The failure to detect heat is a common and costly problem of artificial insemination (AI) programs and a major limiting factor of reproductive performance on many dairies (Nebel and Jobst, 1998). Consequently, a successful AI program must begin with efficient and accurate heat detection. Other critical factors related to a successful AI program include appropriate semen handling, site of semen deposition in the female reproductive tract, and timely AI relative to ovulation.
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Matthew Lucy1 and Joseph Dalton2
1University of Missouri, Columbia, MO
2University of Idaho, Caldwell, ID
Artificial insemination (AI) has been integral in reducing disease transmission, allowing for genetic selection, and increasing the milk yield of dairy cattle. To help dairy producers, veterinarians, and industry professionals make informed decisions related to synchronization protocols to facilitate AI, the Dairy Cattle Reproduction Council (DCRC) has created a dairy cattle synchronization protocol sheet. The protocol sheet was …
Depressed reproductive function during heat stress is one of the most difficult problems to solve on the dairy. Cows exposed to heat stress suffer from two problems that together make it very difficult to breed back cows quickly after calving. First, expression of estrus is reduced. In one study in Florida, 75% to 80% of the expected heats in the summer were not detected (Thatcher and Collier, 1986). Second, the proportion of cows inseminated that conceive and maintain pregnancy …
In English: Economics of Heat Stress: Implications for Management
Prácticamente todo el sur de los Estados Unidos y las áreas cerca del ecuador están sujetas a periodos extendidos de climas cálidos que causan estrés en la vaca lechera en lactancia. Las vacas poseen zonas óptimas de temperatura dentro de la cual no hay un gasto adicional de energía por encima del mantenimiento para calentar o enfriar el cuerpo (West, 2003). Esta zona termo-neutral para el ganado lechero se ha …
en Español: Estrategias de Enfriamiento Durante el Estrés por Calor
Heat stress can be considered as the sum of all the forces acting on the cow to increase body temperature above normal limits. It is difficult for a dairy cow in a hot environment to meet her full potential for either milk yield or fertility. The physiological adjustments the cow makes to prevent body temperature from rising during heat stress help prevent death from heat stroke but also reduce …
en Español: Estrategias para Mejorar la Reproducción Durante el Verano
- Heat stress can occur nearly everywhere, but its duration varies among locations.
- Heat stress can negatively affect all aspects of reproduction. These effects can occur within days.
- Heat stress increases embryo loss and reduces estrous expression, embryo quality and size, endocrine hormones, and immune function. These effects can occur within days.
- Heat stress reduces sperm quantity and quality. Using AI versus bulls may improve the number of pregnant
en Español: La Economía del Estrés por Calor: Implicaciones para el Manejo
Virtually the entire southern United States and areas closer to the equator are subject to extended periods of hot weather which stresses the lactating dairy cow. Cows have optimal temperature zones within which no additional energy above maintenance is expended to heat or cool the body (West, 2003). This thermo-neutral zone for dairy cattle is estimated to be from 32° to 68°F with an upper critical air …