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Notes: In two changeover design experiments, fifteen early- and sixteen late-lactation cows were used to investigate the effects of offering food beet with ad libitum grass silage and concentrates with different CP content on milk yield and quality. In Experiment 1 (early lactation) cows were offered no fodder beet (0) or 4 kg DM d−1 (4) in conjunction with one of three concentrates containing 159, 191 or 244g CP kg−1 DM (L.M.H.). Treatments were therefore 1L/0, 1L/4, 1M/0, 1M/4, 1H/0 and 1H/4. In Experiment 2 (late lactation) cows were offered the same level of fodder beet in conjunction with two concentrates containing 129 and 229 (L,H) g CP kg−1 DM. Treatments were therefore 2L/0, 2L/4, 2H/0 and 2H/4.In both experiments feeding fodder beet reduced silage DM intakes (P 〈 0·001) and increased total DM intake (P 〈 0·05 to P 〈 0·001). The substitution rate (r) ranged from 0·46 to 0·59kg of silage DM (kg−1 fodder beet DM).In Experiment 1, fodder beet tended to increase milk yield, composition and yield of constituents, but the effect was statistically significant for milk protein content only (P 〈 0·01). In Experiment 2, milk yields for 2L/0, 2L/4, 2H/0 and 2H/4 were 11·3, 12·1, 11·7 and 12·5 kg d−1 respectively (s.e.d. 0·43, non-significant), fat contents were 44·4, 47·3, 44·3 and 46·8g fat kg−1 respectively (s.e.d. 0·73, P 〈 0·001), protein contents were 34·3, 35·6, 35·3 and 36·2 g protein kg−1 respectively (s.e.d. 0·28, P 〈 0·001), fat yields were 494, 574, 512 and 579 g fat d−1 respectively (s.e.d. 20, P 〈 0·001) and protein yields were 385, 426, 407 and 442 g protein d−1 (s.e.d. 13, P 〈 0·01) respectively.Increasing CP in the concentrate significantly increased milk yield in Experiment 1 (23·9, 22·5, 23·5, 23·8, 26·2, 26·5kg d−1 for 1L/0, 1L/4, 1M/0, 1M/4, 1H/0 and 1H/4 respectively, P 〈 0·05). Higher CP in concentrate also resulted in significantly increased milk protein yield in early-lactation (P 〈 0·001) and milk protein content in late-lactation (P 〈 0·01) cows. There was a significant interaction between fodder beet and concentrate CP content for milk protein yield (P 〈 0·001) in Experiment 1.

Notes: 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.

Notes: Two experiments examined the effects of different defoliation treatments in spring on sward morphology and animal performance in mid-season and late season. Three treatments were applied in both experiments: Control (C), sward grazed by cows in spring to 6–8 cm grass height. Grazed Aftermath (GA). sward grazed by cows in spring to 3–4cm and allowed to regrow before being grazed by summer-calving cows, Silage Aftermath (SA), sward not grazed in spring, but a primary cut taken and the sward allowed to regrow before being grazed by summer-calving cows. The aim of treatment GA was to produce a sward with a high tiller density and high intake characteristics to meet the forage intake requirements of continuously grazed summer-calving cows, without resorting to offering forage buffers. Experiment 1 was conducted in 1989 on a sandy loam soil and Experiment 2 in 1990 on a heavy loam soil.In both experiments the GA treatment led to high live tiller density and live: dead tiller ratios compared with the C and SA treatments. Differences in sward morphology were also detected by applying double normal distribution analyses to measurements of grass height. The GA treatment also increased sward herbage mass and, to a limited extent, herbage metabolizable energy and crude protein contents. The results from Experiment 1 suggested that these sward effects lead to increased herbage dry-matter intake (as estimated by the n-alkane technique) and milk yield in cows grazing the GA sward. However, in Experiment 2, where conditions for grass growth in mid-season were more favourable than in Experiment 1, the differences in sward morphology produced in spring were quickly lost in June and July. There were therefore no differences in herbage intake or milk yield in the second experiment. Herbage intakes (kgDMd−1± s.e.d) estimated in July for cows on treatments C, GA and SA were 11·0, 13·4, 10·1 ± 2·16 for Experiment 1 and 10·7, 11·1, 11·2 ± 2·32 for Experiment 2. Average milk yield (kgd−1± s.e.d.) for cows on treatments C, GA and SA were 26·1, 28·0, 25·6 ± 0·31 (Experiment 1) and 28·5, 27·3, 28·4 + 0·58 (Experiment 2).The results suggested that acceptable milk yields can be obtained from grazing summer-calving cows, without offering forage buffers, by applying high stocking rates (low grass heights) in spring. However, the benefits of this manipulation could be lost by lax grazing in mid-season.

Notes: Over a 24-week period during the 1986 summer, three groups of January- to March-calving dairy cows were either grazed conventionally (G) or grazed between morning and afternoon milkings and housed overnight and offered grass silage (Si) or a straw/concentrate mixture (St) ad libitum. The straw/concentrate mixture contained proportionately, 0-33 long barley straw, 0·28 ground barley, 0·12 soya bean meal, 0·25 molaferm and 0·22 minerals. The metabolizable energy (ME) and crude protein (CP) contents of the silage fed in weeks 1-8 and weeks 9-24 were 9-5 and 10−6 MJ kg MD−1 and 160 and 191 g kg DM−1 respectively. The straw mix had an ME content of 10−1 MJ kg DM−1 and CP content of 134 g kg DM−1. Partial storage feeding with silage or a straw/concentrate mixture led to a decrease in estimated herbage DM intake. The feeding of the straw/concentrate mixture increased total DM intake, but the estimated total ME intake was similar for treatments G and St. The intakes (kg DM d−1) for treatments G, Si and St were respectively, herbage 11·7,6·8,4·1; total l3·5,13·6,15·0; total ME intake (MJd−1) 163, 155, 163.Animal performance was, for treatments G, Si and St respectively: milk yield (kg d−1) 19·2, 17·5, 19·1 (s.e.d. 0-87); milk fat content (g kg−1) 36·9, 37·6, 37.1 (s.e.d. 1.22); milk protein content (g kg−1) 35·3, 32·9, 33·4 (s.e.d. 0·76).

Notes: 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.

Notes: Abstract— The concentrations of several metabolites, including glucose, glycogen, hexose phosphates, adenine nucleotides, amino acids and some tricarboxylic cycle intermediates were estimated in cerebral tissue of rats killed at various stages of pentamethylenetetrazole convulsions. Prior to and during the seizure there was an increase in glycolytic flux and depletion of energy reserves. An accumulation of alanine concomitant with a decreased citrate level observed before the convulsion indicated that a possible interference of pyruvate entry into the tricarboxylic cycle had occurred. At the tonic extensor phase of the seizure and during post-convulsive sedation a small but significant rise in GABA and an attempt to restore some of the labile constituents to more normal values was apparent. The significance of these results in relation to cerebral metabolic control and possible mechanisms of initiation and arrest of the seizure is discussed.

Notes: A straw/concentrate mixture was offered to set-stocked dairy cows over a 24-week period. The cows were offered grazed herbage only (G), or grazed herbage with a straw/concentrate supplement offered either for 45 min after each milking (B), or overnight (P). The overnight treatment involved housing the cows between afternoon and morning milking. The straw/concentrate mixture contained 0·33 long barley straw, 0·28 barley, 0·12 soya bean meal, 0·25 molaferm and 0·02 minerals. During the first 8 weeks of the experiment an average of 2·25 kg of concentrate were fed, and from weeks 9–24, 2·0 kg of concentrate were fed.The feeding of the straw/concentrate mixture led to a decrease in estimated herbage dry matter (DM) intake, particularly for treatment P. Estimated total DM intakes were increased throughout the experiment by offering the straw/concentrate mixture. However, total metabolizable energy (ME) intakes were only increased in mid-and late season.Milk yield was higher in early season for treatment G; 28·1 kg d−1 compared to 26·8 kg d−1 and 25·5 kg d−1 for treatments B and P respectively. In late season the cows in treatment G had lower milk yields; 13·3 kg d−1 compared to 15·5 kg d−1 and 16·8 kg d−1 for treatments B and P respectively. Milk fat content was increased in early season in treatment P, and milk protein content tended to be reduced throughout the experiment for cows offered the straw/concentrate mixture overnight. Over the whole experiment there were no differences in yield of milk solids.

Notes: Over a 24-week period, three groups of dairy cows were continuously stocked at 8, 10 or 12 cows ha-1 between morning and afternoon milkings, and overnight were housed and offered grass silage ad libitum. Due to a prolonged drought, sward heights only averaged 4·1 cm.The increase in daytime stocking rate led to a decline in herbage intake, and increases in silage intake. At the highest stocking rate (12 cows ha-1), the silage intake failed to compensate for the reduced herbage intake. Consequently the total dry matter and estimated metabolizable energy intakes were lower than for the 8 and 10 cows ha-1 treatments. Milk yields and milk composition were not significantly affected by treatment but the 12 cows ha-1 stocking rate gave the lowest milk and milk solids yields.The utilized metabolizable energy (UME) on the grazed swards was greatest for the 10 cows ha-1 treatment. The sward cut to provide the silage had a UME level (GJ ha-1) 32% greater on average than the grazed swards during the same growth period. The total areas utilized for grazing and silage production for 8, 10 and 12 cows ha-1 were 0·240, 0·224 and 0·215 ha respectively. Fat and protein yields per unit area were greatest for the 10 cows ha-1 group.

Notes: 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.