Fertility Protocol

Fertility is perhaps the most vexing problem dairy farmers face: and for many, possibly the most costly. Vexing; because it is the most multifaceted issue in dairy production. Fertility is ranked equal with feed intake as a driver of profit.

So where does good fertility start? Day of birth! Colostrum is now known to contain substances that ‘switch’ genes on. Poor quality colostrum will leave a heifer calf with a lifelong legacy on many fronts – growth, immunity, production and fertility. Early nutrition follows, as our calf article for May highlights: “Negative energy balance in new born calves”. Next is consistent nutrition through all seasons, especially summer, to ensure consistent weight gain, and well-fortified with supplementary mineral nutrition. For maiden heifers, nutrition is the major influence to fertility.

Shifting now to lactating cows, the first step is dry cow nutrition, particularly calcium intakes. Dry cow nutrition too often is survival in the back paddock or out-block, with no supervision of energy, fibre or protein intakes; let alone minerals. As above, calcium intakes especially during the dry phase are hopelessly inadequate in a ryegrass based diet. The calcium deficiency in dry cow nutrition we are addressing with a high calcium inclusion self-feed loose-lick preparation based on our heifer loose-lick mineral mix.

Blood testing we’ve done on dry cows has revealed not just low blood calcium, but even sub-clinical ketosis from an inadequate energy diet. This can be partially from a low energy diet, but often more so from low protein diets and the unborn, late gestation calf’s, high demand for protein. The dam must convert her inadequate energy intake to protein for the calf and/or, cannibalise body tissue to supply this protein.

Transition is where the work starts, and is often lacking. Adequate energy, fibre and protein rations are essential at a time the cow is preparing for the most traumatic event in her yearly cycle. The DCAD of this ration MUST be right. Too higher DCAD will cause milk fever and ketosis. Too lower DCAD will knock cows down before they calve and most never to rise again. There is a very simple way to manage DCAD – weekly checking a random selection of springer cows’ urine pH. I said this is where the work starts; however, you will never earn more money than from this and the following activities. When the nutrient profile and DCAD of the springer ration is correct, apart from breach presentations, twins etc., the remaining cows should calve effortlessly.

Administering calcium immediately after calving by either drench or boluses will help replace the enormous amount of calcium in the first bucket of colostrum – this first milking of colostrum contains nine times the cow’s whole calcium pool! Calcium is imperative to immunity, and mastitis ‘kills’ pregnancies.

Checking for sub-clinical ketosis using a milk keto test strip on day three after calving and drenching with 300 ml of propylene glycol as required will eliminate early ketosis issues. Recheck several days later to ensure a zero HBHA reading on the test strip. Drench again with propylene glycol if necessary. The fresh cow will be mobilising body fat frantically in these early days of lactation, and frequently, even before she calves. This causes fatty liver syndrome and a dysfunctional liver. Propylene Glycol will get the liver working again.

In the 1980’s our herd was on a Herd Health Program. It resulted in healthy, productive and fertile cows. With the high value of cows calving annually, there are sound economic reasons to follow this program with your vet. Following is the procedure:

1. Every fresh cow is checked internally within a week of calving to ensure she has cleaned and has no uterine infection.
2. Every cow that does not have a heat recorded by day 20 post-calving is checked for corpus luteum activity. We aimed for three recorded heats prior to insemination. Research has highlighted the lowest period of conception is between 60 to 80 days due to negative energy balance immediately after calving producing poor quality eggs.
3. Every cow that did not return to service was pregnancy tested at five weeks post-insemination. This is paramount for two reasons: obviously to be sure she is pregnant and not anoestrus, but also so we have accurate calving dates from which dry-off dates can be calculated, and to be sure she is on a transition/lead feed diet for a minimum of 21 days before calving next year. Failure in adequate dry period and transition is very common, and will severely handicap the new lactation, or worse, cow survival.
4. Wisdom says pregnancy test again mid-gestation and prior to dry-off to ensure we still have a pregnant cow. Contrary to popular belief, carry-over cows are significant liabilities to farm profit and should be culled. I am suspicious that late 2015 we had high levels of fungal growth on pasture possibly causing abortions. My concern of the presence of mycotoxin issues was from a significant increase in loose manure at that time and well into early 2016 in many herds.
5. Lameness is major legacy to fertility. Lame cows do not stand when on heat. Apart from mineral nutrition and avoidance of acidosis, Shoof mats using copper sulphate/zinc sulphate regimes are excellent for hardening soles against stone damage and ensuing hoof infections.
6. Finally, insemination technique. This is an area where unnoticed ‘sloppiness’ can creep in. A client attended a fertility course in the USA last year, and was shocked by data connected to various aspects of insemination technique inadequacy.

John Lyne is a dairy production specialist with Dairytech Nutrition

www.dairytechnutrition.com.au