Dystocia

1
Dystocia
2
Outcomes

• ID factors influencing dystocia
• Explain the ways in which dystocia might be
  avoided, controlled

3
Calf Losses by days at or following calving1

• of Of all
• days losses Why? calf loss
• 1-3 61 dystocia 68
• 4-6 31 accidents 6
• 7-9 38 scours 5
• 10-42 32 pneumonia 12
• 43-wn. 33 (other) 9
• 1Miles City Research, 14 yr. summary

4

• AGA Summary

Can improvement against dystocia be made?
5
Dystocia

• Q What factors might cause dystocia? What
  factors can we manage in improve calving ease?

6
10 (well, ok . . 11) considerations . . .

• Birth weight
• Dams pelvic area
• Calf gender
• Gestation length
• Age, parity of dam

• Dam effect
• Breed effects
• Dams nutrition/condition
• Geographic region
• Exercise
• Endocrine effect

7
Dystocia

• Birthweight is a major cause of dystocia

8
Effect of BWT on CE in Simm-X Heifers (Meacham,
VPI)

• Delivery Method
• Normal Hand Mechanical
• Birth Pull Pull Caesarean
• females 68 34 16 2
• of total 56.7 28.3 13.3 1.7
• Ave. BWT 81 88 100 121

9
Genetic Parameters from AGA Can selection FOR
CALVING EASE be effective?

• CE BW YW GL
  CE(m)
• CE .18 -.86 -.26 -.35 .59
• BW .41 .37 .45 -.42
• YWT .19 .07 -.05
• GL .42 -.12
• CE (m) .13

AGA Sire Summary
10
Genetic Parameters of BWT (CSU)

• Trait h2 rg w/ BWT
• BWT .41 ---
• Wwt .32 .36
• Ywt. .43 .29
• 189 mo. wt. .61 .69

11
Genetic Parameters from AGA Can selection
against birthweight occur?

• CE BW YW GL
  CE(m)
• CE .18 -.86 -.26 -.35 .59
• BW .41 .37 .45 -.42
• YWT .19 .07 -.05
• GL .42 -.12
• CE (m) .13

AGA Sire Summary
12
Can improvement for other traits occur
simultaneously?

• AGA
• Summary

13
Interactions with birthweight . . .

• abnormal presentation
• gender of calf

• gestation length
• small pelvis
• calf effects (breed of sire, calf shape and ?)

14
Pelvic Area Height X Width (cm.2)

• WidthWidest points fr. Right and left shafts of
  ilium.

• HeightDorsal pubic tubercle and sacrum

15
Effect of BWT and Pelvic Area on CE in First Calf
Heifers1

• Calving Score Yrl. PA Calf Bwt.
• 1 (no assist) 151 cm2 72 lbs.
• 2 (minor assist) 145 77
• 3 (major assist) 141 82
• 4 (caesarean) 131 94

CSU data summary fr. BCH-2120. H. Ritchie and P.
Anderson.
16
Off the Hip Trivia

• Ratio of pelvic area to birth weight predicts
  dystocia (r .8)
• Ratios of 2.1 before breeding required no
  assistance. 1.9 required calf puller.

NebGuide G88-895-A. 1991 KSU C-705, 1989
17
Off the Hip Trivia (cont.)

• h2 .4 to .6
• rP .2 between PA and dystocia
• rG .6 between bulls heifers
• bulls ave. smaller than heifers of same age,
  weight
• 10 cm. increase in PA 2 lbs. Bwt. And .02
  decreasein CE score (Miles City, MT data)

18
Bottom Line of Pelvic Area . . .

• Q Why does Ruble still (effectively) use his
  tape system of predicting CE.
• Bottom Line . . .How does PA fit into CE
  management/breeding programs?

• Taylor, 1998 states that it is a questionable
  practice to include pelvic measurements in a
  female selection program. The end results dont
  apparently justify the cost

19
Breed Effect on CE?

• Is there a breed of sire effect?
• Note sire, dam effects (see handouts charts 1 and
  2)
• What about shape (chart 3)?

20
Effects of sire breed on calving difficulty and
calf birth weight.

• Sire Calving BWT
• Breed Difficulty() (lbs.)
• H,A 2.9 79
• Jersey 2.9 69
• Gelbvieh 8.0 86
• Limousin 9.4 86
• Brahman 10.0 90
• Chianina 11.8 89
• Simmental 14.9 89
• Charolais 18.4 91
• Maine Anjou 20.4 91

MARC. Germ Plasm Eval Report.
21
Breed of Sire Effects?Old adage . . .More
variation exists within a breed than between
breeds . . . .

• True or False?
• Refer to MARC diagrams
• Do all Jerseys weigh less than all Charolais?
• Do all Simmental weigh more than all Angus?

22
Breed of Dam Effects?

• Not consistent patternbut gtZebu influence lt
  BWT, dystocia
• E.g. MARC Brahman and Sahiwal F1 dams 1 to 2
  assistance European breed F1s 7 to 17

23
Effect of Gestation Length?

• Phenotypic correlation with dystocia
• Hereford Angus
• GL .10 .25Compare . . .
• BWT .54 .48
• PA -.18 -.22
• Cow wt. -.01 -.20

• (Miles City data . . . )

24
Effect of Gestation Length?

• 1 day .3 to .8 pounds birthweight . .
• Any additional benefits to shorter gestation
  length (e.g. 280 versus 287 days)?
• Also . . .
• h2 .4
• rP of BWT and GL is .4,.and BWT with dystocia is
  .5. Therefore . . .
• Economic value yet to be concluded

25
Dam Effects on Dystocia?

• Effect of dam age (KSU C-705).
• Calving Difficulty
• Age MARC CSU
• 2 yr. 54 30
• 3 yr. 16 11
• 4 yr. 7 7
• gt 4 yr. 5 3

• dam nutrition, condition?
• dam exercise (slight in extremes)?
• Geographical differences?

They also averaged 2.5 to 5 pound lighter
calves!
26
Environmental Effects on Dystocia

• Very little influence
• Energy, protein not proven a factor
• Exercise not a factor
• Region, yearly differences within herd do exist
• Care at calving reduces consequences of variation.

27
Calving Time Management . . when to give
assistance?

• Earlier assistance (at first show versus 2 to 3
  hours of labor . . )
• 91 vs. 81 rebreed rate
• 75 vs. 60 first service rate
• Same (general) for cows and heifers
• Bottom Line . .
• Give 1 hour of intense labor
• Insure feet visible and cervix fully dialated
• Ensure correct position

28
Dystocia Management . . .

• Best management advice
• 1. prevent dystocia genetically.
• Hold birthweight!
• Breed effects are significant, but variation w/in
  breed works
• 2. Manage first-timers carefully.

29
National Cattle Evaluations for Reproductive
Performance
30
Extra Slides . . .
31
Genetic Effects on Reproduction

• Trait h2 Trait h2
• calving ease .15 age _at_ pub .40
• BCS .40
• BSE .10 Gest. Length .40
• prim. abs .30 BWT .50
• 1st svc. concep. .25 Calf Crop .10