- ter. In contrast, Ferrell and Jenkins (1984) re- ported that the maintenance energy required for beef cattle to be about 15% less than dairy cat- tle. However, other studies (Neville and McCul- lough 1969, Neville 1974, Petit and Micol 1981) have indicated higher than predicted require- ments for non-pregnant dry beef cows. The NRC (1984) recommends an energy intake of 73 MJ/ d for a 600 kg beef cow during the middle third of pregnancy, 84 MJ/d during the last third of 13 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. pregnancy and 107 MJ/d post calving with milk production of 9 kg/d. Energy intakes on diet M2 were consistent with these recommendations. Live weight, condition of cows and calving difficulties Based on a recommended condition score of 3.00 (Lowman et al. 1976) for spring-calving cows, the condition of the experimental cows at the beginning of the experiment of 2.64 could be considered to be too low. This may be a result from the previous grazing season and the late weaning of the calves. Achieving the correct condition score at each production stage is par- ticularly important in marginal areas with ex- tended indoor feeding periods. With crossbred cows with a high milk production potential it is extremely important to wean the calves before dam condition begins to decline or the availa- bility of pasture is insufficient to support the energy requirements for maintenance and milk production. During the indoor feeding period cows on feeding level M lost 18 kg while those overwin- tered on feeding level L lost 69 kg, consistent with a decline in condition score of –0.09 and –0.67, respectively. Loss of LW and condition on feeding level M relative to cow size was so marginal, such that in practice losses were negli- gible. The condition of cows (2.03) overwintered on feeding level L was in accordance with rec- ommendations of 2.0 by Lowman et al. 1976 at the beginning of the grazing/mating season and no negative effects were observed in this study. However, the duration of grazing and indoor feeding periods are markedly different between the UK and Finland, and need to be taken into account in addition to such recommendations. The effects of different feeding levels on cow LW during late pregnancy are widely reported (Hight 1966, Drennan and Bath 1976a, Russel et al. 1979, Manninen et al. 2000), although com- Table 7. Effect of pre partum feeding level and post partum concentrate feeding level on milk production. Pre partum Post partum SEM2 Significance1 feeding feeding Low Moderate 1 2 Pre partum Post partum feeding feeding Number of animals 6 6 6 6 Milk yield, (kg/d) Day of lactation 10 10.6 10.9 10.6 11.0 0.72 NS NS 20 10.9 11.0 10.5 11.3 0.57 NS NS 35 10.7 11.8 10.4 12.1 0.45 NS o 50 11.3 12.0 10.8 12.5 1.11 NS o 70 12.1 13.6 12.8 12.9 1.95 NS NS 100 12.6 13.0 13.3 12.3 1.69 NS NS 130 11.8 13.1 12.4 12.5 1.54 NS NS Mean 11.4 12.2 11.5 12.1 1.08 NS NS Milk composition, (g/kg) Fat 43.1 46.9 44.1 45.9 1.33 o NS Protein 30.3 31.7 30.5 31.5 1.03 NS NS Lactose 50.1 48.9 49.1 49.9 0.58 o NS 1 o P<0.10; * P<0.05; ** P<0.01; *** P<0.001; NS not significant. 2 Standard Error of the Mean. 14 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows parisions with earlier studies and current results are difficult due to markedly different conditions. The post calving concentrate feeding level did not in fact affect cow condition or changes in condition which may be attributed to a rela- tively short period from calving to the onset of grazing. Condition at calving was obviously suit- able for this stage of production for mature, crossbred cows, but inspite of this, cows on the diet 1 lost almost double the LW relative to those fed diet 2, but compensated for such losses on pasture. These results are in accordance with earlier results under Finnish conditions with sim- ilar non-mature cows (Manninen et al. 2000). Hodgson et al. (1980) offered spring-calving Hereford-Friesian and Blue-Grey cows hay and concentrate from calving until turnout sufficient for maintenance and either 2.3 or 9.0 kg milk/d and observed that cows on the lower level of feeding lost more LW (1730 vs. 1260 g/d), loss- es which are consistent with values observed in the current study. Only six calvings required slight assistance indicating that cows were of suitable condition at calving for both pre calving feeding levels. This finding is in good accordance with previ- ous studies with mature cows offered different pre calving nutrition levels (Tudor 1972, Dren- nan and Bath 1976a). However, nutrition prior to calving is more critical for first-calf heifers, although no differences were found between beef heifers fed at various pre calving planes of nu- trition (Absher and Hobbs 1968, Bellows et al. 1972, Corah et al. 1975, Spitzer et al. 1995). Live weight of calves, milk production and conception rate Growth rate of all calves was at least satisfacto- ry from birth to weaning which undoubtedly due to a mean milk production of 11.8 kg/d. Howev- er, pre calving feeding levels had no effect on calf birth weight. The period from calving to the onset of grazing was only on average 46 days and may potentially be too short to result in a calf LW response to the post calving concentrate feeding. Baker and Barker (1976) also observed that post calving feeding of Hereford-Friesian cows over a mean period of 54 days had no sig- nificant effect on calf growth rate. In contrast, Hodgson et al. (1980) reported that calves born to dams fed a low plane of nutrition post calving had a lower growth rate relative to a higher plane of nutrition. However, differences in post calv- ing dam feeding had no significant effect on fi- nal calf weight, a finding consistent with the current study. The effects of dam pre partum feeding level on calf performance were marginal, and there- fore the only major difference was observed in LWG before grazing (L:1226 vs. M:1356 g/d). The results are in accordance with a previous study (Manninen et al. 2000). However, the ef- fects of pre calving plane of nutrition level on calf performance are widely reported. Drennan and Bath (1976b) demonstrated that the plane of dam nutrition during late pregnancy had no effect on calf birth weight or subsequent LWG when the cows were fed silage to appetite (ad lib.) or 27.3 kg/d during late pregnancy. In an earlier experiment calves born to dams on low plane of pre calving nutrition were 20% lighter than calves born on the high plane of nutrition (Hight 1966). Calf LWG from various experi- ments that manipulated pre calving plane of nu- trition are markedly different, possibly due to variations in the duration of feeding restriction, breed and condition score prior to calving. In accordance with the results of Rahnefeld et al. (1990) calf sex had the expected effect on calf performance in the current study. Mean milk production was similar between treatment groups and was independent of pre and post partum feeding levels. A marginal increace in milk production was observed after day 50 of lactation which may due to turnout to pasture. It is also well documented that suckler cow milk production increases slowly after calving and reaches a maximum between 1 and 3 months of lactation depending on the balance between calf suckling capacity and dam milk production po- tential (Petit and Agabriel 1989). However, milk 15 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Vol. 10 (2001): 3–18. production in the current study was higher than previously reported for the same dairy-beef crosses (Manninen et al. 1998, 2000). Several studies (Baker and Barker 1976, Nicol 1977, Lowman et al. 1979, Hodgson et al. 1980, Baker et al. 1982, Somerville et al. 1983) have demonstrated the effects of plane of post calving nutrition on milk production. The effects of pre calving feeding level on milk production tend to be less consistent. In some studies, milk production has been shown to be independent of pre calving plane of nutrition (Drennan and Bath 1976a, Russel et al. 1979), but not in all cases (Nicol 1977, Hodgson et al. 1980, Somerville et al. 1983). Feeding level M tended to increase milk fat content, while the reverve was true for lactose. The current results are to some extent consist- ent with the findings by Lowman et al. (1979) who reported that the plane of nutrition in early lactation had no effect on milk composition. Ob- viously in the present experiment the cows fed low plane of nutrition maintained good milk pro- duction at the expence of body reserves support- ed by the negative change at condition score prior to grazing season. The most immediate effects of undernutrition in the suckler cow is a delay in conception and reduced pregnancy rates. Body condition at calv- ing is often considered to have a major role in the reproduction of beef cows, possibly by reg- ulation of the duration of anoestrus (Richards et al. 1986, Osoro and Wright 1992). In general, reproductive performance in this study was sat- isfactory but no statistical evaluation was cur- rently conducted. Furthermore, the sample pop- ulation in the present study was too small to draw firm conclusions about the influence of plane of nutrition on conception rate. All cows on diet L1 became pregnant during the mating period while the worst reproductive performance oc- cured on diet M2. In the present experiment the number of cows per one bull on the mating peri- od was quite high and may have affected the conception rate. Unfortunately no evaluation of the period from calving to the first oestrus was measured in this study and thus, it should be used in the further studies to get more accurete infor- mation about reproduction performance. Conclusions A low plane of nutrition pre partum effected dam LW and condition, but cows compensated for those losses well at pasture. Low plane of nutri- tion pre partum had marginal effects on milk composition and only affected calf performance prior to grazing. Post partum feeding levels only influenced dam LWG before grazing. All feed- ing regimens maintained dam condition suffi- ciently to enable satisfactory conception rates. Based on cow and calf performance, diet L1 ap- peared to supply sufficient energy and therefore, the current data suggests that the plane of nutri- tion pre partum has a greater influence than that post partum in cases of limited periods of graz- ing. The findings of this study also indicate that low level of feeding can be recommended in Fin- land or regions of similar latitude for mature beef crosses with adequate condition at the onset on indoor feeding period if the cows can compen- sate the losses of condition at good and suffi- cient pasture. 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SELOSTUS Sisäruokintakauden energiamäärien vaikutus risteytysemolehmien tuotantoon Merja Manninen ja Harri Huhta Maatalouden tutkimuskeskus Tutkimuksessa selvitettiin poikimista edeltävän, hei- nään ja olkeen perustuvan ruokinnan (M; keskinker- tainen ja L; matala) ja poikimisen jälkeisen väkire- huruokinnan (1: 1,5 ja 2: 3,5 kg ohraa/eläin/d) vai- kutuksia Hereford-Ayrshire ja Limousine-Ayrshire risteytysemojen elopainoon, kuntoon, poikimiseen, maidontuotantoon, maidon koostumukseen ja tiineh- tymiseen sekä niiden Limousin-sonneista syntyneiden vasikoiden kehitykseen syntymästä vieroitukseen. Ennen poikimista kaikki emot saivat 72 vuorokautta 1,5 kg väkirehua päivässä. Sisäruokintakausi jaettiin kolmeen jaksoon: kokeen alusta väkirehuruokinnan alkuun (P1, 97 d), väkirehuruokintajakso ennen poi- kimista (P2, 72 d) ja poikimisen jälkeinen väkirehu- ruokintajakso (P3, 46 d). Laidunkauden pituus oli 114 päivää. Heinän energiapitoisuus (ME; muuntokelpoinen energia, MJ) oli keskimäärin 8,8, oljen 6,1 ja ohran 13,1 MJ ME/kg kuiva-ainetta (KA). Ohutsuolesta imeytyvää valkuaista heinä sisälsi keskimäärin 75, olki 54 ja ohra 105 g/kg KA. M-ruokinnalla eläinten kuiva-aineen syönti oli jaksolla P1 keskimäärin 9,1, jaksolla P2 10,4 ja jaksolla P3 joko 10,4 tai 12,0 kg KA. L-ruokinnalla KA-syönti oli vastaavasti jaksol- la P1 6,7, jaksolla P2 8,0 ja jaksolla P3 joko 8,0 tai 9,7 kg KA. Laidunkauden alkaessa kesäkuun alussa M-ruokinnalla olleet emot olivat keskimäärin 47 kg painavampia kuin L-ruokinnalla olleet emot, jotka puolestaan kuntoutuivat laitumella tehokkaammin kuin M-ruokinnalla olleet emot. Poikimisesta laidun- kauden alkuun 1-väkirehuruokinnalla olleet emot me- nettivät elopainoaan enemmän kuin 2-väkirehu- ruokinnalla olleet emot (–1241 vs. –588 g/d), mutta kuntoutuivat laitumella tehokkaasti. Poikimisen jäl- keinen väkirehuruokinta ei vaikuttanut emojen kun- toon. Sisäruokintakaudella L-emojen kunto heikkeni 18 A G R I C U L T U R A L A N D F O O D S C I E N C E I N F I N L A N D Manninen, M. & Huhta, H. Effects of feeding levels on performance of suckler cows enemmän (–0,67 vs. –0,09) kuin M-emojen kun- to. Poikimiset olivat helppoja. Koetekijät eivät vai- kuttaneet vasikoiden kasvuun ennen vieroitusta. Son- nivasikat kasvoivat lehmävasikoita paremmin (1369 vs. 1241 g/d). Koetekijät eivät vaikuttaneet maidon- tuotantoon, joka oli keskimäärin 11,8 kg/d. M-emo- jen maidon rasvapitoisuus oli korkeampi kuin L-emo- jen (46,9, vs. 43,1 g/kg). Emoista 86,8 % tiinehtyi. Tutkimuksessa poikimista edeltävä ruokinta vai- kutti emoihin ja niiden vasikoihin enemmän kuin poi- kimisen jälkeinen ruokinta. Tuotantotulosten perus- teella L1-ruokinta oli riittävä. Ajanjakso poikimisesta laidunkauden alkuun oli kuitenkin lyhyt, mikä lienee vaikuttanut saatuihin tuloksiin. Huomattavatkin elo- painon ja kunnon menetykset korvattiin hyvällä lai- tumella lyhyen laidunkauden aikana. Tuotantokustan- nuksia voidaan vähentää vaarantamatta eläinten hy- vinvointia ja tuotosta ruokintaa alentamalla, jos eläin- ten kunto on tuotantovaiheeseen sopiva. AGRICULTURAL AND FOOD SCIENCE IN FINLAND Title Introduction Material and methods Results Discussion Conclusions References SELOSTUS