Search Results - (Author, Cooperation:N. E. Young)

2012-09-18

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

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Arctic Regions ; Canada ; *Climate Change ; *Ice Cover ; Seasons

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

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.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

A comparison was made of the effect of a cereal supplement during early lactation on the performance and intake of ewes suckling two lambs while rotationally grazing pasture at stocking rates of 20, 17 or 14 ewes per ha. Supplement (S) at the high (H) and medium (M) stocking rates resulted in higher organic matter (OM) intakes (grass + supplement) of 2040 and 2500 g d-1 respectively, compared with the herbage OM intakes of unsupplemented (U) ewes of 1750 and 2040 g d-1 respectively. At the low (L) stocking rate the total OM intake of supplemented ewes and the herbage OM intake of unsupplemented ewes was similar at 2250 and 2210 g d-1 respectively.Lamb growth rate (g d-1) to 12 weeks of age was significantly lower on treatment UH (229) compared with those on UM (253) and UL (262). Growth rates on S treatments were similar (SH 248; SM 261; SL 272) and there were no significant differences between S and U within stocking rates. Unsupplemented ewes lost significantly more weight during the period of intake measurement than those receiving supplement. The speed of rotation was faster where supplement was not fed at the medium and high stocking rates and herbage accumulation under UH was less than under SH. Only at the high stocking rate did feeding a supplement give a higher financial output.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

The grass intake of three breeds of ewe was measured in the 5th–7th week (Period 1) and the 9th–11th week (Period 2) of lactation. The breeds of ewe were Finnish Landrace × Scottish Halfbred (FH), Finnish Landrace × Scottish Blackface (FB) and Thornber Colburn Colbred × Scottish Blackface (TC2). The immature FH ewes had a lower intake of digestible OM (26±1g/kg LW per day) than the mature FB (32±2g/kg LW per day) and TC2 ewes (33±5g/kg LW per day) in Period 1, but there were no difference between the breeds in Period 2. The intakes in Period 2 were significantly lower than those in Period 1.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Forage brassica catch crops can provide a valuable source of additional feed in the autumn when supplies of other feed are limited. Weaned lambs grazed either (A) a novel hybrid crop, stubble turnip cv. Appin, or (B) a sequence of crops consisting of fodder radish cv. Nerys, followed by forage rape cv. Canard. Forty, 60 or 80 g of crop DM per kg current live weight (LW) were allowed daily and the performance, intake and carcass yield of the lambs were monitored. Lamb LW gains were lower on treatment A (45, 65 and 72 g d-1) than on B (78, 111 and 117 g d-1) at the 40-, 60- and 80-g DM d-1 allowances respectively. Intakes of forage crops, however, did not differ significantly, probably because the estimates of intake were made in the middle of each 14-d allocation period of the crops. The intake values are thus an indication of the potential intake when a relatively plentiful supply of food is available; they were 19·2, 17·2 and 18·2 g OM kg-1 LW for treatment A and 16·2, 19·2 and 19·2 g OM kg-1 LW treatment B at the 40-, 60- and 80-g DM d-1 allowances respectively.Mild anaemia occurred in lambs feeding on both crops. Anaemia was more marked on treatment B, which was consistent with the higher concentrations of S-methyl cysteine sulphoxide (SMCO) but as the performance of animals was superior on treatment B, SMCO intake and anaemia are not thought to be the first or the most important factors in limiting animal performance. Goitrogenic changes in thyroid glands occurred on both crops. Mean weights of paired thyroid glands were 3·22, 4·28 and 4·21 g on treatment A and 3·29, 5·27 and 5·21 g on B at the 40-, 60- and 80-g DM d-1 allowances respectively; the effects of both treatment and allowance were significant (P 〈0·21). Thiocyanate concentrations were higher on treatment A than B, indicating differing glucosinolate concentrations. While this was consistent with animal performance, it was not consistent with the weight of thyroid glands. However, the goitrogenic responses may have been complicated by the ingestion of soil iodine because very high faecal ash values were recorded. Thus, glucosinolates appear not to have affected lamb growth rate by their goitrogenic effect but the possibility remains that they may have influenced performance by other means.

Electronic Resource