Suckling and Excess Fat in the Postpartum Reproductive Activity of Hair Sheep

Objective: To evaluate the effect of excess fat and suckling control on postpartum reproductive activity of hair ewes. Design/Methodology/Approach: Eighty-one (81) hair ewes with average weight of 58±8 kg were used, which on postpartum day 7 were assigned to one of four treatments under a completely randomized design with 2×2 factorial arrangement. Factor A is the type of suckling [continuous suckling (CS) and suckling control (SC)] and factor B, excess fat (with or without). In CS, ewes remained with their offspring 24 hours a day (n=16). In continuous suckling plus fat (CSF), ewes remained with the offspring all day plus the addition of 8% in dietary fat (n=24). In SC, it was 30 min of suckling only twice per day (n=14). In suckling control plus fat (SCF), controlled suckling lasted 30 min, twice a day plus 8% fat (n=25). Results: The response to the treatments was similar (p > 0.05) in onset of estrus, return rate, gestation, prolificacy and fertilization; for the lambing rate variable, there were differences (p ≤ 0.05), the SCF treatment was higher (68%) compared to CS (50%) and CSF (50%), but equal (p < 0.05) to SC (57.1%). Implications: In this experiment, it was observed that the SCF treatment presented a better response, implying that controlling suckling and providing excess fat helps to restore ovarian activity sooner after lambing. Conclusions: Suckling control plus inclusion of dietary excess fat in ovulation induction protocols during early postpartum (around day 25 postpartum) can be included in routine reproductive management of flocks, improving the reproductive efficiency of hair sheep.

Mortality of Dairy Sheep during the Peri-Parturient Period: Results of A Field Investigation in Greece

Objectives of the study were (a) to investigate the incidence risk of peri-parturient mortality in dairy flocks in Greece, (b) to study when such mortality occurs in relation to lambing, (c) to identify clinical problems associated with the deaths, and (d) to evaluate potentially associated factors. The deaths of ewes during the peri-parturient period (10 days before to 7 days after lambing) were monitored in 60 flocks over two years. In the ewes that died, detailed post-mortems were performed. The incidence risk of peri-parturient deaths was 0.7%. The daily incidence rate of deaths before, at, and after lambing was 0.05, 0.04, and 0.03%, respectively. Clinical problems most frequently associated with peri-parturient deaths were pregnancy toxaemia, ruminal acidosis and post-partum genital problems. For the occurrence of peri-parturient deaths in flocks, the average lambing rate in the flocks was the only significant factor. Regarding deaths before or after lambing, the season during which lambing took place and the number of animals in the flock, respectively, were found to be significant. Most ewes (54.5%) that died at lambing (dystocia) were primigravidae.

OESTRUS SYNCHRONIZATION, ARTIFICIAL INSEMINATION AND EARLY REBREEDING IN YANKASA SHEEP

COMPONENTS of an intensive sheep production system including oestrus synchronization, artificial insemination and early rebreeding were investigated in two trials with Yankasa sheep. Treatment of ewes with progrestagen pessaries for 12 days resulted in good synchronization of first and second post-treatment oestrus. In Trial I, (January–February, 1982) 33 ewes were treated, of which 81.8% showed oestrus within 4 days after the end of progrestagen treatment while 72.7% showed a second oestrus within 21 days. In Trial II, (August – September, 1982), 48 eyes were treated, of which 87.5 and 77.1% showed first and second oestrus respectively over the same periods as in Trial I. Mean interval (± s.e.m) between first and second induced oestrus in both trials was 16.4 ±0.1 days (n = 61). About 90% of ewes exhibiting oestrus were detected 2 to 4 and 17 to 20 days after progrestagen treatment for first and second oestrus respectively. Lambing reates of ewes to artificial insemination or natural mating at the second induced oestrus in Trial I were 50.0 and 91.7% respectively, Corresponding lambing rates in Trial II were 65.0 and 86.70%. Rebreeding interval in ewes which lambed in Trial I was 59.1 ±0.8 days following commencement of progestagen treatment approximately one month after lambing. Lambing rate in this group was 78.6%.

Review of Huang-huai sheep, a new multiparous mutton sheep breed first identified in China

Huang-huai sheep are a new multiparous mutton sheep breed that has been cultivated by domestic scientific research institutes, governments, and sheep farms in China. Huang-huai sheep were bred using Dorper sheep as a sire and Small-tailed Han sheep as a dam. The breeding of Huang-huai sheep started in 2003, and three stages have been carried out: crossbreeding innovation, fixation in a two-way-crossbred closed flock, and herd propagation. A pilot test of Huang-huai sheep was conducted on 6 sheep farms from 2017 to 2018, and hereditary properties and production performance were evaluated in 2019. Huang-huai sheep were identified on site by the National Livestock and Poultry Resources Committee of China in December 2019 and approved as a new multiparous mutton sheep breed in China. The genetic distance showed that Huang-huai sheep are most closely related to Dorper sheep, Luxi black-headed sheep, and Small-tailed Han sheep, but the genetic distances are subspecies (0.02–0.20) each other. The body weights of adult Huang-huai sheep are 98.1 ± 5.2 kg (♂) and 71.7 ± 3.5 kg (♀), and those of 6-month-old Huang-huai sheep are 58.50 ± 6.55 kg (♂) and 52.45 ± 5.67 kg (♀). The slaughter rates of 6-month-old sheep are 56.02 ± 1.25% (♂) and 53.19 ± 1.19% (♀). The estrus cycle of Huang-huai sheep is 19.32 ± 2.8 days, the first estrus cycle occurs at 168 ± 12 days, the annual lambing rate of ewes is 252.82% ± 10.69%, the survival rate of lambs is 95.79 ± 0.95%, and the number of weaned lambs per ewe per year is 2.38 ± 0.14. The growth performance, carcass quality, and reproductive performance of Huang-huai sheep have been improved, resulting in considerable economic and social benefits and broader market prospects. This breed represents a new multiparous mutton sheep breed adapted for industrial sheep farms in China.

Oestrus synchronization efficiency in ewes and ram maturity effect on fertility during summer season

The purpose of this study was to investigate oestrus synchronization efficiency and ram maturity effect on fertility of ewes of MIS sheep population during summer season. Research was performed on the experimental sheep farm of the Institute for Animal Husbandry in Belgrade, Serbia. The study included 70 crossbred ewes of MIS sheep population (Pirot Pramenka, Merinolandschaf and Ile de France breed) and 3 Ile de France rams (2 young, sexually unexperienced rams and 1 mature ram). Oestrus was synchronized in all 70 ewes using progestagen impregnated vaginal sponges (30 mg fluorogestone acetate) in combination with 500 IU PMSG. Ewes were mated with rams 48 h later. Obtained fertility and productivity results were as follows: lambing rate 57.14% (40/70), gestation length 147.11, litter size 1.82, stillborn rate 15.07%, birth weight of lambs 4.29 kg and body weight of lambs at 30 days of age 13.07 kg on average. Based on the results obtained in this study it was concluded that presented oestrus synchronization and mating protocol yielded lower than expected lambing rate. The effect of ram maturity on lambing rate was significant (P<0.05), as ewes mated to mature ram had higher lambing rate compared to those mated to two young unexperienced rams. Mature ram also had bigger litter size and higher stillborn rate, as well as lower birth weight of lambs.

Merino ewe lambing after stimulation with prostaglandin and PMSG and insemination with sperm of grey Karakul rambs

Aim. To determine the effectiveness of a two-time treatment with prostaglandin F-2α (PGF2α) followed by the injection of pregnant mare serum gonadotropin (PMSG) for stimulation of sexual activity in sheep in the second half of the estrous season in the scheme of increasing the lambing rate. Methods. Thirty-seven 2.5-yearold ewes of the Askanian Merino breed, which were kept together from the age of one year, were used. In September 2018, 28 animals of this group lambed and had sucklings until November 20. Hormonal stimulation was started on December 7, 2018 by injecting all ewes with 1 ml of synthetic PGF2α and 1 ml of Prozerin. The second injection of PGF2α was given 10 days after the fi rst one. Simultaneously with the second treatment with PGF2α, the animals were injected with 500 IE of PMSG (Sergon, Czech Republic) and 2.5 ml of SuperAminoC (South Korea). The presence of estrus was not detected, and the ewes were forcibly inseminated with freshly obtained sperm of 4 grey rams of the Askanian Karakul breed in the morning for three days, beginning with the fi rst day after the PMSG injection. During the fi rst treatment with PGF2α and 3 days before the second one, the genitals of 12 ewes were sonographically examined. Results. In total, 45.9 % of stimulated animals lambed; the total fecundity was 75.7 %, and the average prolifi cacy – 1.65 ± 0.18 lambs per ewe. Among the animals, which before the experiment had the sucklings, 57.1 % lambed, among those, who did not have the suckling, – 11.1 %. After using the sperm of ram 17314, 77.8 % of ewes lambed, for rams 73697, 73792 and 73796 – 30.0, 44.4 and 33.3 %, respectively. Among the 19 lambs analyzed by wool color, 10 lambs were completely black, 9 were black with white spots. Among the spotted lambs, the color on the back, forearms and hips of one lamb had an additional shade, close to gray. Ultrasound testing showed that the ewes, which before the experiment had sucklings, showed better genital reactivity. According to the distribution of lambs by wool color, an assumption about possible partial incompatibility of the genotypes of Askanian Merino ewes and grey Karakul sheep was made that requires further study. Conclusions. The scheme of stimulating sexual activity based on two-time treatment with PGF2α followed by an injection of PMSG is capable of ensuring lambing of more than 70 % of stimulated sheep with the prolifi cacy of 1.65 lambs per ewe. A factor, increasing the effectiveness of the scheme, is the presence of sucking lambs of ewes before the stimulation starts.

167 Evaluation of an out-of-season breeding system for organic lamb production in missouri

Organic production is one of the fastest growing food and agriculture industry. The seasonality of lamb production affects lamb markets and prices, whereas, an out-of-season breeding and organic fall lamb production scheme may enhance product availability and competiveness. Six rams and 100 Katahdin ewes were selected for an out-of-season breeding during April and May of 2017 and 2018, for two production years. Ewes were synchronized for estrus using CIDR® device (EaziBreed™) (12 d) before breeding and fed ‘flushing’ feed for four weeks. Ewes were bred in mixed sire groups for two estrus cycles (35 d). Animals were rotationally grazed and maintained good body condition score (3.0) throughout the seasons at certified organic farm in Missouri. Mean live weight measured monthly from breeding to lambing were 57.8, 60.1, 62.1, 64.7, and 59.3 kg. Eighty nine ewes lambed in fall 2017 giving birth to 121 lambs (136% lambing rate) and eighty eight ewes lambed in 2018 giving birth to 126 lambs (143% lambing rate). Ninety seven percent of weaned lambs were maintained as an organic production status for marketing. Lamb birth weight, average daily gain weight, weaning weight, and 30 d post weaning weight, post weaning average daily gain weight were recorded for 2017 born lambs as 3.74±0.03 kg, 21.00±0.24 kg, 24.78±0.28 kg, 176±2 g/d respectively. Organic weaner lambs were sold for 5 to 15% higher price values (P &lt; 0.05) per unit than non-organic peer groups at a local livestock auction sale.