Final report for FW22-394
Project Information
This is a pilot study for a larger proposal incorporating more producers and more lambs. Commercial ewe lambs are difficult to get pregnant in their first year and are typically held a year before breeding. Producers that put rams in with ewe lambs have little success (15 to 25%). Other producers don't introduce rams and simply hold the lambs over to the following year. Ewe lamb breeding issues include lamb weight relative to mature weight and the exposure to a ram prior to the actually breeding period. Breeding in the first year increases productivity of the ewe by 20% or more. The growth of the lambs were measured throughout the study. Twin white faced lambs were organized into two groups, one twin was put in the early weaned (EWL) group and the other remained with the mother (NWL) until normal weaning. Another set of twins (CTRL) remained with their mother until normal weaning. The EWL was weaned at three months of age when the flock was moved from the spring range to the summer range. Once weaned the EWL group were fed a ration that is composed of alfalfa hay, corn/barley and soybean meal. Feed intake and growth of the EWL was measured. When the flock was moved from the summer range and the lambs were weaned, the NWL and one twin from the CTRL group was moved to the lots where the EWL were housed and fed the EWL ration for 30-days prior to the rams being introduced. Rams were introduced 30-days prior to the actual breeding period and remain for two weeks. The rams were removed for two weeks then returned for 30 days. Pregnancy was determine by blood assay thirty-days after removal of the rams . We will continue to monitor the growth of these ewes and their lambs until they wean their lambs in the fall. We will track the cost and determine the economic benefit of early weaning. Increasing productivity of the ewe lambs will increase income for the producer. Pamphlets and videos will be produced and disseminated to producers.
The focus of this research is to determine if range ewe lambs can be bred at seven to eight months of age and is it economical. Our objectives include:
- Determine if early weaning commercial ewe lambs can result in increased pregnancies at 8 months of age.
- Determine the percentage bred, lambed, and weaned of early weaned ewe lambs.
- Determine if early weaning is economically beneficial.
Our hypothesis is that the early weaning of range ewe lambs is economically beneficial and will result in the ewes bred in their first year.
We propose to begin the research on April 15th, 2022 when the ewes begin to lamb. We propose to submit our final report by December 15th, 2023. Birth of the lambs will begin on April 15, 2022. Weaning will occur on July 1st. Breeding will occur on November 1st. Ewe lamb lambing will occur on April 15th, 2023. Weaning of lambs will occur on September 1st, 2023.
Cooperators
- - Producer
- - Technical Advisor (Educator and Researcher)
Research
The focus of this research was to determine if range ewe lambs can be bred at eight months of age and is it economical. Our objectives include:
- Determine if early weaning commercial ewe lambs can result in increased pregnancy rate at 8 months of age.
- Determine the percentage bred, lambed, and weaned of early weaned ewe lambs.
- Determine if early weaning is economically beneficial.
We hypothesize that the early weaning of range ewe lambs is economically beneficial and will result in the ewes bred in their first year.
Materials and Methods:
To answer our objectives twenty-four “range” ewes from our commercial sheep operation that lambed twin ewe lambs were selected. The use of the sheep in this study was under the guidance of the BYU IACUC (#22-0608). The twin ewe lambs chosen were white face typically raised as replacement ewes. At birth (April 1st to ~ April 15th) the lambs were weighed, and ear tagged to identify the twins and the groups they were allotted to. These lambs were designated as the F1 lambs and twins were randomly allocated to either the early weaned group (EWL) or the normal weaned group (NWL). An additional twenty-four ewes, with twin ewe lambs, were selected, lambs tagged and were designated as CTRL.
Two weeks after birth (May 1st to May 30th), the ewes and lambs were moved to lamb pastures (LP; Fountain Green, UT,USA). On June 10th the lambs were weighed prior to being moved to the spring range (SR; 2150 to 2506 m elevation, 39.705°, -111.590° N, 39.686°, -111.559° E, Fountain Green, UT, USA). The ewes and lambs were moved from the SR to corals for transport to the mountain range (MR) on July 22nd. The lambs were weighed and the EWL sorted out, weaned and weighed. The ewes and remaining lambs were shipped to the MR (2191 to 2550 m elevation, 39.91°, -111.16° N, 39.88°, -111.12° E, Scofield, UT, USA). The EWL lambs were divided into four groups and housed in drylot pens.
The EWL were housed in drylot pens (6 lambs per pen) with free choice water and trace mineral available. The lambs were fed an alfalfa-based diet supplemented with corn/barley and soybean meal (see Table 1.). The diet was formulated to be simple and meet nutrient requirements and maximize growth. Feed intake was determined weekly and adjusted to provide 10% above intake. Lambs were weighed every two weeks. Average daily gain and feed efficiency were calculated to monitor how the lambs were growing.
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Table 1. Feed compositiona of the diet components expressed on a percent dry matter basis. |
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Alfalfa hay |
Corn/Barley |
Soybean Meal |
|
Dry matter |
90.6 |
88.6 |
89.7 |
|
Crude protein |
21.3 |
12.6 |
50.6 |
|
NDF |
38.1 |
15.8 |
12.1 |
|
ADF |
31.4 |
5.4 |
7.5 |
|
Lignin |
6.9 |
1.3 |
- |
|
NFCb |
28.8 |
65.2 |
27.7 |
|
Starch |
0.8 |
51.7 |
- |
|
Fat |
2.4 |
2.8 |
1.8 |
|
Ash |
9.5 |
3.6 |
7.7 |
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ME, Mcal/kg |
2.44 |
3.35 |
3.61 |
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NEL, Mcal/kg |
1.43 |
1.94 |
1.83 |
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NEm, Mcal/kg |
1.32 |
2.02 |
1.89 |
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|
|
|
|
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Diet composition, % |
51.0 |
45.0 |
4.0 |
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Cost, $/pound |
0.16 |
0.35 |
0.54 |
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Average intake, #/d |
4.0 |
|
|
|
Daily cost, $/d |
0.09 |
0.14 |
0.02 |
|
|
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Total feed cost, $/d |
1.00 |
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aWet chemistry analysis by Dairy One, Ithaca, NY bNFC = non-fiber carbohydrate
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When the sheep were moved from the MR, the NWL and CTRL lambs were weighed and weaned. The EWL, NWL and one CTRL (CTRLTMR) twin were fed the same diet (diet fed to the EWL) and treated the same for the remainder of the study. The other CTRL lambs were moved with non-study ewe lambs to a pasture. From October 15th to November 1st rams were put in with the ewe lambs to initiate estrus cycling. The rams were removed and returned on November 15th for breeding. Ewe lambs were housed together during the breeding period at a ratio of 1 ram:20 ewe lambs. Rams were removed on December 15th. Ewe lamb pregnancy was determined by blood analysis on January 15th. Ewe lambs were moved to the pasture where the rest of the replacement ewe lambs were for the remainder of their gestation. Ewes were sheared March 15th, two weeks before lambing began. The pregnant EWL, NWL and CRTL lambs were separated and placed in the lambing pens. At lambing, the number of lambs (F2 lambs) born, and the weight of the ewes and their lambs were recorded. The ewes and their lambs were moved to lambing pastures then to SR and then to the MR. When the sheep were moved from the MR, the F2 lambs were weaned, weighed, and the percentage of weaned lambs from the ewe lamb groups determined.
This study was organized so that statistical analysis can be used to determine differences between each group of lambs. The EWL group was compared to the NWL lambs as twins. The growth and production of the EWL and NWL lambs were compared to the CTRL lambs as single reared to twin reared for growth and each group compared to each other for reproductive efficiency. This approach allowed us to compare the effects of early weaning lamb production to normal weaning practices. The CTRL group were raised and weaned as we typically do, while splitting the CTRL into a TMR (CTRLTMR) diet fed group and a pasture breeding group showing the effect a 30-day nutrient dense diet can have on breeding efficiency. These comparisons provide information on which method is most economically beneficial. The economic benefit of early weaning was determined using the labor and feed costs against the F2 lambs born, weaned and income from the sale of the F2 lambs.
Environmental issues (drought) altered typical movement chronology between pastures and ranges. Lambing began on April 5th and ended April 19th. The EWL (n=22) group were divided into four pen groups. Dry matter intake (DMI) was determined. Bodyweights are presented in Table 2. The lambs on the MR were moved from the range and weaned on October 8th. The four groups were weighed and the NWL (n=19) and one twin from the CTRL (CTRLTMR; n=17) were transitioned to the EWL TMR. The other CTRL (n=17) twin group was moved to the pasture with other ewe lambs not on the study. The weight data collected from the NWL and CTRLTMR groups were not different and are combined and designated as NWL. The EWL and NWL groups were weighed every two weeks until November 15th. During this period the EWL and NWL groups were fed the TMR ration at a rate of 3.7 pounds per lamb per day. On October 15th the rams (obtained from Joel Shepherd, Shepherd Suffolks, Moroni, UT, USA) were fitted with marking harnesses and introduced into the pen with the ewe lambs at a ratio of 1:20. The rams were removed on November 1st. On November 15th the rams were reintroduced for the 30-day breeding period into the EWL and NWL drylot pen and to the pasture CTRL group. The rams were removed on December 15th. The lambs were weighed on December 15th. Pregnancy was determined by blood analysis.
F1 Ewe Lamb Weights
Weights of the lamb groups at birth, before being moved to the SR and when moved to the MR were not different between the three groups. The EWL lambs weighed 115 pounds at the normal weaning time (Oct. 8, 2022) all of the lambs were weaned. The weaning weights of the other groups were significantly less at 93 pounds for NWL and 82 pounds for the CTRL group. The NWL lambs weight gain increased once they were fed the TMR ration, but their live weights were still significantly less than the EWL group.
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Table 2. Changes in weights from birth to lambing. |
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EWL |
NWL |
CTRL |
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Birth WT, lbs |
13 |
12 |
13 |
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To Spring Range WT*, lbs |
52 |
53 |
47 |
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To Mountain Range WT, lbs |
68 |
68 |
65 |
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Normal wean WT, lbs |
115 |
93 |
82 |
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Beginning Breeding, lbs |
127 |
110 |
84 |
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End of Breeding, lbs |
140 |
123 |
86 |
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F2 Lambing |
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Ewes |
123 |
116 |
** |
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Lambs |
11.5 |
10.5 |
** |
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F2 Weaning |
|
|
|
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F1 Ewes |
141 |
143 |
144 |
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F2 Lambs |
102 |
102 |
** |
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EWL = early weaned lambs; NWL = normal weaned lambs; CTRL = normal weaned lambs treated as normal *Wean weight for EWL group **No data |
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Reproductive Efficiency
The EWL group had a conception rate of 98%. When they lambed, they had a 105% lambing rate for the 22 ewes (22 total ewes in the group, 1 not pregnant, 2 did not lamb, 23 lambs produced). The NWL group had a 65% conception rate and a 64% lambing rate for the 36 ewes (36 total ewes, 12 not pregnant, 3 did not lamb, 23 lambs produced). The lambs born from the EWL and NWL are designated as F2 lambs.
F2 Lambing and Weaning Data
The F1 ewes lambed between March 20 to April 15, 2023. The lambs were identified with ear tags that included the mother's ID. The ewes and the lambs were weighed on the day of parturition. The EWL ewes averaged 123 pounds and the NWL ewes averaged 116 pounds. EWL lamb birth weights averaged 11.5 pounds, while the NWL lambs averaged 10.5 pounds.
The weaning date for 2023 was October 1st. The EWL ewes that lambed weighed 141 pounds and the NWL ewes weighed 143 pounds. The ewes from the CTRL group weighed 144 pounds. No differences were found between the F2 wean weights, the average for the lambs was 103 pounds.
Economics
The cost of alfalfa was $350 per ton ($0.18/pound). The barley/corn grain cost $0.35 per pound and soybean meal was 0.49 per pound. Based on the diet composition (Table 1) the cost of the TMR was $0.25 per pound. The cost per lamb per day was $0.93. The EWL lambs were fed the TMR for 146 days at a cost of $136 per ewe. The NWL lambs were fed for 66 days at a cost per ewe of $61.
The lambs were sold for $2.11/pound. Lambs weighed 102 at weaning. Income from the 17 EWL lambs was $3,659 ($166/ewe for the 22 ewes) and for the 18 NWL lambs $3,874 ($108/ewe for the 36 ewes).
Income for each of the 22 EWL ewes was $30/ewe and $47/ewe for the 36 NWL ewes. Not included in the income from breeding these ewe lambs is the labor. One hour/day was spent feeding these lambs.
Conclusion
Producers need to decide if feeding a TMR to ewe lambs is worth the effort. Our conclusion is that, for the effort, feeding normal weaned lambs a TMR from weaning to breeding was the best method for ewe lamb production under these conditions. Further research is needed to follow lambing differences between the ewe lambs that did lamb and those that did not. Based on producer input, further studies are needed to see what affect breeding ewe lambs has on their production longevity.
Research Outcomes
Producers need to decide if feeding a TMR to ewe lambs is worth the effort. Our conclusion is that, for the effort, feeding normal weaned lambs a TMR from weaning to breeding was the best method for ewe lamb production under these conditions. Further research is needed to follow lambing differences between the ewe lambs that did lamb and those that did not. Based on producer input, further studies are needed to see what affect breeding ewe lambs has on their production longevity.
Education and Outreach
Participation Summary:
We have visited with producers face to face, explained our study and talked about the results. We put together a fact sheet that they could read. Dr. Robinson attended the West Central States Wool Growers meeting in Boise, ID November 3, 2023 and visited with producers attending.
We have visited with producers in our area about some of our results. When asked what their management of ewe lambs is they respond with they do not breed until they are yearlings. They tell us that it is because that's the way it's always been done!! Presenting our findings and the economics resulted in the same response from most of the producers... What affect will it have on the ewe's production longevity. We asked them if they knew that the ewe's production longevity would not be affected, would they consider TMR feeding there weaned ewe lambs and breeding them. The result was about 50% would consider breeding ewe lambs, the remainder were not sure they had the manpower to feed their lambs a TMR rather than putting them out on pasture.
Education and Outreach Outcomes
Of the 29 producers we visited with, all of them were interested but the majority would not consider changing until we could tell them what affect breeding ewe lambs would have on production longevity. They wanted to know if lambing a year early would increase the ewes lambing in the future. Based on feedback from producers, more research needs to be done to find out if the ewe is more productive as she gets older.
Economic potential
Ability to increase lamb weight between lambing and breeding.