Baby Calf Health: Calves Leaving The Ranch At Weaning Get Sick
10/05/2009 01:19PM
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Any stocker operator can attest that management is everything during the first couple of weeks upon receiving cattle. These calves have just undergone the most stressful activity in their life – weaning. Not only have these calves experienced weaning but also transport, marketing, co-mingling and finally being placed in a distinctly different environment. Unfortunately, these stressors create challenges to the immune system, and calves may not have been immunized prior to weaning to protect them against viral diseases. When increased stress is combined with poor immunization, calves become sick. A study conducted in 2007 at the University of Arkansas Livestock and Forestry Branch Station near Batesville observed a 50% occurrence in calf illness within the first 7 days following arrival. Calves were considered ill and were treated with an injectable antibiotic when rectal temperature measured 104° F+ (101.7° F normal). Total incidences finally reached a plateau nearing 70% by day 14 (AMLV, see figure below).
The purpose of the study was to examine the effect of delaying a modified live bovine respiratory disease complex (BRD) vaccine 14 days (DMLV) compared with vaccinating upon arrival (AMLV). All other processing upon arrival occurred as usual: castrating, deworming and vaccinating against clostridial diseases. Delaying vaccination showed a nonsignificant reduction in observed illness (DMLV, see figure above).
In a similar study conducted at the Savoy Research Farm near Fayetteville, the response of delaying the clostridial vaccine, BRD vaccine or both by 14 days was examined. The cattle in that study received a metaphylaxis antibiotic upon arrival, which the cattle in the previous study did not receive. Morbidity rates were still high and averaged 69%. Once again, delaying vaccination did not affect morbidity rates.
The interesting factor within these two studies was morbidity rates were high regardless of whether or not the calves were vaccinated upon arrival or 14 days after arrival. Managing receiving health continues to be an industry challenge. Feedlot research has demonstrated cattle that get sick do not gain as well, have a greater cost of gain and do not grade as well as healthy cattle.
The immune status of calves leaving the farm at weaning appears to be easily compromised by stress and disease exposure through marketing channels and commingling. Development of immunity before calves leave the farm begins with nutrition; trace minerals – copper, zinc and selenium – play a role in immune function and are commonly deficient in forages. Vaccination and vaccine handling are other control points. Too often, cattle producers fail to booster killed vaccines. Improper mixing, expiration and storage temperatures can reduce the effectiveness of vaccines. Finally, management control points can influence post-weaning health and performance.
Preconditioning programs are designed to change weaning management as an effort to reduce morbidity and mortality losses throughout the rest of the production chain. These programs create an environment where calves are weaned on-farm versus on-truck. Buyers of preconditioned calves in the Oklahoma Quality Beef Network program reported a 6.7% morbidity and 0.1% death loss for preconditioned cattle versus 29% and 3% for nonpreconditioned cattle, respectively. Preconditioning is not only designed to get calves through weaning and establish immunity, but also to create a learning environment for calves including drinking from a tank and eating supplement from a bunk.
The challenge for the cow-calf producer is developing a management plan for weaning calves that will yield a positive return on investment. The overlaying question becomes "where is the intersecting point of how much more the industry can pay for calves that are better prepared to face the physiological challenges after leaving the ranch and of the cost imposed upon the cow-calf producer to establish the calf that will overcome those challenges."
In the two studies mentioned earlier, death losses averaged 1.8%. The first study reported a BRD treatment cost of $9.00 per calf. The animal loss and vet medicine cost associated with morbidity at today's market value would impose a per-head cost of $18.50 or $4.27 per cwt. This does not include labor cost. In a recently organized preconditioned calf sale, preconditioned calves received a $4.71 per cwt premium. Some buyers appear ready to pay cow-calf producers the equivalent cost of their expected health-related losses. There is usually enough premium for the cow-calf producer to pay for vaccines and anthelmentics (assuming no on-farm mortality); but each individual producer must determine if the pasture, hay and supplement costs can be kept below $15.00 per head to break even. Otherwise, the value of weight gain will need to exceed the cost of gain to offset the difference.
Source: Shane Gadberry, Assistant Professor, University of Arkansas