In the NAHMS Dairy 2007 study, 82.6% of operations reported retained placentas lasting more than 24 hours and 38.8% reported other reproductive problems (dystocia/metritis, etc.), all of which are common problems in the transition cow period. The study also noted that 15.2% of cow deaths were related to calving issues in fresh cows.
Cow morbidity and mortality during the transition period can be reduced with careful management in several areas that include bunk space, reduction of social stress and cow comfort.
In 2005, Ken Nordlund, DVM, University of Wisconsin, surveyed the transition management practices of 50 Wisconsin freestall herds that averaged 600 cows. Five factors emerged as the primary factors associated with herd average Transition Cow Index scores.
While these findings were from a study of an average of 600-cow freestall farms, Nordlund expects that most of the findings are size neutral, but in order to be effective, they need to be used in a freestall barn system. “I would not extrapolate the findings to either tie stall or grazing herds,” Nordlund explains. “We are now using these five factors as the primary focal points, as we work to improve fresh cow health with our clients.”
Factor #1: Bunk Space
Sufficient space at the feeding fence for all transition cows to eat simultaneously appears to be the most important determinant of transition cow performance, says Nordlund. He recommends a minimum of 30 inches of bunk space/cow in pre-fresh and post-fresh pens (equipped with lockups or vertical dividers) for a 90-minute period after fresh feed is delivered and after every milking. Nordlund says if he had to pick one factor with the most influence over transition cow health, it would be this provision of 30 in. of bunk space.
Nordlund says it’s important with a feeding fence fitted with self-locking stanchions to not assume that a cow can feed in each stanchion. Video studies show that lactating cows fill a row of 24 in. headlocks to a maximum of 80% at peak feeding periods, regardless of the number of cows in the pen. “This suggests that in fresh pens, cows will fill to a space of about 30 inches. It is likely that prepartum cows would benefit from even more space than lactating cows.”
Nordlund explains that 30 inches are required for all (Holstein or equivalent size) cows to eat simultaneously which is important especially for prepartum cows. “If they have to eat in shifts, the later animals eat less, predisposing them to Type II ketosis and fatty liver, more severe immunosuppression, and the cascade of fresh cow problems.”
Nordlund says that dairies should provide for more capacity than the average in prefresh pens. Begin by estimating the average feeding fence space needed for the pre-fresh pen. Calculate the average number of calvings per week by dividing the total number of calvings in the past year by 52. Multiply the average number of calvings per week by the target number of weeks in the pen. Then, multiply that by a factor such as 1.4 to accommodate surges in numbers of cows calving.
If the feeding fence space goal of ~30 inches/cow is reached with the average expected number of cows in the pen, then the pen will typically be over-stocked half of the time. In most situations, provision of space for 140% of the average expected number of calvings will meet the goals for bunk space approximately 90% of the time. During periods of pressure, the number of days that individual cows reside in these pens can be reduced.
If the cows are fed at a post-and-rail feeder, additional space should be provided to allow for dominant cows behavior.
Factor #2: Pen moves and social stress
Research has shown a reduced time spent eating, increased feed evictions and reduced milk yield following pen moves which cause cows to have to re-acclimate and re-establish pecking orders. Nordlund says cows typically experience an increase in the number of antagonistic interactions the first two days after a move into a new group, therefore it’ beneficial to minimize pen moves. If no new cows enter the pen, the group becomes relatively stable.
Nordlund calls this social turmoil. In pens where cows enter at intermittent intervals, like a week or more, extended stays in such pens are considered desirable. However, pens where cows enter and leave on a daily basis are considered to be in constant social turmoil and every effort should be made to minimize the time that prepartum cows spend in these pens.
Individual isolation such as in a calving pen, however, can also be detrimental if done too long, because cows are social animals and isolation can cause stress.
There are about two to three days of social turmoil within a pen after new cows enter. “In the pre-fresh period, we want to minimize the risks for development of fatty liver and Type II ketosis,” Nordlund says.
One strategy is implementing an “all-in” policy where a cohort of cows due to calve within a short period of time, such as a 1 week to 10 days, are assembled with no further additions through the calving process. “Less optimal would be weekly entries of new cows into the close-up pen; and even less attractive are daily entries of new cows into the pen, which result in pens of constant social turmoil,” Nordlund explains.
The health response for the limited number of producers who have constructed barns to accommodate stable social groups prepartum has been impressive, Nordlund notes. “There are several options here, but all involve establishing stable social groups either at dry off or for a close-up period of about three weeks.” They can be bedded packs (100 square feet of bedded area, not counting feeding area) or freestalls. “In the bedded pack option, the cows could calve in the pen,” he says. “In the freestall option, they should be moved to a calving pen once the head or feet of the calf become visible.”
A calving pen can be an individual pen for calf delivery or a group close-up pen where the cow enters several weeks before anticipated delivery, and delivers the calf in the pen. If the calving pen has a stable social structure (no additions), extended stays are fine. If new cows are continually being added, the duration of stay should be limited to 48 hours. Research shows increases in ketosis and displaced abomasums and early lactation culling of cows that stay 3–10 days in daily-entry group calving pens.
It’s common to move cows to calving pens when feet are showing, which minimizes the time in high turmoil pens. However, it requires round-the-clock labor to check and move cows, and employees must be careful that they don’t move cows into calving pens too early. A report by Carrier, et. al. (2006) showed cows that were moved when in labor, but with only mucus showing, had 2.5 times the rate of stillbirths as cows that were moved when the calf’s feet or head were showing.
When the close-up cows are in freestalls, employees often move them into calving pens too early in order to avoid calves delivered into the alleys and resulting in slurry-covered calves. However, early movement into the calving pens increases stillbirth rates. Waiting until an appropriate time will increase the number of calves born in alleys and result in higher exposure of the newborn calf to enteric disease risks and more soiled clothing of workers as they pick up these calves. Nordlund says being able to move cows at the appropriate time requires round-the-clock labor to be checking the pens. “Usually, this is available in herds of about 700 or more cows,” he says. “If there are fewer cows than this, it is usually more feasible to have the close up cows on a bedded pack where they also deliver the calf.”
Bedded pack “all-in” pens with the combined function of pre-fresh period and calving are considered optimal. A feasible strategy requires three pens: one may be freestalls and the last two would be bedded packs. On a weekly move day, for example, the new group of cows on the calving pack would be 0–7 days before due date. The new cows on the second pack would be 8–14 days before due date, and the new group of cows in the close-up freestalls would be 15–22 days before due date. Cow groups stay intact as they move on a weekly basis from pen-to-pen. After calving, cows and their calves are transferred to appropriate pens. At the end of the week, remaining cows would be induced to calve on the last scheduled day in the calving pen.
Because of the stress of isolation pens (i.e., box stalls) for calving, the duration of stay in those pens should be limited to a matter of a few hours.
Factor #3: Amply sized freestalls or bedded packs
Prepartum freestalls need to accommodate the ample dimensions of pregnant cows and allow for some clumsiness in their rising and lying motions. Stalls for prepartum Holsteins and Jerseys should be at least 50 and 45 inches wide, respectively. Length is the distance between the outer corner of the rear curb to the point where the stall surface touches the brisket locator. If a brisket locator is used, it should allow for greater than 70 and 63 inches for Holstein and Jersey cows, respectively.
Evaluating the potential for lunge, bob and rise should reflect three separate items in a freestall: a brisket locator that does not restrict rising motions including the forward swing of the front foot; freedom from impediments to the forward lunge of the head and shoulder, absence of bob zone obstructions; and the neck rail being sufficiently high and forward. To be low-risk, the total stall length should be at least 9 feet long with no obstructions to forward lunge and bob for Holsteins. If the stall is less than 9 feet, but the lower side rail is 11 inches above the stall bed or less, it should allow side lunging and is considered an average risk for transition cows. If the stall is less than 8 feet and has obstructions to side lunging, such as lower divider rails greater than 13 inches above the stall bed, the stall presents major risks to successful transition performance. Finally, the neck rail should be approximately 48–50 inches above the stall surface.
Factor #4: Surface cushion
A deeply bedded pack is preferred for close-up cows in confinement. If there is an external feeding alley, it’s preferable to have 100 square feet of space per cow in the bedded area. If the feeding area is continuous with the bedded pack, the space should provide a minimum of 120 square feet per cow with good bedding.
The number of cows calving per week is estimated by the annual number of cows calving divided by 52 weeks. If cows stay a pen for 3 weeks, the average pen population would be expected to hold three times the number of average calvings per week. If the pen can handle 140% of the average population, it’ll provide the goal space for each cow approximately 90% of the time.
Sand is the preferred bedding for freestalls because of its relatively low risk for mastitis compared to other bedding, though any deep, loose surface is better than a hard surface. Bedding covered-mattresses are viewed as average, and any stall surface such as concrete or other firm packed materials covered with modest bedding should be considered a high risk to successful transitions.
Factor #5: Effective screening program
The primary determinant of the fresh cow screening and treatment program is the quality of the people and how much they care for the cows. Facilities that allow easy restraint without exciting the cows are also critical to these programs.
Optimal screening programs use some form of appetite assessment. The practices of the herdspersons of the elite transition programs in our Nordlund’s study were remarkably similar:
Placement of fresh TMR while fresh cows were being milked.
Observation of them returning to the pen.
Assessment of appetite and attitude.
Herdspersons in the elite herds knew and cared about their fresh cows. Nordlund says this requires both special people and facilities such as sufficient feeding space for all cows to eat simultaneously. Cows that do not lock-up, or cows that lock-up with suppressed appetite or signs of depression, were examined. Other examinations that were conducted where indicated included rectal temperature, observations for vaginal discharge, ketosis, displaced abomasum and lung sounds, etc.
Formal screening programs in lockups for fresh cows need to be efficient and not interfere significantly with their daily time-budget, and should be limited to one hour or less of lockup time. Cows are capable of compensating for a 1–2 hour change in routine, but prolonged lockup in addition to other stressors, can reduce her ability to compensate and catch-up on lying time during transition.
If the cows have access to feed while being examined, feeding and the screening can proceed almost simultaneously. Screening time at a palpation rail, for example, must be weighted as riskier than equivalent time in lock-ups over feed. This antagonism, between holding time and the thoroughness of the screening procedure, puts some severe constraints on the fresh pen.
Nordlund’s study evaluated more than 30 transition management practices and has identified these five factors as the most important, but, he says, these five practices can also be the biggest problems in transition cow management if they are not managed correctly.
Portions of this article were excerpted from the 2008 Dairy Cattle Reproduction Council proceedings.