Across the country, I am seeing dairy cows grazing grass by day and on some farms cows are out by day and night. I am delighted to say that in the majority of cases these cows are looking quite well in regard to optimum body condition score (BCS) with a good metabolic and health status. The transition from non-lactating to lactating can be a stressful time for dairy cows and correct specific management must be the priority here.
Preventing Against a Negative Energy Balance
It is important to monitor dry matter (DM) intake of cows in all stages of lactation so cows do not suffer from negative energy balance (NEB) particularly in early lactation as this is when fertility issues can start to take hold.
High DM intake and an increased ratio of sugar-based feed based ingredients (beet pulp) are associated with good responses to reproductive performance. It is important to note that as the cow approaches calving they endure a reduced intake of between 25-40%, therefore it is important to offer pre-calving cows a higher energy dense diet three weeks from calving.
The hormonal changes prior to calving effect appetite and thereby reduce feed intake shortly before calving. The decrease in feed intake combined with the initiation of lactation and production of colostrum starts a period of NEB, this period must be minimised to offset the degree of mobilisation.
Approximately 33% of cows in each herd suffer a higher degree of mobilisation. When you compare them to the other 77% within the herd that mobilise less, they have a shorter severity of negative energy balance and hence less body condition loss. A greater degree of NEB will lead to more problems such as suppression of the immune system, uterine infection, mammary infections all due to a lower count of white blood cells and higher somatic cell count. Infectious disease post calving can also have a significant effect on fertility, for instance hypocalcaemia (milk fever), retained placenta, difficult calving etc.
Balancing the Diet Appropriately
In terms of dietary support, it is important that sufficient energy is provided matched to the milk yield and genetics of the specific cow. An imbalance of energy or too much protein will have a negative impact on reproductive performance, excessive amount of rumen degradable protein delays first ovulation or oestrus, reduced conception rate to first service. The cow will have to mobilise excessive protein, thereby using up energy in disposing of it.
It cows are already in NEB the problem is exacerbated with more ammonia and urea produced thereby having negative effects on oocyte and embryo development. Altered pH is the biggest challenge in dairy diets, following calving as acidosis is never too far away.
It is important that sufficient minerals are offered post-calving. Pay particular attention to key trace elements to include magnesium, phosphorus, sodium, iodine, selenium. Don’t forget about vitamins noting it is very important to have elevated levels of vitamin E to boost immunity and vitamin A & D.
In summary, dry matter intake, protein, and energy requirements together with an appropriate mineral balance will be crucial to the reproductive performance of the herd. The key will be to balance the diet to the type of cow you have on each specific farm.
At Connolly Red Mills we have tailored feeds to offset some of the associated problems I have mentioned and to have an overall successful breeding programme please contact any member of the nutrition team.