Late Summer Temperatures Shorten Gestation Length Of Fall-Calvers Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist July 29, 2019 10:39 AM

Each year in late July or August, it is time for an important reminder.  Fall-calving season will soon be here.  In fact, the start of the fall calving season often begins before some producers expect it.  The target date for the beginning of fall calving very often is September 1.  Most printed gestation tables predict that calving will take place 283 days (some 285 days) after artificial insemination or natural breeding.  Cows and heifers that gestate in hot weather will often calve a few days earlier than expected.
Oklahoma State University physiologists studied early fall (August) and late fall (October) calving cows. Data from two successive years were combined for 60 Angus X Hereford crossbred cows. The “early” and “late” fall calving cows had been artificially inseminated in early November or early January, respectively. Semen from the same sire was used for all cows. All cows were exposed to a single cleanup bull for 35 days at 4 days after the AI season. The weather prior to calving was significantly different for late pregnancy in the two groups.
The average maximum temperature the week before calving was 93 degrees F. for the “early” fall group. The average maximum temperature the week before parturition in the “late” calving group was 66 degrees F. There was a 100% survival rate for calves in both groups and both groups of cows had very high re-breeding rates (90% and 92%, respectively).
The average gestation length for the “early” cows was 6 days shorter (279 days) as compared to the “late” cows (285 days) in year 1. The average gestation length for the “early” cows was 4 days shorter (278 days) as compared to the “late” cows (282 days) in year 2.  Keep in mind that the gestation lengths listed are AVERAGE.  This means that about half of the cows calved earlier than that.  Records from millions of Holstein dairy cows across the entire United States report a similar pattern (Norman, et al.2009 J. Dairy Sci; 92:5).  Holsteins bred in January and February (calving in October and November) averaged 2 days longer gestation than did Holstein cows bred in October (calving in July and August).
Many of these would be in Northern climates with less heat stress and more moderate temperatures in the summer months.  Here in the Southern Plains, late summer heat is more intense and persistent.  Therefore, producers with early fall-calving cows should expect calves to start coming several days ahead of the “textbook gestation table” dates. They should begin their routine heifer and cow checks at least a week to 10 days ahead of the expected first calving date. Source: Kastner, et al. 2004 OSU Animal Science Research Report.

Keeping Your Vaccines Viable Taylor Grussing And Tracey Erickson, South Dakota State University Extension July 24, 2019 09:13 AM

 

 

There are multiple factors influencing immunity, including but not limited to, medical history, vaccine type, method of administration, age, and species being vaccinated. ( Pirbright Institute )

Vaccines are a vital part of keeping all livestock healthy. Vaccines help in the prevention of disease, which results in less utilization of antibiotics due to fewer sick animals. Vaccines provide protective immunity approximately 21 days following the initial vaccination in the majority of livestock. Some vaccines may require a booster vaccination(s) to ensure immunity for the period designated by the manufacturer. There are multiple factors influencing immunity, including but not limited to, medical history, vaccine type, method of administration, age, and species being vaccinated. A valid Vet-Client-Patient relationship will help you as you select the vaccine of choice for your livestock health program.

Vaccine Types

You are probably utilizing one of two types of vaccines: inactivated (“killed”) vaccines, which contain bacteria or viruses that have been inactivated by heat or chemicals, or modified-live virus (MLV) vaccines, which contain whole viruses that have been altered in such a way that, while they are able to multiply within the body, their ability to cause disease has been taken away.
So how do vaccines become worthless? Proteins are the major components of the organisms that make up both killed and MLV vaccines. Proteins are denatured by the interaction of two major factors: time and temperature. In addition, most common disinfectants will render modified live organisms inactive. So the anti-bacterial soap or even city or rural water, which contains chlorine, can have an effect on vaccines, when residues are present in your syringes or transfer needles. Thus, rinse with distilled water which is near the boiling point.

Things to Consider

Other considerations for handling, storing and using vaccines are as follows:

PURCHASING AND USE CONSIDERATIONS OF VACCINES

Check expiration dates and make sure you can use it before it expires. For MLV vaccines purchase smaller dose instead of larger dose vials, which will enable using the vaccine in a shorter time period. Also remember to purchase an adequate number of needles and plan on replacing the needle about every 5-10 head of cattle. Do not straighten a bent needle, replace it!

TRANSPORTING AND STORING VACCINES

Check the recommended storage temperature, and use a cooler while transporting and while vaccinating to keep the vaccine at the recommended temperature and also to minimize exposure to sunlight. Typically this temperature is between 35 degrees to 45 degrees F unless the product label advises otherwise. Check your refrigerator’s temperature periodically to assure that it is working properly and is keeping the vaccines at the correct temperature.

EQUIPMENT AND WORK AREA

Make sure your equipment is clean and rinsed with distilled water to remove any residues. Set up an area for syringes such that they are kept cool, shaded, and dust-free while working.

WHILE WORKING

Keep vaccines in a cooler with ice packs in summer or possibly hot packs in winter if it is too cold. (Check vaccine labels for proper storage temperature.) Don’t mix more MLV vaccine than can be used in 30 minutes. If using MLV vaccines, only rehydrate the vials either one at a time or as they are needed. Make sure you are using a clean transfer needle and use only the diluent supplied by the manufacturer to rehydrate the vaccine. Always use a brand-new needle to draw up the vaccine into the syringe. When using needle-free injection systems, or syringes that draw doses from a tube attached to the vaccine bottle, care should be taken to assure the bottle and tubing stay cool and shaded from sunlight.

NO JOB IS DONE ‘TIL THE CLEAN-UP

Discard any mixed MLV vaccines that are not used, as they are only viable for about an hour or two after reconstitution. Discard any partial bottles of inactivated vaccine that have been contaminated by dirty needles. Return unmixed MLV and unused inactivated vaccines to proper storage as soon as possible. Clean syringes, transfer needles, and tubing. Make sure to rinse with distilled, boiling water inside and out. Follow the manufacturer’s directions on proper cleaning and maintenance of needle-free injection systems. Burn empty vaccine bottles or follow label directions for disposal of containers and needles.

The Bottom Line

The success of any livestock vaccination program depends on the effectiveness of the vaccine used. Vaccines-which in essence are suspensions of biological organisms – will become ineffective if proper storage and handling recommendations are not followed. Thus, if they are not followed you have in essence wasted a lot of money and time and have increased the potential for livestock illness and death loss due to disease that might have been avoided.
Sources:
Daly, R., Price, A. (March, 2010). Livestock Vaccines: How They Work and How to Ensure They Do Their Job. ExEx11025. SDSU Extension Extra. Brookings, SD.
Williams, P. D., & Paixão, G. (2018). On-farm storage of livestock vaccines may be a risk to vaccine efficacy: a study of the performance of on-farm refrigerators to maintain the correct storage temperature. BMC veterinary research, 14(1), 136. doi:10.1186/s12917-018-1450-z