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1.
Abstract The effects of level of concentrate supplementation on the response of dairy cows to grass silage‐based diets containing a constant proportion of fodder beet were examined. Forty Holstein‐Friesian dairy cows of mixed parity were used in a 2 × 5 factorial design experiment. Two basal diet types [grass silage alone or grass silage mixed with fodder beet in a 70:30 dry matter (DM) ratio] were offered ad libitum, and the effects of five levels of concentrate supplementation (mean = 3·0, 5·3, 7·5, 9·8 and 12·0 kg DM per cow d?1) were examined. Concentrate supplements were offered via an out‐of‐parlour feeding system. These treatments were examined in a three‐period (period length = 4 weeks) partially balanced changeover design experiment. Fodder beet inclusion had no significant effect on the estimated metabolizable energy (ME) concentration of the ration (P > 0·001). Total DM intake, estimated ME intake, milk yield, milk protein content and milk energy output all showed significant linear increases with increasing level of concentrate inclusion (P < 0·001) while, in addition, milk yield and milk energy output exhibited a significant quadratic increase (P < 0·01). The inclusion of fodder beet in the diet reduced silage DM intake (P < 0·01) but resulted in an increase in total DM intake and estimated ME intake (P < 0·001). However, inclusion of fodder beet had no significant effect on milk yield (P > 0·05), while increasing milk protein content and milk energy output (P ≤ 0·05). Milk energy output, as a proportion of estimated ME intake, was significantly (P < 0·001) reduced by fodder beet inclusion (0·44 vs. 0·38). Despite large increases in estimated ME intake with the inclusion of fodder beet at all levels of concentrate supplementation, milk energy output responses were small, resulting in an overall reduction in the efficiency of conversion of ME intake into milk energy output. An increased partitioning of dietary ME intake to tissue gain is suggested as the most likely explanation for the observations made.  相似文献   

2.
Twelve cows were used in a cyclic changeover design experiment to examine the effects of feeding fodder beet (variety Kyros) at three levels (0, 2 and 4 kg dry matter (DM) d?1) with two levels of concentrate feeding (4 and 8 kg DM?1). Silage was offered ad libitum. At the start of the experiment the mean number of days after calving was 46 and the mean live weight 516 kg. The experiment consisted of four 3-week periods with intake and performance measurements during the last week of each period. An in vitro analysis of the feeds for the silage, fodder beet and concentrate respectively was: DM (g kg-?1) 189, 163, 860; crude protein (g kg DM?1) 143,76,201; metabolizable energy (MJ kg DM?1) 104, 133, 13–5. Silage DM intake decreased but total DM intake increased when fodder beet was fed. The DM intakes (kg d?1) for treatments (fodder beet/ concentrate) 0/4, 2/4, 4/4, 0/8, 2/8, 4/8 respectively were: silage DM 91, 79, 78, 83, 70 and 68 (s.e.d. =0.31); and total DM 130, 138, 156, 162, 166, 183 (s.e.d. = 0.36). Feeding fodder beet had no significant effects on milk yield or milk composition, but there was a significant increase in milk protein yield when fodder beet was included in the ration. There were no significant interactions between level of fodder beet feeding and concentrate level. Increasing the level of concentrate feeding led to a highly significant increase in milk yield, milk protein content and yield of milk constituents. The yields for treatments 0/4, 2/4,4/4,0/8, 2/8,4/8 respectively were: milk yield (kg d?1) 206, 204,21 8, 241,235, 244 (s.e.d. = 0–58); fat yield (g d?1) 827, 793, 885, 954, 936, 954 (s.e.d. = 394); and protein yield (g d?1) 622, 628, 679, 774, 777, 814 (s.e.d. = 179). There were no significant differences in milk yield and milk composition when fodder beet was included in the diet which may have been due to the low crude protein content of the diet.  相似文献   

3.
A field experiment was undertaken between April 2003 and May 2004 in southern Tasmania, Australia, to quantify and compare changes in the nutritive value of perennial ryegrass (Lolium perenne L.), prairie grass (Bromus willdenowii Kunth.) and cocksfoot (Dactylis glomerata L.) under a defoliation regime based on stage of leaf regrowth. Defoliation interval was based on the time taken for two, three or four leaves per tiller to fully expand. At every defoliation event, samples were collected and analysed for acid‐detergent fibre (ADF), neutral‐detergent fibre (NDF) and total nitrogen (N) concentrations and to estimate metabolizable energy (ME) and digestible dry matter (DDM) concentrations. Amounts of crude protein (CP) and metabolizable energy (MJ) per hectare values were subsequently calculated. There was a significantly lower (P < 0·001) NDF concentration for perennial ryegrass compared with prairie grass and cocksfoot, and a significantly lower (P < 0·001) ADF concentration for cocksfoot compared with prairie grass and perennial ryegrass, regardless of defoliation interval. The CP concentration of cocksfoot was significantly greater (P < 0·001) compared with the CP concentrations of prairie grass and perennial ryegrass. The estimated ME concentrations in cocksfoot were high enough to satisfy the requirements of a lactating dairy cow, with defoliation at or before the four‐leaf stage maintaining ME concentrations between 10·7 and 10·9 MJ kg?1 DM, and minimizing reproductive plant development. The ME concentrations of prairie grass (10·2–10·4 MJ kg?1 DM) were significantly lower (P < 0·001) than for cocksfoot (as above) and perennial ryegrass (11·4–11·6 MJ kg?1 DM) but a higher DM production per hectare resulted in prairie grass providing the greatest amounts of ME ha?1.  相似文献   

4.
The objective of this study was to investigate the effects of an early (February; F) or delayed (April; A) primary spring grazing date and two stocking rates, high (H) and medium (M), on the grazing management, dry matter (DM) intake of grass herbage and milk production of spring‐calving dairy cows grazing a perennial ryegrass sward in the subsequent summer. Sixty‐four Holstein‐Friesian dairy cows (mean of 58 d in milk) were assigned to one of four grazing treatments (n = 16) which were imposed from 12 April to 3 July 2004. Cows on the early spring‐grazing treatment were grazed at 5·5 cows ha?1 (treatment FH) and 4·5 cows ha?1 (treatment FM) while cows on the late‐grazing treatment were grazed at 6·4 cows ha?1 (treatment AH) and 5·5 cows ha?1 (treatment AM). The organic matter digestibility and crude protein concentration of the grass herbage were higher on the early‐grazing treatment than on the late‐grazing treatment. The cows on the FM treatment had significantly (P < 0·001) higher milk (24·5 kg), solids‐corrected milk (22·5 kg), fat (P < 0·01, 918 g) and protein (831 g) yields than the other three treatments. Cows on the FM treatment had a higher (P < 0·001) DM intake of grass herbage by 2·3 kg DM per cow per day than cows on the AH treatment, which had a DM intake significantly lower than all other treatments (15·2 kg DM per cow per day). The results of the present study showed that grazing in early spring has a positive effect on herbage quality in subsequent grazing rotations. The study also concluded that early spring‐grazed swards stocked at a medium stocking rate (4·5 cows ha?1; FM) resulted in the highest DM intake of grass herbage and milk production.  相似文献   

5.
Two factorial design experiments were carried out in the spring of 1994 and 1995, each of 6 weeks, to quantify the effects of sward height (SH), concentrate level (CL) and initial milk yield (IMY) on milk production and grazing behaviour of continuously stocked dairy cows. In Experiment 1, forty‐five Holstein Friesian cows were in five groups with initial milk yields of 16·9, 21·1, 28·0, 31·5 and 35·5 kg d–1, grazed sward heights were 3–5, 5–7 and 7–9 cm (LSH, MSH and HSH respectively), and concentrates were fed at rates of 0, 3 and 6 kg d–1. In Experiment 2, 48 cows were in two groups with IMY of 21·3 and 35·5 kg d–1, grazed sward heights were 3–5 and 7–9 cm (LSH and HSH), and concentrates were fed at 0 and 6 kg d–1 and ad libitum. Multiple regression models were used to quantify the effects of the three variables on milk yield persistency (MYP), estimated herbage dry‐matter (DM) intake (HDMI), grazing time (GT) and rate of DM intake (RI). The partial regression coefficients showed that increased SH led to increased MYP (Experiment 1 P < 0·001, Experiment 2 P < 0·05), increased HDMI (P < 0·01, P < 0·01), increased GT (P < 0·001, P < 0·05) and increased RI (P < 0·001, P < 0·05). Increasing CL led to increased MYP (NS, P < 0·001), decreased HDMI (P < 0·001, P < 0·001), decreased GT (NS, P < 0·001) and decreased RI (P < 0·001, P < 0·001). Higher IMY level of cows decreased MYP (P < 0·001, P < 0·001), increased HDMI (P < 0·001, P < 0·001), increased GT (P < 0·001, P < 0·05) and increased RI (P < 0·05, P < 0·01). The models were highly significant (P < 0·001), and accounted for 0·48–0·87 of the total variance. The partial regression coefficients quantified the extent to which GT and RI by cows respond positively to higher IMY, and negatively to increased CL, but respond differently (GT declines in response to a higher RI) with increasing SH.  相似文献   

6.
Abstract In 1993 and 1994, 40 cows in early lactation in early spring were assigned randomly to four feeding treatments. One group of cows was kept indoors with access to grass silage ad libitum, plus 6 kg of concentrate daily. The other three groups had access to grass pasture (5–6 h per day in 1993 and 11–12 h per day in 1994) plus grass silage similar to that fed to the previous group while indoors plus 6, 4 or 2 kg of concentrate daily. The average daily allocations of herbage (> 3·5 cm) were 8·5 and 14·0 kg DM cow?1 day?1 in 1993 and 1994 respectively. The treatments were applied for 8 weeks (26 February to 23 April) in 1993, and 7 weeks (11 March to 29 April) in 1994. Cows with access to pasture had lower (P < 0·001) silage dry‐matter (DM) intakes and higher (P < 0·001) total forage DM intakes in both years than those kept indoors. This resulted in significantly higher yields of milk, fat, protein and lactose. Similarly, milk protein concentration was higher (P < 0·05 in 1993; P < 0·001 in 1994). There was a significant linear increase in total DM intake in both years with increased concentrate supplementation. In 1993, there was a linear increase in milk (P < 0·01), fat (P < 0·01), protein (P < 0·001) and lactose (P < 0·01) yields with increased concentrate supplementation. In 1994, only milk protein yield (P < 0·05) was increased. Concentrate supplementation had no effect on milk composition or liveweight change. Cows with access to grazed grass had higher liveweight gains (P < 0·05) than those kept indoors in both years. In 1993, increasing the energy intake increased the processing qualities of the milk produced. The results showed that access to grass pasture resulted in higher milk production, in reduced silage requirement and in reduced level of concentrate supplementation required for a given level of milk production with spring‐calving cows in early lactation compared with those kept indoors.  相似文献   

7.
In one experiment twenty‐four Holstein Friesian cows, average 43 d post‐partum, were used in a changeover design experiment to evaluate the replacement of a cereal‐based concentrate supplement (C) by an ensiled mixture (MGBP) of malt distillers’ grains and molassed sugar beet pellets. The cows were offered grass silage ad libitum [dry matter (DM) content 170 g kg?1, crude protein (CP) concentration 160 g kg DM?1, metabolizable energy (ME) concentration 10·9 MJ kg DM?1] and either C or MGBP at one of three levels (3, 6, 9 kg DM d?1). The composition of C and MGBP were DM content: 853 and 296 g kg?1, CP concentration: 202 and 187 g kg DM?1, ME concentration: 12·6 and 10·8 MJ kg DM?1 respectively. The cows ate all the C supplement but the intakes of MGBP were 2·7, 4·9 and 6·4 kg DM d?1 for the 3, 6 and 9 kg DM d?1 levels of MGBP respectively. Total DM intakes (kg d?1) were 12·5, 15·6, 18·2 for treatments 3‐C, 6‐C and 9‐C and 13·1, 14·4 and 15·9 (s.e., 0·90) for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP respectively. Milk yields (kg d?1) for treatments 3‐C, 6‐C and 9‐C were 19·9, 23·2 and 24·2, respectively, and for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP were, 20·3, 21·3 and 23·0 respectively (s.e., 1·05). Milk fat contents (g kg?1) for treatments 3‐C, 6‐C and 9‐C were 42·8, 42·3, 43·5 respectively and for treatments 3‐MGBP, 6‐MGBP and 9‐MGBP were 39·5, 38·7 and 38·2 (s.e, 1·86), respectively, and milk protein contents (g kg?1) for treatments 3‐C, 6‐C and 9‐C were 30·5, 30·6, 31·8, respectively, and for 3‐MGBP, 6‐MGBP and 9‐MGBP were 30·0, 30·8 and 31·2 (s.e., 0·66) respectively. Milk yield and milk protein contents were significantly higher for the higher levels of supplementary feeding but there was no difference between the types of supplement. The milk fat contents were significantly lower on the MGBP than C supplements. In a second experiment fifteen Holstein Friesian cows, average 126 d post‐partum, were used in a changeover experiment to evaluate the replacement of all (treatment M) or half (treatment MS) of the grass silage (S) in their diet by a mixture of MGBP and straw. All cows received 5·1 kg DM d?1 of concentrate feed. Forage DM intakes were 8·3, 11·2 and 14·2 kg DM d?1 for the S, MS and M treatments respectively. Milk yields (kg d?1) for S, MS and M treatments were 17·0, 19·4 and 20·0 (s.e., 0·56) respectively. Corresponding contents of milk fat and protein (g kg?1) were 42·0, 41·4, 38·6 (s.e., 0·37) and 33·8, 34·1, 34·2 (s.e., 0·42). Ensiled mixtures of malt distillers’ grains and molassed sugar beet pellets can be used to replace some of the conventional concentrates or grass silage for dairy cows giving moderate yields without a loss of production.  相似文献   

8.
The selection and feeding of perennial ryegrass (Lolium perenne L.) varieties (PRV) or perennial grass species (PGS) may affect enteric methane (CH4) output because of changes in the fermentation dynamics in the rumen as a result of differences in herbage chemical composition. The objective of this study was to determine the effects of PRV and PGS harvested throughout the growing season on herbage chemical composition, and in vitro rumen fermentation variables and CH4 output per unit of feed using a batch culture technique. Seven PRV (Experiment 1: Alto, Arrow, Bealey, Dunluce, Greengold, Malone, Tyrella) and six perennial grasses [Experiment 2: perennial ryegrass (Navan), perennial ryegrass (Portstewart), cocksfoot, meadow fescue, tall fescue, timothy; defined as PGS], managed under a simulated grazing regime, were incubated for 24 h with buffered rumen fluid in two separate experiments. The CH4 output per unit of feed dry‐matter (DM) incubated was not affected (P > 0·05) by PRV (range of mean values across PRV of 23·9–25·3 (SEM 0·41) mL g?1 DM) or by PGS (25·6–26·6 (SEM 0·37) mL g?1 DM). The CH4 output per unit feed DM disappearing during the in vitro rumen incubation was not affected by PRV (33·9–35·1 (SEM 0·70) mL g?1 DM), and although there was an overall PGS effect (P < 0·05; 37·2–40·3 (SEM 0·71) mL g?1 DM), none of the paired contrasts between PGS were significant when analysed using Tukey adjusted comparisons. This outcome reflected either small‐scale or a lack of treatment effects on individual herbage chemical composition (e.g. 454–483 g NDF kg?1 DM, 215–224 g CP kg?1 DM and 94–122 g water‐soluble carbohydrate (WSC) kg?1 DM across PRV; 452–506 g NDF kg?1 DM, 208–243 g CP kg?1 DM and 73–131 g WSC kg?1 DM across PGS) and in vitro rumen fermentation variables. Hence, these results provide no encouragement that choices among the grasses examined, produced within the management regimes operated, would reduce enteric CH4 output per unit of feed in vivo. However, the technique utilized did not take account of animal × PRV or PGS interactions, such as potential differences in intake between animals, that may occur under farm conditions.  相似文献   

9.
The yield and chemical composition of thirteen Lotus corniculatus varieties and one Lotus uliginosus variety, when grown and ensiled in the UK, were investigated. Replicate plots of each variety were established in a randomized block design. Dry‐matter (DM) yield was measured over two harvest years. At cuts 1 and 2 of the first harvest year, 1 kg of each variety was ensiled and sub‐sampled for chemical analysis. At cut 2 of the second harvest year, sub‐samples of forage were analysed for condensed tannins. Two L. corniculatus varieties, Oberhaunstaedter and Lotar, had higher DM yields (with Oberhaunstaedter having the highest DM yield at cut 3) in both harvest years compared with other varieties (P < 0·001). Chemical analyses showed differences among silages of varieties of L. corniculatus (P < 0·001) and that the ammonia‐N concentration of L. uliginosus silage was higher than that of L. corniculatus (P < 0·001), despite its lactic acid concentrations being within the range observed for L. corniculatus (17 g kg?1 DM vs. 13–19 g kg?1 DM). Differences (P < 0·001) in HCl/Butanol test absorbance units were found among varieties of L. corniculatus, indicating possible differences in concentrations of condensed tannins. Overall, the variety Oberhaunstaedter was found to be the most suitable variety for silage production. Based on its agronomic performance, L. corniculatus does not compare well with other legumes such as red clover.  相似文献   

10.
Low rates of herbage dry matter (DM) intake impose limits on total daily DM intake in grazing dairy cows. The objective of this study was to increase total daily DM intake and milk production by restricting daily time available for grazing (TAG) and replacing it with time available for eating a maize silage/soyabean meal (TAMS) diet indoors. The treatments (TAG + TAMS) were 20 + 0, 19 + 1, 10 + 10 and 5 + 15 h. Measurements were made of milk production, intake and feeding behaviour. The interactions of TAG + TAMS treatments with sward height (SH) and concentrate level (CL) were also examined. Two experiments, each lasting 42 days, were carried out in spring ( Experiment 1 ) and autumn ( Experiment 2 ) using forty‐eight and twenty‐four Holstein‐Friesian cows respectively. Treatments were arranged in a factorial design with TAG + TAMS treatments, SH ( Experiment 1 only) and CL as the independent variables and a TAG + TAMS of 20 h. Reducing TAG and increasing TAMS significantly reduced estimated herbage DM intake and significantly increased maize silage/soyabean meal intake in both experiments, but there were no significant main effects of TAG + TAMS treatments on milk yield (mean, 27·4 and 25·5 kg d?1 for Experiments 1 and 2 respectively), and yield of milk constituents. Increasing SH ( Experiment 1 ) and CL ( Experiments 1 and 2 ) significantly increased milk yield. In Experiment 1 , there was a significant interaction between TAG + TAMS treatments and SH with the taller sward height of 8–10 cm and the 20 + 0 treatment having the highest milk yield (29·7 kg d?1) and the 5 + 15 treatment the lowest (27·2 kg d?1), whereas at the lower sward height of 4–6 cm, milk yield was lowest on the 20 + 0 treatment (25·5 kg d?1) with the other three treatments being higher (mean, 26·9 kg d?1). Replacing TAG with TAMS significantly increased liveweight gain in Experiment 1 but not in Experiment 2 . Estimated rates of intake of herbage were lower in the autumn experiment ( Experiment 2 , 9·6 g DM min ?1) than in the spring experiment ( Experiment 1 , 29·4 g DM min ?1) but rates of intake of maize silage were higher in the autumn (112·4 g DM min?1) than in the spring (72·5 g DM min?1). In conclusion, in spring the response to replacing TAG with TAMS was dependent on sward conditions with the highest milk fat plus protein yield being on the 20 + 0 treatment at the high sward height and on the 19 + 1 treatment at the low sward height. The high liveweight gain of the 5 + 15 treatment could be an important means of restoring body condition in grazing lactating cows. In autumn, intakes of herbage were low in spite of its high estimated nutritive value with all treatments having a similar level of performance.  相似文献   

11.
Two studies were conducted to examine the effects of incorporating small quantities of straw in the diets of dairy cows. In Experiment 1, forty Holstein Friesian dairy cows were used in a 2 × 4 factorial design experiment, with factors examined consisting of two parities (primiparous and multiparous animals) and four levels of straw inclusion in the diet (0, 0·08, 0·16 and 0·24 of forage dry matter). The basal forage offered in this study was grass silage, and the primiparous and multiparous animals were supplemented with 9·0 and 11·0 kg concentrate d–1 respectively. In Experiment 2, forty‐eight Holstein Friesian dairy cows were used in a 2 × 3 factorial design experiment, with factors examined consisting of two basal forage types (grass silage and zero‐grazed grass) and three levels of straw inclusion (0, 1·0 and 2·0 kg d–1). All animals were offered 7·0 kg d–1 of a concentrate supplement. Both experiments were partially balanced changeover designs, consisting of two, 4‐week periods. In Experiment 1, the total dry‐matter intake followed a significant quadratic relationship (P < 0·05), increasing with low levels of straw inclusion and decreasing at higher levels of inclusion. With increasing levels of straw inclusion, there was a linear decline in milk yield (P < 0·001) and milk protein concentration (P < 0·05), but milk fat concentration was unaffected (P > 0·05). In Experiment 2, the effect of straw inclusion on total dry‐matter intake was quadratic (P < 0·001), with intakes being maximum at the 1·0‐kg level of straw inclusion. Milk yield exhibited a linear decrease (P < 0·001) with increasing level of straw inclusion. Milk fat concentration was lowest at the 1·0 kg rate of straw inclusion (P < 0·05), but milk protein concentration was unaffected by straw inclusion. There were no significant interactions between basal forage type and level of straw inclusion for any of the variables examined (P > 0·05). Despite small increases in total dry‐matter intake at a low level of straw inclusion, there was no evidence that straw inclusion improved either nutrient utilization or animal performance. The reduction in milk yield observed with straw inclusion reflects, to a large extent, a reduction in metabolizable energy intake.  相似文献   

12.
First-harvest direct-cut, double-chopped grass (190 and 164g DMkg?1 in Experiments 1 and 2 resptectively) was ensiled without an additive or, in Experiment 1, with 30 kg t?1 grass of an absorbent additive based on sugar beet pulp (Sweet ‘n’ Dry) or with 3·441 t?1 grass of formic acid and, in Experiment 2, with 30, 50 and 70 kg t?1 grass of Sweet ‘n’ Dry or with 50kg t?1 grass of unmolassed sugar beet pulp. The preservation and nutritive value of the silage, in-silo losses (including silage effluent production), silage intake and animal performance of adult and growing cattle were examined. In Experiment 1 all three silages were well preserved, although the formic acid-treated silage displayed significantly lower pH, ammonia nitrogen (NH3N) [g kg?1 total nitrogen (TN)] and volatile fatty acids (VFAs) than the other two silages. In Experiment 2 absorbent-treated silages displayed significantly lower pH, buffer capacity (Bc), NH3N (gkg?1 TN), CP, modified acid detergent fibre (MADF) and VFAs than untreated silage. Treatment of grass with the absorbent additives at ensiling resulted in reduced effluent production. In Experiment 1 each kilogram of Sweet ‘n’ Dry retained approximately 11 effluent, and in Experiment 2 silages made with Sweet ‘n’ Dry applied at 70kgt?1 and sugar beet pulp applied at 50 kg t?1 produced similar volumes of effluent and each kilogram of absorbent retained 1·0 and 1·31 of effluent respectively. In Experiment 1 sixty beef cattle [mean initial live weight (LW) 460 kg] were grouped according to LW and allocated to treatment at random. For untreated silage (unsupplemented or with 1 or 2 kg supplement head?1 day?1), absorbent-treated silage (unsupplemented or with 1 or 2 kg supplement head?1 day?1) and formic acid-treated silage (1 kg supplement head?1 day?1) the daily silage DM intakes were 6·12, 6·21, 6·40, 7·65, 7·45, 7·11 and 7·85 (s.e. 0·280) kg respectively, the daily liveweight gains were 0·22, 0·56, 0·81, 0·59, 0·74, 0·81 and 0·75 (s.e. 0·071) kg respectively and daily carcass gains were 0·31, 0·47, 0·67, 0·47, 0·61, 0·70 and 0·57 (s.e. 0·043) kg respectively throughout a 75-day feeding period. In Experiment 2, fifty-six growing cattle (mean initial weight 312 kg) were grouped according to LW and allocated to treatment at random. For untreated silage (unsupplemented or with 1·5 kg Sweet ‘n’ Dry or 1·5 kg commercial concentrates head?1 day?1), silage treated with Sweet ‘n’ Dry at 30, 50 and 70 kg t?1 grass and silage treated with 50kg sugar beet pulp t?1 grass the daily silage DM intakes were 5·46, 5·28, 5·33, 6·21, 6·27, 6·60 and 6·62 (s.e. 0·154) kg respectively and daily liveweight gains were 0·39, 0·75, 0·81, 0·63, 0·76, 0·94 and 1·75 (s.e. 0·052) kg respectively throughout a 122-day feeding period. In this experiment 360g kg?1 more absorbent was required when it was included at ensiling rather than offered as a supplement to untreated silage to achieve the same individual animal performance.  相似文献   

13.
In a 16-week winter feeding experiment, 48 autumn calving cows and heifers were used to compare a control diet, with two diets including fodder beet at a low and a high level. The control diet was ad libitum silage and 6 kg d-1 of concentrates (13.4 MJ (kg DM)-1 of ME and 197 g (kg DM)-1 of CP). The cows offered fodder beet were fed the control diet (C) plus fodder beet at either 2 (L) or 4 (H) kg DM d-1. Soya bean meal was offered with the fodder beet at 0.5 or 1.0 kg d-1 for diets L and H, respectively.
Total dry matter and metabolizable energy intakes were 15.2,16.4 and 17.3 kg DM d-1; 177, 195 and 211 MJ d-1 for treatments C, L and H, respectively. The mean milk yields were not significantly affected by the feeding of fodder beet. There was a significant improvement in the fat and protein content of the milk and yield of constituents. The milk composition and yield of solids were: fat content 42.3,44.2 and 45.9 (s.e.d. 1.25) g kg-1; protein content 33.0, 34.5, 35.3 (s.e.d. 0.76) g kg-1; fat yield 964,1027,1095(s.e.d. 63.2); protein yield 757, 801, 841 (s.e.d. 48.8) for treatments C, L and H, respectively. The treatments had no significant effect on live weight or condition score change.  相似文献   

14.
Grazed sward surface height was controlled within the range 3·25–4·75 cm during spring and summer in two experiments. In Experiment 1, the effects of stocking two breeds of ewe of similar size but different potential levels of reproductive performance [Brecknock Cheviot (C) and Beulah Speckled Face (B)] at different annual stocking rates of twelve (SR12) and twenty (SR20) per hectare, rates of nitrogen fertilizer of 100 (N100) and 200 (N200) kg N ha?1 annum?1 and different lamb:ewe ratios (C1·2, B1·2 and B1·5) were measured in four treatments (SR20N200C1·2; SR20N200B1·2; SR20N200B1·5; SR12N100C1·2) replicated three times. In each of three years animal performance and yield of silage from areas of pasture surplus to grazing requirements were measured. In Experiment 2, breed B was compared with the Welsh Mule (W) breed, a larger with a higher potential reproductive performance, at two stocking rates, two rates of nitrogen fertilizer and two lamb:ewe ratios set on the basis of results from Experiment 1 (SR18N200B1·5; SR12N100B1·5; SR18N200W1·5; SR18N200W1·7). The treatments were replicated three times. The same terminal sire (Suffolk) was used in both experiments. A primary aim of the experiments was to test the validity of the experimental procedures used for comparing breeds of sheep where nutrition is provided predominately from grazed pastures. In Experiment 1, there was no difference between breeds C and B in the live weights of individual lambs at weaning at the same SR (20), N rate (200) and lamb:ewe ratio (1·2). Breeds C and B produced similar total yields of lamb (633 kg lamb ha?1± 10·5) and silage (193 kg DM ewe?1± 37·7), but breed B had a higher level of potential reproductive performance (1·59 vs. 1·37 lambs ewe?1: P < 0·001). The treatments SR20N200B1·5 and SR12N100C1·2 produced, respectively, greater and lesser yields of lamb (725 vs. 384 kg lamb ha?1, P < 0·001) and lesser and greater yields of silage (123 vs. 327 kg DM ewe?1, P < 0·001). In Experiment 2, the live weight of lambs at weaning from breed W were heavier than from breed B (29·1 vs. 26·2 kg lamb?1, P < 0·01) but there was no significant difference in total yield of lamb weaned between breeds W and B at the same SR (18), N rate (200) and lamb:ewe ratio (1·5) (747 kg lamb ha?1± 19·2), or in the yield of silage (66 kg DM ewe?1± 16·4), but breed W had a higher potential reproductive performance (1·85 vs. 1·58 lambs ewe?1, P < 0·05). The treatments SR18N200W1·7 and SR12N100B1·5 produced, respectively, greater and lesser yields of lamb (840 vs. 473 kg lamb ha?1, P < 0·001) and similar and greater yields of silage (60 vs. 141 kg DM ewe?1, P < 0·05). The experimental approach adopted and the management protocols used provided a basis for ranking the performance of the breeds of ewes examined at appropriate levels of annual stocking rate, N-fertilizer input and lamb:ewe ratio.  相似文献   

15.
The objective of this experiment was to use diurnal and temporal changes in herbage composition to create two pasture diets with contrasting ratios of water‐soluble carbohydrate (WSC) and crude protein (CP) and compare milk production and nitrogen‐use efficiency (NUE) of dairy cows. A grazing experiment using thirty‐six mid‐lactation Friesian x Jersey cows was conducted in late spring in Canterbury, New Zealand. Cows were offered mixed perennial ryegrass and white clover pastures either in the morning after a short 19‐day regrowth interval (SR AM) or in the afternoon after a long 35‐day regrowth interval (LR PM). Pasture treatments resulted in lower pasture mass and greater herbage CP concentration (187 vs. 171 g kg?1 DM) in the SR AM compared with the LR PM but did not affect WSC (169 g kg?1 DM) or the ratio of WSC/CP (1·0 g g?1). Cows had similar apparent DM (17·5 kg DM cow?1 d?1) and N (501 g N cow?1 d?1) intake for both treatments. Compared with SR AM cows, LR PM cows had lower milk (18·5 vs. 21·2 kg cow?1 d?1), milk protein (0·69 vs. 0·81 kg cow?1 d?1) and milk solids (1·72 and 1·89 kg cow?1 d?1) yield. Urinary N concentration was increased in SR AM, but estimated N excretion and NUE for milk were similar for both treatments. Further studies are required to determine the effect of feeding times on diurnal variation in urine volume and N concentration under grazing to predict urination events with highest leaching risk.  相似文献   

16.
Abstract A glasshouse study was undertaken to determine the physiological and morphological changes in cocksfoot (Dactylis glomerata L.) during regrowth after defoliation. Individual plants were arranged in a mini‐sward in a randomized complete block design. Treatments involved harvesting each time one new leaf had expanded (one‐leaf stage), up to the six‐leaf stage, with the plants separated into leaf, stubble (tiller bases) and roots. Stubble and root water‐soluble carbohydrate (WSC), stubble and leaf dry matter (DM), tiller number per plant and leaf quality (crude protein (CP), estimated metabolizable energy (ME) and mineral content) were measured to develop optimal defoliation management of cocksfoot‐based pastures. WSC concentration in stubble and roots was highest at the five‐ and six‐leaf stages. Mean WSC concentration (g kg?1 DM) was greater in stubble than roots (32·7 ± 5·9 vs. 9·4 ± 1·5 respectively). There was a strong positive linear relationship between plant WSC concentration and leaf DM, root DM and tillers per plant after defoliation (Adj R2 = 0·72, 0·88 and 0·95 respectively). Root DM plant?1 and tiller DM tiller?1 decreased immediately following defoliation and remained low until the three‐leaf stage, then increased from the four‐leaf stage. Tillers per plant remained stable until the four‐leaf stage, after which they increased (from 9·9 ± 0·5 to 15·7 ± 1·0 tillers plant?1). Estimated metabolizable energy concentration (MJ kg?1 DM) was significantly lower at the six‐leaf stage (11·01 ± 0·06) than at any previous leaf regrowth stage, whereas CP concentration (g kg?1 DM) decreased with regrowth to the six‐leaf stage. Both the levels of ME and CP concentrations were indicative of a high quality forage throughout regrowth (11·37 ± 0·04 and 279 ± 8·0 for ME and CP respectively). Results from this study give a basis for determining appropriate criteria for grazing cocksfoot‐based pastures. The optimal defoliation interval for cocksfoot appears to be between the four‐ and five‐leaf stages of regrowth. Delaying defoliation to the four‐leaf stage allows time for replenishment of WSC reserves, resumption of root growth and an increase in tillering, and is before herbage is lost and quality falls due to onset of leaf senescence.  相似文献   

17.
Six mid‐lactation multiparous Holstein–Friesian dairy cows were used to examine the potential of a fermented whole‐crop barley (Hordeum vulgare)/kale (Brassica oleracea) bi‐crop as a feed compared with a first‐cut perennial ryegrass silage. The barley/kale bi‐crop was grown as a strip intercrop, and was harvested and ensiled as an intimate mixture [0·80 barley and 0·20 kale on a dry‐matter (DM) basis]. Animals were offered ad libitum access to one of three experimental diets in a duplicated Latin Square design experiment: (i) Bi‐crop (the barley/kale bi‐crop); (ii) Grass (the grass silage); and (iii) Mix (a 1:1 fresh mixture of Bi‐crop and Grass). All animals also received a standard dairy concentrate at a rate of 4 kg d?1 in equal portions at each of two milkings. The Bi‐crop and Grass silages contained 346 and 293 g DM kg?1, 108 and 168 g crude protein kg?1 DM, 268 and 36 g starch kg?1 DM, and had pH values of 3·87 and 3·80 respectively. Animals offered the two bi‐crop silage‐containing diets consumed more forage DM than those offered grass silage (14·6, 14·9 and 12·6 kg DM d?1 for Bi‐crop, Mix and Grass respectively; s.e.d. 0·45, P < 0·01) and yielded more milk (24·0, 23·9, 22·6 kg d?1 for Bi‐crop, Mix and Grass respectively; s.e.d. 0·26, P < 0·01). However, differences in the partitioning of dietary nitrogen towards milk protein and away from excretion in urine suggest a more efficient (rumen) utilization of feed protein by animals offered diets containing the bi‐crop silage. It is concluded that, despite having a low crude protein concentration, barley/kale bi‐crop silage offers excellent potential as a feed for lactating dairy cows.  相似文献   

18.
Herbage allowance is one of the important pasture factors in the determination of intake by grazing livestock. Ingestive behaviour of 12 adult Angus cows (Bos taurus) was measured over a range of allowances (0·25 to 0·72 kg dry matter (DM) per 100 kg live weight (LW) for a 1-h period) of vegetative tall fescue (Festuca arundinacea Schreb.). A balanced change-over design was used to estimate direct, residual and permanent effects of herbage allowance on rate of DM intake, rate of biting and herbage DM intake per bite. In Experiment 1, herbage DM intake per meal increased linearly from 0·68 to 1·72 kg (100 kg LW)?1 as DM allowance increased from 0·25 to 0·72 kg (100 kg LW)?1 h?1. Cows grazed at ·30 kg (100 kg LW)?1 h?1 and stopped grazing when the sward was reduced to a height about 10 to 12 cm above the soil surface, approximately defined by the tops of pseudostems. In Experiment 2, herbage DM intake rates of 0·29, 0·47 and 0·42 kg (100 kg LW)?1 h?1 were recorded as cows grazed allowances of 0·43, 0·70 and 0·90 kg (100 kg LW)?1 h?1 for most of the 1-h grazing period. Limiting herbage DM allowances in Experiment 2 were associated with small reductions in rate of biting and herbage DM intake per bite as allowance declined. Sward DM density (>5 cm) was an important variable in the determination of herbage DM intake rates at lower herbage allowances.  相似文献   

19.
Two experiments were conducted to examine the ‘long‐term’ effect of feed space allowance and period of access to feed on dairy cow performance. In Experiment 1, three horizontal feed space allowances (20, 40 and 60 cm cow?1) were examined over a 127‐d period (14 cows per treatment). In Experiment 2, 48 dairy cows were used in a continuous design (10‐week duration) 2 × 2 factorial design experiment comprising two horizontal feed space allowances (15 and 40 cm cow?1), and two periods of access to feed (unrestricted and restricted). With the former, uneaten feed was removed at 08·00 h, while feeding took place at 09·00 h. With the latter, uneaten feed was removed at 06·00 h, while feeding was delayed until 12·00 h. Mean total dry‐matter (DM) intakes were 19·0, 18·7 and 19·3 kg cow?1 d?1 with the 20, 40 and 60 cm cow?1 treatments in Experiment 1, and 18·1 and 18·2 kg cow?1 d?1 with the ‘restricted feeding time’ treatments, and 17·8 and 18·1 kg d?1 with the ‘unrestricted feeding time’ treatments (15 and 40 cm respectively) in Experiment 2. None of milk yield, milk composition, or end‐of‐study live weight or condition score were significantly affected by treatment in either experiment (P > 0·05), while fat + protein yield was reduced with the 15‐cm treatment in Experiment 2 (P < 0·05). When access to feed was restricted by space or time constraints, cows modified their time budgets and increased their rates of intake.  相似文献   

20.
The effect of spreading mown perennial ryegrass (Lolium perenne) herbage over the total ground area on water loss during field-wilting was compared with leaving herbage in swaths (three swaths put together into one, occupying 0·18 of ground area) in three experiments. Spread crops were not tedded during wilting but were rowed up immediately before harvest. In all experiments, conventional silage-making equipment was used on a field scale. Feeding value was assessed with lactating dairy cows and growing heifers (Experiment 1) and sheep (Experiment 3). The periods of field wilting were 48 h (Experiment 1), 24 h (Experiment 2) and both 24 h and 48 h (Experiment 3). Spreading the crop was associated with larger increases in loss of water in all three experiments compared with leaving grass in swaths. Losses of dry matter (DM) during wilting were similar in Experiment 2 but were higher for the swathed crop wilted for 48 h than for 24 h in Experiment 3. Spreading resulted in restricted fermentations associated with higher crop DM contents at ensiling. In Experiment 1 the concentrations of DM, ash and water-soluble carbohydrate in silage were higher (P < 0·001) for spreading the crop and the concentrations of crude protein and neutral-detergent fibre were lower (P < 0·05) than for swathed material. In Experiment 3, spreading was associated with higher concentrations of water-soluble carbohydrates and ethanol and lower concentrations of fermentation acids, ammonia-N and neutralizing value in silage. Voluntary DM intake of silage by dairy cows and heifers was higher for spread than for swathed material (P < 0·05), but in Experiment 3 (sheep) there were no significant differences between treatments in voluntary intake of DM. The increased intake by dairy cows of silage from spread herbage was reflected in increased concentrations of milk fat (P < 0·01) and protein (P < 0·05) but not in milk yield (P > 0·05). It is concluded that spreading herbage during field wilting prior to ensiling accelerates water loss and has the potential to improve the feeding value of the ensiled product.  相似文献   

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