Act now for dairy cow breeding success in 2020

Act now for dairy cow breeding success in 2020

Immunity and health

Early lactation can be a period of stress for the cow, as there are several physiological and nutritional changes during this time. It is also a time when we want to ensure that she has an optimal immune status to maximise fertility. Some cows will have a higher risk of uterine infections due to retained placenta and metritis after calving. Uterine infections and ovarian problems will inevitably influence fertility.

Trace minerals, such as selenium, play a crucial role in maintaining a healthy immune system in the period around calving. Other trace minerals, such as copper, and major minerals, such as phosphorus, play critical roles in ovulation or cycling. If there is a deficiency of either, then anoestrus is a real possibility.

When we are feeding minerals, we should focus not just on the number on the bag, but also the form of those minerals. Research has proven that feeding trace minerals in an organic form, such as Alltech’s Bioplex^® Copper and Zinc and Sel-Plex^®, an organic form of selenium, have greater availability compared with inorganic forms, resulting in improved storage and utilisation by the animal. These support the cow’s body systems, especially the immune system, and aids overall cow performance. An added value of feeding Bioplex and Sel-Plex minerals is that smaller quantities of these much more biologically active trace mineral sources can be fed, reducing levels excreted in the faeces. Also, we need to be aware that not all organic minerals are the same, which means bioavailability will vary from mineral to mineral.

Research has shown that feeding organic trace minerals in the form of Bioplex and Sel-Plex increased conception rates by 7.5% (O’Donnell et al., 1995). They also reduced the age at calving for first lactation heifers by 26 days — whose dams were fed these organic trace minerals compared to dams fed a control — and increased milk yield by 1.7kg per day (Pino et al., 2015).

Important factors post-calving

The other three key pillars of your dry cow programme — body condition score (BCS), nutrition and management — apply in the eight weeks post-calving. How you manage the cow under these pillars will go a long way in deciding the success of breeding in 2020. Minimising body condition loss in early lactation and presenting cows for breeding at a minimum BCS of 2.75 will all help to improve conception rates during the breeding season. Feeding the cow to maximise dry matter intake and energy intake in early lactation can help to reduce the severity of weight loss and improve reproductive efficiency. The more milk a cow produces the more energy she must ingest to minimise negative energy balance in early lactation. Farmers should also be aware of the risk of feeding excess protein in early lactation. High levels of protein in the diet post-calving will push milk yield, but unless matched to energy intake, this milk will be produced by mobilising body reserves; hence the term “milking off the cow’s back.”

The strategy employed should be to use low-protein compounds with high-energy ingredients for grazing cows to ensure the cow is increasing BCS prior to mating, optimising reproductive performance. Management of the diet is of paramount importance and farmers should be aware of the risk of acidosis when increasing the concentrate levels in the diet and changing cows from an indoor diet straight to lush spring grass. The rumen is not designed for abrupt changes, so when cows are fed increasing levels of concentrates or are going to grass too soon or immediately after calving, difficulties can arise due to an increased acid load in the rumen. It is recommended that cows are brought in at night for the first 7–10 days after calving and presented with palatable forage to encourage rumination and allow for gradual dietary changes.

The inclusion of Yea-Sacc^® from Alltech in your dairy cows’ parlour nuts is also a feasible option to help maintain rumen pH in early lactation. The use of Yea-Sacc from Alltech has been proven to reduce the number of hours that rumen pH is below the critical level of 5.8.

Pre-breeding fertility examinations

While the breeding period is still a few months away, farmers may want to carry out pre-breeding examinations in certain cases. At a minimum, it is advisable that all cows are checked to make sure they are breeding one month before the start of breeding, and those that are not, receive pre-breeding veterinary examinations to check for residual uterine infections (endometritis). It has clearly been shown that fertility performance improves in herds where cases of endometritis are detected and successfully treated by six weeks post-calving. Similarly, the treatment of ovarian cysts and the management of the anoestrus, non-cycling cow are crucial to optimal reproductive performance. Cows that are particularly at risk of uterine infections include cows that had retained placenta and metritis after calving. Uterine infections and ovarian problems are much more prevalent in herds where the transition period was less than optimal and where significant negative energy balance occurs in the post-calving period.