http://hdl.handle.net/2097/6605 2013-05-21T15:12:36Z 2013-05-21T15:12:36Z Stevenson, J.S. Carmill, J.A. Zarkouny, S.E. Hensley, B.A. http://hdl.handle.net/2097/6791 2010-12-03T21:44:06Z 2010-12-03T00:00:00Z

Embryo survival in lactating dairy cows Stevenson, J.S.; Carmill, J.A.; Zarkouny, S.E.; Hensley, B.A. Rates of embryo survival in lactating dairy cows were assessed in three separate studies. Based on pregnancy diagnoses 27 to 29 days after timed inseminations, survival to days 40 to 50 or day 57, depending on the study, varied from 9 to 88% in cows that were not cycling before insemination compared to 57 to 90% in cows that were cycling. Previously anestrous cows had lower rates of survival. In one study, supplementing cows with progesterone before insemination improved embryo survival.

2010-12-03T00:00:00Z Stevenson, J.S. Cartmill, J.A. Zarkouny, S.E. Hensley http://hdl.handle.net/2097/6790 2010-12-03T21:42:42Z 2010-12-03T00:00:00Z

Anestrus in lactating dairy cows before ovulation synchronization Stevenson, J.S.; Cartmill, J.A.; Zarkouny, S.E.; Hensley The incidence of anestrus in dairy cattle prior to first inseminations carried out after a minimum of 60 days postpartum ranged from 4 to 58% in first-lactation cows and 14 to 50% in older cows. Dairy cows with more days in milk, older than 2 years, and in better body condition (probably reflective of greater postpartum dry matter intakes) were more likely to cycle than thinner cows. Cows that were not cycling before the first week of insemination conceived at lower rates and took longer to become pregnant.

2010-12-03T00:00:00Z Smith, J.F. Harner, J.P. Brouk, M.J. http://hdl.handle.net/2097/6787 2010-12-03T21:41:58Z 2010-12-03T00:00:00Z

Keeping cows cool Smith, J.F.; Harner, J.P.; Brouk, M.J. Heat stress occurs when a dairy cow’s internal heat load is greater than her capacity to lose unwanted heat to the environment. Effects of heat stress include: increased respiration rate, increased water intake, increased sweating, decreased dry matter intake, slower rate of feed passage, decreased blood flow to internal organs, decreased milk production, and poor reproductive performance. Lower milk production and reproductive performance cause economic losses to dairy producers. The ordered priorities for reducing heat are: increasing water availability; providing shade in the housing areas (both dry and lactating cows) and holding pen; reducing walking distance to the parlor; reducing time in the holding pen; improving holding pen ventilation and freestall ventilation; adding cooling for the holding pen and exit lane; cooling close-up cows (3 wk before calving); cooling housing for fresh and earlylactation cows; and cooling housing for midand late-lactation cows.

2010-12-03T00:00:00Z Brouk, M.J. Smith, J.F. http://hdl.handle.net/2097/6755 2010-12-01T22:45:22Z 2010-12-01T00:00:00Z

Factors affecting dry matter intake by lactating dairy cows Brouk, M.J.; Smith, J.F. Feed intake is the single most critical factor of dairy production, and performance of dairy cattle can be enhanced or hindered by environmental factors that affect it. These environmental factors can by divided into physical and climatic conditions. On modern dairies, the physical factors may be of more concern. Modern facilities provide the cow with protection from the natural elements. However, these same facilities can enhance or hinder dry matter intake. Facilities should provide adequate access to feed and water, a comfortable resting area, and adequate protection from the natural elements. Critical areas of facility design related to feed intake include access to feed and water, stall design and surface, supplemental lighting, ventilation, and cow cooling. The total system should function to enhance cow comfort and intake. It is important to remember that choices made during construction of a facility will affect the performance of animals for the life of the facility, which is generally 20 to 30 yr. Producers, bankers, and consultants too often view the additional cost of cow comfort from the standpoint of initial investment rather than long-term benefit.

2010-12-01T00:00:00Z