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J. Anim. Sci. 2004. 82:3654-3661
© 2004 American Society of Animal Science

ANIMAL PRODUCTION

High linoleic acid safflower seed supplementation for gestating ewes: Effects on ewe performance, lamb survival, and brown fat stores1

H. B. Encinias2, G. P. Lardy3, A. M. Encinias2 and M. L. Bauer

Department of Animal and Range Sciences, North Dakota State University, Fargo 58105


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results and Discussion
 Literature Cited
 
Objectives of this study were to determine whether feeding high-linoleic safflower seed to gestating ewes increases cold tolerance and survival in lambs, and whether brown adipose tissue (BAT) stores in lambs are affected by prepartum safflower seed supplementation. In Trial 1, 234 gestating ewes (122 in yr 1 and 112 in yr 2; 75.5 and 81.2 ± 0.6 kg initial BW for yr 1 and 2, respectively) were allotted randomly to one of two dietary treatments (four pens•treatment–1•yr–1). Ewes were fed alfalfa-based diets containing (DM basis) either 2.8 (LF) or 5.7% (HF) dietary fat beginning 55 (yr 1) and 42 (yr 2) ± 1 d prepartum. In Trial 2, 40 Rambouillet cross ewes gestating twins (82.9 ± 1.7 kg BW) were used in 2 yr (20/yr) and were fed diets containing (DM basis) either 1.9 (LF) or 4.9% (HF) dietary fat beginning 53.4 ± 1.4 d prepartum. The basal diet was 37.5% each of grass and alfalfa hays and 25% corn silage (DM basis). Cracked safflower seeds (18% CP, 32% fat, 25.6% linoleic acid; DM basis) were used as the supplement in HF, whereas safflower meal and corn were used as the supplement in LF for both trials. At parturition, one lamb from each ewe was selected randomly for slaughter. Perirenal (PR) and pericardial (PC) BAT was excised and weighed, and the carcass was frozen for compositional analysis. In Trial 1, more lambs from HF 0.03; 15.4 vs. 5.8 ± 2.8%), and dams survived (P = 0.03; 88.4 vs. 78.3 ± 2.9%), fewer died due to starvation (P = there was a tendency for fewer to die due to pneumonia (P = 0.07; 0.0 vs. 1.7 ± 0.6%). Ewes fed HF tended to wean more lambs per ewe (P = 0.09; 1.4 vs. 1.2 ± 0.06) but had similar lamb weight weaned per ewe (P = 0.51; 23.1 ± 1.22 kg). In Trial 2, prepartum ewe plasma NEFA and glucose concentrations increased with advancing gestation (P < 0.001). Lamb rectal temperature tended (P = 0.08) to be higher in LF lambs and tended (P = 0.06) to increase following parturition. Perirenal BAT weight did not differ among treatments (33.01 ± 1.66 g; P = 0.28; 0.62 ± 0.30% BW; P = 0.60). Lambs from LF dams tended (P = 0.08) to have greater PC BAT weight; however, the effect was not significant when expressed as a percentage of BW (0.13 ± 0.007; P = 0.98). High-linoleic safflower seeds fed during the last 45 d of gestation may be beneficial in improving lamb survivability. Our data do not indicate this response was a result of increased BAT stores. More research is necessary to determine mechanisms that enhance lamb survival when high-linoleic saf-flower seed is fed during gestation.

Key Words: Ewes • Lamb • Linoleic • Safflower • Supplementation • Survival


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results and Discussion
 Literature Cited
 
Cold and cold-induced starvation account for 50% of perinatal lamb death (Samson and Slee, 1981Go). Lambs produce 50 to 60% of their heat through shivering thermogenesis, and 40 to 50% through nonshivering thermogenesis (Alexander and Williams, 1968Go). Brown adipose tissue (BAT) is responsible for nonshivering thermogenesis. Lambs are born with almost 100% BAT unlike other species, which are born with brown and white adipose tissue (WAT; Gemmell et al., 1972Go; Alexander and Bell, 1975Go).

Gibney and L’Estrange (1975)Go fed feed high in linoleic acid and increased linoleic acid content of fat stores in lambs. Linoleic acid is the major fuel for heat production in BAT (Lammoglia et al., 1999aGo). Linoleic and linolenic acid supplementation (sunflower and linseed oil) increased the thermogenic capacity of BAT by 75% and doubled the content of uncoupling protein-1 (UCP1) in rats (Nedergaard et al., 1983Go).

Because cold stress can begin at parturition, the optimal period for enhancing the thermogenic potential is before parturition. Few studies have examined supplemental fat for gestating ewes and its subsequent effects on the neonatal lamb. Budge et al. (2000)Go reported that well-fed ewes (150% ME requirement; AFRC, 1992Go) had lambs with 22% more UCP1 abundance and twice the thermogenic activity in BAT during the final 65 d of gestation as lambs from ewes fed at 100% requirement. Lammoglia et al. (1999aGo,bGo) fed a control diet (2.2 and 1.7% dietary fat) or high-linoleic safflower seeds (5.1 and 4.7% dietary fat) to heifers during the last third of gestation and reported that calves from safflower-fed dams were better able to maintain body temperature. We hypothesized that feeding high-linoleic safflower seed to gestating ewes would increase BAT stores in neonatal lambs and improve lamb survival. Our objectives were to determine whether feeding high-linoleic safflower seed increases the cold tolerance and survival in lambs, and whether BAT stores in lambs are affected by prepartum safflower seed supplementation.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results and Discussion
 Literature Cited
 
Animal Care and Study Location

Ewes and lambs were handled and cared for following protocols approved by the North Dakota State University Institutional Animal Care and Use Committee. Trial 1 was conducted at the North Dakota State University Hettinger Research Extension Center located just west of Hettinger, ND, whereas Trial 2 was conducted at the main station in Fargo. Ambient temperatures were obtained from the North Dakota Agricultural Weather Network (NDAWN, 2002Go). In Trial 1, ewes were housed outdoors, with no supplemental heat source. In Trial 2, ewes were housed in an unheated barn, with continual access to outdoor runs. The doors to the runs remained open throughout the study. Ewes were not exposed to a supplemental heat source.

Trial 1

Animals and Diets. Beginning 55 (yr 1) and 42 (yr 2) ± 1 d before lambing, 122 (yr 1) and 112 (yr 2) gestating western white-faced (predominantly Rambouillet) ewes (78.7 ± 0.6 kg initial BW) were allotted randomly to one of two dietary treatments (four pens•treatment–1•yr–1). Pregnancies were verified with real-time ultrasound. Ewes were fed diets formulated to contain (DM basis) either 2.8 (low fat, LF) or 5.7% (high fat, HF) dietary fat. Diets were delivered ad libitum via a 3-m-long self-feeder with feed access on both sides as a total mixed ration, and diets were calculated to be isocaloric and isonitrogenous. Diets were based on finely chopped alfalfa hay. Cracked safflower seeds (Carthamus tinctorius L., variety Centennial; 18% CP, 32% EE, 0.8 g of linoleic acid/g of fatty acid [DM basis]) served as the fat source in HF diets (Table 1Go). Solvent-extracted saf-flower meal was used as a protein source in LF supplement. Ewes were allowed ad libitum access to a trace mineralized salt block. The mineral block consisted of ≥65.3% NaCl, 7.26% Ca, 6.37% P, ≥0.13% Zn, ≥0.05% Fe, ≥0.04% Mn, ≥0.011% Cu, ≥0.0033% I, and ≥0.0013% Co; as-fed basis. Animals were housed in 3 m x 30 m pens with access to a 3 m x 9 m covered barn. Ewes and lambs from both treatments were managed similarly until weaning.


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  		Table 1. Diet and nutrient composition of low- and high-fat diets fed to gestating ewes in Trial 1 (DM basis)
 
Data Collection. At the onset and conclusion of supplementation, ewes were weighed, and BCS assessed by palpation using a five-point scoring system (1 = emaciated, and 5 = obese). Upon lambing, birth weights were recorded. Lamb mortality was recorded and separated by cause. Diagnosis included the following categories: found dead, pneumonia, or starvation. Lambs classified as found dead were dead when found without having suckled. Lambs found with excessive salivation around the mouth (indicative of heavy breathing) were classified as having died from pneumonia. Deaths of emaciated lambs were classified as starvation. Lambing rates were calculated by dividing the number of lambs born per pen by the number of ewes per pen. In calculating mortality, the number of lambs that died (total or of a specific cause) per pen was divided by the total lambs born per pen. Surviving lambs were weighed at weaning. Lambs weaned per ewe was calculated by dividing the number of lambs surviving until weaning per pen by the number of ewes per pen. The sum of lamb weaning weight per pen was divided by the number of ewes per pen to calculate lamb weight weaned per ewe.

Laboratory Analyses. Diets were sampled each time feed was added to the self-feeder. Samples were dried at 50°C in a forced-air oven for 48 h and ground in a Wiley mill to pass a 2-mm screen. Safflower seeds were ground using an electric coffee grinder (Braun Aromatic KSM2, Boston, MA). Samples were analyzed for DM, OM, CP, Ca, and P (Methods 930.15, 942.05, 990.02, 968.02, and 965.17, respectively; AOAC, 1997Go; Table 1Go). Analysis of ADF was conducted according to Goering and Van Soest (1970)Go, and NDF analysis was conducted by the method of Robertson and Van Soest (1991)Go. Long-chain fatty acids were extracted in methane from saf-flower seeds and analyzed by gas chromatography (Outen et al., 1976Go) only to report linoleic acid content of seeds.

Statistical Analyses. Data were analyzed with analysis of variance for a completely randomized design using the GLM procedures of SAS (SAS Inst., Inc, Cary, NC). The model contained effects of treatment, year, and their interactions. Pen served as experimental unit for all response variables. Means were separated by the LSD procedure. In cases where no significant (P > 0.05) year x treatment interaction existed, data across years were combined and only main effects were reported. The number of lambs born per ewe was analyzed as a covariate for the variables of lambs weaned per ewe and lamb weight weaned per ewe.

Trial 2

Animals and Diets. Forty mature, Rambouillet-cross ewes were included (20/yr; 82.9 ± 1.7 kg initial weight) in a study over two consecutive years. On approximately d 40 of gestation, pregnancies were verified with real-time ultrasound. Beginning 53.4 ± 1.4 d prepartum, ewes were stratified by weight and allotted randomly to one of two dietary treatments (DM basis), fed to provide similar amounts of ME and CP and containing either 1.9 (LF) or 4.9% (HF) dietary fat (Table 2Go). Ewes had ad libitum access to a common basal diet consisting of 37.5% brome grass hay, 37.5% alfalfa hay, and 25% corn silage (DM basis) delivered once daily at 0715. In addition, 0.29 kg of LF or 0.25 kg of HF supplement (DM basis) per ewe was offered separately from the basal diet once daily at 0700. Safflower seeds rolled to crack the hull were supplemented in the HF diet. Low-fat supplement contained solvent extracted safflower meal, corn, and molasses (Table 2Go). Trace mineralized salt blocks were available for ad libitum consumption (98% NaCl, ≥0.4% Zn, ≥0.16% Fe, ≥0.12% Mn, ≥0.033% Cu, ≥0.01% I, and ≥0.004% Co; as-fed basis). Ewes were housed 1 wk before initiation of supplementation and fed individually in 2.4 x 3.4 m pens bedded with sunflower hulls. Water was shared between two pens and was available for ad libitum consumption.


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  		Table 2. Composition and nutrient analysis of low- and high-fat diets fed to gestating ewes in Trial 2 (DM basis)
 
Data Collection. A thermometer located in the barn monitored ambient barn temperature, and high and low temperatures were recorded daily. Samples of feed ingredients were collected weekly for nutrient analysis. Basal diet and supplement refusals were weighed and subsampled weekly to assess intake. Initial ewe BW was averaged over 3 d, and ewes were weighed every subsequent 2 wk (1-d weights) until the first ewe lambed. Jugular blood was sampled on each weigh day for analysis of glucose and NEFA concentrations. Blood was collected with EDTA-additive (1.74 mg/mL), allowed to cool for 30 min on ice, and centrifuged (1,300 x g for 25 min at 4°C). Plasma was stored in polypropylene tubes at –20°C until analysis.

Ewes were checked every 2 h after initial signs of parturition were observed. Within 20 min after parturition and before nursing, ewes and lambs were moved indoors and birth weights of lamb(s) were recorded. Ewe and lamb jugular blood was sampled at parturition and processed as stated above.

One lamb from each ewe was chosen randomly to be slaughtered. In the case of a singleton birth, the singleton was slaughtered. Lambs were placed into a surgical plane of anesthesia by i.v. injection of sodium pentobarbitol (20 mg/kg BW; Gray, 1986Go) and exsanguinated. Brown adipose tissue was dissected from the perirenal and pericardial area. Tissue samples were rinsed in saline and weighed.

Sibling lambs were allowed to suckle. Body temperature was monitored with a rectal thermometer at 2, 4, 6, 12, 24, and 48 h after parturition. Jugular blood samples were collected from lambs at 24 and 48 h following birth and processed as stated above.

Laboratory Analyses. Feed ingredients were sampled every 2 wk, and handled and analyzed as described in Trial 1. Plasma samples were analyzed for glucose using a hexokinase method (Infinity protocol; Sigma Chemical Co., St. Louis, MO). Nonesterified fatty acids were analyzed enzymatically with a NEFA C kit (Wako Chemicals USA, Richmond, VA), with modifications according to Johnson and Peters (1993)Go.

Carcasses were ground and mixed using a Hobart mixer with a grinding attachment. After mixing, a sub-sample was lyophilized and analyzed for DM and ash (AOAC, 1997Go). Crude protein, ether extract, and long-chain fatty acids were analyzed as described above.

Statistical Analyses. Data were analyzed with AN-OVA using the GLM procedures of SAS (SAS Inst., Inc., Cary, NC). Initial ewe BW was used as a stratification measure. Ewe served as the experimental unit for ewe performance, ewe plasma metabolites, and colostrum analyses. Lamb was the experimental unit for all lamb variables. Ewe BWand lamb tissue weights were analyzed as a completely randomized design, with effects for treatment and year, and treatment x year interactions. All other variables were analyzed as a split-plot in time, the model containing effects of treatment, period, year, and interactions. Animal within treatment x year served as the main-plot error term (Gill and Hafs, 1971Go). The subplots, or periods, were tested using residual error. When no significant (P > 0.05) treatment x year interactions existed, data were combined across year, and only main effects are reported. Litter size and sex were included in the model as a covariate for lamb birth weight and were removed from the model when not significant (P > 0.05). Means were separated by the LSD method, and significance was noted at P < 0.05.


   Results and Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
Literature Cited
 
Trial 1

Climatic Conditions. Average high and low temperatures during supplementation were 0.0 and –12.8°C for yr 1 and –0.7 and –12.2°C for yr 2. During lambing, average high and low temperatures were 7.9 and –5.6°C for yr 1 and –6.8 and –17.8°C for yr 2 (NDAWN, 2002Go). The long-term average high and low temperatures for this location during this time period were –3 and –15°C.

Ewe Performance. Data were combined across year for all variables with the exception of BW change as no treatment x year (P > 0.05) interactions existed. Dry matter intake was not different between treatments and averaged 2.91 ± 0.09 kg/d (data not shown; P = 0.87). Body condition at the onset (3.66 ± 0.03; P = 0.45) and conclusion (3.92 ± 0.02; P = 0.46) of supplementation was similar for LF and HF fed ewes (Table 3Go). Differences in initial (78.7 ± 0.6; P = 0.25) and final BW (95.0 ± 0.9; P = 0.22) were not detected. A treatment x year interaction was detected for BW change (P = 0.05). In yr 1, LF ewes gained more weight than HF ewes, whereas the opposite occurred in yr 2. However, the differences between treatments were small and not biologically significant (18.9 vs. 16.7 kg for LF and HF, respectively, in yr 1, and 14.3 vs. 15.5 kg for LF and HF, respectively, in yr 2). A lack of difference in BW and condition were expected as both diets provided equal amounts of energy. The lack of difference in body condition and weight agrees with Lammoglia et al. (1999a)Go, who fed isocaloric and isonitrogenous diets including safflower seeds to heifers. Three treatment diets containing different types of oilseeds (soybeans, safflower, and sunflower seeds) did not result in differences in heifer body condition or weight gain compared with a control diet that was similar in energy and protein (Bellows et al., 2001Go). Similar results have been observed with mature cows (Lammoglia et al., 1997Go). De Fries et al. (1998)Go, however, observed increased body condition with no change in BW for cows fed isocaloric and isonitrogenous diets including rice bran (5.2% dietary fat) following calving compared with those fed a basal diet with no rice bran (3.7% dietary fat).


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  		Table 3. Influence of control or high-linoleic safflower seed supplementation on ewe prepartum performance (Trial 1)
 
Lamb Birth Weight, Mortality, and Weaning Performance. Birth weights of lambs were not different (P = 0.24), which was likely due to the isocaloric nature of the dietary treatments (Table 4Go) and similar DM intakes. Additional energy provided to the dam during the last trimester has been hypothesized to stimulate greater fetal growth (NRC, 1985Go). The current results agree with supplemental fat studies in beef females, where no difference in birth weight of calves from LF and HF fed dams was observed when diets were (Bellows et al., 2001Go) or were not isocaloric (Espinoza et al., 1995Go).


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  		Table 4. Influence of control or high-linoleic safflower seed supplementation of ewes on lamb birth weight, mortality, and weaning weight (Trial 1)
 
Lambs from HF dams had greater survivabilities (P = 0.03; Table 4Go). There was no difference (P = 0.43) in numbers of lambs found dead; however, more (P = 0.03) lambs from LF dams died due to starvation, and more lambs from LF dams tended (P = 0.07) to die from pneumonia. Lambs were weaned at 68 and 56 ± 1 d of age in yr 1 and 2, respectively. There was no difference (18.5 ± 0.7 kg; P = 0.18) in weaning weights across treatments. Bellows et al. (2001)Go reported a tendency for increased weaning weight in calves nursing heifers fed supplemental fat during the last 65 d of pregnancy. Espinoza et al. (1995)Go reported that calves from HF supplemented dams have had increased weaning weight; however, fat supplementation continued approximately 44 d after parturition in that particular study. Lambs born per ewe was a significant (P < 0.001) covariate for lambs weaned per ewe and lamb weight weaned per ewe. Due to higher mortality at parturition, the number of lambs weaned per ewe tended to be lower for the LF treatment (P = 0.09); however, lamb weight weaned per ewe was similar (23.1 ± 1.2 kg; P = 0.51) across treatments.

Increases in lamb survival in this study may be due to an increase in the thermogenic capacity of BAT. Studies in which rats were fed diets with high concentrations of linoleic acid resulted in increased BAT activity and increased overall thermogenesis (Schwartz et al., 1983Go; Nedergaard et al., 1983Go). Calves from heifers supplemented with high-linoleic safflower during gestation were able to maintain body temperature longer when exposed to cold (Lammoglia et al., 1999bGo). Unlike rats, lambs and calves are born with only BAT and negligible amounts of WAT (Gemmell et al., 1972Go; Casteilla et al., 1987Go, 1989Go). In lambs and calves, BAT morphologically changes to WAT beginning as early as 2 to 4 d after birth (Thompson and Jenkinson, 1969Go), and may conclude within 3 wk (Casteilla et al., 1987Go). Rats have both WAT and BAT at birth, and maintain depots of BAT into adulthood. During cold stress in lambs, blood flow to BAT deposits increases five- to sixfold (Alexander et al., 1973Go). These points demonstrate the importance of BAT in neonatal lambs and their dependence on the tissue for survival during cold stress.

Slee et al. (1980)Go stated that mortality rates on sheep farms tend to be underestimated because of the fact that typical survey data tend to be reported from the "best-managed farms." Up to 50% of neonatal lamb death is caused by cold stress and what is termed "un-dernutrition," or starvation; however, these authors further stated that lambs classified as "starved" may have died of hypothermia, which caused immobility and prevented suckling. Even deaths classified as "born dead" may have occurred from acute hypothermia immediately after parturition. Less severe cold stress at birth can decrease the suckling drive, thereby decreasing nutrient intake at a time when energy expenditure is greatest (Slee et al., 1980Go). In our study, lambs from dams fed HF had a mortality percentage of 11.6%, whereas 21.7% of lambs from LF dams died (P = 0.03). The increase in thermogenesis from BAT may be due to activation of UCP1, or thermogenin. Uncoupling protein is the vehicle for heat production from BAT. Uncoupling protein-1 uncouples oxidative phosphorylation in the mitochondria, resulting in heat loss instead of ATP production. Uncoupling protein-1 is stimulated by both cold exposure and free fatty acids (Lowell and Flier, 1997Go). Upon cold exposure, the sympathetic nervous system stimulates lipolysis, and released fatty acids then stimulate the action of UCP1 (Ganong, 1999Go). Supplementation with a high linoleic feedstuff may increase the linoleic acid content of BAT, a major fuel for BAT thermogenesis (Lammoglia et al., 1999aGo), which may stimulate UCP1 to increase heat production.

Lambs are most susceptible to hypothermia from birth to 5 h of age and again 12 to 36 h after birth (Eales et al., 1982Go). During the first period, lambs suffer hypothermia due to excessive heat loss, whereas during the second period, heat production is depressed due to energy reserves being depleted. Stott and Slee (1985)Go indicated a viable lamb must be homeothermic at birth and possess sufficient energy reserves for survival. Methods imposed during fetal development to increase the thermogenic capacity and energy reserves of the lamb at the onset of parturition could decrease mortality due to cold stress in the first 36 h after birth. The current study indicated that lambs had greater survivabilities when dams had been fed a high-linoleic saf-flower during the last 45 d of gestation.

Trial 2

Climatic Conditions. Average high and low ambient barn temperature during the trial were –0.2 and –5.6°C (yr 1), and –2.3 and –10.2°C (yr 2). Average high and low outdoor temperatures in Fargo during yr 1 and 2 were –2.8 and –12.9°C, and –6.3 and –16.4°C, respectively (NDAWN, 2002Go). Long term average high and low temperatures at this location for this time period are –7 and –16°C.

Ewe Variables. There were no differences in initial (average 82.9 ± 1.7 kg; P = 0.92; data not shown) or final ewe BW (average 93.9 ± 2.0 kg; P = 0.48; data not shown). This response would be expected because the diets were similar in energy. Similar results with prepartum fat supplementation have been reported by Bellows et al. (2001)Go using heifers fed isocaloric diets containing 2.0, 3.3, 4.2, or 4.5% fat. As expected, basal diet DMI did not differ (P ≥ 0.21) among treatments, but intake (kilogram and percentage of BW) decreased (P < 0.001) approaching parturition in both treatments (Table 5Go). A decrease was expected as gestation progressed due to expansion of the uterus, limiting distension of the rumen (NRC, 1985Go).


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  		Table 5. Influence of control or high-linoleic safflower seed supplementation on ewe prepartum basal diet DMI (Trial 2)a
 
There were no treatment and treatment x period interactions for ewe plasma NEFA (P = 0.13; Table 6Go); however, ewe plasma NEFA exhibited a period effect (P < 0.001). Lack of treatment differences would suggest that animals were in similar energy status. Nonesterified fatty acids are a measure of mobilization of lipid stores, but may also reflect fat addition in the diet. In 20 separate studies, lactating cows fed dietary fat almost always had increased NEFA (Grummer and Carroll, 1991Go). Due to rapid growth of the fetus during late gestation, the nutrient demand on the ewe causes lipogenesis to decrease and lipolysis to increase (Freetly and Ferrell, 2000Go). Results in the current study would agree with Freetly and Ferrell (2000)Go, who reported that liver use of NEFA increased as parturition approached. Noble et al. (1978)Go reported that ewes fed a hay-based diet supplemented with rumen-protected PUFA during the final 8 wk of gestation had increased PUFA in all plasma lipid fractions, including NEFA, compared with ewes receiving a low-fat supplement. Also, NEFA increased with increasing fat in the diet (Scibilia et al., 1987Go). In our study, plasma NEFA were only different (P = 0.02) at parturition (795 vs. 1047 ± 73 µEq/L for HF and LF, respectively).


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  		Table 6. Influence of control or high-linoleic safflower seed supplementation on ewe plasma NEFA and glucose concentrations (Trial 2)
 
A treatment x period interaction (P = 0.05) was observed for plasma glucose. Plasma glucose concentration increased with advancing gestation and spiked in both treatments at parturition, with LF being higher (P = 0.003). Pregnant ewe circulating glucose levels increase with advancing pregnancy as the glucose demand by the gravid uterus increases (Freetly and Ferrell, 2000Go). A summary of 26 studies demonstrated that supplemental fat did not affect circulating glucose in lactating dairy cows (Grummer and Carroll, 1991Go).

Lamb Variables. Birth weights of lambs were not different between treatments (5.4 ± 0.1 kg; P = 0.27); however, incidence of multiple birth, as expected, did covary (P < 0.001) with birth weight. Because ewes on both treatments consumed similar amounts of dietary energy, similar birth weights were anticipated. Additional energy provided to the dam during the last trimester may increase fetal growth (NRC, 1985Go). The current results agree with supplemental fat studies in beef females (Espinoza et al., 1995Go; Bellows et al., 2001Go).

Because no significant treatment effects or treatment x period interactions existed, treatments were pooled (Table 7Go) for plasma NEFA and glucose concentrations, and only period data are reported. Plasma NEFA for lambs up to 48 h after parturition did not differ across treatments (P = 0.34) and period (P = 0.16), and did not interact (P = 0.54). Lamb plasma glucose increased (P < 0.001; Table 7Go) with time, whereas there was no effect of treatment (P = 0.67) and no treatment x period interaction (P = 0.59). Lammoglia et al. (1999b)Go reported higher plasma glucose in cold-challenged calves from cows fed a HF diet during the final trimester of gestation. Increased NEFA and glucose have been reported elsewhere in cold-exposed lambs and calves, respectively (Alexander et al., 1968Go; Godfrey et al., 1991Go). Lambs in the current study were not subject to severe cold stress because they were moved indoors after ewes lambed. It is unknown whether lambs from HF lambs would have had greater glucose and NEFA values than LF lambs if colder conditions were imposed.


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  		Table 7. Influence control or high-linoleic safflower seed supplementation of ewes on lamb plasma NEFA and glucose concentrations (Trial 2)a
 
Lamb rectal temperatures tended to be slightly higher in lambs (P = 0.08; Table 8Go) from LF ewes, and no treatment x time interaction occurred postpartum (P = 0.37). Lammoglia et al. (1999b)Go also reported a nonsignificant main effect of dietary fat on calf rectal temperature; however, numeric advantages were observed in the cold-exposed calves from dams receiving LF diet during late gestation. Conversely, in a similar study, calves from cows receiving a HF diet during gestation have been reported to have higher rectal temperatures during imposed cold exposure (Lammoglia et al., 1999aGo). All rectal temperatures observed in this study were within the thermoneutral zone for sheep. At –4°C, a diet fed to dairy calves containing 25% fat resulted in higher rectal temperature than a diet containing 10% fat; however, there was no difference at 10°C (Scibilia et al., 1987Go). Following parturition, lambs are exposed to cold stress due to exiting the temperature-controlled uterine environment and being wet with amniotic fluid. Lack of overall treatment difference in rectal temperatures may be due to the absence of extended cold stress as lambs were moved indoors after they were born.


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  		Table 8. Influence control or high-linoleic safflower seed supplementation for ewes on lamb rectal temperature, brown adipose weight, and carcass composition (Trial 2)
 
Weight of perirenal brown fat deposits was similar (P = 0.28) for lambs from ewes fed LF or HF prepartum diets (Table 8Go). Treatments were not different (P = 0.60) when perirenal fat was expressed as a percentage of lamb BW. Brown adipose tissue dissected from the pericardial area tended (P = 0.08) to be heavier in LF lambs; however, this effect disappeared when expressed as a percentage of BW (P = 0.98). Nedergaard et al. (1983)Go also reported no difference in BAT weight in rats fed high or low amounts of essential fatty acids. Late-term fetuses from ewes fed at 150% metabolic requirements (AFRC, 1992Go) had less BAT than those from ewes fed at 100% requirements with a higher thermogenic capacity (Budge et al., 2000Go). Alexander and Bell (1975)Go reported no relationship in lambs between the dissectable amount of BAT and the maximal thermogenic response to cold. Increased glucose supply to lambs was reported to increase adipose deposition (Stevens et al., 1990Go). Glucose supply to the lambs here was not different based on maternal plasma glucose and, therefore, was not sufficient enough to result in augmentation of adipose in lambs from HF dams.

Lamb carcasses contained similar amounts of ash (P = 0.21), CP (P = 0.94), and ether extract (P = 0.55; Table 8Go), indicative of similar gross body condition at birth. In addition, as weights of BAT deposits were not different, we would not expect differences in overall fat in the carcass. Composition of the fat might reflect the added dietary linoleic acid; however, this variable was not measured.

The variables measured in the current study were hypothesized to reflect lamb thermogenic capacity or cold tolerance. Perhaps a more severe degree of cold stress was necessary to elicit the responses seen elsewhere. Lammoglia et al. (1999aGo,bGo) imposed cold stress by placing calves in a cold room maintained at a temperature of 9°C for 200 min. Lambs in the current study endured a limited amount of cold stress, perhaps only for the first 2 h of life. Lambs from HF dams may have a greater potential to mount a thermogenic response when challenged. This response would be better measured by quantifying UCP1 activity in BAT stores. Nedergaard et al. (1983)Go reported that total UCP1 content, not BAT wet weight, is the most relevant measure of potential for nonshivering thermogenesis.

The two studies taken together indicate beneficial effects of ewe supplementation with high linoleic saf-flower seed during gestation (Trial 1). However, the mechanism by which high linoleic safflower seed acts in gestating ewes does not seem to be increased BAT stores (Trial 2). We did not measure activity of UCP1 in either study. Uncoupling protein-1 activity may have been responsible for stimulating some of the production responses we observed related to decreased mortality (Alexander and Bell, 1975Go; Nedergaard et al., 1983Go). These results suggest feeding high-linoleic safflower seed to ewes during the last 45 d of gestation increases lamb survivability at parturition with no changes in ewe body weight or condition, which suggests an economic benefit from supplementation. Further research is necessary to elicit the mechanism by which survival is increased and to identify types of fat sources that cause such a response.


   Footnotes
 
1 This material is based on work supported by the Cooperative State Research, Education, and Extension Service, USDA, "Alternative Crops Project" Grant No. 99-34216-7498. The authors gratefully acknowledge the assistance of N. Riveland and J. Bergman for obtaining the safflower seed, and T. Faller and the technical staff at the Hettinger Research and Extension Center for their assistance with care of sheep used in this project and with data collection. Back

2 Current address: New Mexico State Univ., Clayton Livestock Res. Center, Clayton 88415. Back

3 Correspondence: 177 Hultz Hall (phone: 701-231-7660; fax: 701-231-7590; e-mail: glardy{at}ndsuext.nodak.edu).

Received for publication October 13, 2003. Accepted for publication August 30, 2004.


   Literature Cited
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 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
 Literature Cited
 


AFRC. 1992. Pages 812–815 in Agricultural and Food Research Council Technical Committee on Response to Nutrients. Report No. 9. CAB Int., Wallingford, U.K.

Alexander, G., and A. W. Bell. 1975. Quantity and calculated oxygen consumption during summit metabolism of brown adipose tissue in newborn lambs. Biol. Neonate 26:214–220.[Medline]

Alexander, G., A. W. Bell, and J. R. S. Hales. 1973. Effects of cold exposure on tissue blood flow in the newborn lamb. J. Physiol. 234:65–77.[Abstract/Free Full Text]

Alexander, G., S. C. Mills, and T. W. Scott. 1968. Changes in plasma glucose, lactate, and free fatty acids in lambs during summit metabolism and treatment with catecholamines. J. Physiol. 198:277–289.[Abstract/Free Full Text]

Alexander, G., and D. Williams. 1968. Shivering and non-shivering thermogenesis during summit metabolism in young lambs. J. Physiol. 198:251–276.[Abstract/Free Full Text]

AOAC. 1997. Official Methods of Analysis. 16th ed. Assoc. Offic. Anal. Chem., Arlington, VA.

Bellows, R. A., E. E. Grings, D. D. Simms, T. W. Geary, and J. W. Bergman. 2001. Effects of feeding supplemental fat during gestation to first-calf beef heifers. Prof. Anim. Scient. 17:81–89.[Abstract/Free Full Text]

Budge, H., J. Bispham, J. Dandrea, E. Evans, L. Heasman, P. M. Ingleton, C. Sullivan, V. Wilson, T. Stephenson, and M. E. Symonds. 2000. Effect of maternal nutrition on brown adipose tissue and its prolactin receptor status in the fetal lamb. Pediatr. Res. 47:781–786.[Medline]

Casteilla, L., O. Champigny, F. Bouillaud, J. Robelin, and D. Ricquier. 1989. Sequential changes in the expression of mitochondrial protein mRNA during the development of brown adipose tissue in bovine and ovine species. Biochem. J. 257:665–671.[Medline]

Casteilla, L., C. Forest, J. Robelin, D. Ricquier, A. Lombet, and G. Ailhaud. 1987. Characterization of mitochondrial-uncoupling protein in bovine fetus and newborn calf. Am. J. Physiol. 252:E627–E636.

De Fries, C. A., D. A. Neuendorff, and R. D. Randel. 1998. Fat supplementation influences postpartum reproductive performance in Brahman cows. J. Anim. Sci. 76:864–870.[Abstract/Free Full Text]

Eales, F. A., J. S. Gilmour, R. M. Barlow, and J. Small. 1982. Causes of hypothermia in 89 lambs. Vet. Rec. 110:118–120.[Abstract]

Espinoza, J. L., J. A. Ramirez-Godinez, J. A. Jimenez, and A. Flores. 1995. Effects of calcium soaps of fatty acids on postpartum reproductive activity in beef cow and growth of calves. J. Anim. Sci. 73:2888–2892.[Abstract]

Freetly, H. C., and C. L. Ferrell. 2000. Net flux of nonesterified fatty acids, cholesterol, triacylglycerol, and glycerol across the portal-drained viscera and liver of pregnant ewes. J. Anim. Sci. 78:1380–1388.[Abstract/Free Full Text]

Ganong, W. F. 1999. Review of Medical Physiology. 19th ed. Appleton and Lange, Stamford, CT.

Gemmell, R. T., A. W. Bell, and G. Alexander. 1972. Morphology of adipose cells in lambs at birth and during the subsequent transition of brown to white adipose tissue in cold and warm conditions. J. Anat. 133:134–164.

Gibney, M. J., and J. L. L’Estrange. 1975. Effects of dietary unsaturated fat and of protein source on melting point and fatty acid compotition of lamb fat. J. Agric. Sci. 84:291–296.

Gill, J. L., and H. D. Hafs. 1971. Analysis of repeated measures of animals. J. Anim. Sci. 33:331–336.

Godfrey, R. W., S. D. Smith, M. J. Guthrie, R. L. Stanko, D. A. Neuendorff, and R. D. Randel. 1991. Physiological responses of newborn Bos indicus and Bos indicus x Bos taurus calves after exposure to cold. J. Anim. Sci. 69:258–263.[Abstract]

Goering, H. K., and P. J. Van Soest. 1970. Forage fiber analysis. USDA Handbook, No. 379. Washington, DC.

Gray, P. R. 1986. Anesthesia in goats and sheep Part II. General anesthesia. Compend. Contin. Educ. Pract. Vet. 8:S127–S135.

Grummer, R. R., and D. J. Carroll. 1991. Effects of dietary fat on metabolic disorders and reproductive performance of dairy cattle. J. Anim. Sci. 69:3838–3852.[Abstract]

Johnson, M. M., and J. P. Peters. 1993. Technical note: an improved method to quantify nonesterified fatty acids in bovine plasma. J. Anim. Sci. 71:753–756.[Abstract]

Lammoglia, M. A., R. A. Bellows, E. E. Grings, and J. W. Bergman. 1999a. Effects of prepartum supplementary fat and muscle hypertrophy genotype on cold tolerance in newborn calves. J. Anim. Sci. 77:2227–2233.[Abstract/Free Full Text]

Lammoglia, M. A., R. A. Bellows, E. E. Grings, J. W. Bergman, R. E. Short, and M. D. MacNeil. 1999b. Effects of feeding beef females supplemental fat during gestation on cold tolerance in newborn calves. J. Anim. Sci. 77:824–834.[Abstract/Free Full Text]

Lammoglia, M. A., S. T. Willard, D. M. Hallford, and R. D. Randel. 1997. Effects of dietary fat on follicular development and circulating concentrates of lipids, insulin, progesterone, estradiol 17ß, 13, 14-dihydro-15-keto-prostaglandin F2{alpha}, and growth hormone in estrous cyclic Brahman cows. J. Anim. Sci. 75:1591–1600.[Abstract/Free Full Text]

Lowell, B. B., and J. S. Flier. 1997. Brown adipose tissue, ß3-adrenergic receptors, and obesity. Annu. Rev. Med. 48:307–316.[Medline]

NRC. 1985. Nutrient Requirements of Sheep. 6th ed. Natl. Acad. Press, Washington, DC.

NDAWN. 2002. North Dakota Agricultural Weather Network. Available: http://ndawn.ndsu.nodak.edu/index.html. Accessed July 11, 2003.

Nedergaard, J., W. Becker, and B. Cannon. 1983. Effects of dietary essential fatty acids on active thermogenin content in rat brown adipose tissue. J. Nutr. 113:1717–1724.

Noble, R. C., J. H. Shand, J. T. Drummond, and J. H. Moore. 1978. Protected polyunsaturated fatty acid in the diet of the ewe and the essential fatty acid status of the neonatal lamb. J. Nutr. 108:1868–1876.

Outen, G. E., D. E. Beever, and J. S. Fenlon. 1976. Direct methylation of long chain fatty acids in feeds, digesta, and faeces without prior extraction. J. Sci. Food Agric. 27:419–425.[Medline]

Robertson, J. B., and P. J. Van Soest. 1991. Methods for dietary fiber, neutral detergent fiber, and non-starch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583–3597.[Abstract]

Samson, D. E., and J. Slee. 1981. Factors affecting resistance to induced body cooling in newborn lambs of 10 breeds. Anim. Prod. 33:59–65.

Schwartz, J. H., J. B. Young, and L. Landsberg. 1983. Effect of dietary fat on sympathetic nervous system activity in the rat. J. Clin. Invest. 72:361–370.

Scibilia, L. S., L. D. Muller, R. S. Kensinger, T. F. Sweeney, and P. R. Shellenberger. 1987. Effect of environmental temperature and dietary fat on growth and physiological responses of newborn calves. J. Dairy Sci. 70:1426–1433.

Slee, J., R. G. Griffiths, and D. E. Samson. 1980. Hypothermia in newborn lambs induced by experimental immersion in a water bath and by natural exposure outdoors. Res. Vet. Sci. 28:275–280.[Medline]

Stevens, D., G. Alexander, and A. W. Bell. 1990. Effects of prolonged glucose infusion into fetal sheep on body growth, fat deposition, and gestation length. J. Dev. Physiol. 13:277–281.[Medline]

Stott, A. W., and J. Slee. 1985. The effect of environmental temperature during pregnancy on thermoregulation in the newborn lamb. Anim. Prod. 41:341–347.

Thompson, G. E., and D. M. Jenkinson. 1969. Nonshivering thermogenesis in the newborn lamb. Can. J. Physiol. Pharmacol. 47:249–253.[Medline]


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