5 keys to preventing poor transition cows
5 keys to preventing poor transition cows
By Ken Nordlund, D.V.M.
The author is a clinical professor of food animal production medicine at the University of Wisconsin-Madison School of Veterinary Medicine.
To boost transition success, focus on feed bunk space, pen moves, ample-size free stalls or bedded packs, surface cushion, and effective screening of cows needing attention.
In 2005, we surveyed the transition management procedures of 50 Wisconsin free stall herds, some with over 600 cows. A wide range of management practices, housing characteristics, and animal evaluations were recorded. Five factors emerged as primary items associated in evaluating the overall effectiveness of transition cow management programs.
Obviously, this list is not comprehensive. There will be many potential risks to individual transition programs that are not listed. However, the risk factors presented here are considered to be common problems in today’s intensively managed free stall dairies.
No. 1 – Bunk space
Sufficient space at the feed bunk for all transition cows to eat at once appears to be the most important determinant of transition cow performance in our current industry. We recommend a minimum of 30 inches of bunk space per cow in both pre-fresh and post-fresh pens for 90 minutes after fresh feed is delivered and after every milking.
To determine feeding space per cow it is important to measure the length of the feedline. If it is fitted with self-locking stanchions do not assume that a cow can fit into every stanchion. Our video studies show that lactating cows fill a row of 24-inch headlocks to a maximum of only 80 percent at peak feeding periods, regardless of the number of cows in the pen.
This suggests that in fresh pens cows will fill to a spacing of about 30 inches. It is likely that prepartum cows would benefit from even more space than lactating cows.
Calculating feeding space per cow in the transition pen on a single day may not represent the typical situation, due to variations in the number of cows calving each week throughout the year. Therefore, it will be helpful to estimate typical stocking pressure in the pre-fresh and post-fresh pens.
First, calculate the average number of calvings per week by dividing the total number of calvings during the past year by 52. Then multiply the average number of calvings per week by the target number of weeks that cows spend in the pen.
If the feeding space goal of approximately 30 inches per cow is reached with the average number of expected cows in the pen, then the pen will typically be overstocked half of the time. In most situations provision of space for 140 percent of the average expected number of calvings will meet the goals for feed bunk space approximately 90 percent of the time. During periods of pressure, most dairy managers reduce the number of days that individual cows reside in these pens. However, it is preferable to minimize these adjustments of time in special management pens.
Recommendations for 30 inches of space assume that the pens are equipped with lock-ups or other vertical dividers between feeding spaces. If cows are fed at a post-and-rail feeder, additional space should be provided because dominant cows appear to clear subordinates sooner in these situations.
No. 2 – Pen moves and social stress
Each pen move requires that a cow familiarize herself with the surroundings and reestablish a pecking order in the group. Recent study has shown that reduced time spent eating, increased feeding evictions, and reduced milk yield occurs following a pen move. Minimizing the number of regroupings through the transition period is consistent with successful transition programs.
In most situations steps to reduce any moves will result in improved transition performance.
Cows are social animals. Isolation from the herd creates stress for a cow, and separating a single cow into a separate calving pen for more than a couple of days appears to be a high-risk practice. However, movement into a new social group also creates stress as the cow establishes rank within the group. The first two days after a move into a new group are characterized by a dramatic increase in the number of antagonistic interactions, most of them physical. If no additional new cows enter the pen, the group becomes relatively stable.
A concept of the “social turmoil profile” of a pen has recently been described. 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 them.
Close-up pens. There are many different approaches to close-up and calving pens. The basic idea we bring to an evaluation of pen moves is, there is a period of about two to three days of social turmoil in a pen after new cows enter. During the pre-fresh period we want to minimize the risks for development of fatty liver and Type 2 ketosis.
The optimal entry policy for the close-up pen would be an “all in” pen where a cohort of cows due to calve within a short period of time, such as one week to 10 days, is assembled, with no further additions made through the calving process. Less optimal are weekly entries of new cows into the close-up pen, and even less attractive are daily entry of new cows into the pen which results in constant social turmoil.
Calving pens can refer to either a pen into which a cow is moved hours before delivering her calf, or it could be a close-up pen where cows enter several weeks prior to their anticipated calving date and they deliver their calves there.
If the calving pen has a stable social structure (no additions), extended stays are fine. But if new cows are intermittently being added we recommend that the duration of the stay be limited to 48 hours.
Clinical data from field investigation by the Food Animal Production Medicine group at the University of Wisconsin show dramatic increases in ketosis, displaced abomasums, and early-lactation culling of cows that stay three to 10 days in daily-entry group calving pens.
When cows are moved on a daily basis to calving pens, they should be selected carefully so that few of them spend more than 48 hours in these high turmoil pens.
It has become common to move cows to calving pens when the calf’s feet are showing. This effectively minimizes the amount of time spent in high turmoil pens, but it presents a new set of challenges. First, it requires round-the-clock labor to check and move cows. Second, this labor must be monitored carefully to ensure they do not move cows into calving pens too early.
In a report on moving cows when calving was imminent, cows that were moved when in labor but with only mucus showing, had 21/2 times the rate of stillbirths as did cows that were moved when the calf’s feet or head were showing.
When close-up cows are in free stalls, there is a tendency by laborers to move them into calving pens too early. By doing so there are fewer calves delivered in the alleys and they can avoid having to pick up slurry-covered calves.
Basically, early movement into the calving pen increases stillbirth rates, whereas waiting until a more appropriate time will increase the number of calves born in alleys, result in higher exposure of the newborn calves to disease risks, and more soiled clothing of workers as they pick up the calves.
Isolation pens or box stalls would appear to minimize social turmoil. However, because cows are social animals and separation from the herd is usually a stressful experience, if cows are moved to individual box stalls for calving the duration of stay should be limited to a few hours.
Bedded pack “all in” pens that serve combined functions of a pre-fresh period and calving are considered optimal. There are several ways to achieve this goal, but a feasible strategy requires three pens; one may be free stalls and the last two would be bedded packs.
On a weekly move day, for example, the new group of cows on the bedding pack would be zero to seven days before their due dates. New cows on the second pack would be 8 to 14 days out, and the new group of cows in close-up free stalls would be 15 to 22 days out. Cow groups stay intact as they move from pen to pen on a weekly basis. After calving the individual cow and calf are removed and transferred to appropriate pens. As the end of the week approaches, remaining cows would be induced to calve on the last scheduled day in the calving pen.
No. 3 – Ample-size free stalls or bedded packs
A deeply bedded pack is the preferred housing for close-up cows in confinement housing. The guideline of 100 square feet of space per cow includes the bedded area only and assumes that cows have access to an external feeding alley or outside lot. If the feeding area is contiguous with the bedded pack, the space should provide a minimum of 120 square feet per cow with good bedding covering most of the area.
The pack should be sized to accommodate surges in cow numbers. The estimated number of cows calving per week is estimated by dividing the number of cows calving per year by 52. If the plan is to leave cows in a pen for three weeks, then the average pen population the pen would be expected to hold is three times the average number of calvings per week. If the pen is sized to handle 140 percent of the average population, it will provide the goal space for each cow approximately 90 percent of the time.
If free stalls are used, sand is the preferred material because it presents relatively low risk for mastitis compared to organic products. However, any deep, loose surface will be an improvement over a hard surface. Mattresses covered with modest quantities of shavings or other materials 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.
No. 4 – Surface cushion
Prepartum free stalls, in particular, need to accommodate the ample dimensions of pregnant cows and allow for some clumsiness in their lying and rising motions. Stalls for prepartum Holsteins and Jerseys should be at least 50 inches wide 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 there is no brisket locator, the total stall length is the stall resting length. This should be 70 inches of stall length or more for Holsteins and 63 inches or more for Jerseys.
Evaluating the potential for lunge, bob, and rise should reflect assessments of three separate items in a free stall:
• 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, and absence of bob zone obstructions
• The neck rail being sufficiently high and forward
For a stall to be considered low risk for Holstein cows its total length should be at least nine feet, with no obstructions to forward lunge and bob.
If the stall is less than nine feet, but the lower side rail is 11 inches or less above the stall bed, it should allow side lunging and is considered an average risk for transition cows. If the stall is less than 8 feet long and has obstructions to side lunging, such as divider rails more than 13 inches above the stall bed, then it presents major risks to successful transition performance. Finally, the neck rail should be approximately 48 to 50 inches above the stall surface.
No. 5 – Effective screening of cows needing attention
While difficult to assess, 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 is also critical to these programs.
Optimal screening programs appear to use some form of appetite assessment. The practices of the herdspersons of elite transition programs in our survey were remarkably similar:
• Placement of fresh TMR while fresh cows were being milked
• Observation of them returning to the pen
• Self-locks engaged
• Assessment of their appetite and attitude
Similarly, herdspersons in the elite herds knew and cared about the fresh cows under their watch. Obviously, this requires both special people and facilities.
Back to the bunk space issue, it requires sufficient feeding space for all cows to eat at once. Cows that don’t lock up, or cows that lock up with suppressed appetite or signs of depression were examined. Other examination procedures, including rectal temperature, observations for vaginal discharge, ketosis, displaced abomasum, lung sounds, and so forth were conducted when primary assessments indicated further evaluation was needed.
Lock up less than one hour . . .
While formal screening programs in lock-ups for fresh cows are a desirable practice, they need to be efficient so as to not interfere significantly with their daily time budget. Screening programs that lock up cows for one hour or less are considered optimal. Extended lock-up times add substantially to the stresses of transition.
While cows are quite capable of compensating for a one- to two-hour change in routine, if lock-up is prolonged and is in association with other stressors such as overstocking, then the ability of the cow to catch up on lying time may be exceeded. One recent study found that, when cows were deprived two to four hours of lying time, they only managed to recover about 40 percent of that lying time during the next 40 hours.
The location of screening procedures has a substantial impact on the time constraints. If cows have access to feed while being examined, feeding and screening can proceed almost simultaneously. Screening time at a palpation rail, for example, must be regarded 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.