Economic losses from and the national research program on mastitis in the United States.

Scientific papers estimating economic losses from mastitis were reviewed. Reduced milk production from cows with subclinical mastitis was responsible for the largest losses. Losses from mastitis in the United States in 1976 were estimated by usable responses to a survey from 33 states representing 9.5 million cows or 86% of the dairy cow population. Losses of milk yields caused by mastitis were 386 kg/cow per yr and losses of discarded milk 62 kg/cow per yr. Annual losses per cow from mastitis were a) reduced milk production, $81.32; b) discarded milk, $12.88; c) cost of veterinary services, $1.97; d) cost of drugs, !3,86; e) increased labor, $2.28; f) decreased sale value, $5.72; g) increased replacement costs, $9.32; h) total, $117.35. For the 11 million cows in the United States 1976 losses from mastitis were $1.294 billion. Mastitis research was supported publicly at 22 locations under 43 projects. Approximately 24 scientist years were involved and $2.7 million of public funds were expended annually. If economic losses from mastitis were reduced 2% per year for 10 yr by research and expenditures for mastitis research remained the same, the benefit to cost ratio from mastitis research would be approximately 9.6 to 1.     

Economic effect of short (35-d) compared with conventional (60-d) dry period management in commercial Canadian Holstein herds

The Canadian dairy industry operates under a supply management system with production quotas (expressed in kilograms of butterfat per day) owned by dairy producers. Any management strategy influencing production responses must, therefore, be evaluated to estimate its effects on quota needed to sell the milk produced. In the present study, half of the cows from 13 commercial herds (850 cows, average of 70 cows per herd) were assigned to be managed for a short dry period (SDP; 35 d dry) and the other half was managed for a conventional dry period (CDP; 60 d dry) to evaluate the economic impact of a steady state involving either CDP or SDP. Economic variables included in the partial budget were: variations in revenues from milk and components as well as animals sold; costs related to feeding, reproduction, replacement, housing, and treatments. All variables were first estimated on a cow basis for each herd individually, and average results were used to calculate the partial budget for an average herd. Yearly milk and component yields per cow increased, which implies that fewer cows are required to produce the same amount of quota. Accordingly, 2 scenarios were investigated: in the first one, available quota was kept constant, and herd size was adjusted to avoid over-quota production. Consequently, the partial budget was calculated considering that 5 fewer cows were present in the herd. In this situation, switching to an SDP management increased net annual income for the farm by $2,677 (Can$), which represents $41.38 per cow. In the second scenario, the number of cows was kept constant, but additional quota (5.5 kg/d, $25,000/kg) was bought to allow selling all of the milk produced. In this case, net farm income was increased by $17,132 annually with SDP, which represents $245.18 per cow. This budget includes interest on the purchase of quota. A comparison of partial budgets for individual herds involved in the study revealed considerable variation among herds. Switching from a CDP to a SDP management would be beneficial for average dairy herds in eastern Canada.     

Estimating efficiency in automatic milking systems

Milking data of 34 single automatic milking system (AMS) units on 29 Galician dairy farms were analyzed to determine the system capacity in each farm under actual working conditions. Number of cows, milk yield, milkings per cow per day, actual milking time, rejected milking time, cleaning time, and machine downtime were used to determine the number of cows milked per AMS unit to obtain the optimal values of milkings per cow and milk production. Multiple linear regression data analysis was used to model the linear relationship between the dependent variable, milk yield per AMS per year, and the predictor variables: number of cows per AMS, milkings per cow per day, milk flow rate, and rejections per AMS per year. An AMS unit milked 52.7±9.0 cows daily at 2.69±0.28 milkings per cow, with a total milking downtime of 1,947±978 h/yr and a milk yield of 549,734±126,432 kg/yr. The predictor variables cow and milk flow rate had a greater level of influence on the milk yield per AMS than milkings per cow and rejections, and explained the 87% of the variation. The AMS in Galician dairy farms could facilitate an increase of 16±8.5 cows per AMS without impairing milking performance; in this way, the quantity of milk obtained per robot annually could be increased (185,460±137,460 kg). This would make it possible to recoup the cost of the system earlier. In the present situation, the daily milking throughput could be maximized at 2.4 to 2.6 milkings per cow.     

Modeling the effect of an outbreak of bovine herpesvirus type 1 on herd-level milk production of Dutch dairy farms.

One of the impacts of disease is its effect on milk production. In the present study the effect of an outbreak of bovine herpesvirus type 1 on milk production at the herd level of certified bovine herpesvirus type 1-free dairy farms was modeled. The objective was to study several linear models to quantify the effects of a bovine herpesvirus type 1 outbreak on milk production accounting for the repeated measurements and incorporating our assumptions about the most likely duration of effects of this virus. Because milk production is measured at regular intervals, the data consisted of repeated measurements at the herd and cow levels. A marginal model, a subject-specific random-effect model, and a transition model were developed. The effect of a bovine herpesvirus type 1 outbreak was statistically significant in the random-effect model, and this model fitted the investigated farms best. However, a transition model might be a better model for generalizing the results to the whole population of Dutch dairy farms. The effect of a bovine herpesvirus type 1 outbreak on milk production derived from the random-effect model amounted to, on average, a loss of 0.92 kg of milk per cow per day during a period of 9 wk. The milk production loss varied from almost none to 2 kg of milk per cow per day. This reduction resulted in an average loss of Dfl 372 (Dfl1 = $US $0.50) with lower and upper confidence limits of, respectively, Dfl 12 and Dfl 730 per bovine herpesvirus type 1 outbreak.     

Effect of Business and Dairy Herd Management Practices on the Variable Cost of Producing Milk

A Cobb-Douglas-type function was used to study the effect of several business and dairy herd factors on the variable cost of production per 45.4 kg milk in 410 New York State dairy herds. The model used was a recursive system of equations with milk sold per cow per year and total variable cost associated with milk production as endogenous variables. Solutions were obtained using the two-stage least squares procedure. Relationships were essentially linear between variable production cost per 45.4 kg of milk and average age of the herd, percent days in milk, average age at first calving, average body weight, average days dry, fat test, and kilograms of concentrates fed. For average days open, herd size, number of cows per worker, tillable acres per cow, percent cows leaving the herd, and capital investment per cow, relationships were curvilinear. A lower variable production cost was associated with those herds having fewer days open, younger age at first calving, higher percent days in milk, lower percent cows leaving the herd, and heavier cows. Average body weight of all cows, average days dry, cows per worker, and tillable acres per cow had very little relationship with the variable production cost.     

Effects of selection and crossbreeding strategies on industry profit in the New Zealand dairy industry

The effects of selection and crossbreeding on the New Zealand dairy industry net income were evaluated with a deterministic model over a 25 yr planning horizon. Several mating strategies involving Holstein-Friesian, Jersey and Ayrshire cattle were evaluated. These strategies were straight breeding, upgrading to Holstein-Friesian, upgrading to Jersey, upgrading to Ayrshire, use of the best bulls irrespective of breed and two- and three-breed rotational crossbreeding. Industry productions of milk, fat, protein, and lactose were calculated assuming that 12,000 kg of dry matter per hectare was utilized from 1,224,911 hectares of pasture. Profitability was the difference between income (international sale of whole milk powder, casein, butter, and beef from salvage animals) and costs (farm expenses, milk collection, manufacture, and marketing). Casein and whole milk powder were valued at NZ$8.345 and NZ$3.306/ per kilogram, respectively, over 25 yr. Butter was valued at NZ$2.995/kilogram for base year production levels and NZ$0.45/kilogram for marginal increases in production. Upgrading to Holstein-Friesian resulted in the highest industry net income (NZ$1119 million) followed by straight breeding (NZ$1086 million) and two-breed rotational Holstein-Friesian x Jersey (NZ$1076 million). However, if the marginal value of extra butter production was assumed equal to the average base value, then upgrading to Jersey resulted in the highest industry net income (NZ$1185 million) followed by two-breed rotational Holstein-Friesian x Jersey (NZ$1177 million) and use of the best bulls (NZ$1173 million). Future costs and prices of dairy products have major impact on mating strategies.     

The economic implications of bioengineered mastitis control.

This paper estimates the cost of mastitis for the New York dairy sector. The average cost is found to be $125 per cow from reduced milk production, treatment, and increased culling. At the 1988 cow inventory, this translates to approximately $100 million annually for the entire dairy farm sector. When quality and production losses for the processing sector are added, the cost to the New York industry alone is nearly $150 million annually. Two promising new treatments, a bacteriocin and a vaccine, are evaluated. Both have shown effectiveness in preliminary trials against Staphylococcus aureus. Assuming that further development will allow the treatments to be effective against the major bacterial sources of mastitis infections, the treatments are projected to increase the annual income of the New York dairy industry by $18.8 to $39.7 million. The bacteriocin could replace antibiotic usage, a desirable goal in the opinion of many, and the vaccine promises to immunize cows against mastitis very effectively.     

Major advances in extension education programs in dairy production

The dairy industry has seen structural changes in the last 25 yr that have an impact on extension programming. The number of cows in the United States has decreased by 17%, whereas the number of dairy farms has decreased by 74%. The average milk production per cow has increased from 5,394 to 8,599 kg/lactation. Even though there are fewer farms, dairy farm managers are asking for more specific and targeted information. The extension resources available have also decreased during this period. Because of these changes, shifts have taken place in extension programming and staffing. A key change has been a shift to subject matter-targeted programs and workshops. Extension has also incorporated and expanded use of the Internet. Discussion groups, subject matter courses, and searchable databases are examples of Internet use. There will be continuing shifts in the demographics of the US dairy industry that will influence future extension efforts. It is also probable that fewer extension professionals will be available to provide programming due to changes in funding sources at national, state, and local levels. Future shifts in extension programming will be needed to provide the information needs of the industry with a smaller number of extension workers.     

Economics of using bovine somatotropin in dairy cows and potential impact on the US dairy industry

Budgets with a microcomputer spreadsheet were developed to evaluate the economics of bovine somatotropin use and to estimate the impact on US dairy cow numbers. Income over feed and variable costs increased with somatotropin use and low feed prices. With high feed prices, income responses were less favorable, and when combined with low milk prices, somatotropin use resulted in less income than from control cows. Price of somatotropin did not have a major effect on production costs. The number of cows needed to meet US milk requirements is primarily influenced by per capita consumption and production per cow. With continuing yearly increases in per capita consumption of 2 kg of milk equivalent and cow milk yields of 114 kg, the number of milk cows needed through 1992 remains at the 1987 figure of approximately 10.3 million. In the scenario of a 15% increase in milk yield due to somatotropin, 20% of cows receiving the hormone, and cows receiving the hormone being 10% above the national average of all cows; the number needed in 1992 is 9.77 million, or a drop of 5.4% from 1987. Somatotropin use will have a less drastic effect on cow numbers than originally predicted.     

Welfare effects of the use of recombinant bovine somatotropin in the USA

The welfare effects of increased milk production associated with the use of recombinant bovine somatotropin (rBST) on dairy operations in the USA were examined for 1996. Results that derived from three different estimates of the milk-production response to rBST were evaluated and compared. One estimate, derived from a survey of dairy producers in Connecticut, led to economic-impact estimates that were not statistically significant. A second, derived from a national survey that concentrated on the health and management of dairy cattle, led to estimates that were unbelievably high. A third, derived from a national survey that concentrated on the economics of dairy producers, provided the most reasonable estimates of economic impacts. Results of economic analysis, using the latter results, indicated that if rBST had not caused milk production to increase, then the market price of milk would have been 2.2 +/- 1.5 cents/kg higher, and the total value of the milk produced would have risen from Dollars 23.0 +/- 0.6 billion to Dollars 24.1 +/- 1.0 billion. A welfare analysis demonstrated that the increased milk production (and the reduced market price) associated with the use of rBST in the USA caused the economic surplus of consumers to rise by Dollars 1.5 +/- 1.0 billion, while the economic surplus of dairy producers fell by Dollars 1.1 +/- Dollars 0.8 billion. Increased milk production associated with rBST yielded a total gain to the US economy of Dollars 440 +/- 280 million. An analysis of annual percent changes in the number of dairy cows per operation, milk production per cow, total milk production, total number of dairy cows, and total number of dairy operations in the USA suggested that the dairy industry's long-term economic growth path was stable from 1989-2001 inclusive, and did not receive a shock resulting from the introduction of rBST.     

Characteristics of Minnesota dairy farms that significantly increased milk production from 1989-1993

This study evaluated factors that affected decision making and changes within the Minnesota dairy industry. The 50 herds selected for this study had at least 75 cows registered with the Dairy Herd Improvement Association in 1993 and were selected based on the total percentage increase in milk production on the farm from 1989 to 1993. These 50 herds had a mean herd size of 131 cows and a mean milk production of 8807 kg per cow in 1993. On average, from 1989 to 1993, the surveyed herds increased their total milk output by 90%, increased their herd size by 51 cows, and increased mean herd milk production by 926 kg. Of the farms, 50% were partnerships or family corporations, and 50% were owned by a single family. The surveyed producers were 39 yr of age on average. During the period studied, the use of free-stall housing increased from 36 to 48%, use of the milking parlor increased from 32 to 54%, and use of tie stalls decreased from 42 to 28%. The daily hauling of manure decreased from 34 to 20% on these farms. The use of hired labor increased by a mean of 0.61 full-time workers and 0.34 part-time workers. Strategies for herd growth included internal growth (no purchased animals), 24%; the purchase of cows, 24%; and the purchase of springers, 52%. Over 90% of the producers were very satisfied or somewhat satisfied with dairy farming operations, but only 33% of the spouses were very or somewhat satisfied. Satisfaction levels were positively associated with overall production levels on the farms. Although there is no single established pattern for the expansion of herds, practices utilized by those producers surveyed can be scrutinized by others who are contemplating expansions to determine what might be efficient for their operations.     

Major advances in nutrition: relevance to the sustainability of the dairy industry

The typical cow has a maintenance requirement of about 10 Mcal of net energy for lactation (NE_L) per day. Each kilogram of milk takes an additional 0.7 Mcal of NE_L. Thus, the cow producing 45 kg of milk per day needs 4 times as much total energy as she needs for her maintenance requirement alone. The elite cow producing 90 kg/d needs 7 times as much total energy as she needs for maintenance alone. Consequently, the efficiency of using feed energy is much greater for the elite cow than it was for the cow of 100 yr ago consuming a diet of mostly forage. With increased productivity has come the need for fewer cows to produce milk on a per capita basis and increases in net income per cow. However, compared with energetic efficiency, the efficiency of using feed protein to make milk protein has not increased as dramatically, partly because cows are often fed protein in excess. This nitrogen waste is an environmental concern; N losses in manure contribute to water pollution and ammonia emissions from dairy farms. However, the complexities of protein nutrition and limitations in measuring feed N fractions make accurate specifications for feed protein fractions difficult. The economic risk of underfeeding protein is greater than the risk of overfeeding protein, so protein efficiency has not been maximized in the past, nor is it likely to be maximized in the near future. Most cows also are fed excess P, a notable contaminant of surface waters, but several recent studies have shown that feeding P above NRC recommendations has no utility for milk production or fertility. The goal of this article is to examine the impact of nutrition on productivity, efficiency, environmental sustainability, and profitability of the dairy industry.     

平衡的乳品矿物质复合物

国内乳业近年发展迅速,1990~2000年间,中国乳品消费总量平均以7.5％的速度增长;2000年的消费增长更高达10.4％。虽然如此,2001年,中国人均乳品消费量仍仅为8.01千克,这与100千克/年的世界人均消费量仍存在很大差距。业界预测,到2010年,我国乳品需求总量约为2,325.7万吨,人均消费量达到14.31千克,市场发展潜力巨大。     

Assessment of the productivity effects associated with epizootic hemorrhagic disease in dairy herds

Epizootic hemorrhagic disease is caused by a Culicoides-borne Orbivirus. In cattle, the disease is characterized by reduced milk production and mortality. Recent outbreaks of epizootic hemorrhagic disease virus (EHDV) in North Africa, Israel, and Turkey increase the risk of its invasion into central and northern Europe. An outbreak of EHDV in Israel during the fall of 2006 enabled an assessment of the consequent production losses to the dairy cattle industry. Reduction in milk production and involuntary culling were modeled using a 4-yr database of monthly milk and mortality records from 48 affected and 63 unaffected herds. These indices were compared between periods of outbreak and no outbreak and assessed for various levels and exposure onset. Geospatial kriging interpolation of serological results from 127 herds was used to assess the total outbreak losses for the dairy cattle industry in Israel. Herds affected during the first, second, and third month of the outbreak (September-November) experienced an average loss of 207 (95% CI = 154-261), 137 (63-211), and 52 (27-76) kg of milk/milking cow, respectively, during the outbreak period. An average excess mortality and involuntary culling of 1.47/100 cows was documented in herds affected in September. High correlation was observed between EHDV seroprevalence and milk loss; average milk loss for herds with seropositivity of 26 to 50, 51 to 75, and 76 to 100% was 84, 133, and 204 kg of milk/milking cow, respectively. A 1.42% (0.91-1.93%) increase in mortality was observed in herds with seroprevalence above 50%. Losses for the dairy cattle industry interpolated from these data were estimated at US$2,491,000 (US$1,591,000-3,391,000), an average loss of US$26.5/cow in the Israeli dairy cattle. This equals 0.55% of the average total value production of a dairy cow in Israel. This is the first study to estimate the production losses caused by EHDV or any bluetongue-like disease.     

Efficiency of use of imported nitrogen, phosphorus, and potassium and potential for reducing phosphorus imports on Idaho dairy farms

Eight commercial dairies from south central Idaho were surveyed to estimate the whole-farm surpluses of N, P, and K and to investigate the possibility of reducing P excretions through dietary manipulation. Nitrogen, P, and K imports and exports were monitored in a 12-mo period, and samples from the diets, feeds, feces, urine, and manure were collected at regular farm visits. Soils from manure-amended fields were sampled in the spring and fall. In all cases, the largest import of N, P, and K to the dairy was with purchased feeds. Major nutrient export items were milk and manure and forages, in the case of a dairy with a large land base (dairy F). Whole-farm N surplus varied from 90 to 599 t/yr (91 to 222 kg/yr per cow). The efficiency of use of imported N varied from 25 to 64%, with dairy F having the greatest efficiency of imported N use. Phosphorus and K surpluses were also significant (average of 29 and 182 t/yr and 12 and 76 kg per cow per year, respectively). During the study period, dairy F was a net exporter of K. The average efficiency of use of imported P and K was 66 and 58%, respectively. Soil P levels in the 30-cm layer were above state threshold standards, most likely from overapplication of manure. Soil nitrate-N concentrations were also high, but K concentrations were within the accepted range. Average P content of the lactating cow diets at the start of the study was 0.49% and was reduced to 0.38%. The estimated reduction in imported P due to the reduced dietary P levels was from 5.7 to 61.4 t/yr per farm, or on average 12 kg per cow per year. This study demonstrated that in addition to exports with milk and manure, export of nutrients with forages produced on the farm (dairy F) is a major factor in reducing whole-farm N, P, and K surpluses.     

Prediction of effects of dairy selection indexes on methane emissions

Global warming caused by greenhouse gas emissions is a threat to the survival of humans and other organisms living on Earth. The greenhouse gases released from the dairy sector of New Zealand accounted for 18.2 Mt of carbon dioxide equivalent (CO₂-eq) in 2016, mainly from methane generated by enteric fermentation in the rumen of milking cows and their replacement stock. A productivity commission established by the New Zealand government in 2018 estimated that methane emissions from livestock needed to be reduced from 2016 levels by 10 to 22% by 2050 (i.e., 2.8 to 6.1 million t lower), so as to restrict future increases in global temperature to less than 2°C. In this study, we evaluated genetic effects of 8 traits included in the New Zealand national dairy breeding objective, on 3 types of methane emissions metrics: gross methane emissions per dairy cow per year (E), methane emissions per hectare (EH), and methane emissions intensity per milk protein equivalents (EI), as carbon dioxide equivalents. These effects were then aligned with recent genetic changes in these traits brought about by breeding schemes, so that the overall genetic trend for each metric into the future was estimated. The results showed that EH and EI are currently being reduced at rates of −2.31 kg of CO₂-eq per hectare per cow per year (current average is 6,915 kg of CO₂-eq/ha per cow per year) and −0.04 kg of CO₂-eq per kg of milk protein equivalents per cow per year, respectively (current average is 9.7 kg of CO₂-eq/milk protein-eq per cow per year). These improvements directly reflect increased production efficiency through selection for farm profitability. If the pastureland area in New Zealand remains the same, at the same productivity and with no increase in supplementation rates from external land sources, in 20 years gross emissions would be reduced by only 0.6%, or 89 Mt. Increased production efficiency will likely result in corresponding changes to the stocking rate, to fully utilize the pasture resource available, and might further encourage a greater rate of intensification via supplementary feeding. Both consequences of current genetic selection could negate any benefits for the national greenhouse gas inventory. New selection criteria for reduced methane production are needed to help achieve New Zealand's national methane reduction targets.     

Past, present, and future perspectives of small ruminant dairy research

The objectives of this paper are to review small ruminant dairy research in relation to the dimensions of the dairy goat and dairy sheep industries in the United States and the world. At least 10 countries depend on goats and sheep for between 30 to 76% of total milk supply. Leading among developed countries is Greece producing 178 kg milk per person per year with 61% from sheep and goats. Most developing countries need research, extension service, and public support to improve apparent productivity of goats and sheep. Domestic supply from all milk sources is <100 kg/person per year, and annual apparent yields average <100 kg of milk/goat, <50 kg of milk/sheep, which makes supplies of animal protein and calcium from domestic sources very low. Statistical data on goat and sheep production for United States are not available. The small population of DHIA tested US dairy goats averaged in recent years >700 kg of milk/goat per year, and some dairy sheep breeds may produce as much as 650 kg/yr. The need for more milk availability appears to be reflected in the dramatic increases of dairy goat populations during the last 20 yr: 52% for the world, 56% for developing, 17% for developed countries, while sheep populations decreased by 3% for the world, by 6% in developed, but increased 14% in developing countries. Research has been sparse on the unique qualities of goat and sheep milk compared with cow milk. Much development work by various agencies has been devoted to reducing mortality and improving feed supplies in harmony with the environment; this work is mostly published in proceedings of scientific meetings, often not in English. Results have shown in many cases that dairy goats and dairy sheep can be very profitable, even in developing countries with difficult climate and topographical conditions.     

Estimating production benefits through simulation of group and individual feeding of dairy cows.

Objectives were 1) to develop DMI and milk prediction equations, 2) to use these equations to simulate group and individual feeding of dairy herds, and 3) to estimate effects of group and individual feeding on FCM production. University of New Hampshire data were used to predict DMI from previous DMI and cow and ration characteristics. The same data were used to predict milk production from DMI and previous milk production. Feeding was simulated for 100 cows over 50 4-wk periods in a number of trials. Effects of individual feeding, additional groups, herd calving intervals, and within-herd variation of annual milk production per cow on daily FCM per cow were isolated in average and high producing herds. Changing from one group to individual feeding can increase daily FCM per cow by .5 to 1.1 kg and two groups to individual feeding by 0 to .8 kg without changing total herd nutrient intake. Reallocation of the same amount of nutrients to two groups instead of one can increase daily milk production by .15 to .8 kg of FCM per cow, reallocation to three groups instead of two by 0 to .6 kg of FCM per cow, and reallocation to four groups instead of three by 0 to .35 kg of FCM per cow.     

Factors associated with profitability in pasture-based systems of milk production

The global dairy industry needs to reappraise the systems of milk production that are operated at farm level with specific focus on enhancing technical efficiency and competitiveness of the sector. The objective of this study was to quantify the factors associated with costs of production, profitability, and pasture use, and the effects of pasture use on financial performance of dairy farms using an internationally recognized representative database over an 8-yr period (2008 to 2015) on pasture-based systems. To examine the associated effects of several farm system and management variables on specific performance measures, a series of multiple regression models were developed. Factors evaluated included pasture use [kg of dry matter/ha and stocking rate (livestock units/ha)], grazing season length, breeding season length, milk recording, herd size, dairy farm size (ha), farmer age, discussion group membership, proportion of purchased feed, protein %, fat %, kg of milk fat and protein per cow, kg of milk fat and protein per hectare, and capital investment in machinery, livestock, and buildings. Multiple regression analysis demonstrated costs of production per hectare differed by year, geographical location, soil type, level of pasture use, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, breeding season length, and capital investment in machinery, livestock, and buildings per cow. The results of the analysis revealed that farm net profit per hectare was associated with pasture use per hectare, year, location, soil type, grazing season length, proportion of purchased feed, protein %, kg of fat and protein per cow, dairy farm size, and capital investment in machinery and buildings per cow. Pasture use per hectare was associated with year, location, soil type, stocking rate, dairy farm size, fat %, protein %, kg of fat and protein per cow, farmer age, capital investment in machinery and buildings per cow, breeding season length, and discussion group membership. On average, over the 8-yr period, each additional tonne of pasture dry matter used increased gross profit by €278 and net profit by €173 on dairy farms. Conversely, a 10% increase in the proportion of purchased feed in the diet resulted in a reduction in net profit per hectare by €97 and net profit by €207 per tonne of fat and protein. Results from this study, albeit in a quota limited environment, have demonstrated that the profitability of pasture-based dairy systems is significantly associated with the proportion of pasture used at the farm level, being cognizant of the levels of purchased feed.     

我国奶业发展状况与对策分析

<正> 当前,我国奶业经过连续多年高速增长后,正处于转型的关键时期。因此,深入分析我国奶业的发展形势,把握其正确的发展方向,事关整个奶业产业的生存与发展。我国奶业发展的主要特点(一)原料奶生产能力显著增强我国奶业经过10多年的超常规发展,目前已成为仅次于印