@conference {40905, title = {Effects of Mimosa Bark extract containing condensed tannins on rumen metabolism in sheep and milk production by grazing cows.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {126-129}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A Mimosa Bark extract (MB) was given to sheep and cattle to provide condensed tannins (CT) at levels which increased growth in lambs. The effects on rumen metabolism in sheep and milk production in grazing cows were studied in two experiments during spring 1994. MB contained 507g CT/kg bark and was administered as a water suspension (280g/litre). In Experiment 1, six rumen fistulated wethers were offered fresh pasture for two periods of 10 and 14 days, during which each sheep was drenched twice daily with 12.5 ml of either water or MB suspension (4.1 g CT/kg pasture DM intake), in a cross-over design. MB did not significantly affect DM intake, in sacco DM disappearance or apparent digestibility of DM or nitrogen (N), but ruminal ammonia-N and plasma urea concentrations were significantly decreased (P<0.05). In Experiment 2, 30 Friesian cows grazing mixed pasture were allocated to one of three treatments: undrenched control (C) or twice daily drenching with 90 (L) or 180 (H) ml of MB suspension (1.8 or 3.6 g CT/kg pasture DM intake) for three weeks. No significant differences in yields of milk or milk constituents were observed. Live weight and condition score changes did not differ significantly. Plasma urea concentrations were significantly lower (P<0.05) in treatment H than in treatment C. These results indicate that drenching with MB, at daily rates of 4 g CT/kg pasture DM intake, reduced ruminal protein degradation in sheep and cattle, but did not increase milk production. }, issn = {1176-5283}, author = {Mashudi and Brookes IM and Holmes CW and Wilson GF} } @conference {40834, title = {Nitrogen application to dairy pasture - the effect of rate and timing of spring nitrogen applications on the concentration of pasture nutrients}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {276-279}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Nitrogen (N) fertiliser was applied to ryegrass/white clover dairy pasture in late winter/early spring. Four rates of N (0, 20, 40, 80 kg N as urea) were applied to pregrazed and premown pasture with a residual herbage mass of 1000 kgDM/ha-1 (stubble height of 1.5 cm). Samples were collected from separate 2m2 plots 2, 4, 6 and 8 weeks after N application to detect nutrient changes over time from N appli}, issn = {1176-5283}, author = {Moller S and Edwards NJ and Parker WJ and Hodgson J and Wilson GF} } @conference {40603, title = {The effects of condensed tannin in Lotus corniculatus upon nutrient metabolism and upon body and wool growth in grazing sheep.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {219-222}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Lotus corniculatus containing 23 g/kg DM of extractable condensed tannin (CT) and 35 g total CT/kg DM was fed to sheep in two experiments. In both experiments half the sheep received supplementation with polyethylene glycol (PEG), which binds and inactivates CT, enabling the effects of CT to be quantified by comparing control sheep (CT operating) with PEG sheep (CT inactivated). Experiment 1 was conducted indoors, with sheep held in metabolism crates and fed hourly to determine the effects of CT upon apparent digestibility and upon plasma irreversible loss (IRL) rates of methionine, cystine and inorganic sulphate, using 35S labelling. Experiment 2 as a field trial with weaned lambs given a restricted allowance of either lotus corniculatus (CT-containing) or lucerne (non CT-containing), with or without PEG supplementation. In Experiment 1, CT slightly lowered the apparent digestibility of organic matter (0.77 vs 0.80; P<0.1), hemicellulose (0.61 vs 0.67; P=0.118) and markedly reduced nitrogen apparent digestibility (0.72 vs 0.80; P<0.01), but had no effect upon cellulose digestibility. CT increased the IRL of plasma cystine (13.1 vs 7.0 mmol/min; P<0.05) and reduced the IRL of plasma inorganic sulphate (36.8 vs 48.1 mmol/min; P<0.01) but had no effect upon plasma methionine IRL. In Experiment 2, live weight gain and wool growth were similar for sheep grazing lucerne (with and without PEG supplementation) and for sheep grazing lotus with PEG supplementation. In sheep grazing lotus, action of CT increased wool production (12.1 vs 10.9 g/d; P<0.05) and slightly increased live weight gain (203 vs 188 g/d; P=0.07). These experiments showed that CT in Lotus corniculatus increased the amount of cystine available for body synthetic reactions and increased wool growth.}, issn = {1176-5283}, author = {Wang Y and Waghorn GC and Douglas GB and Barry TN and Wilson GF} } @conference {40569, title = {Effects of herbage allowance and a high protein supplement on performance of dairy cows grazing on autumn-winter pastures}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {83-86}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two experiments were conducted to assess aspects of the feeding value of winter pasture for lactating dairy cows. During May 1989, three groups of 10 Friesian cows were offered daily herbage allowances of 43 (High, H), 20 (Medium, M) and 13 (Low, L) kg dry matter (DM) per cow, for a four week period in early lactation. Daily herbage intakes, assessed by cutting pastures before and after grazing, were 12.4, 9.1 and 7.6 kg DM per cow, respectively. "Covariance adjusted" daily milk yields (15.6, 12.4 and 9.4 litres/cow), milkfat yields (0.64, 0.54 and 0.41 kg/cow) and protein yields (0.50, 0.36 and 0.28 kg/cow) differed significantly (P<0.01) between treatments. Responses/kg extra herbage DM eaten were 1.0 and 1.9 litres, 31 and 84 g milkfat and 43 and 52 g protein for the H-M and M-L increments, respectively. Apparent liveweight gains and proportion of cows showing oestrus were also positively related to allowance. During June 1990, two groups of 15 Friesian cows in early lactation were transferred from a herbage and grass silage ration to a high herbage allowance of 63 kg DM/cow daily. The yields of milksolids and especially protein immediately increased substantially (P<0.01); the protein concentration increasing from 3.02 to 3.70\%. For a period of two weeks, the cows in one of the groups (Treatment) also consumed 2.7kg DM daily of a high protein concentrate supplement (Brewers{\textquoteright} grain and soyabean products). Daily milk yields (Control 20.3, Supplemented 22.5 litres), milkfat yields (C 0.87, S 0.94 kg) and protein yields (C 0.75, S 0.82 kg) were increased significantly (P<0.05) by the supplement. Herbage intakes were measured and substitution rates of 0.71 and 0.45 kg pasture DM/kg concentrate DM were estimated using two alternative techniques. The combined results indicate that the nutritive value for milk production of winter pasture is relatively high, provided that a high daily allowance is offered from pastures with more than 2,000 kg DM/ha pre-grazing mass. However, the relatively large increase in milk production caused by the concentrate supplement suggests that aspects of its nutritive value may constrain high levels of milk production where allowance is high. }, issn = {1176-5283}, author = {Suksombat W and Holmes CW and Wilson GF} } @conference {40500, title = {Effects of rumensin anti-bloat capsules on plasma magnesium concentration and aspects of health and performance of pastured dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {247-250}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A total of 134 ewe lambs born in 1991 from the Ruakura "Kamo" out- of-season breeding flock were run with harnessed vasectomised rams from weaning and inspected weekly for onset of puberty and subsequent oestrus activity. The breeding values for date of lambing (BV) for these animals were calculated from a pedigree and performance database. Multiple regression analysis were performed to determine the value of factors associated with hogget oestrus for predicting BV. While all the factors analysed, date of puberty, age and weight at puberty and number of subsequent oestrus cycles, had significant effects, none were as useful a predictor as date of birth(Bday). Season of birth (autumn vs spring) also exerted considerable influence on date of first tup and number of cycles. The results indicate that the best method of selection at present is that based on date of birth. Further research is needed to understand the interaction between season of birth and BV as they influence the onset of puberty.}, issn = {1176-5283}, author = {Wilson GF and Lynch GA and Van Der Wel C} } @conference {40464, title = {Liveweight, feed intake and feed conversion efficiency of lactating dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {95-100}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A method was developed to isolate mammary cell clumps (acini), from lactating sheep and maintain these in culture for more than 48 h. Performance of these cells was assessed by the measurement of lactose secreted into media using a sensitive bioluminescence assay. Lactose production was dependent upon cell density at seeding, lactose output per cell being 5-6 fold higher (6-7 fmol/cell/h) at 0.25x10 6 cells per ml medium compared to 2.5x10 6 cells per ml medium over 24 h of culture. Lactose output declined with time in culture, irrespective of cell density, falling to <1 fmol/cell/h over the period 24-48 h. 2-deoxy glucose uptake by mammary cells tended to increase with time in culture. 2-deoxy glucose uptake was significantly higher in cells from starved sheep (p<0.05) and in cells cultured in medium containing foetal calf serum, insulin, hydrocortisone, prolactin and prostaglandin E2 (p<0.001). Lactose output of acini was not affected by starvation of the ewe for 18 h before removing mammary tissue, and increased slightly (11\%) at low cell density in response to the additions of hormones and/or foetal calf serum to culture medium (p<0.05).}, issn = {1176-5283}, author = {Holmes CW and Wilson GF and Kuperus W and Buvaneshwa S and Wickham B} } @conference {40461, title = {Pasture protein and soluble carbohydrate levels in spring dairy pasture and associations with cow performance}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {83-86}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A survey on the East Coast of the North Island was conducted to provide information on the on-farm performance of drought tolerant pastures, including perceptions on animal toxicity problems. During October- December 1990 over 250 paddocks on 102 sheep/beef farms in Gisborne (23, Hawkes Bay (32) and the Wairarapa (47) were surveyed. Botanical composition was measured for each survey paddock from turf cores. No animal health problems were reported for prairie grass pastures, but farmers commented on improved animal performance from this pasture type. Animal health problems mentioned by farmers surveyed were: (1) ryegrass staggers, being reported for 58\% of survey farms and 9\% of survey paddocks. Ryegrass staggers was usually mentioned for paddocks with a high perennial ryegrass content (>40\% cores containing ryegrass). It was mentioned less frequently for mixed ryegrass- cocksfoot swards (>40\% ryegrass, >10\% cocksfoot) than for swards containing similar levels of ryegrass but little cocksfoot. (2) Bloat was mentioned more frequently for paddocks sown with tall fescue (15\%) than for other pasture types (3\%). Tall fescue swards had a higher clover content than ryegrass swards. (3) Stock ill-thrift (low growth rate) was mentioned for 6 of the 260 survey paddocks. The common feature of these paddocks was a moderate to high cocksfoot content (21- 72\% cores containing cocksfoot). (4) Phalaris toxicity was mentioned by 18\% of farmers who had phalaris pastures.}, issn = {1176-5283}, author = {Moller S and Matthew C and Wilson GF} } @conference {40365, title = {The effects of milking once daily throughout lactation on the performance of dairy cows grazing on pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {13-16}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The influence of selection for rapid (Fast GC) or slow (Slow GC) clearance of exogenous glucose on the pH of lamb meat was investigated using preslaughter stress, adrenaline and energy supplement treatments. Ultimate pH values were elevated (P<0.001) by a high level of preslaughter stress in the Fast GC line only. This response was suppressed by an oral energy supplement, indicating that recharge of muscle glycogen stores was impaired. The demonstration of this genetic relationship makes the selection lines valuable for study of the influence on meat quality of post mortem energy metabolism in muscles. }, issn = {1176-5283}, author = {Holmes CW and Wilson GF and MacKenzie DDS and Purchas J} } @conference {40335, title = {Non-milk constituents in replacers for calf rearing}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {323-326}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {This study was carried out to investigate central nervous system pathways which may be involved in the depression of food intake exhibited by parasitised lambs. Ten lambs with intake depression (c.20\%; p<0.05); as a result of chronic infection with 4000 T.colubriformis larvae/day together with 10 non-infected animals were used in a factorially designed experiment. The factors were a 24 h fast or no fasting followed by; saline solution (control), or 0.6 mg/kg brotizolam (blocks satiety signals at the ventromedial hypothalamus), or 0.125 mg/kg of naloxone (an opioid antagonist), all in a 2 ml volume given i.v. immediately prior to feeding. Trickle infection depressed mean daily intake by 20\% (p<0.05), likewise short term intake was depressed by infection (p<0.05). Fasting stimulated both short term and daily intake by approximately 100\% (p<0.001) and 12\% (p<0.05) respectively. Naloxone depressed cumulative intake for up to 2 h (p<0.01 - p<0.001) while brotizolam stimulated intake at both 60 and 120 minutes (p<0.001). These results show that opioid signals stimulate food intake in lambs and that fasting will overcome the effects of parasitism on appetite in the short term. A lack of opioid signals may be a factor in parasite induced food intake depression. }, issn = {1176-5283}, author = {Wilson GF and Brookes IM and Lynch GA and Billington AC} } @conference {39933, title = {Blood metabolites and infertility in dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {17-20}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Kallikrein-like enzyme (KE) activity has been detected in bovine saliva from the front of the mouth and from the cannulated mandibular gland. The maximal activity (39 mUnits ml-1) was present in secretions from the mandibular gland of cows stimulated with carbachol (parasympathomimetic). A lower activity (24 mUnits m-1) was obtained under isoprenaline (sympathomimetic) combined with carbachol stimulation. No detectable KE activity was present in parotid gland secretions. When tested for vasodilator activity in sheep, all samples tested were positive, but the greatest response was mandibular secretions collected under carbachol stimulation. Using purified salivary proteins, it was demonstrated that the KE activity was associated with bands 7 and 8, major proteins secreted by the mandibular gland.}, issn = {1176-5283}, author = {Wilson GF and MacKenzie DDS and Holmes CW} } @conference {39953, title = {The effect of level of milk intake on growth rate and herbage intake of Friesian bull calves of high and low breeding index}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {45}, year = {1985}, month = {Jan}, pages = {103-106}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Protein (NAN) flow to the small intestine was measured in early- weaning ram lambs grazing pure swards of white clover (W), lucerne (L), ryegrass (R) and prairie grass (P) at high allowances. Lambs were weaned at 6 weeks of age and measurements made at 8 and 12 weeks of age. Live-weight gain (LWG) measured over 6 weeks after weaning was higher for lambs grazing on legumes (308 }, issn = {1176-5283}, author = {Wang X-J and Brookes IM and Wilson GF} } @conference {39824, title = {Nutritional and physiological studies of differences between Friesian cows of high and low genetic merit}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {43}, year = {1983}, month = {Jan}, pages = {67-70}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Fleece tenderness is a serious fault of New Zealand crossbred wool costing the sheep industry between $50 and $100 million annually. Wool fibres break at the point where fibre diameter is at its minimum and factors which influence minimum fibre diameter will influence the incidence of fleece tenderness, e.g. breed and strain of sheep, age of ewe, level of feeding and reproductive status. Tender fleeces are on average lighter than sound fleeces and often have other associated faults such as cotting and yellow discolouration. Variation in minimum winter fibre diameter accounts for only about 40\% of the variation in staple strength within a flock suggesting that factors other than fibre diameter may be involved. There are fibre structural and compositional differences between sound and tender wools of the same diameter and these may be associated with fleece tenderness. The wool producer can influence the incidence of fleece tenderness by the level of feeding during mid pregnancy but it may not always be economic to feed better. Choice of shearing time will also influence the level of fleece tenderness. A preliminary estimate of the heritability of fleece tenderness of 0.58 }, issn = {1176-5283}, author = {Davey AWF and Grainger C and MacKenzie DDS and Flux DS and Wilson GF and Brookes IM and Holmes CW} } @conference {39710, title = {The magnesium status of grazing dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {41}, year = {1981}, month = {Jan}, pages = {53-60}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Wilson GF} } @conference {39459, title = {The influence of a protected tallow supplement on milk yield and composition}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {35}, year = {1975}, month = {Jan}, pages = {41-46}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Wilson GF and Brookes IM} } @conference {39424, title = {Nutritive characteristics of maize silage and maize silage/grass rations for cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {34}, year = {1974}, month = {Jan}, pages = {78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Waghorn GC and Wilson GF} } @conference {39305, title = {The influence if protein supplements on milk yield and composition}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {30}, year = {1970}, month = {Jan}, pages = {123-127}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Wilson GF} }