Ryan M. Breiner

Insemination timing affects pregnancy rates in beef cows treated with CO-Synch protocol including an intravaginal progesterone insert.

Our objective was to determine the optimal time to artificially inseminate lactating beef cows (Bos taurus typicus) after using the standard CO-Synch protocol that also included a progesterone-releasing, intravaginal controlled internal drug release (CIDR) insert. Cows (N=605) at three locations were inseminated at four different times after CIDR insert removal and the prostaglandin F(2alpha) administration of the CO-Synch+CIDR protocol: 48, 56, 64, or 72h. Blood samples were collected 9 to 10 d before and on the day of CIDR insertion. Based on elevated (>1 ng/mL) serum progesterone concentrations, 60% of 605 cows had previously ovulated (were cycling) at the initiation of the study, with a range of 39.6% to 67.9% among locations (P<0.05). Age of cow, body condition score, and days postpartum affected (P< or =0.05) cycling status before ovulation was synchronized. Averaged across treatments, pregnancy rate to artificial insemination (AI) at Day 32 was affected (P< or =0.05) by pretreatment cycling status and body condition. Younger cows (< or =3 yr) tended to have greater AI pregnancy rates when inseminated at 56h, whereas older cows had similar pregnancy rates when inseminated at 56h or later (timing of AI by age interaction; P=0.085). Pregnancy loss between Days 32 and 63 was greatest (quadratic effect; P<0.05) when cows were inseminated at 48 and 72h. In summary, insemination times at or after 56h improved AI pregnancy rates when using the CO-Synch+CIDR program. Further work is warranted to examine age effects on timing of AI in the CO-Synch+CIDR program.

Attitudes of cow-calf producers toward NAIS are guarded

The introduction of a National Animal Identification System (NAIS) into the United States has generated much confusion and controversy. The goal of the NAIS is to utilize 48-hour traceback in the event of an animal disease outbreak, identify all animals that have had contact with the diseased animal, and link animals to their premises of origin. The NAIS has led to new technology and guidelines with the potential to change the production and marketing landscape of the beef industry. Moreover, these advances have led to public policy issues that have changed the rhetoric of the industry. The objective of this study was to examine perceptions and attitudes of cowcalf producers toward emerging beef technologies and policy issues through a nationwide mail survey. By understanding the demographics of today’s producers in addition to their current practices, the industry can work toward better educating and understanding the concerns of these producers.

Effect of adding Aureomycin® for anaplasmosis control or Rumensin® to mineral supplements on summer beef cowherd performance

Two hundred forty-six commercial Angusbased cows were used to determine the effect of adding Aureomycin for anaplasmosis control or Rumensin to mineral supplements on summer beef cowherd performance. Cow/calf pairs were randomly allotted to summer native-pasture groups by treatment, and were fed an industry-standard mineral/trace mineral supplement for the duration of the trial. The study had three treatments: (1) control mineral supplement with no medication added, (2) the same base supplement with the addition of Aureomycin (0.5 mg/lb cow body weight daily), and (3) the base supplement with the addition of Rumensin (200 mg/cow daily). Feed additives were blended into the mineral mix to provide the targeted daily consumption. Treatments were initiated May 6 and maintained through October 6. Mineral intake was similar among treatments. Cow and calf weight gains were similar among treatments during the first 32 days of the study. By the trial end, there were no significant differences in cow body condition score gains and pregnancy rates. Total calf gains for the duration of the trial were similar for groups supplemented with Aureomycin, and Rumensin, and both were greater than for control calves (21 and 18 lb greater, respectively). Overall herd health was enhanced by feeding Aureomycin when compared with control or Rumensin. Foot rot was the main health concern in this trial, and the addition of Aureomycin to mineral supplements reduced foot rot. Introduction

Presynchronizing PGF2α and GnRH injections before timed artificial insemination CO-Synch + CIDR program

Introduction Fixed-time artificial insemination is an effective management tool that reduces the labor associated with more conventional artificial insemination programs requiring detection of estrus. The 7-day CO-Synch + controlled internal drug release (CIDR) insert protocol has been shown to effectively initiate estrus and ovulation in cycling and non-cycling suckled beef cows, producing pregnancy rates at or greater than 50% in beef cows. The gonadotropin-releasing hormone (GnRH) injection that begins the CO-Synch + CIDR program initiates ovulation in a large proportion of cows, particularly anestrous cows. The CIDR, which releases progesterone intravaginally, prevents short estrous cycles that usually follow the first postpartum ovulation in beef cows. Our hypothesis was that inducing estrus with a prostaglandin injection followed 3 days later with a GnRH injection, 7 days before applying the 7-day CO-Synch + CIDR protocol, might increase the percentage of cycling cows that would exhibit synchronous follicular waves after the onset of the CO-Synch + CIDR protocol. We also hypothesized that the additional GnRH injection would increase the percentage of anestrous cows that would ovulate, thereby increasing pregnancy outcomes.

Exposure of prepubertal beef bulls to cycling females affects neither age at puberty nor ability to pass an initial breeding soundness examination

Introduction Age at puberty is a crucial factor influencing a young bull’s ability to pass a breeding soundness examination (BSE) at a year of age, and reducing that age may prove beneficial to beef producers. For beef females, exposure to mature bulls is known to hasten the onset of puberty and also can reduce the duration of postpartum anestrus. Relatively little research has evaluated the effects of female exposure on beef bull sexual development. Bulls are thought to use visualization rather than olfaction as their primary and preferred way to detect estrus in females. The purpose of this study was to determine whether continuous, long-term fence-line exposure of prepubertal beef bulls to estrouscycling beef females influences a bull’s age at puberty and subsequent ability to pass a BSE.

Presynchronizing Prostaglandin F2α injection before timed artificial insemination CO-Synch + CIDR program

Introduction Fixed-time artificial insemination is an effective management tool that reduces the labor associated with more conventional programs that require detection of estrus. The 7-day CO-Synch + controlled internal drug release (CIDR) insert protocol has been shown to effectively initiate estrus and ovulation in cycling and non-cycling suckled beef cows, producing pregnancy rates at or greater than 50% in beef cows. The gonadotropin-releasing hormone (GnRH) injection that begins the CO-Synch + CIDR program initiates ovulation in a large proportion of cows, particularly anestrous cows. The CIDR, which releases progesterone intravaginally, prevents short estrous cycles that usually follow the first postpartum ovulation in beef cows. Our hypothesis was that inducing estrus with a prostaglandin injection 3 days before applying the 7-day CO-Synch + CIDR protocol might increase the percentage of cycling cows that would exhibit synchronous follicular waves after the onset of the CO-Synch + CIDR protocol, thereby increasing pregnancy outcomes.

Optimizing a new 5-day CIDR-CO-Synchtimed artificial insemination program

Introduction The 7-day CO-Synch + CIDR protocol is a popular ovulation-synchronization program used by cow-calf producers to facilitate artificial insemination (AI). A progesterone-impregnated controlled internal drug release (CIDR) insert is placed intravaginally and an injection of gonadotropin-releasing hormone (GnRH) is given. After 7 days, prostaglandin F2α (PGF2α) is administered and the CIDR insert is removed. Between 58 and 72 hours after insert removal, cows are inseminated after another injection of GnRH to induce ovulation. Timed AI pregnancy rates generally have ranged from 40 to 60% when suckled cows are treated with the 7-day CO-Synch + CIDR protocol.

Precutting round alfalfa and cornstalk balesdecreases time and fuel required for balebreakup in a vertical mixer

Introduction Properly mixing and distributing nutrients throughout a ration can be equally as important as including them in the formulation. Many factors, including forage type, particle length, and mixer type, affect the homogeneity of total mixed rations. Particle size plays an important role in digestion and animal performance and, therefore, is an important consideration from harvest through feeding. An increase in particle size results in a less uniform distribution of nutrients throughout the total mixed ration. Typically, diets with a high proportion of forages have the lowest uniformity of nutrients in individual batches of complete feed.

Round bale alfalfa processing method does notinfluence feeding or mixing characteristics in atotal mixed ration

Introduction Nutritionists and producers often assume that ingredients in a total mixed ration are uniformly mixed. However, many factors may affect ration homogeneity, including particle size, shape, and density and mixer discharge location. Forages are often ground prior to mixing in a total mixed ration to reduce variation in forage particle length. However, preprocessing forages while baling may facilitate particle length reduction and eliminate the need to grind forages prior to mixing. Objectives of this study were to determine the effects of forage processing method on uniformity and particle length of the total mixed ration at different discharge locations throughout mixing.

Cornstalk round bale processing method doesnot influence feeding characteristics or feedrefusals

Introduction Nutritionists and producers often assume that ingredients in a total mixed ration are uniformly mixed. However, many factors can affect ration homogeneity, including particle size, particle shape, differences in density of feed ingredients, and relative point at which the mixture is discharged from a mixer batch. Forages often are ground prior to mixing in a total mixed ration to reduce variation in forage particle length. Preprocessing forages during baling may facilitate particle length reduction, eliminating the need to grind forages prior to mixing. The objectives of this study were to determine the effects of forage processing on (1) uniformity of the ration discharged from the mixer at different points, (2) particle length throughout the mixing process by bale type, and (3) difference in feed refusals of mixed rations based on forages processed by different methods.