Review: Perspective on high-performing dairy cows and herds.

Milk and dairy products provide highly sustainable concentrations of essential amino acids and other required nutrients for humans; however, amount of milk currently produced per dairy cow globally is inadequate to meet future needs. Higher performing dairy cows and herds produce more milk with less environmental impact per kg than lower performing cows and herds. In 2018, 15.4% of the world's dairy cows produced 45.4% of the world's dairy cow milk, reflecting the global contribution of high-performing cows and herds. In high-performing herds, genomic evaluations are utilized for multiple trait selection, welfare is monitored by remote sensing, rations are formulated at micronutrient levels, health care is focused on prevention and reproduction is managed with precision. Higher performing herds require more inputs and generate more waste products per cow, thus innovations in environmental management on such farms are essential for lowering environmental impacts. Our focus is to provide perspectives on technologies and practices that contribute most to sustainable production of milk from high-performing dairy cows and herds.

Invited review: Learning from the future-A vision for dairy farms and cows in 2067.

The world's population will reach 10.4 billion in 2067, with 81% residing in Africa or Asia. Arable land available for food production will decrease to 0.15 ha per person. Temperature will increase in tropical and temperate zones, especially in the Northern Hemisphere, and this will push growing seasons and dairy farming away from arid areas and into more northern latitudes. Dairy consumption will increase because it provides essential nutrients more efficiently than many other agricultural systems. Dairy farming will become modernized in developing countries and milk production per cow will increase, doubling in countries with advanced dairying systems. Profitability of dairy farms will be the key to their sustainability. Genetic improvements will include emphasis on the coding genome and associated noncoding epigenome of cattle, and on microbiomes of dairy cattle and farmsteads. Farm sizes will increase and there will be greater lateral integration of housing and management of dairy cattle of different ages and production stages. Integrated sensors, robotics, and automation will replace much of the manual labor on farms. Managing the epigenome and microbiome will become part of routine herd management. Innovations in dairy facilities will improve the health of cows and permit expression of natural behaviors. Herds will be viewed as superorganisms, and studies of herds as observational units will lead to improvements in productivity, health, and well-being of dairy cattle, and improve the agroecology and sustainability of dairy farms. Dairy farmers in 2067 will meet the world's needs for essential nutrients by adopting technologies and practices that provide improved cow health and longevity, profitable dairy farms, and sustainable agriculture.

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.

Growth, nutrient utilization, and body composition of dairy calves fed milk replacers containing different amounts of protein.

Male Holstein calves < 1 wk of age were allowed a 2-wk adaptation period after purchase, and then were blocked by BW and assigned randomly within block to either a baseline slaughter group or one of four experimental groups (n = 8 to 9 per group). Treatments were isocaloric milk replacers (12.5% solids) fed at 12% of BW that contained 16.1, 18.5, 22.9, or 25.8% CP (DM basis) from whey protein sources. After a 6-wk feeding period, all calves were slaughtered and the weights and chemical composition of the viscera-free carcasses (VFC; including head, hide, feet, and tail) were determined. Gain of BW (0.38, 0.45, 0.56, and 0.62 kg/d) and gain:feed ratio (0.51, 0.59, 0.71, and 0.78) increased linearly (P < 0.001) as dietary CP increased; rate of change in body length, wither height, and heart girth also increased linearly (P < or = 0.05). Balance measurements conducted during wk 3 and 4 of the experimental period showed that both absorbed N (16.9, 20.0, 25.8, and 30.6 g/d) and retained N (7.6, 9.0, 13.2, and 15.6 g/d) increased linearly (P < 0.001) as dietary CP increased. Retained N as a percentage of absorbed N increased linearly (P < 0.01) as dietary CP increased (44.3, 44.7, 50.7, and 50.9%), whereas biological value was unaffected (71.1, 68.7, 69.5, and 67.3%; P = 0.26). Digestible energy and ME represented 94.5 and 89.7% of intake energy, respectively, and were not affected by dietary CP content. Plasma urea N concentration increased linearly (2.9, 3.3, 4.6, and 6.0 mg/dL) as dietary CP increased. Contents of water (68.2, 69.1, 70.2, and 70.5%; P < 0.001) and protein (19.6, 20.0, 20.0, and 20.2%; P < 0.10) in VFC increased linearly, whereas contents of fat (7.2, 6.2, 5.5, and 5.2%; P < 0.001) and ash (5.1, 5.2, 4.8, and 4.7%; P < 0.02) decreased linearly as dietary CP increased. Trends in visceral tissue composition were similar to those for VFC. The content of water in VFC tissue gain increased, whereas contents of fat and energy decreased, as dietary CP increased. Final VFC energy and gain of energy in VFC were not affected by dietary CP. At similar initial ME intakes, increasing dietary CP (i.e., increasing protein: energy) linearly increased ADG, gain:feed, N retention, and deposition of lean tissue in VFC, demonstrating that diet composition can markedly affect components of body growth in preruminant dairy calves.

Keeping extension programs current in order to meet the needs of a dynamic dairy industry.

Extension is one of three missions of land-grant colleges. Funding and support include local, state, and federal dollars plus industry support, competitive grants, and user fees. To evaluate changes and emphasis, a survey of 13 selected dairy states was conducted to evaluate changes in dairy full-time equivalents (FTE) in the last 10 yr (1989 compared with 1999) at county or unit, regional, and state levels. A reduction of 5 to 34% in FTE occurred at all three levels. Surveys of dairy support state specialists in other related departments were also collected from the 13 states based on 1999 data. Wide ranges in state specialist support in other departments were reported. Changes and future program needs were collected from a 13-state survey. Two futuristic dairy information delivery programs are illustrated. The Illinois extramural CD-ROM-based instructional program used existing technologies to reach broad clientele bases, allowed students to receive instruction when time was available and earn college credit. The National Dairy Database (NDD) is an Internet-based delivered program with 23 domain areas that contained peer reviewed material. Users can access the new NDD by subscribing to an Internet address (which will be updated as new material is received) or by purchasing a CD-ROM.

Effects of yeast culture (Saccharomyces cerevisiae) on prepartum intake and postpartum intake and milk production of Jersey cows.

Yeast cultures (Saccharomyces cerevisiae; YC) have been added to diets for dry and lactating dairy cows to attempt to improve ruminal fermentation, potentially increasing dry matter intake (DMI) and milk yield. Jersey cows (14 primigravid and 25 multigravid) were fed total mixed rations prepartum and postpartum that were either supplemented or not supplemented with YC. The YC was a dried product that was top-dressed at 60 g/d for approximately 21 d prepartum and 140 d postpartum. The DMI was increased by YC during both the last 7 d prepartum (9.8 vs. 7.7 kg) and during the first 42 d of lactation (13.7 vs. 11.9 kg). The treatment-by-day interaction was significant for DMI during the first 21 d postpartum, indicating that cows supplemented with YC increased DMI more rapidly than did nonsupplemented cows. A significant treatment-by-day interaction indicated that cows supplemented with YC lost body weight less rapidly postpartum than did non-supplemented cows. A significant interaction of treatment by day indicated that cows supplemented with YC reached peak milk production more quickly than did nonsupplemented cows. However, total milk produced during the first 140 d of lactation did not differ. Concentrations of fat, protein, lactose, total solids, and urea N in milk, as well as somatic cell count, were not significantly affected by YC. Supplementation of YC increased DMI during the transition period and increased DMI postpartum.

Feed additives.

Feed additives used to supplement dairy rations can increase daily feed cost from 2 to 65 per animal. The economic response (benefit to cost ratio) varies from $2.00 to $12.00 for each dollar invested in a specific additive. Knowledgeable dairy veterinarians must understand the role of each additive, when it will be beneficial, inclusion level, strategies and limitations associated with an additive, research and field recommendations, and measurable responses to monitor. Dairy additives and various methods to evaluate their role and economic response objectively are discussed.

Feeding supplemental niacin for milk production in six dairy herds.

Six dairy farms representing 300 lactating dairy cows were used to assess effects of feeding 6 g of supplemental niacin during the first 10 wk of lactation. Means for niacin and control cows for 10 wk postpartum were 31.2 and 31.1 kg/day milk, 3.7 and 3.6% milk fat, and 30.3 and 30.2 kg/day 4% fat-corrected milk. A scoring system with 1 to 5 scale was utilized to measure body condition of dairy cows at parturition. Average body condition score for niacin and control cows at calving was 3.1. High producing heifers in first lactation receiving niacin (greater than 28 kg/day of milk) produced more milk than controls (31.8 compared to 30.2 kg/day). Thin cows (body condition score 2) receiving niacin produced less milk than controls with a body condition score of 2 (27.0 compared to 30.7 kg/day). Analyzing body condition scores 3 and 4 revealed no difference of milk production for niacin and control groups; however, milk production increased as scores for body condition increased.

Breeding practices on Illinois Holstein farms.

Questionnaires requesting breeding information were mailed to 1,148 Illinois Holstein herds in the Dairy Herd Improvement program. A total of 591 questionnaires (51%) were returned. Dairy producers with herds producing over 7,100 kg of milk returned 64% of their questionnaires whereas 34% of dairy producers with herds producing less than 5,900 kg returned their questionnaires. State average and standard errors were: 23 +/- 1 bulls used per 100 cows, 78 +/- 2% dairy producers select the bulls, 96 +/- 1% herds use artificial insemination, 2.1 +/- .1 artificial insemination organizations per herd, 29 +/- 2% herds participate in young sire testing programs, 87 +/- 1% farmers consider calving ease indicators in mating heifers, and 17 +/- 2% farmers consider calving ease indicators in mating cows. Breeding practices positively associated with increasing rolling herd average milk production were number of bulls per herd and per 100 cows, self as bull selector, use of artificial insemination, number of artificial insemination organizations, and participation in young sire testing programs. Three breeding practices were negatively associated with increasing rolling herd average milk production: artificial-insemination technician as bull selector and consideration of calving ease for mating heifers and cows. Dairy producers also were asked to rate the emphasis placed on traits in bull and cow selection. For bull selection, udder conformation and Predicted Difference milk were most important. In cow selection, milk production, followed by udder conformation, feet and legs, and fat percentage, was the most important trait.