Summarize the following:
You can apply tags shortly after birth, during the calf's weaning period, or around the time that you begin branding young or fully-grown cows. The time that you choose will depend mostly on how operations are carried out on your farm or ranch. For some, tagging calves at birth may make it easier to keep up with them as they grow. Others may prefer not to bother with it until a cow is headed for auction. If you'd rather not take on the task of tagging yourself, the officials at the feedlot or auction will usually be more than happy to do it for you. Some experienced ranchers recommend holding off on tagging until the calf no longer needs its mother's milk. Attempting to tag a newborn calf could disrupt its bond with its mother. In order to tag a fully grown steer or heifer, it will first be necessary to safely restrict its movement. Attach a halter or nose ring to the cow and guide it into the chute. Once it's inside, tie the lead rope to 1 side of the gate tight enough to keep the cow from moving its head more than a couple inches (about 2.5-5 cm). A head gate typically isn't necessary for securing young calves. Simply lay the calf down on its side and hold it firmly yet gently. It may help to have an assistant on hand to help hold the calf still. Erratic movement could increase the risk of injury to either you or the cow, or result in a botched tagging that must be repeated. The tagging process will go much smoother for both of you if your subject is calm. Ease the cow's nerves by petting it and speaking to it in a soothing voice. Stroking its ears will also help it get used to having them handled. The cow will be less likely to struggle if it doesn't feel afraid. Find a soft spot somewhere in the middle portion of the ear between the upper and lower cartilage. The fleshy part of the ear will provide optimum visibility, offer the least resistance, and result in the least amount of discomfort to the cow. Always keep your tagging equipment a safe distance away from the ear canal or surrounding cartilage.

summary: Determine the best time to tag your cattle. Use a chute with a head gate to secure the cow. Make sure the cow is relaxed. Locate a suitable tagging site on the cow's ear.

Summarize the following:
The standard equation for absorbance is A = x l x c, where A is the amount of light absorbed by the sample for a given wavelength, is the molar absorptivity, l is the distance that the light travels through the solution, and c is the concentration of the absorbing species per unit volume. Absorbance can also be calculated using the ratio between the intensity of a reference sample and the unknown sample. It is given by the equation A = log10(Io/I). Intensity is obtained using a spectrophotometer. The absorbance of a solution will change based on the wavelength that is passed through the solution. Some wavelengths will be absorbed more than others depending upon the makeup of the solution. Remember to state which wavelength is being used for your calculation. Using algebra we can divide absorbance by the length and the concentration to get molar absorptivity on one side of the equation: = A/lc. We can now use this basic equation to calculate molar absorptivity for a given wavelength. Absorbance between readings can vary due to the concentration of the solution and the shape of the container used to measure intensity. Molar absorptivity compensates for these variations. A spectrophotometer is a piece of equipment that passes a specific wavelength of light through a substance and detects the amount of light that comes out. Some of the light will be absorbed by the solution and the remaining light that passes through can be used to calculate the absorbance of that solution. Prepare a solution of known concentration, c, for analysis. Units for concentration are molar or moles/liter. To find l, measure the length of the cuvette, the piece that holds the liquid samples in the spectrophotometer. Units for path length are measured in centimeters. Using a spectrophotometer, obtain a measurement for absorbance, A, at a given wavelength. The unit for wavelength is meters, but most wavelengths are so small, they are actually measured in nanometers (nm). Absorbance has no units. Using the values you obtained for A, c, and l, plug them into the equation = A/lc. Multiply l by c and then divide A by the product to solve for molar absorptivity. For example: Using a cuvette with a length of 1 cm, you measured the absorbance of a solution with a concentration of 0.05 mol/L. The absorbance at a wavelength of 280 nm was 1.5. What is the molar absorptivity of this solution? 280 = A/lc = 1.5/(1 x 0.05) = 30 L mol-1 cm-1
summary: Understand the Beer-Lambert law for absorbance, A = x l x c. Rearrange the Beer-Lambert equation to solve for molar absorptivity. Obtain values for the variables in the equation using spectrophotometry. Plug in the values for the variables and solve the equation for molar absorptivity.