Extenders for use with chilled semen

Details of the types of extenders that are used have been given earlier in this chapter. Some work has been carried out to investigate the relative efficacy of different extenders for use specifically with stored chilled semen. A similar advantage in the use of NFDSMG extender over other common extenders is evident with cooled semen as with fresh semen (Francl et al., 1987). Comparisons between skimmed milk and NFDSMG extenders supported this apparent superiority of NFDSMG, with motility rates...

Milk and milkproduct extenders

Table 7.4 gives examples of some of the extenders based on milk and milk products that are in use today. These extenders include non-fat dried skimmed milk-glucose extender (NFDSMG) or Kenney, one of the most popular diluents used in the UK (Kenney et al., 1975), along with E-Z Mixin, which is very similar in composition but is more popular in the USA. Both are classified as NFDSMG extenders and are commonly used for extending semen prior to storage, but also for evaluation, as they are...

Storage temperature

The final storage temperature is known to have an effect on subsequent fertility. Semen is commonly cooled to between 4 and 5 C, though for short-term storage it may be cooled to room temperature (20 C). Good results have been achieved with semen stored for 12-24 h at 20 C (Province et al., 1985 Francl et al., 1987). As might be expected, the lower the temperature, the lower is the depression in metabolic rate and, therefore, the longer the preservation of spermatozoan viability. However,...

Methods of transportation

If the advantages of chilling semen are to be fully realized, then an effective means of storage and transportation while still maintaining a cool environment needs to be devised. Several containers have been designed in an attempt to satisfy this requirement. The one in most widespread use is the Equitainer (Hamilton-Thorn Research, Danvers, Massachusetts) (Figs 7.2 and 7.3). Fig. 7.2. The Equitainer, a common method of cooling and transporting cooled semen, fully assembled and ready for use....

Packaging for frozen semen

Ampule Method Semen Storing

Several methods are available for the packaging of spermatozoa for freezing. They include glass ampoules or vials (Fig. 7.4) polypropylene, polyvinyl or plastic round or flat straws (usually 0.5-1.0 ml in volume) (Fig. 7.5), flat aluminium packets (10-15 ml) pellets (0.1-0.2 ml) and macrotubes (Merkt et al., 1975b Loomis et al., 1984 Amann et al., 1987 Blach et al., 1989 Haard and Haard, 1991 Piao and Wang, 1988). In initial work, semen was frozen in glass ampoules or vials with a volume of...

Creamgel extenders

Table 7.5 gives some examples of cream and gel extenders in use today. The addition of gelatin to an extender is thought to act as a membrane stabilizer. Work by Householder et al. (1981), comparing skimmed milk with skimmed milk plus gelatin, demonstrated an advantage with gelatin pregnancy rates of 43.8 and 62.5 , respectively, were obtained. Previous work by Pickett et al. (1975a) had indicated a similar advantage for cream-gel extenders over raw semen. The pregnancy rates reported were...

Chilled Semen

In order to extend the time span of the viability of spermatozoa, their metabolic rate has to be slowed down, so reducing the rate at which the substrates within the surrounding extender are used and the rate at which toxins are produced. As a general rule the metabolic rate of cells (and, therefore, spermatozoa) can be reduced by cooling, though carbon dioxide and other metabolic inhibitors, such as proteinase inhibitors, have been used to produce a similar but less successful effect on...

Extenders for use with frozen semen

Many of the extenders used for the cryopreservation of stallion semen are based upon those used for cool storage, as detailed earlier, but with the addition of cryoprotectants. Initially, heated whole cow's milk plus 10 glucose was used as an extender for freezing stallion semen. In fact this extender was used to store the semen that resulted in the first pregnancy, in a mare, as a result of AI with frozen semen (Barker and Gandier, 1957). Out of the seven mares inseminated, one pregnancy...

TRIS extenders

One of the major problems encountered in storing semen is the accumulation of metabolic by-products, or waste, which subsequently have an adverse or toxic effect on spermatozoa. Buffers have been used in an attempt to counteract this. The most popular buffer used in equine semen extenders is tris hydroxymethyl -aminomethane TRIS . Table 7.6 gives an example of an extender based on TRIS. In common with TES A-tris hydroxymethyl methyl-2-aminomethane-sulphonic acid , MES 2- A-morpholino...

Extenders

Regardless of the method of storage, semen should be mixed with an appropriate extender immediately post collection. Some systems allow for the semen to be added directly to the extender within the collection vessel of the artificial vagina. The composition of extenders varies enormously, but they are normally based upon milk or egg yolk products plus antibiotics. The exact components of the extender will vary with the method of storage and possibly between stallions, but the same basic...

EKenneys modified Tyrodes extender jaz and Ducharme 1995

Sodium penicillin 150,000 units Distilled water made up to 100 ml Add 65 of the above Kenney extender to 35 v v Tyrode's medium Table 7.4. Milk and milk-product-based extenders in use today continued . Table 7.4. Milk and milk-product-based extenders in use today continued . Bovine serum albumin fatty acid free BSAAFF f Non-fortified skimmed milk extender Varner and Schumacher, 1991 Heat the milk to 92-95 C for 10 min in a double boiler cool, and add the polymixin B sulphate. pH adjusted to...

Removal of seminal plasma

The components and function of seminal plasma have been discussed at some length in Chapter 4. In summary, seminal plasma has several functions it modifies spermatozoa to allow progressive motility during ejaculation and within the female tract it acts as a transport medium providing metabolic substrates to maintain the viability of spermatozoa up to the time of fertilization and finally, due to its volume, it increases the chance of even distribution of spermatozoa within the uterine body and...

Other major components within extenders

The four main types of extender for use with stallion semen have been considered. However, much work has been carried out on the addition of other components to improve what are still relatively poor and very variable conception rates. This section will consider some of the other types of extenders used and the components included. The inclusion of citric acid in an extender for stallion semen is relatively common. It acts like a buffer, in a similar way to TRIS. However, it also acts as an...