Post on 31-Jul-2020
Re-Breeding Nutritional Requirements
Kelley Neuhold, Ph.D.—Tech. Services
“The most economically relevant trait in beef cattle production is reproductive
performance.” -- J.N. Wiltbank, 1994
Nutrient Consumption Reproductive Consequence• Inadequate Energy Intake • Delayed puberty, suppressed estrus and
ovulation, suppressed libido and spermatozoa production
• Inadequate protein intake • Suppressed estrus, low conception, fetal resorption, premature parturition, weak offspring
• Vitamin A deficiency • Impaired spermatogenesis, anestrous, low conception, abortion, weak offspring, retained placenta
• Phosphorus deficiency • Anestrus, irregular estrus• Selenium deficiency • Retained placenta• Copper deficiency • Depressed reproduction, impaired immune
system, impaired ovarian function
• Zinc deficiency • Reduced spermatogenesis
Table 1. Influence of Inadequate Dietary Nutrient Intake on Reproduction in Beef Cattle (Bearden And Fuquay, 1992)
Mature Cow’s Requirement2nd
TrimesterLast
TrimesterLactation
CP, % 6.2 7.8 10.2
TDN, % 45.9 52.6 58.7
NEm, Mcal/lb 0.39 0.49 0.59
Ca, % 0.15 0.25 0.3
P, % 0.12 0.16 0.2NRC, 1996
Young Cow’s Requirement2nd
TrimesterLast
TrimesterLactation
CP, % 6.8 8.6 11.2
TDN, % 50.5 57.9 64.6
NEm, Mcal/lb 0.43 0.54 0.65
Ca, % 0.17 0.28 0.3
P, % 0.12 0.16 0.2NRC, 1996
Target BCS for Rebreeding
• Target BCS was first suggested in 19701
• Literature suggest that ≥5 at calving time to ensure adequate postpartum breeding2
• Cows in BCS 7 to 9 at calving were able to return to estrus with in 60 d no matter BW change pre or post-calving3
1Randel, 19902Dziuk & Bellows, 1983; Richards et al, 19863Whitman, 1975
BCS at Calving No. of cows % cycling 60 d % cycling 90 d
Thin (1-4) 272 46 66Moderate (5-6) 364 61 92Good (7-9) 50 91 100
Body Condition at Calving and Return to Estrus After Calving
Adapted from Whitman, 1975
Effect of BCS at Calving on Postpartum Interval and BCS at Breeding Conception Ratea
Body Condition Score
Post partum interval (d)
Conception Rate (%)
3 (thin) 89 704 (thin) 70 805 (moderate) 59 946 (moderate) 52 1007 (good) 31 100A Adapted from Ken Odde, CSU Department of Animal Science “They are what they eat”
0
10
20
30
40
50
60
1-49 50-99 100-199 200+ All
Perc
ent o
f ope
ratio
ns
Herd size
19972008
Use of BCS Tool by Size & Yr
USDA NAHMS
Energy partitioning by the cow:1.Basal metabolism2.Activity3.Growth4.Energy reserve (basic)5.Pregnancy6.Lactation7.Energy reserve (additional)8.Estrous cycle and pregnancy initiation9.Energy reserve (excess)
Short & Adams, 1988
Energy• Pregnancy rates are greatly impacted by energy
intake• Inadequate energy intake in the 3rd trimester
can reduce pregnancy even with adequate energy intake post-calving
• Further declines are seen when energy intake is inadequate in both periods
• Conception rates of 50-76% with inadequate energy compared to 87-95% when energy intake is adequate
Randel, 1990
Effect of Dietary Energy on Pregnancy Rates in Suckled Cows and Heifers
Adequate* Inadequate* P Source
Pre-Calving
68 60 <0.05 Dunn et al, 1969
78 60 0.1 Bellows & Short, 1978
Post-Calving
95 50 <0.01 Whiltbank et al, 1962
87 64 <0.01 Dunn et al, 1969
92 76 <0.05 Richards et al, 1986
* % PregnantAdapted From Randel 1990
The Current Fad is Fat
Fat Advantages
• Energy dense• Potential reproductive benefits• Improve visual appearance/condition
Fat Disadvantages
• Can depress fiber digestion of high forage diets
• Handling/storage, etc.• Delivering the fat to the cow’s mouth• Can depress overall intake
How much fat/oil can be added to a high forage diet and not decrease
fiber digestion??????
ADDED Fat levels, forage intake and digest
• Hess, et al., 2008--Optimal inclusion levels• Maintain forage digestibility, but fat may
replace some forage– 3% of dietary dry matter or less– May decrease forage intake slightly, but still
increase total dietary energy• Maintain forage digestibility and intake
– 2% of dietary dry matter or less– No change on forage intake
Jenkins, 1987, Mixed Grass Hay incubated with increasing corn oil
0
5
10
15
20
25
30
35
40
0% Corn Oil 2% Corn Oil 4% Corn Oil 6% Corn Oil 8% Corn Oil 10% Corn Oil
48 Hr In Vitro Fiber Digestibility, %48 Hr In Vitro Fiber Digestibility, %
Supports Hess, somewhere between 2-4% added fat starts to depress fiber digestion
Compared corn vs corn oil as energy
• Whitney, et al., 2000—In Vitro data & fed heifers
• Brome Hay @ 9.2% protein was the base• Equal dietary Protein concentration• Equal dietary Energy concentration
– Corn alone– Added 3% corn oil replacing part of the corn– Added 6% corn oil replacing almost all the corn
In Vitro Diets
% of Dry Matter Brome hay only Corn/ SBM
Corn/SBM +3% degummed
Soy oil
Corn/SBM +6% degummed
Soy oil
Brome hay 100 72.3 77.4 81.0
Cracked Corn 18.6 11.9 4
Soybean Meal 5.7 6.3 7.2
Soybean Oil 3 6.2
CP 9.2 11.2 11.2 11.0
ME, Mcal/lb 1 1.09 1.09 1.14
Whitney et al., 2000
In Vitro digestibility
60.468.1 66.1
61.1
24.131
34.829.3
0
10
20
30
40
50
60
70
80
Brome Hay Alone Corn/SBM Corn/SBM+3%degummed soyoil
Corn/SBM+6%degummed soyoil
In Vitro Digestibility, % 24-hr Dry matter disappearance, %
Whitney et al., 2000
*Based on NRC, ‘96 TDN values, the Corn/SBM diet is estimated to be 7.7% more digestible than the brome alone or 65.1%
Feed intake of Heifers in Exp 2 & 3soy oil replaced corn on equal energy basis
Dry basis Corn/ SBM
Corn/SBM +3% degummed
Soy oil
Corn/SBM +6% degummed
Soy oil
Brome hay, lb/hd/d 14.9 14.6 14.5
Cracked Corn, lb/hd/d 3.8 2.3 0.7
Soybean Meal, lb/hd/d 0.18 1.3 1.4
Soybean Oil, lb/hd/d 0.6 1.2
Mineral supp 0.30 0.29 0.29
Total Av. DMI, lb/hd/d 20.2 19.0 18.0
CP 11.2 11.2 11.0
ME, Mcal/lb 1.09 1.09 1.14
Total ME intake Mcal/d 22 20.7 20.5
Whitney et al., 2000
Heifer performance in Exp 2 & 3
Dry basis Corn/ SBM
Corn/SBM +3% degummed
Soy oil
Corn/SBM +6% degummed
Soy oil
Heifer ADG, lb/hd/d Exp 2 1.78 2.0 1.74
Feed efficiency,lb feed/lb gain Exp 2
9.9 8.6 9.4
Exp 2 repro
% pregnant 91.7 90.9 100
% bred AI 67 50 50
Days preg@ preg check 89.4 92.1 89.0
Exp 3 repro
% pregnant 92.9 100 92.9
% bred AI 65 73 54
Days preg @ preg check 93.3 104.6 93.8
Whitney et al., 2000
• Adding 3% corn oil replacing corn maintained or tended to improve the performance of the heifers
• Similar to the in vitro trends, adding 6% corn oil may have suppressed fiber digestion decreasing the energy delivered
Whitney et al., 2000
IMPORTANT: On low quality forages, protein in many cases is first limiting
• Need a Protein, fat, mineral supplement for the greatest potential for improved performance
• 3.5 to 4% of diet DM as fat depresses fiber digestion
• Fat can have positive effects on Reproduction– Females may see a fat effect but source and amount
of fat are important• Linoleic (Safflower)
– Tends to be energy effect rather than a fat effect
Protein• Pregnancy rates can also be greatly impacted
by protein intake• Both pre and post-calving inadequate protein
intake can lower pregnancy rates• Sasser et al. (1989) found pregnancy rates
reduces from 74% to 32% with inadequate protein intake on isocaloric diets
Randel, 1990
Effect of Dietary Protein on Pregnancy Rates in Suckled Cows and Heifers
Adequate* Inadequate* P SourcePre-Calving
84 12 <0.01 Garmendia et al, 1969
58 21 <0.02 Mobley et al, 1983
88 56 <0.11 Fleck & Lusby, 1986
Post-Calving91 71 <0.01 Kropp et al, 1983
95 80 <0.01 Hancock et al, 1985
92 76 <0.05 Rakestraw et al, 1986
* % PregnantAdapted From Randel 1990
When supplementing low quality forages <8% protein, what happens
to forage intake?????
Forage dry matter intake relative to forage crude protein concentrationSource: Adapted from Moore and Kunkle, 1995.
The impact of a small amount (1.8 lbs) of protein supplement on forage intake by
cowsItem No
suppl. + Suppl.%
change
Forage protein content,%TDN of forage, %Supplement protein, %Forage intake, lbsTotal intakeProtein in diet, %TDN in diet, lbs
545-
161657
5454221238
11
+30+41
+49
Montana Beef Network
What happens to forage digestibility when supplementing a low quality
(<8% protein) forage???
DelCurto et al., 1990a532 lb. steers-fed prairie hay
0
10
20
30
40
50
60
Dietary % CP Forage intake Total intake DMdigestibility, %
No supp13% CP Supp26% CP Supp39% CP Supp
Supplements fed @ 2.14 lb/hd/d
At what forage quality level do we lose the improvement in fiber
digestion?????
DelCurto et al., 1990a532 lb. steers-fed prairie hay
0
10
20
30
40
50
60
Dietary % CP Forage intake Total intake DMdigestibility, %
No supp13% CP Supp26% CP Supp39% CP Supp
Supplements fed @ 2.14 lb/hd/d
Cow Nutrition Effects Calf Performance
• Research suggest that cows with adequate nutrition cycle earlier and conceive sooner then cows with inadequate nutrition
• Cows that conceive earlier calve earlier!• Typically age is the great determinate of calf
weight– i.e. calves that are older weigh more
Funston et al., 2012
*
*Conceived 10 days later. French et al, 2012
Take Home• Nutrition and reproduction are highly related• Inadequate protein and energy pre and/or
post-calving can increase postpartum interval and reduce conception rates on first cycle
• Older calves weigh more• 11/21/13 528 lb steers brought $1.91/lb
– $1008.48
Questions?