Kg Of Milk Fat Research Articles

Factors associated with the financial performance of spring-calving, pasture-based dairy farms

As land becomes a limiting resource for pasture-based dairy farming, the inclusion of purchased supplementary feeds to increase milk production per cow (through greater dry matter intake) and per hectare (through increased stocking rate) is often proposed as a strategy to increase profitability. Although a plausible proposition, virtually no analysis has been done on the effect of such intensification on the profitability of commercial pasture-based dairy farm businesses. The objective of this study was to characterize the average physical and financial performance of dairy systems differing in the proportion of the cow’s diet coming from grazed pasture versus purchased supplementary feeds over 4 yr, while accounting for any interaction with geographic region. Physical, genetic, and financial performance data from 1,561 seasonal-calving, pasture-based dairy farms in Ireland were available between the years 2008 and 2011; data from some herds were available for more than 1 yr of the 4-yr study period, providing data from 2,759 dairy farm-years. The data set was divided into geographic regions, based on latitude, rainfall, and soil characteristics that relate to drainage; these factors influence the length of the pasture growth season and the timing of turnout to pasture in spring and rehousing in autumn. Farms were also categorized by the quantity of feed purchased; farms in which cows received <10, 11–20, 21–30, or >30% of their annual feed requirements from purchased feed were considered to be categories representative of increasing levels of system intensification. Geographic region was associated with differences in grazing days, pasture harvested per hectare, milk production per cow and per hectare, and farm profitability. Farms in regions with longer grazing seasons harvested a greater amount of pasture [an additional 19kg of dry matter (DM)/ha per grazing day per hectare], and greater pasture harvested was associated with increased milk component yield per hectare (58.4kg of fat and 51.4kg of protein more per tonne of DM pasture harvested/ha) and net profit per hectare (€268/ha more per tonne of DM harvested). Milk yield and yield of milk components per cow and per hectare increased linearly with increased use of purchased feed (additional 30.6kg of milk fat and 26.7kg of milk protein per tonne of DM purchased feed per hectare), but, on average, pasture harvested/hectare and net profit/hectare declined (−0.60 t of DM/ha and −€78.2/ha, respectively) with every tonne of DM supplementary feed purchased per hectare. The results indicate an effect of purchased feeds not usually accounted for in marginal economic analyses (e.g., milk to feed price ratio): the decline in pasture harvested/hectare, with the costs of producing the unutilized pasture in addition to the cost of feed resulting in a lower profit. In conclusion, greater milk component yields per cow were associated with increased profit per hectare, and a greater use of purchased feeds was associated with an increase in the yield of milk components. However, on average, increasing yield of milk components through the supply of purchased feeds to pasture-based cows was associated with a decline in pasture harvested per hectare and profitability. The decline in pasture harvested per hectare with increased use of purchased supplements per cow is probably the primary reason for the low milk production response and the failure to capitalize on the potential benefits of purchased supplements, with the associated costs of growing the unutilized pasture, in conjunction with increased nonfeed variable and fixed costs outweighing the increased milk production and revenue from supplementation. Farmers considering intensification through use of purchased supplements to increase the stock-carrying capacity of the farm (i.e., stocking rate) must ensure that they focus on management of pasture and total cost control to capture the potential benefits of supplementary feed use.

Production Response of Dairy Cows Fed Soybean Meal Heat Treated with Different Methodologies

This study evaluated the production response of dairy cows fed soybean meal (SBM) ruminally protected by three different methods. Treatments were a control diet containing solvent-extracted SBM (SESBM) and three diets in which part of the SESBM was replaced either by expeller SBM (ESBM; SoyPlus®; West Central Soy, Ralston, IA), SESBM nonenzymatically browned with xylose (SESBM + X; SoyPass®; LignoTech, Overland Park, KS), or SESBM cooked with soybean hulls and water (SESBM + SHW; AminoPlus®; AG Processing Inc., Omaha, NE). Sixteen Holstein cows were utilized in a 4 × 4 Latin square design with 21-d periods. Diets were formulated to be isonitrogenous (CP = 17.5% of DM), isoenergetic, and to have similar NDF and fatty acid concentrations. The SESBM diet was deficient in ruminally undegraded protein (RUP), but the other three diets were designed to have adequate and equal RUP levels. Contrasts tested RUP level (SESBM vs ESBM, SESBM+ X, and SESBM + SHW), expeller vs cooking (ESBM vs SESBM + X and SESBM + SHW), and the effect of different procedures within cooking (SESBM +X vs SESBM + SHW). There were no significant effects on DMI or milk production when feeding SBM vs ruminally protected SBM. Feeding protected SBM decreased protein percentage, but not protein yield. Revenue ($/d per cow) was calculated for each cow within treatment using $2.62/kg of milk fat and $4.33/kg of milk protein. Ninety percent confidence intervals (least squares means for revenue ± 1.64 × SED [standard error of the difference]) were 8.29 ± 0.30 for SESBM, 8.31 ± 0.30 for SESBM, 8.31 ± 0.30 for SESEBM + X, and 8.55 ± 0.30 for SESBM + SHW. These data do not support indiscriminate use of protected SBM.

Production Responses to Bovine Somatotropin in Northeast Dairy Herds ,

The commercial response to bovine somatotropin was examined in northeast dairy herds from 1990 to 1998 (4-yr preapproval and 4-yr postapproval). With DHI records and Monsanto customer files, a control group (never purchased Posilac) and a bovine somatotropin (bST) group (used on at least 50% of cows) were identified. A total of 340 herds were involved and, over the 8-yr period, there were over 80,000 cows, 200,000 lactations, and 2million test days. Herd management comparisons demonstrated the response to bST was relatively constant each year of the postapproval period. Assuming 100% of cows were supplemented, response to bST over a 305-d lactation equaled 894kg of milk, 27kg of milk fat, and 31kg of milk protein. Comparisons of lactation curves were used to identify where the bST response occurred in the lactation cycle. Analysis demonstrated the responses in milk, milk fat, and protein yield were minimal in the early phase of lactation, and then gradually increased until reaching a plateau over the last half of the lactation cycle. Persistency of lactation was also improved by bST, indicating the opportunity exists to extend lactation with combined use of bST and altered reproductive management. Average age and days in milk did not differ between control and bST herds. Thus, stayability and herd-life of animals were not altered by bST treatment. Somatic cell count (SCC) linear scores were minimally affected in herds utilizing bST and the pattern of SCC over the lactation cycle was unaffected. Overall bST improved lactation yield and persistency consistently over the 4-yr postapproval period with no effects on cow stayability and herd-life.

Does extra feeding of cows during winter and early spring pay?

The effect of winter and spring feeding on milk production was investigated on a Mid-Canterbury dairy farm. High feeding of Friesian/Jersey cows to gain 64kg of liveweight during winter resulted in an extra 20kg of milkfat and 15 kg of milk protein production compared with feeding to maintain empty body liveweight. Extra feeding of cows during the first 8 weeks of lactation produced 7 kg of milkfat and 6 kg of milk protein over that period. The carry-over effect from this for the next 22 weeks of lactation of normal feeding was an extra 11 kg of milkfat and 5 kg of milk protein per cow. Simple financial analysis showed that off-farm wintering of cows to either maintain or gain liveweight and consequent high spring feeding were profitable options returning $40-42 per cow after extra grazing and topping costs. Keywords: winter, spring, feeding, milkfat,milk. protein, production

Energy Nutrition and Metabolism of the Lactating Dairy Cow

The genetic trend for increasing milk yield in the dairy cow population is impressive evidence of the application of genetic principles in dairy cattle selection. Walton (31) recently predicted that by the year 2000, individual cow records will approach 31,800kg of milk per year and 1,360kg of milk fat. Top individual herd averages will be nearly 16,000kg of milk and 635kg of milk fat. If these predictions are close, the subject of energy nutrition and metabolism will remain a relevant topic for many years. It will be a continuing challenge to design feeding systems and diet formulations that support this high production. An appropriate question is what high genetic merit for milk production means to a nutritionist or physiologist. To me it means the physical capacity and the physiological drive for cows to eat large volumes of energy-dense feeds, to assume negative energy balance through much of the first trimester of lactation, and to partition most of the feed energy plus energy from body stores into milk energy.I will sketch a broad picture of energy nutrition and metabolism in the lactating cow and identify those areas in knowledge and understanding that constrain dairy scientist from assisting cows of superior genetic merit to produce milk more efficiently. I see five areas for potential improvement in use of energy by lactating cows: a) increased production, b) increased energy consumption, c) increased digestive efficiency, d) increased metabolic efficency, and e) changed energy flow to partition more dietary energy to mik and less to body reserves for a longer period during lactation. I will attempt to relate the symposium speakers’ presentations to some of these areas.

Studies on pre-milking preparation 1. Half minute wash and stimulus compared with machine milking action alone

Abstract Twelve sets of identical twin cows of Jersey and Jersey cross breed were used in a split-twin design trial to compare lactation production using the 2 following milking regimes: 30 s of cold water washing and manual stimulation of the udder before machine milking; and milking machine alone. Manually stimulated cows, on average, outproduced their non-stimulated mates by 657 litres of milk and 33 kg of milkfat, which was about 32% of the average production of the non-stimulated group. Milkfat yield of the non-stimulated twin was significantly related to the duration of the milk ejection response. Correlations of within-set milkfat yield difference with lactation length and milkfat production level of the non-stimulated twin mate were highly significant.

Environmental and Genetic Trends in Production and Their Effects on Sire Evaluation

The objectives of the investigation were to estimate, from DHIA records initiated between December, 1956, and November, 1962, the magnitudes of the intraherd environmental and genetic trends in the milk and milk fat production of the New York State, Holstein, artificially sired, DHIA population and to determine the effects of these trends on the New York State sire-evaluation procedures. The total intraherd trend was estimated to be 176±8kg of milk and 6.4±0.3kg of milk fat per year. Estimates of the intraherd environmental and genetic trends indicated an environmental trend of 128±17kg of milk and 4.9±0.7kg of milk fat per year and a genetic trend of 47±17kg of milk and 1.5±0.6kg of milk fat per year.Product-moment correlations between standard estimates of sire breeding values and estimates adjusted for the effects of the genetic trend were close to one. However, there were two categories of sires where significant differences between the two types of proofs were noted: 1) sires that had not recently been used in the population, and 2) sires that had above or below average birth dates and, in addition, had relatively few daughters.