Good Transition Management is the key to good reproductive performance
“The majority of dairy cows are normal from a reproductive perspective”, that was the message from Professor Mark Crowe University of Dublin for dairy farmers attending three on farm “Pregnancies for Profit” workshops run by Wynnstay in conjunction with Elanco in November 2014.
Extensive studies of ovarian function have shown that 50-80% of the dominant follicles present on the ovaries post calving will ovulate. More importantly the presence of cystic ovaries is very over reported and in reality only occurs in up to 5% of cows post calving. Pulses of Luteinizing hormone (LH) are primarily responsible for the fate of the dominant follicle and therefore it is important that we understand what affects LH secretion in order to improve fertility in the dairy cow. Professor Crowe highlighted sub optimal Body Condition Scoring (BCS) at calving, declining negative energy balance in early lactation, excessive BCS loss in early lactation and reduced DMI. These effects are directly related to poor fertility in the previous lactation and inadequate transition cow management. One of the most significant changes dairy farmers can make to their management is ensuring that all cows spend at least three weeks on the transition diet. These cows will produce more milk, get in-calf sooner and last longer in the herd as a result. As one would expect health status also has a significant effect on resumption of ovarian function. Sick cows are less likely to cycle especially those which have suffered from dystocia, retained foetal membranes or a uterine infection. Again good transition cow management is the key. Sub-clinical ketosis is one of the main indicators of poor transitional health and is the gateway for a plethora of diseases that will affect fertility, production and survival.
Fertility in lame cows is severely compromised. As one would expect they demonstrate less intensity of bulling activity but also produce less progesterone, have less frequent LH pulses and produce smaller follicles. In terms of fertility this demonstrates the importance of inspecting feet at drying off and adopting an effective foot bathing regime. Follicle size is also significantly affected by mastitis. The incidence of mastitis in early lactation can be reduced by good hygiene at the point of drying off and in the dry cow housing.
Uterine infections were also demonstrated to effect ovarian function. High numbers of pathogens in utero caused slower follicle growth and produced small corpus lutei. Adequate Vitamin E, Selenium and chelated minerals in the transition cow and early lactation diet has been shown to have a positive effect on reducing transitional diseases and lameness especially when combined with effective transition cow management.
According to Professor Crowe 75-85% of cows will ovulate by day 42 of lactation. Unfortunately a large proportion of these will not be seen on heat and be identified as being non-cycling and requiring intervention unless an effective method of heat detection is employed. Professor Crowe’s recommended strategy is to conduct effective pre breeding heat detection and intervening with cows not seen bulling by 42 days. With good heat detection and fresh cow monitoring the need for the vet to routinely palpate each cow post calving is greatly reduced. Fresh cow monitoring can be simplified by the use of BellaAg health boluses that measure the cow’s body temperature every 15 minutes. These are excellent at identifying the first signs of transitional health issues and negate the need for manual temperature checking. Heat detection rates can be significantly improved by increasing the frequency of observations. However in most herds the time for heat detection is at a premium. Employing a combination of methods such tail chalking, the use of activity monitors, and manual observations can pay large dividends.
Late gestation and early lactation nutrition, transition management, and introducing a structured protocol to reproductive management including pre-breeding heat detection will provide significant financial benefits from more milk and a reduction in the number of forced cullings. Transition 80/20 is an innovative approach to transition cow management introduced by Wynnstay which includes recommendations and protocols for successful transition management with associated products to support the cow through this short but key period of the production cycle.
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