Effect of Continuous Suckling/”Ewe-rearing” on Growth and Level of Parasitism of Lambs and on Productivity and Profitability of Lamb Operations

Effect of Continuous Suckling/”Ewe-rearing” on Growth and Level of Parasitism of Lambs and on Productivity and Profitability of Lamb Operations

Summary

The purpose of this project is to evaluate the effect of continuous suckling/“ewe-rearing” on growth, intestinal parasitism, and productivity and profitability of sheep production in Appalachia. Weaning at approximately 3-4 months of age is routinely practiced by most lamb producers. One reason weaning is practiced is so that lambs can be placed into feedlots and grown and fattened to reach market weight and condition. However, weaning prior to slaughter may not be necessary as there is an increasing demand for younger lambs at lighter slaughter weights with minimal finish.

Weaning has been associated with psychological and nutritional stress on the lamb that might compromise the growth, immune function, and welfare of the young animal resulting in an overall decline in productivity. In some studies, continuous suckling has been shown to lower susceptibility to parasitism and increase pre-slaughter growth rates of lambs. Worm burden has been shown to be reduced in young lambs consuming milk compared to their counterparts on dry-feed. Higher growth rates have been observed in late-weaned and un-weaned lambs. The proposed study will further examine the impact of continuous suckling on growth rate and potential interactions with type of diet.

An increase in the demand and price for lighter (< 100 lbs) market lambs in the Northeastern United States, suggests that market weights can potentially be achieved by 3-5 months of age. Lambs for this market can be finished on pasture while still suckling their dam and in so doing avoid the stress of weaning and subsequent effects on the health and growth of the lambs. If successful, the results of this study will lead to the development and adoption of a low-cost, simple management strategy that can enhance agriculture sustainability by increasing productivity and profitability of sheep enterprises while improving the health and welfare of lambs.

Objectives/Performance Targets

The overall objective of the proposed project is to investigate the potential benefit of continuous suckling/“ewe rearing” on the productivity of sheep enterprises. The specific objectives include:

1. To determine the effect of continuous suckling/“ewe-rearing” with and without supplementation on growth rate of lambs The project commenced in May on one of the University farms, when the spring born lambs were at the proper age (about 3 months). They were divided into 4 groups: suckling, supplemented (SS); suckling, no supplement (SU); weaned, supplemented (WS); and weaned, no supplement (WU). The lambs were weighed every two weeks for three (3) months. In August when one of our producers had lambs of approximately three months of age we started a trial with 2 groups, both being supplemented with one group weaned and one continuously suckling.

2. To determine the effect of continuous suckling/“ewe-rearing” with and without supplementation on degree of parasitism of lambs Within the four groups: SS, SU, WS, and WU, 10 lambs were randomly chosen from which to take fecal samples and 6 lambs from each of the groups were randomly chosen from which to collect blood samples . The fecal samples were collected at initiation and once a month thereafter. Fecal samples were processed using McMaster’s solution and fecal eggs were counted. The blood samples were used to assess packed cell volume (PCV). This data is in the process of being analyzed.

3. To determine the effect of continuous suckling/“ewe-rearing” on weight and body condition changes of ewes The dams of the lambs were assigned a body condition score and weighed initially then once a month following initiation of the study. Data is currently being analyzed.

4. To compare the economic benefit of continuous suckling/“ewe-rearing” of lambs to market to the traditional practice of weaning lambs and fattening to market The lambs were sold at the end of the study in order to assess the potential economic benefit. We have yet to analyze the economic impact of this project as of yet. We are scheduled to do this in the first part of 2014.

Accomplishments/Milestones

For 2012, lambing records were obtained and animals were identified for the project. The project was initiated a bit later that anticipated due to when the lambs were born. The lambs were broken into the four random groups, weighed, and blood and fecal samples collected from the University farm and in two groups on the producer’s farm. The ewes were assigned a body condition score (BCS) and weighed. All of the animals were evaluated for parasite load using the FAMACHA system; lambs and ewes were treated with anthelmintic, if necessary. The lambs were weighed approximately every two weeks and the fecal and blood samples were collected every other time they were weighed (once a month). The ewes were weighed once a month. After collection, fecal samples were processed within 7 days using McMasters solution, and fecal egg counts were determined. Blood collected was used to determine Packed Cell Volume (PCV).

We have collected quite a bit of additional data that we are working on analyzing. Previous analysis has suggested that suckling lambs have a greater growth rate than weaned lambs, regardless of supplementation; however, the data collected over the past year needs to be added to the data that was already analyzed.

Impacts and Contributions/Outcomes

The growth characteristics of experimental lambs are included in Table 1. Birth weights, the average age at start, initial weights, and pre-average daily gain were all significantly different between the two replicates (Table 1). The end weights differed between the two replicates (p=0.0011) while the overall weight gain and the overall average daily gain was not significantly different between replicate 1 and replicate 2. This possibly was due to starting the second replicate an average of 12 days later than the first.

The growth performances of the lambs used in replicates 1 and 2 are included in Table 2 where the growth performance data from the two replicates were pooled together. The age at start and initial weights were not significantly different between the treatments. The overall average daily gain (ADG) during the trial period was higher in the suckling lambs than in the weaned lambs. The supplemented lambs had a significantly higher ADG than those that were not supplemented. Likewise, Overall weight gain was greater in suckling lambs and supplemented lambs. End weights were significantly greater in suckling as well as in supplemented lambs. Supplement X weaning system (P =0.1) among supplemented lambs, there was a tendency for higher growth rates in continuous suckled than in weaned lambs. There was a significant interaction between supplementation and replicate.

We have written a draft of a paper with these results from the last year and the trial we ran prior to that. The results of these studies have direct implications on the management practices that producers might employ to enhance the productivity and profitability of small-scale sheep operations in the Northeastern United States. As soon as the current data is completely analyzed, a bulletin will be written for the West Virginia Small Ruminant Producers (WVSRP). A power point presentation was prepared for the Annual Sheep short course, however because of location, the equipment needed was not available and it was not presented, but it is be put on the website of the WVSRP. The results still to be analyzed will also be presented to producers at the Annual Short-course held by the WVSRP, which has had an average attendance of over fifty producers and eight extension agents. We presented the data we collected last year at the Animal Science Joint Annual Meeting in Indianapolis. We also intend to present the data that is still to be analyzed at one of the Animal Science meetings in the coming year. Finally, we intend to discuss our results with all of the producers with which we routinely work.

• Weaning Tables

Collaborators: