Some evidence exists that cow body condition score (BCS) is associated with risks to animal health, and that higher BCS in extensively kept animals provides a buffer against cold conditions or other adverse weather events. Not surprisingly, measures of BCS feature in dairy cattle welfare assessment protocols. However, the degree to which BCS predicts welfare state, particularly in relation to the level of "hunger" experienced, is not well researched. The aim of this study was to examine associations between naturally arising variations in BCS in dairy cattle and time spent engaged in activities used as proxy indicators of hunger. Holstein-Friesian cows (n=113) of either North American or New Zealand ancestry were allocated to 1 of 3 levels of concentrate-feed supplementation (0, 3, or 6 kg of dry matter/d) and also offered pasture in excess of requirements. Body condition score (1 to 10 scale), pasture dry matter intake (DMI), and time budgets for grazing, ruminating, standing, and lying were recorded during early, mid, and late lactation. Body condition score varied over a wide range (2.5 to 8.5) and, within genetic strain and supplementation level, was inversely associated with pasture DMI, rate of DMI, and the proportions of time spent grazing and ruminating. In comparison, variation in BCS (within genetic strain and supplementation level) was directly associated with variations in time spent lying (in late lactation). Nevertheless, pasture DMI and time spent in the key behavioral activities were all within the normal expected limits for pasture-fed dairy cows. Thus, thin cows appeared able to achieve their nutritional requirements. Furthermore, even though thinner cows traded-off a small portion of their lying time in late lactation to forage longer, they still rested for normal periods each day. Based on these results, we found no difference in the welfare status of naturally thin and fat cows when they were offered generous pasture allowances with or without concentrate supplementation. The extent to which this pertains under conditions of persistently low feed allowances that result in reductions in BCS remains to be determined.

A botanical survey of 24 commercial dairy pastures ranging in post-sowing age and perennial ryegrass type (mid-season diploid, late-season diploid, tetraploid) was undertaken in each of Waikato-Bay of Plenty (BoP), Taranaki and Canterbury during autumn/winter. The mean perennial ryegrass proportion (85% of total DM) and tiller density (3252 m −2 ) was greatest in Canterbury and the broadleaved weed proportion lowest (2%). Conversely, Waikato-BoP had the lowest ryegrass proportion (59%), tiller density (1817 m −2 ) and greatest proportion of broadleaved weeds (15%), with Taranaki intermediate. Tiller density was greater in pastures sown with diploid rather than tetraploids (averaging 3033 vs. 1784 m −2 ). Grass grub (Costelytra zealandica, 11 m −2 ) populations were lowest in the youngest age category pastures where nematode populations were highest (80 g −1 dry soil). The soil seedbank was dominated by unsown species (with total species emergence averaging 4594 seeds m −2 ), with negligible ryegrass emergence.

Growth responses of perennial ryegrass (Lolium perenne L.) diploid cv. Alto and a tetraploid breeding line of Alto infected with wild-type fungal endophyte to three types of stress were studied in a semi-controlled environment. The stresses imposed were: soil-moisture deficit (wilting point vs field capacity), severe defoliation (2.5 vs 6 cm cutting height), and root-feeding invertebrate infestation (nil vs 600 grass grubs (Costelytra zealandica) m–2). Stress treatments were applied simultaneously in a fully factorial design for 8 weeks followed by a 4-week recovery period. Total plant biomass was reduced to a similar extent for both ploidies by soil-moisture deficit (43% reduction), severe defoliation (31% reduction) and root-feeding invertebrates (13% reduction) at the end of the treatment period. At the end of the recovery period, feeding by grass grubs reduced root biomass by 34% and total plant biomass by 25% in the tetraploid cultivar, but there was no effect in the diploid cultivar. Although compensatory growth occurred during the recovery period, one or more aspects of plant growth (e.g. tillering, biomass) remained lower in previously stressed plants at the end of the recovery period. The lower tiller density and total biomass of the tetraploid, in combination with greater allocation of resources to shoot growth and greater susceptibility to root-feeding invertebrates, may compromise its persistence in the field.

The objective of this study was to compare the health, physiology, and behavior of group-housed calves reared on wood shavings with those reared on alternative surfaces. At 1 wk of age, 80 calves were moved into 1 of 20 experimental pens (n = 4 calves/pen) where they remained until 6 wk of age. Pens had floors covered with pea gravel (PG), rubber chip (RC), sand (SA), or wood shavings (WS; n = 5 pens/substrate). Body weight, cleanliness, health, and skin surface and vaginal temperature were recorded at 1, 3, and 6 wk of age. Escherichia coli numbers were assessed on the skin surface of the shoulder and in the feces of calves at 3 and 6 wk of age. Blood samples were taken at 1, 3, and 6 wk of age to measure hematological values and cortisol, IgG, and lactate concentrations. Behaviors (lying, running, and self-grooming) were recorded in the home pen at 1, 3, and 6 wk of age using video recorders and accelerometer data loggers. At 6 wk of age, calves were tested individually in an arena test and behavior was recorded continuously for 20 min. Body weight did not differ among calves reared on PG, RC, SA, or WS, regardless of age. All calves were clean and no calves displayed any signs of lameness, leg lesions, or injuries at wk 1, 3, or 6, regardless of substrate. The number of E. coli recovered from a surface area of 100 cm on the shoulder of each calf was affected by rearing substrate, with more E. coli recovered from calves reared on WS than PG, RC, or SA at 3 and 6 wk of age. Fecal E. coli counts were not affected by rearing substrate at 3 or 6 wk of age. Over the entire study period, calves reared on PG and SA had lower skin temperatures than calves reared on RC or WS, but skin temperature was similar between calves reared on PG and SA. However, vaginal temperature did not differ among calves reared on different substrates at 1, 3, or 6 wk of age. Hematology values and cortisol, IgG, and lactate concentrations of calves were similar among rearing substrates over the 6-wk study period. In the home pen, rearing substrate did not influence time spent lying; however, calves reared on WS performed more lying bouts than calves reared on PG or SA. In addition, rearing substrate did not influence the time calves spent running; however, calves reared on WS spent more time self-grooming than calves reared on PG, RC, and SA. During a 20-min arena test, running, bucks, jumps, and kicks performed by calves was not affected by rearing substrate. In conclusion, the physiology and behavior of calves reared on PG, RC, and SA was similar to WS, which is considered the preferred rearing substrate to use when rearing calves. Therefore, PG, RC, and SA may be acceptable substrate options when rearing group-housed dairy calves.

Yellow bristle grass (YBG) causes significant production loss on dairy farms as it is unpalatable to stock and can reduce forage intake and milk production This weed is rapidly spreading in North Island dairy pastures and effective control strategies are needed Botanical surveying was undertaken in February 2008 on 12 dairy farms in Waikato to ascertain its presence in pastures in relation to key management factors YBG cover was negatively associated with Olsen P pH paspalum cover and postgrazing residual dry matter in January Stocking rate time since pasture renovation inclusion of a cropping phase prior to renovation sowing rate during renovation ryegrass undersowing after renovation and cover of ryegrass clovers other dicots annual grasses and amount of bare ground had no significant effect on YBG cover Results suggest that while improved soil fertility and increasing pasture competition will enhance YBG control YBG seeds can survive during pasture renovation leading to rapid reinfestation of pastures