Implementing a simple but meaningful transition cow management program is critical for the survival and performance of both newborn calves and lactating dairy cows. During the transition period, many biological processes (e.g., colostrum, calving, inflammation, energy and calcium balance) are largely dependent on dry matter intake (DMI) of pre- and postpartum cows and first-calf heifers.
The top three factors affecting DMI are:
Physical fill: Something in the diet affects the cow such as low digestibility of fiber, poor quality forages, increased particle size, etc.
Metabolic: Something in the diet affects the cow such as increased fat content, increased propionic acid, decreased rumen pH, decreased protein content in diet, increased moldy feed, increased mycotoxin load, etc.
Management and environment: Something is affecting animal feeding behavior such as poor cow comfort, reduced water intake, empty bunks, reduced lineal bunk space per animal, increased heat stress, increased calving rate, grouping of animals, feed and water quality within reach of animals, facilities, lameness, etc.
Assuming the diet variables are under control, DMI is largely determined by cow comfort, which is determined by the consistency of management of grouping of animals, feed and water quality within reach of animals, facilities, and environment (e.g., bedding, heat abatement). However, there are three additional management areas with direct implications on the maternity and onset of lactation.
1) Increased calving frequency per day: Although this could be multi-factorial, during summer months cows are less likely to conceive in a timely manner after calving due to heat stress. Therefore, many farms experience an increased daily calving rate at some point during the calendar year. This means that more cows are moved into prepartum pens once per week and more pregnant cows are calving per day.
Prepartum DMI is a positive correlation with postpartum DMI within the first 12 days in milk, which in turn is associated with health status and milk yield.
A recent study assessed the effect of calving rate on pre- and postpartum DMI and milk yield. The combination of calving rate and DMI prepartum explained at least 7 pounds/day and 5.3 pounds/day of the observed variation in postpartum DMI and milk yield. These findings provide evidence that increased transition cow flow as determined by calving rate affected pre- and postpartum stocking density, which in turn reduced pre- and postpartum DMI and milk yield.
Behavioral changes associated with frequent animal displacement or competition for feed at the bunk, water and bedding space likely explain, at least in part, the observed differences. Check your heat abatement system to ensure is in working conditions. A practical solution when calving rate is above mean for the farm is to offer more TMR at the bunk for close-up and fresh cows to always ensure TMR availability within their reach so cows can cope with increased turmoil caused by moving larger groups of animals within pens.
The patterns of calvings and post-partum health events could be assessed by looking at: Length of dry period, length of stay in close-up pen, gestation length and twin pregnancies, parity, sire, calendar week, calendar month.
2) Prepartum vaccination relative to pen change with an acidogenic diet: Dairy farms are drying-off their lactating cows using two dry period lengths: at 216-220 days pregnant and some at 234-238 days pregnant. Many dairy farms vaccinate their cows to prevent mastitis and calf diarrhea at the time of dry-off and then administer a booster vaccine at 21 days prior to parturition (dpp). Generally, the booster vaccine is administered when cows are moved from the far-off into the prepartum pens with an anionic diet to prevent hypocalcemia.
For Holstein cows, gestation length is 276±6 days. Because there is variation in normal gestation length, when cows are booster vaccinated at 21 or 28 dpp, the proportion of cows that stay within the close-up pen with ≥20 days is ~41% or ~88%, respectively. New research showed that prepartum cows benefited by administering the booster mastitis and calf diarrhea vaccines at 28 dpp followed by pen change with acidogenic diet at 21 dpp (greater serum glucose, ~46% reduction in subclinical hypocalcemia [from 31.9 to 17.3%], and 19% more colostral IgG at calving) compared to cows vaccinated plus pen change at 21 dpp.
An alternative solution is to vaccinate prepartum cows followed by pen change with an acidogenic diet at 28 dpp. The proposed explanation for this biological response is that the booster vaccination triggers an inflammatory process for at least seven days inhibiting the receptor in parathyroid gland responsible for calcium homeostasis while the acidogenic diet via metabolic acidosis is trying to stimulate it. The transfer of IgG from blood into the mammary gland is an active process that requires energy and calcium. The shorter the timing of vaccination followed by pen change with an acidogenic diet relative to calving, the lower the concentration of IgG in colostrum and more likely to experience metabolic issues early in lactation. Consult and discuss your vaccination program with your veterinarian, especially when using a short dry-off period.
3) Adjust management for twin pregnancies: In dairy cattle, successful pregnancy results in the birth of one calf. However, the birth of two or more calves could occur at a rate of 3-5%. Birth of twin calves has been associated with genetics, season, parity, breeding program and high milk yield. It has been shown that high milk-producing cows have reduced blood progesterone due to increased metabolism to support milk yield. This reduction of blood progesterone occurs at the time of peak milk yield and breeding during the selection of the preovulatory follicle around 60 days in milk. Cycling dairy cows inseminated following estrus detection are more likely to experience double ovulation resulting in twin pregnancies (10-15%) compared to cows bred following timed-AI (3-5%).
Dairy cows confirmed with twin pregnancies almost always experience short gestation length and more hypocalcemia at calving. Cows confirmed pregnant with twins should be moved into the prepartum pen with an anionic diet 10 days earlier than the rest of the cows, at 245 ± 3 days of gestation. Because cows pregnant with twins had reduced gestation length, this management strategy allows enough exposure to the anionic diet to prevent hypocalcemia.
Plan to vaccinate and move cows into the prepartum pen at least 10 days earlier than typically planned for cows confirmed with twin pregnancies. Increase the proportion of multiparous cows bred using timed-AI by reducing heat detection. This reproductive strategy allows most high milk-producing cows to develop the pre-ovulatory follicle under the influence of high blood progesterone, thus increasing the likelihood of single ovulation. Extend the voluntary waiting period from 50 or 60 to 70 DIM to allow cows more time to recover their uterine environment and start breeding cows right after the peak milk yield when DM intake supports production and liver metabolism.
An ounce of prevention is worth a pound of cure! Please have this discussion with your veterinarian, nutritionist, and breeding team. These little details make the difference at the end of the day.
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