@article {51532, title = {Diet selection of cattle and bonded small ruminants grazing arid rangeland}, journal = {Sheep Research Journal}, volume = {8}, number = {1}, year = {1992}, month = {1992}, pages = {11-18}, abstract = {

Cattle, sheep and goats, when together on the same range are referred to as grazing in common, or as being managed under mixed grazing (Allen, 1991). Most mixed grazing schemes are designed to take advantage of dietary differences among livestock species. Grazing strategies involving more than one animal species should promote more uniform forage utilization and greater livestock production than is possible under single species grazing (Anderson et al., 1985).

}, keywords = {goats, grazing behavior, liveweight, microhistological analysis, Mixed stocking, sheep}, url = {/files/bibliography/389.pdf}, author = {Clarence V. Hulet and D.M. Anderson and V.B. Nakamatsu and L. W. Murray and Pieper, Rex D.} } @article {51531, title = {Effects of age and flock size on flocking behavior in Rambouillet and Rambouillet x Polypay female sheep}, journal = {Sheep Research Journal}, volume = {8}, number = {3}, year = {1992}, month = {1992}, pages = {112-115}, abstract = {

Although intraspecies cohesiveness or flocking behavior in some breeds of adult sheep is well recognized (Hunter,1960), age effects and numbers of sheep within and among ages independent of maternal attachment is not clear. Young ewe lambs from our New Mexico flock just weaned from their dams refused to stay with a group of adult ewes bonded to cattle (flerd). In contrast, a group of yearling ewes tenaciously stayed close to peer yearling ewes bonded to cattle (Anderson et al.,1988). In attempts to increase the numbers of young bonded lambs in flerds we observed that when group size approached or exceeded 12, lambs frequently became independent of cattle and formed small independent lamb groups. However, when the original small confinement groups were maintained as separate units until the lambs were 6 months or more of age, the small flerd could be combined into larger groups and would maintain close affinity quite consistently (Hulet,1989). Bonded older lambs, yearlings and mature ewes have been maintained in large groups (\>80) with cattle with consistent close affinity of the sheep to cattle over long periods of time (\>3 years). These contrasting behaviors raised the question as to the age at which the flocking instinct, independent of maternal attachment, expresses itself.

}, keywords = {behavior, flocking, management, sheep}, url = {/files/bibliography/390.pdf}, author = {Clarence V. Hulet and D.M. Anderson and Shupe, W. Larry and L. W. Murray} } @article {51533, title = {Field versus pen bonding lambs to cattle}, journal = {Sheep Research Journal}, volume = {8}, number = {2}, year = {1992}, month = {1992}, pages = {69-72}, abstract = {

Complementary grazing of cattle and sheep promotes more uniform and efficient utilization of forages, because of differences in dietary preferences (Stoddard and Smith, 1943; Baker, 1985). Therefore, it is possible to co-graze 2 or 3 sheep for each cow on many ranches without reducing cow numbers. However, coyote predation and locating sheep in shrub infested pastures conducive to coyote predation are two challenges that confront mixed-species management systems (Etchepare, 1985; Merrill, 1985).

}, keywords = {behavior, bonding, mixed-species stocking, predator, sheep}, url = {/files/bibliography/391.pdf}, author = {Clarence V. Hulet and D.M. Anderson and Shupe, W. Larry and L. W. Murray} } @article {51572, title = {Bonding of Spanish kid goats to cattle and sheep}, journal = {Applied Animal Behavior Science}, volume = {30}, year = {1991}, note = {Reprinted with permission from Elsevier, {\textcopyright} 1991. http://www.sciencedirect.com/science/journal/01681591}, month = {1991}, pages = {97-103}, abstract = {

Spanish kid goats, white-face range lambs, and yearling beef heifers were used to study the effects of close interspecies confinement on bonding of the small ruminant species to each other or to cattle. Treatment groups consisted of (1) 3 Spanish kids, 3 heifers and 3 young lambs (43{\textendash}53 days with no previous exposure to cattle); (2) 3 Spanish kids, 2 heifers and 3 older lambs (74{\textendash}105 days with some previous exposure to cattle). Each of these treatments was replicated three times. During field testing, following 30 days pen confinement, the older lambs stayed closer (P\<0.05) to the heifers than did the younger lambs. However, no difference (P\>0.05) existed between young and old lambs following 60 days pen confinement. Spanish kids did not differ (P\>0.05) in the degree of bonding from lambs. After testing at 60-days, the groups originally confined together were re-combined and sorted into kid-heifer and lamb-heifer groups and tested at pasture for affinity of kid goats to heifers and lambs to heifers, independent of the other small ruminant species. Lambs separated from cattle during the 3-h test; whereas kid goats consistently stayed with cattle. In an extended field test, kid goats stayed with cattle over a 5-consecutive-day test with no observed separations. It was concluded that Spanish kids can bond to cattle and stay with them under free-ranging conditions. The data also suggest that with lambs, a bond may become stronger as the time of close association is extended beyond 30 days.

}, doi = {10.1016/0168-1591(91)90088-F}, url = {/files/bibliography/373.pdf}, author = {Clarence V. Hulet and D.M. Anderson and J. N. Smith and Shupe, W. Larry and L. W. Murray} } @article {51573, title = {Can multi-species grazing help protect stock from coyotes?}, journal = {National Wool Growers{\textquoteright} Magazine}, volume = {81}, number = {(3)}, year = {1991}, month = {1991}, pages = {32-33}, abstract = {

Stocking ranges or pastures with more than one animal species often \ contributes to a more uniform and complete use of the available while providing a higher net return to producer. Cattle prefer grass, sheep \ prefer forbs (weeds) and goats prefer browse (shrubs and trees).

}, url = {/files/bibliography/372.pdf}, author = {Clarence V. Hulet and D.M. Anderson} } @article {51668, title = {Behavior, a key to more efficient and profitable lamb and wool production - a review}, journal = {SID Research Journal}, volume = {5}, year = {1989}, month = {1989}, pages = {26-33}, author = {Clarence V. Hulet} } @proceedings {51667, title = {Managing sheep to optimize profit}, year = {1989}, month = {1989}, pages = {17-32}, address = {Louisville, KY}, abstract = {

Sheep production is one of the oldest human agricultural enterprises. Management techniques for improving performance date from the earliest flocks. In the beginning and for hundreds of years, improvements in management were entirely dependent on the observational skill or "eye of the shepherd." Fifty years ago, fall-lambing was limited mostly to Dorset sheep. Range sheep operators wanted only one lamb per ewe. Most of the extra lambs were sacrificed and ewes were not bred before they were 18 months of age. A sick sheep was considered a dead sheep.

}, url = {/files/bibliography/349.pdf}, author = {Clarence V. Hulet} } @article {51666, title = {A Review: Understanding sheep behaviour, a key to more efficient and profitable lamb and wool production}, journal = {SID Research Journal}, volume = {5}, year = {1989}, month = {1989}, pages = {26-33}, abstract = {

A knowledge of sheep behavior can help to improve production efficiency. Flocking instinct and social attachments provide methods to improve the efficiency of managing sheep through bonding to cattle to reduce loss to predation and minimize stress at weaning. Characteristics of sheep movement behavior have contributed to the design of efficient sheep-working facilities and management systems. Cattle, sheep and goats are complementary in transforming the range resource into red meat and fiber. Grazing behavior and diet learning are leading to improved forage utilization and range management. Periodic exposure of rams to ewes increases testes size, fertility and libido. Exposure of ewes, previously isolated from males, to rams during the transitional period between the non breeding and breeding season can initiate early breeding and fall lambs. Ewe lambs are shy breeders and should be mated separately from mature ewes. Orphan lambs can be fostered to ewes with extra milk utilizing odor transfer techniques resulting in higher and more efficient lamb production. Stress management can improve rate of gain following weaning and in feedlot lambs.

}, keywords = {behavior, management, production, sheep}, url = {/files/bibliography/347.pdf}, author = {Clarence V. Hulet} } @article {51722, title = {Bonding of goats to sheep and cattle for protection from predators}, journal = {Applied Animal Behavior Science}, volume = {22}, year = {1988}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1988. (http://www.sciencedirect.com/science/journal/01681591)}, month = {1988}, pages = {261-267}, abstract = {

Fourteen 5-month-old mohair goats previously confined with heifers for 60 days were randomized into two groups. Group 1 was confined with two heifers for an additional 14 days. Group 2 was confined with eight previously cattle-bonded sheep and a heifer for 14 days. A third group of six non-bonded sheep and seven goats, and three heifers with calves served as a control. The three groups were randomized among three brushy range pastures averaging 190 ha and rotated whenever a goat or sheep was found dead or missing. Control goats, control lambs and Group 1 goats were observed to move independently of the cattle. Group 2 goats consistently stayed with the bonded sheep and cattle. Sheep and goats which did not stay with cattle were killed by predators starting 5 days after going to pasture. Within 10 days all goats, one lamb from the control group and six of the seven goats from Group 1 were dead, wounded or missing. Only the smallest goat in Group 2 was lost. This group was rotated among the three pastures for an additional 21 days with no further loss.

}, doi = {10.1016/0168-1591(89)90021-X}, url = {/files/bibliography/330.pdf}, author = {Clarence V. Hulet and D.M. Anderson and J. N. Smith and Shupe, W. Larry and D.A. Taylor Jr. and L. W. Murray} } @proceedings {51724, title = {Bonding to facilitate multispecies grazing}, year = {1988}, month = {1988}, pages = {42-43}, abstract = {

Cattle, sheep and goat diets have been shown to be complementary for efficient range forage utilization. Multispecies grazing has therefore been recommended, but has generally remained unimplemented because of unacceptably high predation losses of sheep and goats. An account of the social attachment of a ram to horses the temporary attachment of individual wether sheep to steers and of guard dogs to sheep suggested that social bonding of sheep and goats to cattle might be possible. Cattle protect their calves from predators. If bonding would occur then the close association of sheep and goats to cattle might provide protection from predation by coyotes and dogs.

}, url = {/files/bibliography/334.pdf}, author = {Clarence V. Hulet and D.M. Anderson and Shupe, W. Larry and J. N. Smith} } @article {51723, title = {Effects of breeding season, nutritional environment and lambing management on lamb production of Southwest Rambouillet ewes}, journal = {Theriogenology}, volume = {29}, number = {6}, year = {1988}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1988. (http://www.sciencedirect.com/science/journal/0093691X)}, month = {June 1, 1988}, pages = {1295-1302}, abstract = {

Effects of season, nutritional environment and lambing management were studied on the numbers and weights of lambs produced in fine-wool sheep in southwestern New Mexico over a 2-yr period. One group of ewes was maintained and lambed on arid range (range-range). A second group was maintained on range except during lambing and early lactation (range-pasture). The third group was maintained on irrigated pasture (pasture-pasture). Groups 2 and 3 were lambed together on irrigated pasture or in drylot, depending on the season, and maintained as one group on pasture until the lambs averaged 60 d of age. At about 60 d of age, all lambs were weaned and fed in the drylot as one group. Fall lamb production was much lower (P\<0.001) than at other seasons of the year. Changing the breeding time for the fall lambing from April to mid May greatly improved lamb production. The primary problems with fall lambing appeared to be a lower percentage of ewes showing estrus and a lower twinning rate. Lamb production based on birth and survival rate and weaning weights of ewes lambing on range was markedly lower to lamb production of range-managed ewes lambing in drylot or on pasture (P\<0.001). The difference was primarily due to low lamb survival on the range. The causes of loss appear to be predation, deficient mothering ability and exposure. Lambing season had no real effect on wool production, but pasture-managed ewes produced 0.4 kg more grease wool than ewes kept continuously on the range (P\<0.05). Lamb production can be improved by lambing ewes in drylot or on pasture, by avoiding lambing during coldest months, and by providing shelter from cold and wind the first 3 d of life.

}, keywords = {breeding season, lamb production, lambing management, nutrition, rangesheep}, doi = {10.1016/0093-691X(88)90009-X}, url = {/files/bibliography/335.pdf}, author = {Clarence V. Hulet and Shupe, W. Larry and L. W. Murray} } @article {51779, title = {Bonding of sheep to cattle as an effective technique for predation control}, journal = {Applied Animal Behavior Science}, volume = {19}, year = {1987}, note = {Reprinted with permission from Elsevier, {\textcopyright} 1987. http://www.sciencedirect.com/science/journal/01681591}, month = {1987}, pages = {19-25}, abstract = {

Nine lambs that had been bonded to cattle were placed with 7 heifers in pastures frequented by coyotes (Canis latrans) to determine whether multi-species grazing with bonded lambs would reduce predation. Unbonded lambs were grazed alone in a nearby pasture. Bonded lambs with cattle and unbonded lambs were rotated among pastures to reduce pasture bias. None of the bonded lambs were lost to predation during the entire 163-day study (Trials 1, 2 and 3). Four of 8 unbonded lambs were lost, presumably to predators, during a 19-day period, and 9 of 15 unbonded lambs and ewes were lost to predation during a later 43-day period. Bonding sheep to cattle may be an effective method for reducing coyote depredation on sheep.

}, doi = {10.1016/0168-1591(87)90198-5}, url = {/files/bibliography/318.pdf}, author = {Clarence V. Hulet and D.M. Anderson and J. N. Smith and Shupe, W. Larry} } @article {51778, title = {Coyotes, guard dogs and electric fences}, journal = {Rangelands}, volume = {9}, year = {1987}, month = {1987}, pages = {102-105}, abstract = {

In 1983 sheep were introduced on the Jornada Experimental Range (JER) in southwest New Mexico to determine if cattle and sheep grazing would lead to more efficient utilization of the range. It was rumored that there were many coyotes in the area and predation was expected to be a serious problem. A year after the sheep were introduced, the Fishery and Wildlife Sciences Department at New Mexico State University (NMSU) in cooperation with USDA estimated from scent-post visitations and helicopter gunning that coyote density was 1 per 2.7 square miles (Kumm 1985).

}, keywords = {fencing, predation, sheep}, url = {/files/bibliography/319.pdf}, author = {Clarence V. Hulet and Shupe, W. Larry and V. W. Howard Jr.} } @article {51836, title = {Effects of nutritional environment and ram effect on breeding season in range sheep}, journal = {Theriogenology}, volume = {25}, number = {2}, year = {1986}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1986. (http://www.sciencedirect.com/science/journal/0093691X)}, month = {February 1, 1986}, pages = {317-323}, abstract = {Effects of season, nutritional environment, and presence of rams on incidence and rate of ovulation in fine-wool sheep in southern New Mexico were investigated over 14 months (February 1983{\textendash}March 1984). Number of corpora lutea (CL) were observed each month by laparoscopy in random samples from six ewes in each subgroup. Seasonality of ovulation in fine-wool sheep managed on range was much more marked than in animals managed on alfalfa hay in drylot. Incidence of ovulation approached zero in range-managed ewes during May, June, and July (8\%, 0\%, 4\%) but was higher (P<0.05) in the alfalfa-drylot group (42\%, 17\%, 75\%), respectively. Although the incidence remained lower (P<0.05) in August in range-managed than in drylot ewes (50\% and 83\%, respectively), both groups were ovulating at a high rate during September through January. Incidence of ovulation dropped dramatically both years in the range-managed group in February compared with that of the alfalfa-drylot group (48\% and 36\% vs 100\% and 83\%). Mean ovulation rate per ewe ovulating did not differ (P>0.10) between nutrition groups within the 14 months. Body weight was related to CL number during periods of seasonal transition only. Continuous or intermittent presence of a ram had no real effect on either incidence or rate of ovulation during the transitional months. Nutritional environment can affect seasonality of breeding in fine-wool range sheep. This effect may not be consistently modified by presence of rams.}, keywords = {breeding season, nutrition, ovulation, ram effect, range sheep}, url = {/files/bibliography/300.pdf}, author = {Clarence V. Hulet and Shupe, W. Larry and Ross, T.T. and Richards, W.A.} } @proceedings {51835, title = {Managing ewes for more lambs}, year = {1986}, month = {1986}, pages = {76-78}, abstract = {

Studies have clearly demonstrated that the best way to increase profitability in the sheep business is to increase the number of lambs born per lambing. It is then obvious the more of these additional lambs that survive to market weight, and the more quickly they reach that weight, the more profitable they will be, in most cases. This presentation will be limited to the first two of these three important factors affecting sheep production profitability.

}, url = {/files/bibliography/298.pdf}, author = {Clarence V. Hulet} } @proceedings {51834, title = {Polypay sheep and their usefulness in farm flock operations}, year = {1986}, month = {1986}, pages = {89-103}, abstract = {

The shepherding of sheep is essentially as old as the existence of man. Man{\textquoteright}s very survival, especially in harsh environments, at times has been very dependent on the attributes of sheep. His wealth has been equated to the number of sheep he owned, and his comfort and well-being were greatly enhanced by his flock of sheep.

}, url = {/files/bibliography/299.pdf}, author = {Clarence V. Hulet} } @inbook {51917, title = {Advances in reproductive management techniques for more efficient and profitable lamb production}, year = {1984}, month = {1984}, pages = {359-367}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

From about 1960 until 1980, sheep numbers in the U.S. declined steadily from about 35 million down to about 12 million head. The rapid and large decline greatly concerned sheep industry leaders because volume is often critical to efficient marketing, transporting, slaughtering, and merchandising.

}, url = {/files/bibliography/262.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @inbook {51916, title = {Animal behavior and production efficiency}, year = {1984}, month = {1984}, pages = {387-397}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

Animal performance is greatly affected by stress that can result from physical, social, mental, psychological, and emotional factors, individually or in combinations. It has been documented that cattle gain better when cared for by a kindly gentle person than by one who dislikes cattle. Emotional stress can cause duodenal ulcer and death in dogs. There is no reason to believe that sheep are not subjected to emotional and psychological stress. The stress of weaning, shipping, and even a change of feed can lead to poor performance and even illness and death. The objective of this discussion is to make us more aware of social, emotional, and psychological factors that may limit or enhance productivity in sheep.

}, url = {/files/bibliography/263.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @article {51900, title = {Development of the Polypay breed of sheep}, journal = {Journal of Animal Science}, volume = {58}, number = {1}, year = {1984}, month = {1984}, pages = {15-24}, abstract = {

Achievement of improved reproductive performance in most domestic sheep breeds of the United States has been regarded with considerablecaution because of low heritabilities for reproductive traits. However, this view is changing with increasing availability of exotic breeds that have high reproductive capacity. The characterization of these exotic breeds in crosses with domestic breeds has shown that major improvement in reproductive rate is attainable. Crossbreeding has been demonstrated to be an effective method for exploiting the commercial value of highly prolific breeds (Turner, 1969; Carter, 1976; Dickerson, 1977; Jakubec, 1977; Meyer et al., 1977). The development of composite breeds that combine the potential for greatly increased reproductive rate along with the desired growth, carcass and fleece attributes is an important extension from crossbreeding for achieving important and permanent increases in production efficiency (Carter, 1976; Smith et al., 1979; Hulet et al.,1981).

}, url = {/files/bibliography/267.pdf}, author = {Clarence V. Hulet and Ercanbrack, S.K. and A. D. Knight} } @conference {51913, title = {Effects of nutritional environment on breeding season in range sheep}, booktitle = {Journal of Animal Science}, volume = {59(Suppl 1)}, year = {1984}, month = {1984}, pages = {339}, abstract = {

The objectives were to determine effects of the season, nutritional environment, and presence of the ram on incidence and rate of ovulation in finewool sheep in southern New Mexico. Mature ewes (144 head) were randomized into groups maintained either on arid Southwest range or in drylot on alfalfa hay (1.59 kg/head/day). These nutrition-environment groups were further randomized into ram-exposure subgroups to test effects of continuous or intermittent exposure (30-day periods) to sterile rams. Both drylot and range-managed ewes were in good condition and gained weight during the study (9.8 and 5.1 kg/ewe). Copora lutea were observed twice each month for 13 months in random samples of three to six ewes from each subgroup. Seasonality of ovulation in finewool sheep managed on the range was much more marked than in animals managed on alfalfa hay in drylot. The incidence of ovulation approached zero in the range-managed ewes during May, June, and July (8\%, 0\%, and 4\%, respectively), compared with 42\%, 17\% and 75\% for the alfalfa-drylot group (P\<.02, P\<.10, P\<.01). Although the incidence of ovulation in the range-managed group increased to 50\% in August, the incidence was still lower (P\<.05) than in the drylot-hay group (83\%). The incidence of ovulation also was lower (P\<.01) in the range-managed than the drylot ewes during February (33\% vs. 83\%). Ovulation rate was highest in October (1.66) and November (1.63) and lowest in March (1.14) and May (1.14). The mean annual ovulation rate of the drylot group (1.48) was very similar (P\>.10) to that of the range-managed group (1.39). Continuous or intermittent presence of a ram had no real effect on either the incidence or rate of ovulation. It is concluded that the nutritional environment can significantly affect seasonality of breeding in finewool range sheep. This may not be consistently modified by ram exposure.

}, keywords = {breeding season, nutrition, ovulation rate, range sheep}, url = {/files/bibliography/268.pdf}, author = {Clarence V. Hulet and Shupe, W. Larry and Ross, T.T.} } @article {51914, title = {Polypay breed improvement}, journal = {Lamb and Wool Products}, volume = {1}, number = {5}, year = {1984}, month = {1984}, pages = {7-10}, abstract = {

While living with my family in New Zealand a few years ago, we experienced many new things. One of these. which should be of great significance to this group. was that the per capita consumption of lamb, hogget, and mutton was higher than that of any other meat. I asked why. After some investigation, I found that the retail price of lamb and hogget was less than that of any other meat --- including chicken. Then, we might suppose that although this would naturally stimulate sales. the New Zealand sheep farmer would soon go broke unless he got better prices. However, that also has not happened. Then, how can we account for this apparent paradox?

}, url = {/files/bibliography/264.pdf}, author = {Clarence V. Hulet} } @proceedings {51918, title = {Some observations on the role of behavior in sheep production and future research needs}, volume = {1}, year = {1984}, month = {1984}, pages = {407-411}, abstract = {

The influence of behavior on sheep production is not generally well understood or appreciated. There is need for behavior research to evaluate the effects of behavior in production and in experimental designs. The roles of behavior, in both intensive and range management systems, and including such factors as man-animal interactions, predation, reproduction, nutrition and transportation, are areas that deserve more research activity for optimal sheep production.

}, url = {/files/bibliography/266.pdf}, author = {Clarence V. Hulet and Bond, J.} } @inbook {51915, title = {Techniques in early weaning of lambs}, booktitle = {Sheep and Goat Handbook}, year = {1984}, month = {1984}, pages = {353-358}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

The only justifiable reason for early weaning of lambs is to improve the overall efficiency of the production system. It can be more efficient to put the feedstuffs directly into the lamb, rather than indirectly through the ewe in the form of milk. Increased efficiency in this case is dependent on the physiological age of the lamb, the relative costs of the two ewe diets, the costs of the lamb diet, the rate of gain of the lamb, and other benefits that might accrue, such as earlier marketing of lambs while the price is higher, enhanced opportunity to rebreed the ewe for a second lamb crop, and the opportunity to operate a larger production unit without increasing acreage.

}, url = {/files/bibliography/265.pdf}, author = {Clarence V. Hulet}, editor = {Baker, F.H. and M. Miller} } @inbook {51937, title = {Accelerated lambing: Its role in the sheep industry}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {171-178}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

The cost of maintaining a ewe for a year is often quite high, and unless the returns from lamb and wool exceed these costs by a reasonable amount, a sheep enterprise will not be profitable. Thus, increasing the frequency of lambing or the number of lambs born per lambing, or both, without a comparable increase in maintenance and labor costs, should increase net return. Any increase in the number of lambings in relationship to the age of the ewe is referred to as accelerated lambing and includes: 1) starting lamb production at a younger age, and 2) breeding and lambing at intervals more frequent than 12 months.

}, url = {/files/bibliography/242.pdf}, author = {Clarence V. Hulet and Stellflug, J.N.}, editor = {Baker, F.H.} } @inbook {51954, title = {Development of the Polypay breed of sheep}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {137-151}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

Development of the Polypay breed was undertaken to combine into a composite breed the potential for greatly increased reproductive capacity along with desirable growth rate and carcass quality. Four breeds were selected for the foundation of the new breed-the Rambouillet and the Targhee for hardiness, large body size, long breeding season, herding instinct and fleece characteristics; the Dorset for carcass quality, milking ability and long breeding season and the Finnsheep for early puberty, early postpartum fertility and high lambing rate. Dorset x Targhee and Finnsheep x Rambouillet matings were first made in 1968, and reciprocal Dorset-Targhee x Finn-Rambouillet matings were initiated in 1969. Beginning in 1970, the respective two-breed crosses and the four-breed cross (Polypay) were each mated inter se and selected, along with straight bred Rambouillets and Targhees, or lamb production when given two opportunities to lamb/year. Initial comparisons among straightbreds and inter se mated groups showed few important differences in meat-type body conformation, body condition or growth rate, but superior annual reproductive performance by Polypays. Fertility of Polypays at 1 yr of age was high and comparable to that of the Finn- Rambouillets. Response of Polypays to twice-a-year lambing was superior to responses of Rambouillets, Targhees, Dorset-Targhees or Finn-Rambouillets. The 1974 to 1975 annual production of young Polypays was about 13\% more lambs weaned than from Finn-Rambouilets and 18\% more weight of lamb weaned than from Dorset-Targhees, the best of the other groups for these traits. The current (1979 to 1981) reproductive performance of Polypay ewes selected for high once-a-year lambing rate under typical range management conditions is very competitive with that of 89 Finn cross- breds. Annual production of mature Polypays on the twice-a-year lambing schedule was 1.78 lambs weaned and 58.6 kg of lamb weaned/ewe put into fall breeding.

}, keywords = {Composite Breed Development, Polypay, Reproductive Performance, Selection}, url = {https://pdfs.semanticscholar.org/dae2/6928c6101933dc0b1bc6a0dc17684083152c.pdf}, author = {Clarence V. Hulet and Ercanbrack, S.K. and A. D. Knight}, editor = {Baker, F.H.} } @article {51955, title = {Effects of early weaning and lambing time on accelerated lambing in Polypay sheep}, journal = {Theriogenology}, volume = {20}, year = {1983}, note = {Reprinted with permission from Elsevier, Copyright {\textcopyright} 1983. (http://www.sciencedirect.com/science/journal/0093691X)}, month = {August 1, 1983}, pages = {141-149}, abstract = {

Effects of early weaning, lactation, and day-of-year lambing on the ability of Polypay ewes to rebreed following winter and summer lambings were evaluated. Winter lambing ewes did not successfully rebreed while lactating. However, when winter-born lambs were weaned at 31 days postpartum, more ewes rebred and produced summer lambs (35.7\%) than when lambs were weaned at 41 days postpartum (23.6\%). Ewes that lambed during the early part of the winter lambing period had an advantage over later lambing ewes in the percentage which subsequently lambed the following summer. This was apparently the result of a difference in length of breeding exposure rather than a higher fertility rate during the early part of the breeding period. When summer lambing ewes were rebred during the early part of the summer breeding period (late summer to early fall), stress associated with lactation did not affect subsequent winter lambing performance. Summer lambing ewes belonging to a late weaning (80 days) treatment group did not differ (P\>0.05) from those belonging to an early weaning (31 days) treatment group in winter fertility, prolificacy, day-of-year lambing or lambing interval.

}, keywords = {early, effects, lambing, Polypay sheep, weaning}, doi = {10.1016/0093-691X(83)90209-1}, url = {/files/bibliography/243.pdf}, author = {Clarence V. Hulet and Stellflug, J.N. and A. D. Knight} } @inbook {51956, title = {Increasing market lamb production efficiency}, booktitle = {Sheep and Goat Handbook}, year = {1983}, month = {1983}, pages = {407-415}, publisher = {Winrock International, Westview Press}, organization = {Winrock International, Westview Press}, address = {Boulder, CO}, abstract = {

Lamb production efficiency should be measured in relation to the total pounds of lamb meat produced per pound of feed consumed by the entire flock. The quality and cost of feed consumed by the entire flock. The quality and cost of that feed also must be considered.\  These assumptions imply that for greatest lamb-production efficiency--every female in the flock should begin production as early in life as possible and produce lambs as rapidly as management constraints permit. Lambs should be fed until efficient gains stop.

Four practices that can have a great impact on improving efficiency are: 1) breeding ewes to lamb at 1 year of age, 2) producing more twins, 3) improving rate and efficiency of gain, and 4) producing larger lambs.

}, url = {/files/bibliography/240.pdf}, author = {Clarence V. Hulet and Ercanbrack, S.K.}, editor = {Baker, F.H.} } @article {JRN54842, title = {Improving reproductive efficiency in sheep}, year = {1978}, abstract = {

The efficiency of lamb production can be improved by overcoming the major reproductive problems of sheep: (a) low lambing rate; (b) restricted breeding season; (c) low fertility during the early postpartum period; (d) late puberty; and (e) perinatal lamb losses.

Lambing rate is being improved impressively by increasing the ovulation rate through crossbreeding., selection, and improved management. Little progress has been made in reducing embryonic and fetal mortality, a problem especially prevalent during the early part of the breeding season and in hot environments. Some progress is being made toward reducing the restrictions to lamb production efficiency caused by the short breeding season. The breeding season is being eliminated, lengthened, or modified through breeding and selection hormone therapy and controlling exposure to light. Much more needs to be done to permit lambing at any time of year and to shorten lambing intervals to less than one year.

Little progress has been made in improving fertility during the early postpartum interval. This an important area for future investigation in order to shorten lambing intervals. Age at puberty has been reduced and fertility improved in ewe lambs through crossbreeding, selection, improved nutrition, and management. The breeding of ewe lams is commonly practiced throughout the United States with increasing success every year. New research data in management and disease control suggest success each year. New research data in management and disease control suggest way to markedly reduce losses of perinatal lambs. Further progress may come through the development of new vaccines for the prevention of losses caused by enzootic abortion in ewes and scours in lambs.

}, keywords = {Improving reproductive efficiency, sheep}, author = {Clarence V. Hulet} } @article {JRN54834, title = {Some factors affecting response of anestrous ewes to hormone treatment}, journal = {Journal of Animal Science}, volume = {34}, year = {1972}, month = {June 1972}, pages = {1011-1019}, chapter = {1011}, abstract = {

Summary

Several experimental, range and farm flocks were used to study the effects of various environmental factors on response of the anestrous ewe to hormone therapy. Lactating ewes started on estrogen, progesterone and repeat PMS treatment beginning 18 to 24 days post-partum were significantly more fertile than ewes started on treatment 2 to 8 days post-partum. Ewes which lambed in June following the treatment described above were more fertile than ewes which lambed in February. However, both those lambing in June and February were more fertile than those lambing in April. Anestrous ewes suckling single lambs proved generally to be more fertile than ewes suckling twin lambs. In another study dry ewes (failed to lamb) were more fertile than ewes which lambed but did not raise their lambs. Ewes which lambed but failed to raise their lambs were in turn more fertile than ewes raising singles which in turn more fertile than ewes raising twins. A treatment including an intramuscular injection of 2 mg estradiol-17β at the time of progesterone implantation resulted in an apparent improvement in fertility in one flock and a significant improvement in fertility in another flock over other hormone treated ewes not receiving this estrogen pretreatment. Estradiol-17β (.025 mg) reduced fertility at the first estrus when it was given at the same time as the first PMS. The overall treatment effect did not, however, differ from other treatments. Young early post-partum ewes (1, 2 or 3 years old) whether lactating or nonlactating were significantly more fertile following hormone therapy than mature ewes of the same status. Dorset x Targhee crossbred ewes appeared to be more fertile following hormone therapy than Rambouillet, Targhee or Columbia ewes of the same ages. The response of Suffolk ewes to hormone treatment was significantly lower than other breeds studied in the same flock. Hormone treated lactating anestrous ewes given a high level of nutrition appeared to be more fertile than those on a standard level of nutrition.

}, keywords = {Anestrous Ewes, Factors Affecting Response, Hormone Treatment}, doi = {10.2527/jas1972.3461011x}, url = {https://dl.sciencesocieties.org/publications/jas/pdfs/34/6/JAN0340061011}, author = {Clarence V. Hulet and F. Stormshak} } @article {JRN54843, title = {Induction of Fertile Estrus in Lactating and Dry Anestrous Ewes Using Oral Progestogens and Repeated PMS Treatment}, journal = {Journal of Animal Science}, volume = {26}, year = {1967}, month = {1967}, pages = {545-548}, chapter = {545}, abstract = {

Mature ewes of predominately Columbia type were used to determine the effects of two oral progestogens, 6-chloro-Δ6-17 acetoxy-progesterone (CAP) and 6-methyl-17-acetoxy-progesterone (MAP), and PMS on fertility in lactating and nonlactating (early weaning) ewes. The 184 lactating ewes were randomized into three treatment series. The two different oral progestogens were used in series 1 and 2. MAP was used in series 3. Series 1 received two short progestogen treatments (3 and 8 days) each followed by PMS 24 hr. later. Series 2 received a long progestogen treatment (14 days) followed by PMS 1 and 17 days later. Series 3 was like series 2, except that MAP was given again for 3 days before the second PMS. Forty-one ewes from the early-weaning group were also randomized into the series 1 and 2 treatments. Treatment started March 19 when the lambs were 30 to 90 days of age.

Only 4\% of the treatment-1 series lactating ewes were marked by fertile rams following the first PMS as compared to 54\% of the treatment-2 series lactating ewes (P\<.01). Eighty-six percent in the treatment-1 series showed estrus following both PMS injections. Other estrous data were unreliable and excluded.

There was no significant effect of kind of progestogen or of lactation on percent of ewes lambing and of lambs at 2 weeks postpartum, but there was a significant effect of the length of the progestogen treatment before the first PMS on both variables. A comparison of the response of lactating ewes in treatment series 3 with treatment series 2 appears to indicate that there is a definite advantage in repeating the treatment with PMS irrespective of the occurrence of heat. A comparison of the treatment-1 and -2 series indicates that there is little or no detrimental effect of PMS on established pregnancies. The ewes lambing in the treatment-2 series had a higher percentage of lambs alive at about 14 days postpartum than the treatment-1 and treatment-3 series (128\%, 97\% and 100\%, respectively).

}, keywords = {Dry Anestrous, ewes, Induction of Fertile Estrus, Lactating, Oral Progestogens, Repeated PMS Treatment}, doi = {10.2527/jas1967.263545x}, url = {https://dl.sciencesocieties.org/publications/jas/pdfs/26/3/JAN0260030545}, author = {Clarence V. Hulet and W.C. Foote} } @article {JRN54838, title = {Relationship between ovulation rate and reproductive performance in sheep}, journal = {Journal of Animal Science}, volume = {26}, year = {1967}, month = {May 1967}, pages = {563-566}, chapter = {563}, abstract = {

An index or criterion for predicting \ the \ future reproductive performance of yearling ewes could be most useful \ in \ developing a more efficient sheep industry. It has long been assumed \ that \ there \ is an \ important \ relationship \ between ovulation rate and lamb production, but the repeatability of ovulation rate within a breeding season \ and \ between breeding seasons \ is unknown.

Until recently, surgical procedures have been time-consuming and have discouraged the study of \ these relationships. \ However, use of the laparotomy cradle as developed by Lamond (1963) and use of local \ anesthesia have made practical the examination of reproductive organs in large numbers of live animals.

The objective of this study was to determine the relationship between two ovulation rates measured at a 35-day interval during the peak of the breeding season and the relationship between the mean of these ovulations and \ previous lifetime lamb production. The relationship between the number of corpora lutea (CL) at the first and second observation periods to the number of embryos resulting from matings at the second observation period was also studied.

}, keywords = {ovulation rate, reproductive performance, sheep}, url = {/files/bibliography/1912-1.pdf}, author = {Clarence V. Hulet and W.C. Foote} }