Days For Cows Research Articles

Influence of level of concentrate feeding on milk production and pasture utilization by Friesian cows grazing tropical grass-legume pasture

Four groups of four Friesian cows grazed green panic (Panicum maximum var. trichog1ume)- glycine (Glycine wightii cv. Tinaroo) pastures at 4 cows ha-1 for 36 weeks from January to October 1975. Cows were individually fed 0, 2, 4 and 6 kg cow-1 day-1 respectively of a maize-soybean meal concentrate. Fat corrected milk (FCM) response to concentrate was linear and was related to the total concentrate intake (X) by the equation, FCM = 1992 + 1.03 X (R.S.D. � 23; P < 0.001) Persistency of lactation decreased with decreasing levels of concentrate feeding (P < 0.01) and lactation length was reduced for cows receiving low levels of concentrates (P < 0.05). Milk fat content was reduced (P < 0.05) and solids-not-fat and casein contents increased by concentrate feeding (P < 0.05). Cows fed 6 kg concentrate cow-1 day-1 were 50 kg cow-1 heavier at drying off than cows fed no concentrate (P < 0.05). Pasture yield on offer to cows was increased linearly with increased concentrate feeding (P < 0.05) and pasture intake by cows was estimated to decrease by 0.9 kg for each kg of concentrate fed (P < 0.05). FCM response to concentrate appeared to increase markedly when pasture on offer fell below 2500 kg DM ha-1. We conclude that FCM response to concentrate will usually be linear for cows grazing tropical pastures, and the size of this response will be strongly influenced by the period of feeding and the yield of pasture on offer to cows.

Short-term effects of herbage allowance on milk production, milk composition and grazing time of cows grazing nitrogen-fertilized tropical grass pasture

The short-term effects of varying the quantities of herbage allocated (15, 25, 35, 55 kg DM cow-1, day-1) to lactating Jersey cows strip grazing 3-week regrowths of nitrogen-fertilized Panicum maximum cv. Gatton panic pastures, upon the diet selected, milk production, milk and milk fat composition and grazing time, were measured. Sixteen cows were used in a latin-square design with experimental periods of 1 4 days. With increasing herbage allowance milk yields rose, averaging 8.9, 9.9, 10.4 and 10.6 kg milk cow-1, day-1 respectively. A lower solids-not-fat percentage in milk from cows receiving 15 kg DM cow-1, day-1 and a lower percentage protein from cows receiving 15 and 25 kg DM cow-1 day-1 indicated a lower intake of digestible energy by cows at these lower herbage allowances. Molar percentages of short-chain fatty acids in milkfat (C6, C8, C10, C14) increased linearly and oleic acid (C18:1) decreased linearly as herbage allowance increased, showing that a higher proportion of the milk fat was coming from energy in the feed and a smaller proportion from body reserves. Cows selectively grazed leaf from the uppermost layers of the swards. As herbage allowance was restricted, a higher proportion of pasture was eaten and this came mainly from pasture growing 10 cm or more above ground level. Total time spent grazing was similar for all herbage allowances but the proportion of night grazing was consistently lower at the higher intensities of grazing.

A comparison of zulu sorghum, bulrush millet and white panicum in terms of yield, forage quality and milk production

Yield and nutritive value of three summer annual forages, hybrid forage sorghum (Sorghum spp. hybrid cv. Zulu), bulrush millet (Pennisetum typhoides cv. Tamworth) and white panicum millet (Echinochloa crusgalli var. edulis) were determined in three experiments. Uninterrupted growth was measured every 2 weeks between 4 and 12 weeks after sowing, and leaf, stem and inflorescence components analysed for nitrogen, phosphorus, calcium, magnesium, sodium and potassium and dry matter digestibility by an in vitro technique. The value of 10-week-old herbage, from crops grown with 50 kg ha-1 N, was determined by grazing with 18 Jersey cows and by feeding chopped material to 12 cows indoors. White panicum was the lowest yielding forage (up to 6,360 kg ha-1 at 10 weeks) but contained the highest concentration of nitrogen, phosphorus, calcium and magnesium in both leaf and stem fractions at all stages of growth. After 10 weeks growth this feed contained a high proportion of seed and was eaten in arger quantities than zulu sorghum or bulrush millet. Cows grazing white panicum produced the highestr lmilk yields (6.5 and 7.1 kg cow-1 day-1 indoors and grazed) and milk from these cows contained a highe solids-not-fat and protein content than milk from cows fed bulrush millet or sorghum. Zulu sorghum was highest yielding (1 1,240 kg ha-1 at 12 weeks in experiment 1 and 81 50 kg ha-1 at 10 weeks in experiment 2). With advancing maturity stem content increased (>80 per cent from 8 weeks onwards) and the nitrogen content of both leaf and stem fractions rapidly declined to sub-optimum levels. Milk production of cows feeding on zulu sorghum was low, averaging 4.7 and 6.0 kg cow-1 day-1 for indoor and grazing experiments. Bulrush millet produced high forage yields with a higher leaf content than zulu sorghum and milk yields were higher. Butterfat content of milk from cows feeding on bulrush millet was lower than when cows were fed the other forages. It was concluded that these three forages are capable of providing a large bulk of feed but their feeding value at a semi-mature stage of growth is similar to perennial tropical pastures.

Effects of stocking rate and energy supplementation on milk production from tropical grass-legume pasture

Forty Friesian cows were grazed continuously on a green panic (Panicum maximum var. trichoglume)/glycine (Glycine wightii cv. Tinaroo) pasture at stocking rates of 1.3, 1.6, 1.9 and 2.5 cows ha-1 for two years on the Atherton Tableland, Queensland. A supplement of 3.6 kg crushed maize cow-1 day-1 was fed for 50 days post-partum to half the cows in each group in both years. Milk yield per cow was reduced from 3811 kg lactation-1 at 1.3 cows ha-l to 3289 kg lactation-1 at 2.5 cows ha-1. With increasing stocking rate milk yield per hectare increased linearly to 8309 kg ha-1 at 2.5 cows ha-1. At 1.9 and 2.5 cows ha-1 cows lost weight over the two years and in late lactation levels of milk solids were often low. Also at these stocking rates cows had to be supplemented for up to 60 days during the main dry season. Legume content of the pasture declined linearly (P < 0.05) with increasing stocking rates. Maize feeding in early lactation increased milk yield over the total lactation by approximately 12 per cent, the response being 2.3 kg milk per kg maize fed, Response was greater at lighter stocking rates as cows in the heavier stocking rate treatments dried off prematurely. It was concluded that per hectare milk production from tropical grass/legume pastures can approach that from temperate pastures and that energy supplementation early in lactation would substantially increase per cow production.

Grazing time and pattern of grazing of Friesian cows on a tropical grass-legume pasture

Grazing time and pattern of grazing were recorded for 40 milking Friesian cows grazing a Panicum maximum var. trichoglume-Glycine wightii cv. Tinaroo pasture at stocking rates of 1.3, 1.6, 1.9 and 2.5 cows ha-1. These measurements were taken during summer and winter in a tropical upland environment. In a second experiment the effect on grazing time of feeding 4.5 kg crushed maize cow-1 day-1 was assessed using 16 milking Friesian heifers grazing P. maximum var. trichoglume-G. wightii cv. Tinaroo pasture at a stocking rate of 1.3 cows ha-1. Daily grazing time was similar at approximately 600 minutes in summer and winter, though in summer cows reduced day grazing and increased night grazing time. Reduction in day grazing was closely associated with daily maximum temperature. Grazing patterns showed a lower percentage of cows grazed during the middle of the day in summer than in winter and a higher percentage of cows grazed throughout summer nights than during winter nights. There was some evidence of a positive relationship between grazing time and milk yield. No significant relationship between pasture yield and grazing time was established. Feeding 4.5 kg maize cow-1 day-1 reduced grazing time per day by approximately 15 per cent.

GRASSLAND RECORDING. III

A previous paper (2) reported that the utilized‐stareh‐equivalent (U.S.E.) system did not reflect the quantity or quality of herbage consumed better than a much simpler cow‐day (C.D.) system, and. in all the cases studied, the correlation between U.S.E. and CD. was greater than + 0·877.The existing methods of C.D. evaluation are unsatisfactory because methods of equating classes of stock arc widely different and many are arbitrary.An examination has been made of published measurements of herbage intake of groups of sheep and cattle. A regression analysis of cattle intakes gave the equation: dry matter intake (lb) = 0·0234 liveweight + 0·7.The use of this equation is advocated as a basis for assessing the relative herbage intake of cattle and sheep of known liveweights in order to compute the total herbage consumption corrected to C.D.