Wednesday, August 29, 2018

When Do We Intervene and Assist a Cow or Heifer in Labor? Glenn Selk, Oklahoma State University August 15, 2018 10:33 AM

Before the fall calving season commences, now is the time to put together and post a protocol for family members and hired employees to follow when they find a cow or heifer starting in the process of calving. An issue facing the rancher at calving time, is the amount of time heifers or cows are allowed to be in labor before assistance is given. Formerly, traditional text books, fact sheets and magazine articles stated that “Stage II” of labor lasted from 2 to 4 hours. “Stage II” is defined as that portion of the birthing process from the first appearance of the water bag until the baby calf is delivered. Research data from Oklahoma State University and the USDA experiment station at Miles City, Montana clearly show that Stage II is much shorter, lasting approximately 60 minutes in first calf heifers, and 30 minutes or less in mature cows.
Table 1. Research Results of Length of Stage II of Parturition
No. of Animals
Length of Stage II
USDA (Doornbos, et al.1984. JAS:59:1)
24 mature cows
22.5 min.
USDA (Doornbos, et al.1984. JAS:59:1)
32 first calf heifers
54.1 min.
Oklahoma State Univ.
(Putnam, et al. 1985. Therio:24:385)
32 first calf heifers
55.0 min.
In these studies, heifers that were in stage II of labor much more than one hour or cows that were in stage II much more than 30 minutes definitely needed assistance. Research information also shows that calves from prolonged deliveries are weaker and more disease prone, even if born alive. In addition, cows or heifers with prolonged deliveries return to heat later and are less likely to be bred for the next calf crop. Consequently a good rule of thumb: “If the heifer is not making significant progress 1 hour after the water bag or feet appear, examine the heifer to see if you can provide assistance. Mature cows should be watched for only 30 minutes before a rectal examine is conducted.” Make certain the cervix is completely dilated before pulling on the chains. If you cannot safely deliver the calf yourself at this time, call your local large animal veterinarian immediately.
Most ranches develop heifers fully, and use calving ease bulls to prevent calving difficulties. However, a few difficult births are going to occur each calving season. Giving assistance in a timely manner will save a few more calves, and result in healthier more productive two-year old cows to rebreed next year.

Wednesday, August 22, 2018

Additional Informaton on Armyworms - Allen Knutson, Extenstion Entomologist Texas A&M AgriLife Extension Service

    Regarding fall armyworm in pastures and hay, the pyrethroid insecticides are commonly used as they are effective and generally less costly, due to some being available as generics.  Pyrethroid insecticides can be recognized by their active ingredient which ends in “thrin” and include beta-cyfluthrin, cyfluthrin, gamma and lambda cyfluthrin and zeta-cypermethrin.  Prevathon and Besiege can provide longer residual control but can be more expensive than pyrethroids.  Intrepid, Tracer and Dimilin should be applied when armyworms are small, , less than ½ inch.  Dimilin is sometimes added to a pyrethroid insecticide to extend the control period. 
    Fall armyworms can also damage fall planted small grains and other forage grasses.  The insecticides labeled for these crops can be different than those listed here for pastures and hay.
    Fall armyworms can be active through October and even into early November if temperatures remain warm.  

As always,  check products before you purchase to make sure they fit your need.  Read the label to ensure you use the correct amount for the most effective control.   Also follow container disposal procedures when container is empty.

The Fall Armyworm – A Pest of Pasture and Hay. Allen Knutson Extension Entomologist, Texas A&M AgriLife Extension Texas A&M AgriLife Research and Extension Center, Dallas

The fall armyworm, Spodoptera frugiperda, is a common pest of bermudagrass, sorghum, corn, wheat and rye grass and many other crops in north and central Texas.  Larvae of fall armyworms are green, brown or black with white to yellowish lines running from head to tail.  A distinct white line between the eyes forms an inverted “Y” pattern on the face.  Four black spots aligned in a square on the top of the segment near the back end of the caterpillar are also characteristic. Armyworms are very small (1/8 inch) at first, cause little plant damage and as a result often go unnoticed.  Larvae feed for 2-3 weeks and full grown larvae are about 1 to 1 1/2 inches long. Given their immense appetite, great numbers, and marching ability, fall armyworms can damage entire fields or pastures in a few days.

Once the armyworm larva completes feeding, it tunnels into the soil to a depth of about an inch and enters the pupal stage. The armyworm moth emerges from the pupa in about ten days and repeats the life cycle.  The fall armyworm moth has a wingspan of about 1 1/2 inches. The front pair of wings is dark gray with an irregular pattern of light and dark areas.  Moths are active at night when they feed on nectar and deposit egg masses.  A single female can deposit up to 2000 eggs and there are four to five generations per year. The fall armyworm apparently does not overwinter in north Texas, but survives the winter in south Texas.  Populations increase in south Texas in early spring and successive generations move northward as the season progresses. 

Management.  Fall armyworm outbreaks in pastures and hay fields often occur following a rain which apparently creates favorable conditions for eggs and small larvae to survive in large numbers.  Hay fields with a dense canopy and vigorous plant growth are often more susceptible to armyworm infestations than less intensely fertilized and managed fields. Irrigated fields are also susceptible to fall armyworm infestations, especially during drought conditions.  Also monitor volunteer wheat and weedy grasses in ditches and around fields which may be a source of armyworms that can move into the adjacent crop.

Look for fall armyworm larvae feeding in the crop canopy during the late evening and early morning and during cool, cloudy weather.  During hot days, look for armyworms low in the canopy or even on the soil surface where they hide under loose soil and fallen leaves.  A sweep net is very effective for sampling hay fields for fall armyworms.  When fields are wet with dew, armyworms can stick on rubber boots worn while walking through the field. Small larvae chew the green layer from the leaves, creating a “window pane” effect and later notch the edges of leaves. 

The key to managing fall armyworms is frequent inspection of fields to detect
infestations before they have caused economic damage.   Once larvae are more than ¾  inch long, the quantity of foliage the eat incvreases dramatically.  During their final 2-3 days of feeding, armyworms eat 80% of the total foliage consumed during their entire development.

The density of armyworms sufficient to justify insecticide treatment depends on the stage of crop growth and value of the crop.  Seedling plants can tolerate fewer armyworms than established plants.  Infestations of more than 2-3 armyworms (1/2 inch or longer) per square foot may justify an insecticide application. If practical, apply insecticides early in the morning or late in the evening when armyworm larvae are most active and therefor most likely to come into contact with the insecticide spray.  If the field is near harvest, an early harvest, rather than an insecticide treatment, is an option.

Parasitic wasps and flies, ground beetles, and insect viruses help suppress armyworm numbers. However, these natural enemies can be overwhelmed when large numbers of migrating moths move into an area and weather conditions favor high survival of eggs and larvae.