Cow fertility remains an area of concern for many dairy farmers. Sometimes cows can be physically full but still need extra energy to encourage cycling activity. Bypass fats are an effective way to improve reproductive performance, but not all fats are equal.
Bypass fats come in many different forms. They can differ in energy content from 29 to 37 Megajoules of Metabolisable Energy (MJME) per kg Dry Matter (DM), fat concentration from 84 to 99 percent fat, digestibility from 80 to 95 percent and C18 content from 5 to 45 percent. Therefore, it is important to look further than just the cost per tonne and evaluate what specific purpose you are using bypass fats for.
Some bypass fats are more effective at reducing body condition loss. This is due to the types of fats that are contained within them. In cows, most body fat is stored in the form of C18:1. Feeding a bypass fat that is rich in C18 fats can send a signal to fat tissue that body condition doesn’t need to be mobilised. Therefore, C18 rich bypass fats such as GoldenFlake® can assist in reducing body condition loss and help encourage cycling activity.
Minimising body condition loss post-calving is one of the most effective strategies to support cycling activity. ‘How far she drops’ is more important than the absolute Body Condition Score (BCS) she is pre-mating. At mating, if two cows both have a BCS of 4.0, the cow that has fallen from a 4.5 BCS at calving has a significantly better chance of getting in calf than a cow that has fallen from 5.5 BCS. Trial work by Butler et al (1989)¹ showed an 18.5 percent better conception rate on cows that lose less than 0.5 BCS versus those cows losing 1 BCS in early lactation. The DairyNZ In Calf data² also shows this effect on both the six week in calf rate and empty rates.
Along with its high C18 fat content, GoldenFlake® can help provide a ‘rising plane of nutrition’ by providing 37 MJME per kg. This concentrated energy means that 250 g of GoldenFlake provides the same energy as nearly 850 g of Palm Kernel. Not only does this energy help reduce body condition loss, it also assists in driving milk production.
Hardened bypass fats like GoldenFlake are palatable and do not interfere with the rumen as the fats are protected from rumen microbes and are digested later in the intestine. Hardened bypass fats do not interact with other feeds in the diet. This allows for an increase in the feed rate during times of poor weather or when an additional energy boost is needed (colostrum cows or lighter weighing cows).
To discuss the suitability of feeding your cows GoldenFlake® for improved reproductive performance, talk to your local PGG Wrightson Technical Field Representative today.
¹Butler W.R., Smith R,D. (1989). Interrelationships between energy balance and postpartum reproductive function in dairy cattle. Journal of Dairy Science 72(3) 767-783.
²DairyNZ In Calf Tool. www.dairynz.co.nz.