White clover can reduce fertilizer‐N requirements, improve sward nutritive value and increase environmental sustainability of grazed grasslands. Results of previous experiments in glasshouse conditions and on mown plots have suggested that white clover may be more susceptible than perennial ryegrass to treading damage on wet soils. However, this phenomenon has not been investigated under actual grazing conditions. This experiment examined the effects of treading on clover content, herbage production and soil properties within three clover‐based grazing systems on a wet soil in Ireland for 1 year. Treading resulted in soil compaction, as evidenced by increased soil bulk density (P < 0·001) and reductions in the proportion of large (air‐filled) soil pores (P < 0·001). Treading reduced annual herbage production of both grass and white clover by similar amounts 0·59 and 0·45 t ha−1 respectively (P < 0·001). Treading reduced the sward clover content in June (P < 0·01) but had no effect on annual clover content, clover stolon mass or clover content at the end of the experiment. Therefore, there was little evidence that white clover is more susceptible to treading damage than perennial ryegrass under grazing conditions on wet soils.

Sixty multiparous, Holstein-Friesian pregnant dry dairy cows were allocated to three forage treatments (n = 20; fodder beet, kale or grass silage) at two feeding allowances (n = 30; high and low) for 70 (s.e. of mean, 16) d before parturition. Cows offered the high feeding allowance were offered 9 kg of dry matter (DM) of kale or fodder beet grazed in situ plus 5 kg DM of baled grass silage daily or clamp grass silage ad libitum offered indoors. Cows offered the low feeding allowance were offered 6 kg DM of kale or fodder beet grazed in situ plus 3AE5 kg DM baled grass silage daily, or 9AE5 kg DM of clamp grass silage daily offered indoors. After calving, all cows received a daily allowance of 14 kg DM perennial ryegrass herbage at pasture plus 4 kg concentrate cow )1 for the first 35 d of lactation. Cows offered grass silage had a greater increase in body condition score prepartum compared to those offered kale or fodder beet. Cows offered fodder beet pre-partum had a greater milk solid and solids-corrected milk yield in the first 35 d of lactation than those offered kale and grass silage prepartum. Offering fodder beet and kale pre-partum increased plasma non-esterified fatty acid concentrations pre-partum relative to offering grass silage. Offering kale pre-partum resulted in higher insulin-like growth factor-1 concentration post-partum but lower plasma copper concentration pre-partum and at calving than kale or grass silage. Offering the higher forage allowance pre-partum resulted in a higher plasma calcium concentration at calving and higher plasma non-esterified fatty acid concentration post-partum.

The effects on the performance of dairy cows offered kale, swedes, and perennial ryegrass in situ and perennial ryegrass silage fed indoors to dairy cows pre-partum during winter in Ireland was examined. Eighty-eight spring-calving dairy cows were randomly assigned to one of four offered treatments; (i) 8 kg of dry matter (DM) of kale leaf and stem + 4 kg DM of perennial ryegrass silage (treatment K), (ii) 8 kg DM of the root and leaf of swedes + 4 kg DM of perennial ryegrass silage (treatment S), (iii) 12 kg DM of perennial ryegrass herbage (treatment G) offered in situ and (iv) perennial ryegrass silage offered ad libitum indoors (treatment ID). Cows on treatments K, S and ID had a greater (P < 0AE001) increase in body condition score (0AE20, 0AE14 and 0AE50 units respectively) pre-partum than cows on treatment G which lost 0AE22 units. Prepartum treatment had no effect on variables of milk production in the following lactation. In the first 100 d of lactation, cows on treatment G pre-partum had a lower milk fat concentration (35AE6 g kg )1 ) compared with cows on treatments S and ID (38AE3 and 39AE3 g kg )1 respectively). There was no effect of treatment on the intervals between parturition and first insemination (mean 74AE6 d) and conception (mean 96AE1 d). The results suggest that offering kale and swedes to dairy cows pre-partum resulted in a similar lactation performance to dairy cows grazing a perennial ryegrass sward or offered perennial ryegrass silage indoors.

Two field experiments were conducted at Teagasc, Moorepark, Ireland, to determine the effect of sowing date and nitrogen application on the dry-matter (DM) yield and crude protein (CP) content of forage rape and stubble turnips. The first experiment consisted of three sowing dates (1 August, 15 August and 31 August) with four rates of fertilizer N (0, 40, 80 and 120 kg N ha )1 ) on forage rape DM yields. The second experiment consisted of three sowing dates (1 August, 15 August and 31 August) with four rates of fertilizer N (0, 40, 80 and 120 kg N ha )1 ) over two soil sites (fertile or nitrogen depleted) on forage rape and stubble turnip DM yields. A delay in sowing from 1 to 31 August characterized a 74AE5% decrease in forage rape DM yield, while stubble turnip DM yield decreased by 55AE5%. Forage rape DM yields increased positively up to 120 kg N ha )1 at the first two sowing dates over both sites. In contrast, stubble turnips showed less response beyond 40 kg N ha )1 on site 1 in the first two sowing dates, while DM yield increased positively up to 120 kg N ha )1 on the less fertile site.The results indicate that the optimal sowing time for forage rape and a stubble turnip in Ireland was early August.

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Introduction Ruminal pH is a critical factor in the normal and stable function of the rumen. A reduction in ruminal pH below normal (< 5.6) can have significant impact on microbial activity, rumen function, and animal productivity and health (Nagaraja and Titgemeyer, 2007). Forage brassicas are an alternative forage source offered to dairy cows for in -situ grazing. However, there is a scarcity of literature examining the effect of feeding diets composed of high proportions of kale (brassica oleracea) or kale alone on rumen pH and VFA production in the rumen.