Effects of maternal nutrition regimen of ewes on performance, carcass, and meat traits of their feedlot-finished lambs

Abstract

The objective of this study was to evaluate the effects of diets with two energy levels fed to Ile de France ewes during the last third of gestation on the performance, carcass, and meat traits of their offspring. Treatments were: D0: maternal diet meeting the requirements for the last third of gestation, and D20: maternal diet containing an additional 20% energy requirements. Twenty single-born male lambs, ten from each group of ewes, were weaned at 60 d (18.3 ± 1.4 kg initial BW) and fed a common finishing diet. Animals were slaughtered when they reached 32 kg BW. Dry matter intake, average daily gain, feed conversion, and days on feed were unaffected by treatments (P≥0.09). No effects were observed on hot and cold carcass weights, dressing percentage, chilling loss, commercial cuts yields, and loin-eye area (P≥0.17). Meat pH, thawing loss, cooking loss, shear force, and water holding capacity were also not affected by treatments (P≥0.09). Temperature and meat color, as well as centesimal composition were similar between treatments (P≥0.27). Adding 20% energy on top of the requirements of Ile de France ewes during the last third of gestation does not influence the performance, carcass traits, nor meat traits of their offspring.

Key words
energy; fetal programming; lamb; sheep; tissue composition

MATERIALS AND METHODS

All experimental procedures followed the principles of animal experimentation from the National Council for the Control of Animal Experimentation (CONCEA) and were approved by the Committee of Ethics in Animal Use (CEUA) from São Paulo State University (approval #018943/14).

Local, experimental treatments and management

The experiment was conducted at the Sheep Laboratory from the Animal Science Department, São Paulo State University “Julio de Mesquita Filho” (FCAV/Unesp), Jaboticabal, São Paulo, Brazil (21°15’22” S latitude and 48°18’58” W latitude, 595 m altitude).

Fifty Ile de France ewes, averaging 20 months old and 60 ± 4.1 kg body weight (BW), were mated with the same Ile de France ram by natural service during the breeding season. Upon reaching 100 days of gestation, the 50 ewes underwent an ultrasound examination of the gravid uterus, after which 40 animals in a single pregnancy were selected. This new lot was divided into two groups of 20 pregnant ewes, which were allocated to two 0.5-ha paddocks cultivated with Tifton-85 bermudagrass (Cynodon spp.), which were kept with forage sward at 4 cm, to not affect feed intake. Paddocks were equipped with feedbunks and waterers.

The experimental diets fed to the ewes (Table I) had two levels of energy: one was formulated to meet the nutritional requirements of the last third of gestation (D0), and the other had an additional 20% of the energy requirements (D20), following NRC (2007) recommendations. Diets were delivered twice daily at 0700 and 1700 h (50:50), to allow ad libitum access to feed, observing approximately 10% orts. Samples of diets (delivered and refused) were sampled weekly for later chemical analyses, and the amount of feed delivered was adjusted daily.

Table I
Ingredient and chemical composition of diets fed to experimental ewes at the last third of gestation.

Item	Diet
	D0	D20
Ingredient (% DM)
Corn silage	70.00	30.00
Soybean meal	19.88	20.90
Ground corn	8.16	43.10
Mineral-vitamin premix1	1.00	1.00
Calcitic limestone	0.54	0.80
Dicalcium phosphate	0.22	0.00
Soybean oil	0.00	4.00
NaCl	0.20	0.20
Analyzed nutrient composition
Dry matter, %	48.79	72.41
Organic matter, % DM	93.14	94.35
Crude protein, % DM	15.47	15.59
Ether extract, % DM	2.85	6.99
Minerals, % DM	6.86	5.65
Neutral detergent fiber, % DM	42.74	25.62
Acid detergent fiber, % DM	25.88	13.94
Total carbohydrates, % DM2	74.82	71.77
Non-fibrous carbohydrates, % DM3	32.08	46.15
Metabolizable energy, Mcal kg-1 DM4	2.39	2.87

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation.
  ¹Composition per kilogram: calcium - 120 g; chlorine - 90 g; sodium - 62 g; magnesium - 54 g; phosphorus - 50 g; sulfur - 34 g; zinc - 1.600 mg; manganese - 1.500 mg; iron - 1.064 mg; fluorine (max) - 730 mg; copper - 50 mg; iodine - 25 mg; selenium 20 mg; cobalt - 10 mg; Vit. A - 100.000 IU; Vit. D3 - 40.000 IU; Vit. E - 600 IU.
  ²Calculated according to Sniffen et al. (1992).
  ³Calculated according to Weiss (1999).
  ⁴Estimated based on NRC (2007).

After lambing, the ewes were allocated to the maternity paddock (approximately 1 ha), which was also cultivated with Tifton-85 bermudagrass and equipped with feedbunks and waterers, where they were fed a common diet, formulated according to NRC (2007) for lactation phase, and a creep-feeding diet was provided to the lambs

Performance evaluations

The survival rate from birth to weaning was 80%, resulting in 32 lambs. From those, 20 single-born male lambs (18.3 ± 1.4 kg initial BW), 10 from each treatment were used. Lambs were weaned 60 days after lambing, with 18.3 ± 1.4 kg BW, identified according to the mothers’ prenatal dietary treatment, dewormed, vaccinated against clostridial diseases, and housed in individual 1-m² suspended slatted-floor pens. The animals’ entry interval into the feedlot facility was 20 days.

The lambs’ diets had a roughage:concentrate ratio of 40:60 and were composed of 16% crude protein (CP) and 3.00 Mcal ME^-1 kg DM, following the recommendations of the NRC (2007), to meet the requirements of growing lambs with an expected average daily weight gain of 300 g (Table II). The animals were fed the total mixed ration twice daily, at 0700 and 1700 h (50:50), to allow ad libitum access to feed, allowing approximately 10% orts. Feed and orts were weighed daily and adjusted. Feed samples were collected weekly and 10% orts were collected daily for dry matter (DM) determination and DM intake (DMI) calculation.

Table II
Ingredient and chemical composition of diets fed to experimental feedlot lambs.

Item	Diet
Ingredient (% DM)
Corn silage	40.00
Soybean meal	21.00
Ground corn	36.25
Mineral-vitamin premix1	1.00
Limestone	0.30
Dicalcium phosphate	1.45
Analyzed nutrient composition
Dry matter, %	66.28
Crude protein, % DM	15.88
Ether extract, % DM	3.07
Minerals, % DM	6.77
Neutral detergent fiber, % DM	30.21
Acid detergent fiber, % DM	17.04
Metabolizable energy, Mcal kg−1 DM2	2.64

• ¹Composition per kilogram: calcium - 120 g; chlorine - 90 g; sodium - 62 g; magnesium - 54 g; phosphorus - 50 g; sulfur - 34 g; zinc - 1.600 mg; manganese - 1.500 mg; iron - 1.064 mg; fluorine (max) - 730 mg; copper - 50 mg; iodine - 25 mg; selenium 20 mg; cobalt - 10 mg; Vit. A - 100.000 IU; Vit. D3 - 40.000 IU; Vit. E - 600 IU.
  ²Estimated based on NRC (2007).

Every 14 days, the lambs were weighed and the incidence of Haemonchus contortus was monitored by the Famacha® method (Van Wyk & Bath 2002). Using the initial BW (IBW), final BW (FBW), and days on feed (DOF), we calculated the average daily gain (ADG = [FBW-IBW]/DOF). The feed conversion (FC) was calculated as FC = DMI/ADG.

Carcass and meat traits

When lambs reached approximately 32 kg BW, they were harvested at the FCAV/Unesp experimental abattoir, after a 16-h solid fast, following a humane slaughter, according to MAPA (2000), and slaughter weight (SW) was recorded. The carcass pH and temperature were measured 45 min after the slaughter (pH_45min, T_45min), in triplicate, by inserting a penetration electrode, equipped with a pH meter and thermometer (Testo 205, Testo AG, Lenzkirch, Germany), into the Longissimus lumborum muscle between the 12th and 13th ribs. After measurements, the carcasses were weighed to access the hot carcass weight (HCW) and transferred to a cold room at approximately 6 °C, where they remained for 24 h, hung by the gastrocnemius tendons. After chilling, meat pH values (pH_24h), temperature (T_24h), and the color attributes by the coordinates L* (lightness), a* (redness), and b* (yellowness), were measured according to Miltenburg et al. (1992), using a colorimeter (CR-400, Konica Minolta Sensing Inc., Osaka, Japan). The carcasses were reweighed to determine the cold carcass weight (CCW). Hot carcass yield (HCY % = (HCW/SW) × 100), cold carcass yield (CCY % = (CCW/SW) × 100), carcass dressing percentage (CD % = (HCW/SW) × 100), and chilling loss (CL % = [(HCW − CCW)/HCW] × 100) were also calculated.

Carcasses were sectioned into two half-carcasses, and the left half was divided into five anatomical regions: neck, shoulder, ribs, loin, and leg (Silva Sobrinho et al. 2008). Using a digital caliper and a graduated tape at the 13th rib over the Longissimus dorsi muscle, we measured the maximum length (measure A), maximum depth (measure B), minimum fat thickness on the muscle (measure C), and maximum fat thickness on the surface of the 13th rib, at 11 cm from the midline (measure F), and the loin-eye area (LEA) was calculated using the following formula: (A/2 × B/2)π, following methodology described by Silva Sobrinho et al. (2003).

Meat quantitative analyses, including water holding capacity (WHC), thawing (TL) and cooking (CKL) losses, shear force (SF), and centesimal composition, were performed on the Longissimus lumborum muscle. The water holding capacity (WHC), was determined by adapting the filter-paper press method, proposed by Hamm (1986), using 500-mg samples and 10-kg load pressing for 5 min. Results were expressed as a percentage of water lost relative to the initial sample weight. The TL was determined following the methodology described by Koohmaraie et al. (1996). Fresh meat samples were weighed, frozen, and kept in a BOD incubator at 5 °C for 16 h, to reach an internal temperature between 2 and 5°C. After incubation time, samples were reweighed and TL was calculated. To determine CKL, samples were weighed in grill pans and heated in a gas oven at 170 °C until reaching an internal temperature of 71 °C. Afterward, they were removed from the oven, cooled to room temperature, and reweighed. Subsequently, to determine the shear force, six sub-samples were collected with a 1.27-cm diameter cylinder punch (Wheeler & Koohmaraie 2002), evaluated with a texture analyzer (CT3, Brookfield Engineering Laboratories Inc., USA) coupled to a 1.016-mm-thick Warner-Bratzler blade, and values were expressed in kgf. Analyses of the centesimal composition of the Longissimus lumborum muscle for moisture, protein, fat, and minerals followed the recommendations described by Silva & Queiroz (2002).

For dissection, the legs were thawed at 10 °C in a refrigerator for 8 h and cleaned for removal of any extra tissue, adjunct fat, and other soft tissues medial to the pelvic bone and coccygeal vertebrae. Thus, they were weighed and dissected following the methodology described by Brown & Williams (1979), separating the groups of tissues: fat (external, subcutaneous, and intermuscular), bones, muscles (Biceps femoris, Semitendinosus, Adductor, Semimembranosus, and Quadriceps femoris) and others (tendons, glands, and blood vessels). The leg muscularity index (LMI) was calculated according to Purchas et al. (1991): LMI = √(W5M/FL)/FL, where WM5 = weight (g) of the five muscles surrounding the femur (Biceps femoris, Semitendinosus, Adductor, Semimembranosus, and Quadriceps femoris) and FL = femur length (cm).

Statistical analyses

The experiment was carried out in a completely randomized design with two treatments, ten replications, and lambs were considered the experimental units. The following statistical model was used: Y_ij = μ + T_i + e_ij, where Y_ij = observed value of the dependent variable i; μ = overall mean; T_i = effect of treatment i (i = 1–2); and e_ij = random error. Data were submitted to normality (Kolmogorov-Smirnov) and variance homoscedasticity (Levene) tests and analyzed using the GLM procedure of SAS statistical software (version 9.2). The significance was defined as P<0.05.

RESULTS

Performance traits

The average days on feed were similar between the lambs born from ewes fed diets with or without the additional 20% energy (average = 54 d; P=0.67), with no effect on initial body weight (average = 18.3 kg; P=0.09) and final body weight (average = 32.4 kg; P=0.32). No treatment differences were also observed on lamb’s DMI (average = 1.06 kg; P=0.09), ADG (average = 0.254 kg; P=0.32) nor for FC (average = 4.15; P=0.09; Table III).

Table III
Effects of maternal nutrition on dry matter intake and feedlot performance of lambs.

Item	Diet		P-value	SEM
	D0	D20
Days on feed, n	55.00	53.00	0.67	0.11
Initial body weight, kg	18.00	18.63	0.85	0.14
Final body weight, kg	32.50	32.30	0.32	0.15
Average daily gain, kg	0.27	0.24	0.32	0.05
Dry matter intake, kg	1.10	1.02	0.09	0.10
Feed conversion, kg kg-1	4.04	4.30	0.09	0.12

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.

Carcass and meat traits

Carcass quantitative traits, such as HCW (average = 15.0 kg; P=0.19) and CCW (average = 14.5 kg; P=0.17), their respective yields (average HCY = 47.5%; P=0.56, and average CCY = 46.1%; P=0.57), and dressing percentage (average = 56.8%; P=0.56) did not differ (Table IV) between treatments tested. The same was true for the commercial cuts, which average values were 1.70 kg shoulder (P=0.37), 0.470 kg neck (P=0.77), 1.67 kg ribs (P=0.31), 0.85 kg loin (P=0.47, and 2.50 kg leg (P=0.51; Table V).

Table IV
Effects of maternal nutrition on carcass traits of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
HCW, kg	14.82	15.18	0.19	0.22
CCW, kg	14.37	14.73	0.17	0.30
FCW, kg	25.89	27.00	0.12	0.22
HCY, %	47.33	47.76	0.56	0.41
CCY, %	45.89	46.37	0.57	0.52
CD, %	57.34	56.22	0.56	0.57
CL, %	3.04	2.92	0.77	0.39

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean. HCW - hot carcass weight; CCW - cold carcass weight; FCW - full-carcass weight; HCY - hot carcass yield; CCY - cold carcass yield; CD - carcass dressing percentage; CL - chilling loss.

Table V
Effects of maternal nutrition on commercial cuts yield of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
Left half-carcass, kg	7.15	7.39	0.29	0.15
Shoulder, kg	1.69	1.71	0.37	0.11
Neck, kg	0.47	0.48	0.77	0.01
Ribs, kg	1.69	1.63	0.31	0.14
Loin, kg	0.87	0.84	0.47	0.07
Leg, kg	2.48	2.52	0.51	0.06

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.

Regarding carcasses’ tissue composition, similar percentage values were observed for bone (average = 17.4%; P=0.90), muscle (average = 65.8%; P=0.55), and fat (average = 14.3%; P=0.73; Table VI). The LMI values of both treatments were similar (average = 0.53; P=0.36). The same trend was observed for femur weight and length (averages = 139.20 g [P=0.60], and 16.2 cm [P=0.49], respectively).

Table VI
Effects of maternal nutrition on tissue composition and leg muscularity index of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
Muscle:bone ratio	3.74	3.85	0.94	0.01
Leg muscularity index (LMI)	0.54	0.52	0.36	0.11
Femur weight, g	138.39	140.02	0.60	0.10
Leg weight, kg	2.36	2.37	0.88	0.03
Femur length, cm	16.00	16.35	0.49	0.16
Bone, %	17.43	17.25	0.90	0.02
Muscle, %	65.16	66.47	0.55	0.05
Fat, %	14.60	13.98	0.73	0.02
Others, %	2.81	2.31	0.22	0.20

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.

The characteristics of Longissimus dorsi muscle of lamb born from ewes fed diets with or without 20% additional energy were similar for maximum length (average = 5.33 cm; P=0.93), maximum depth (average = 3.26 cm; P=0.58), minimum fat thickness (average = 2.67 mm; P=0.55), maximum fat thickness (average = 5.33 mm; P=0.74), and LEA (average = 13.97 cm²; P=0.17; Table VII).

Table VII
Effects of maternal nutrition on length (A), maximum depth (B), minimum thickness (C), and maximum thickness (F) of fat and loin-eye area (LEA) of the Longissimus muscle of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
A, cm	5.38	5.40	0.93	0.06
B, cm	3.15	3.38	0.58	0.07
C, mm	2.72	2.63	0.55	0.08
F, mm	5.28	5.39	0.74	0.55
LEA, cm²	13.52	14.43	0.17	0.40

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.

Meat qualitative traits, evaluated at 45 min: pH_45min (average = 6.63; P=0.64), T_45min (average = 37.4 °C; P=0.85), L*_45min (average = 31.8; P=0.38), a*_45min (average = 12.4; P=0.38), b*_45min (average = 2.3; P=0.74), and at 24h postmortem: pH_24h (average = 5.67; P=0.63), T_24h (average = 6.88 °C; P=0.58), L*_24h (average = 37.6; P=0.83), a*_24h (average = 14.6; P=0.26), b*_24h (average = 2.05; P=0.71), as well as TL (average = 2.61%; P=0.21), WHC (average = 61.35%; P=0.89), SF (average = 2.83 kgf cm^-²; P=0.33) and CKL (average = 27.8%; P=0.09) did not differ between treatments (Table VIII).

Table VIII
Effect of maternal nutrition on meat qualitative traits of Longissimus muscle of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
pH45 min	6.64	6.61	0.64	0.06
pH24 h	5.69	5.66	0.63	0.04
Temperature45 min, oC	37.35	37.53	0.85	0.005
Temperature24 h, oC	7.00	6.77	0.58	0.05
Color45 min
L*	32.04	31.54	0.38	0.11
a*	12.16	12.66	0.38	0.11
b*	2.22	2.35	0.74	0.02
Color24 h
L*	37.72	37.40	0.83	0.007
a*	14.39	14.80	0.27	0.17
b*	1.91	2.19	0.71	0.02
Thawing loss, % (TL)	2.61	2.32	0.21	0.21
Cooking loss, % (CKL)	27.80	22.60	0.09	0.35
Water holding capacity, % (WHC)	61.20	61.50	0.89	0.003
Shear force, kgf (SF)	2.98	2.69	0.33	0.13

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.
  L* - lightness; a* - redness; b* - yellowness.

The centesimal composition of the Longissimus lumborum muscle was unaffected by treatments, with average minerals (average = 1.07%; P=0.42), protein (average = 19.6%; P=0.48), fat (average = 2.08%; P=0.48), and moisture (average = 77.8%; P=0.66; Table IX).

Table IX
Effects of maternal nutrition on the centesimal composition of the Longissimus muscle of feedlot lambs.

Item	Diet		P-value	SEM
	D0	D20
Minerals, %	1.10	1.04	0.42	0.09
Protein, %	20.10	19.07	0.48	0.07
Fat, %	1.89	2.27	0.48	0.07
Moisture, %	77.46	78.21	0.66	0.02

• D0 - diet meeting the nutritional energy requirements (NRC 2007); D20 - diet containing 20% more than the energy requirement of a pregnant ewe in the last third of gestation; SEM - standard error of the mean.

DISCUSSION

Performance traits

The results found in recent studies in which fetal programming was evaluated, especially when testing the overnutrition of ewes and the effects on the offspring, are highly heterogeneous (Sartori et al. 2020).

It is known that the development of skeletal muscle is dependent on the availability of nutrients during the fetal stage and malnutrition limits post-natal muscle growth, increasing the time and costs necessary to achieve the market weight of these animals (Du et al. 2013, Bell & Greenwood 2016). On the other hand, some research indicates that overnourishing ewes during gestation could negatively impact the performance of the offspring, impairing organ development (Wallace et al. 2002; using Border Leicester × Scottish Blackface), myogenesis in fetal skeletal muscle (Tong et al. 2009; using Rambouillet × Columbia ewes) and causing light birth weights (Da Silva et al. 2001; using Border Leicester × Scottish Blackface ewes). Reed et al. (2014), working with Dorset, Shropshire, and Southdown ewes reported that both over (140%) or restricted (60% requirement) maternal nutrition of ewes during gestation affect muscle fiber cross-sectional area, lipid accumulation, muscle fiber type, and gene and protein expression in the muscle of lambs, impairing post-natal muscle growth.

In the present study, lambs from the two different treatments reached similar weights at 60 days of age (feedlot initial BW), maintained the same DMI and ADG during the finishing phase, and were slaughtered at the same final body weight, resulting in a similar number of days on feed. Similar results were observed by Peel et al. (2012), who overfed ewes 22% above the recommended nutritional requirements and observed no effect on the post-natal performance of lambs. The same was reported by Wilson et al. (2016), who fed beef cows in late gestation 100 or 125% energy requirements and observed no effects on the performance or carcass traits of the offspring. In contrast, Oliveira (2020), studying fetal programming using Dorper × Santa Inês ewes fed up to 110% energy requirements, observed that the surplus energy resulted in lambs with the best performance at 60 days of age.

Research has shown prepartum diets cause notable changes in gene expression in fetal Longissimus dorsi muscle, subcutaneous, and perirenal adipose tissues. Peñagaricano et al. (2014) evaluating the effects of ewe’s maternal nutrition on the structure, physiology, and metabolism of the offspring, reported that the diet with high fiber, protein, and fat concentrations impacted fetal subcutaneous and perirenal adipose tissues, and many of the most significantly altered genes are associated with skeletal muscle development (i.e., MYOD1, ANKRD1, HIRA). Sousa et al. (2023) overfed Morada Nova ewes (21% more ME than the requirements or 26% more ME and CP), and reported significantly improved production rates, hormonal profile, placental characteristics, neonatal behavior, and lambs’ performance. However, the diets used in the current study were not different enough to translate those effects in lamb’s feedlot performance.

Carcass and meat traits

Despite the similarity between treatments, the average HCW (15.0 kg), CCW (14.5 kg), and CD (56.8%) were greater than those found by Zundt et al. (2006), who studied feedlot-finished lambs born from ewes supplemented in the initial, middle, and last thirds of gestation, and found average HCW, CCW, and CD of 13.96 kg, 13.61 kg, and 55.63%, respectively. Those differences are probably due to differences in the breed and nutritional regimen adopted in both trials. However, the CD values of the present research (56.8%) agree with those proposed by Sañudo & Sierra (1986), as adequate for sheep commercial carcasses.

The lack of effects of treatments on commercial cuts yield (left half-carcass, shoulder, neck, ribs, loin, leg) follows the same trend of performance traits. It indicates no changes occurred in body composition, which was confirmed with the centesimal analysis of the Longissimus. There are no reported results in the literature, so far, of commercial cuts of animals from fetal programming with the use of overfeeding, especially with the sheep species, showing the relevance of the present study. What is well-established is that lamb cut yields are reduced when ewes undergo nutrient restrictions of 40 or 30% during pregnancy (Piaggio et al. 2018).

According to Du et al. (2015), the skeletal muscle matures at late gestation in sheep (approximately day 105 of gestation) and nutrient restriction after this stage has no major impact on muscle fiber number, only in the size of the muscular fibers. It should be noted that diet D0 was sufficient to meet the nutritional requirements of ewes in the last third of pregnancy without compromising the post-natal growth of their lambs. On top of that, the surplus of 20% dietary energy did not influence either the carcass characteristics, or affect the qualitative traits of the Longissimus dorsi muscle, such as maximum length and depth, minimum and maximum fat thickness, and LEA.

Despite not differing between both groups of lambs, mean values for leg muscularity index (0.52) were higher than the 0.47 reported by Endo et al. (2015), who evaluated the leg muscularity index of Ile de France lambs fed fresh or hydrolyzed sugarcane. The nutritional uptake from diet D0 met the nutritional needs of the fetuses, not limiting their post-natal growth. Therefore, the 20% surplus energy in the ewes’ diet was not necessary to stimulate hyperplasia of the muscle cells during the fetal development of their lambs.

The greater nutrient supply during fetal development provides an increase in the number of adipocytes formed and the size of muscle fibers, whereas restriction leads to a reduction in the number of fibers and an increase in the concentration of collagen, which are factors that reduce meat tenderness in young animals (Mohrhauser et al. 2015). However, the 20% surplus energy in the ewes’ diet did not affect the qualitative traits of the Longissimus muscle of the lamb’s carcasses. The pH values are within the normal range for sheep meat proposed by Sañudo (1992), which should range between 6.56 and 6.69 for pH_45min and between 5.66 and 5.78 for pH_24h, providing stability to the meat-quality parameters such as color, water holding capacity, and tenderness, since these are closely related to the pH value (Leão et al. 2012). Results obtained herein confirm the assumptions of those authors since the association of lower thawing and cooking losses with an increased water-holding capacity of meat resulted in greater nutrient retention, juiciness, and meat tenderness, which are characteristics desired by the consumer.

Color variables L*, a*, and b* represent the lightness, redness, and yellowness of the meat, respectively. Meats presenting high L* and b* values are considered pale and yellowish, whereas higher a* values indicate redder meat, which is more attractive to the consumer (Miltenburg et al. 1992). According to Sañudo et al. (2000), for sheep meat, the ideal range of values is between 30.03 and 49.47 for L*, 8.24 to 23.53 for a*, and 3.38 to 11.10 for b*. The ewe diets with or without the surplus of 20% energy on top of the requirements during the last third of gestation did not influence the color of the lamb meat, and the L* and a* values agree with the values proposed by the aforementioned authors, despite a slight variation in b*. Leão et al. (2012) reported similar b* values in the meat of lambs fed diets containing sugarcane or corn silage and two levels of concentrate, averaging 2.12 and 4.93 at 45 min and 24 h postmortem, respectively.

Data from previous studies show that improving the nutritional status of cows during mid to late gestation can improve meat tenderness and increase adipose tissue deposition and growth in steers, as well as decrease the moisture content of the Longissimus muscle (Underwood et al. 2010). The lack of effect on quality traits of the Longissimus muscle shows that both treatments were considered adequate in providing nutrients to the fetus and that 20% surplus energy is not enough to cause either improvements or detrimental effects in the post-natal development of the muscle.

The meat centesimal analysis reflects the variation in carcass composition stemming from several factors, such as genetics and nutrition. However, we observed that providing only the nutritional requirements of ewes in the last third of gestation (D0), was sufficient to meet the nutritional demands for the development of the lambs, which resulted in meat with similar centesimal composition, with values close to those recommended by Tornberg (2005) for sheep meat, as follows: 75% moisture, 20% protein, 3% fat, and 2% non-protein substances (minerals, vitamins, and carbohydrates), approximately.

The lack of effects of the energetic overfeeding of ewes on the performance of lambs makes this strategy economically unfeasible and unnecessary. However, further studies are needed to elucidate the metabolic mechanisms involved in fetal programming, which still leads to controversial results.

In conclusion, adding 20% energy on top of the NRC (2007) requirements of Ile de France ewes, during the last third of gestation, considering the experimental conditions, does not significantly influence the performance, carcass quantitative traits, nor meat qualitative traits of their offspring.

ACKNOWLEDGMENTS

The authors thank the staff from Sheep Laboratory, Animal Science Department, São Paulo State University “Julio de Mesquita Filho”.

REFERENCES

• BARKER DJP, MARTYN, CN, OSMOND C, HALES CN & FALL CHD. 1993. Growth in utero and serum cholesterol concentration in adult life. Br Med J 307: 1524-1527.
• BELL AW & GREENWOOD PL. 2016. Prenatal origins of postnatal variation in growth, development, and productivity of ruminants. Anim Prod Sci 56: 1217-1232.
• BROWN AJ & WILLIAMS DR. 1979. Sheep carcass evaluation: measurement of composition using a standardized butchery method. Langford: Agricultural Research Council, Meat Research Council, 16 p.
• COSTA TC, GIONBELLI MP & DUARTE MS. 2021. Fetal programming in ruminant animals: understanding the skeletal muscle development to improve meat quality. Anim Front 11: 66-73.
• DA SILVA P, AITKEN RP, RHIND SM, RACEY PA & WALLACE JM. 2001. Influence of placentally mediated fetal growth restriction on the onset of puberty in male and female lambs. Reproduction 122: 375-383.
• DU M, HUANG Y, DAS AK, YANG Q, DUARTE MS, DODSON MV & ZHU J. 2013. Meat science and muscle biology symposium: manipulating mesenchymal progenitor cell differentiation to optimize performance and carcass value of beef cattle. J Anim Sci 91: 1419-1427.
• DU M, WANG B, FU X, YANG Q & ZHU M. 2015. Fetal programming in meat production. Meat Sci 109: 40-47.
• ENDO V, SILVA SOBRINHO AG, LIMA NLL, MANZI GM, CIRNE LGA, SANTANA VT & ALMEIDA FA. 2012. Muscularity and leg tissue composition of lambs fed with hydrolyzed sugarcane. World Acad Eng Technol 6: 1165-1167.
• HAMM R. 1986. Functional properties of the myofibrillar system and their measurements. In: BECHTEL PJ (Ed), Muscle as food, New York: Academic Press Inc., New York, USA, p. 135-199.
• KENYON PR & BLAIR HT. 2014. Foetal programming in sheep - Effects on production. Small Rum Res 118: 16-30.
• KOOHMARAIE M, DOUMIT ME & WHEELER TL. 1996. Meat toughening does not occur when rigor shortening is prevented. J Anim Sci 74: 2935-2942.
• LEÃO AG, SILVA SOBRINHO AG, MORENO GMB, SOUZA HBA, GIAMPIETRO A, ROSSI RC & PEREZ HL. 2012. Características físico-químicas e sensoriais da carne de cordeiros terminados com dietas contendo cana-de-açúcar ou silagem de milho e dois níveis de concentrado. Rev Bras Zootec 41: 1253-1262.
• MAPA. 2000. Ministério da Agricultura, Pecuária e Abastecimento. Instrução Normativa n° 07 de janeiro de 2000. Regulamento técnico de métodos de insensibilização para o abate humanitário de animais de açougue. S.D.A./M.A.A. Diário Oficial da União, Brasília.
• MILTENBURG GAJ, WENSING TH & SMULDERS FJM. 1992. Relationships between blood hemoglobin, plasma and tissue iron, muscle heme pigment, and carcass color of veal. J Anim Sci 70: 2766-2772.
• MOHRHAUSER DA, TAYLOR AR, GONDA MG, UNDERWOOD KR, PRITCHARD RH, WERTZ-LUTZ AE & BLAIR AD. 2015. The influence of maternal energy status during mid-gestation on beef offspring tenderness, muscle characteristics, and gene expression. Meat Sci 110: 201-211.
• NRC. 2007. Nutrient Requirements of Small Ruminants: Sheep, Goats, Cervids, and New World Camelids, 7th ed., Washington: The National Academic Press, 384 p.
• OLIVEIRA GM. 2020. Implications of pregnant sheep nutrition on progeny’s myofibers and blood parameters. (Doctoral dissertation). Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP.
• OSÓRIO JCS, OSÓRIO MTM, PEDROSO CES, MUNÕZ S, ESTEVES R, MENDONÇA G & CORRÊA F. 2005. Zootecnia de ovinos. Pelotas: Editora da Universidade PREC/UFPEL, 243 p.
• PEEL RK, ECKERLE GJ & ANTHONY RV. 2012. Effects of overfeeding naturally-mated adolescent ewes on maternal, fetal and postnatal lamb growth. J Anim Sci 90: 3698-3708.
• PEÑAGARICANO F, WANG X, ROSA GJ, RADUNZ AE & KHATIB H. 2014. Maternal nutrition induces gene expression changes in fetal muscle and adipose tissues in sheep. BMC Genom 15: 1034.
• PIAGGIO L, QUINTANS G, SAN JULIÁN R, FERREIRA G, ITHURRALDE J, FIERRO S, PEREIRA ASC, BALDI F & BANCHERO GE. 2018. Growth, meat and feed efficiency traits of lambs born to ewes submitted to energy restriction during mid-gestation. Animal 12: 256-264.
• PURCHAS RW, DAVIES AS & ABDULLAH AY. 1991. An objective measure of muscularity: changes with animal growth and differences between genetic lines of Southdown sheep. Meat Sci 30: 81-94.
• REED SA, RAJA JS, HOFFMAN ML, ZINN SA & GOVONI KE. 2014. Poor maternal nutrition inhibits muscle development in ovine offspring. J Anim Sci Biotechnol 5: 43.
• SANGLARD LP, NASCIMENTO M, MORIEL P, SOMMER P, ASHWELL M, POORE MH, DUARTE MS & SERÃO NVL. 2018. Impact of energy restriction during late gestation on the muscle and blood transcriptome of beef calves after preconditioning. BMC Genomics 19: 702.
• SAÑUDO C. 1992. La calidad organoléptica de la carne com especial referencia a la especie ovina: factores que la determinam, metodos de medida y causas de variacion. In: CURSO INTERNATIONAL SOBRE PRODUCCIÓN DE GANADO OVINO, 3., Zaragoza. Proceedings. Zaragoza: INIA, 117 p.
• SAÑUDO C, ALFONSO M, SÁNCHEZ A, DELFA R & TEIXEIRA A. 2000. Carcass and meat quality in light lambs from different fat classes in the EU carcass classification system. Meat Sci 56: 89-94.
• SAÑUDO C & SIERRA I. 1986. Calidad de la canal en la especie ovina. Ovino 11: 127-153.
• SARTORI ED, SESSIM AG, BRUTTI DD, LOPES JF, MCMANUS CM & BARCELLOS JOJ. 2020. Fetal programming in sheep: effects on pre- and postnatal development in lambs. J Anim Sci 98: 1-12.
• SILVA DJ & QUEIROZ AC. 2002. Análise de alimentos: métodos químicos e biológicos, 3rd ed., Viçosa: Universidade Federal de Viçosa, 235 p.
• SILVA SOBRINHO AG, KADIM IT & PURCHAS RW. 2003. Effect of genotypes and age on carcass and meat quality characteristics of ram lambs. J Agric Mar Sci 8: 73-78.
• SILVA SOBRINHO AG, SAÑUDO C, OSÓRIO JCS, ARRIBAS MMC & OSÓRIO MTM. 2008. Produção de carne ovina, 1st ed., Jaboticabal: Fundação de Apoio à Pesquisa, Ensino e Extensão, 228 p.
• SNIFFEN CJ, O’CONNOR DJ, VAN SOEST PJ, FOX DG & RUSSEL JB. 1992. A net carbohydrate and protein system for evaluating cattle diets: carbohydrate and protein availability. J Anim Sci 70: 562-3577.
• SOUSA MAPD ET AL. 2023. Overnutrition of ewe in late gestation and the impact on placental efficiency and lamb’s performance. Animals 13: 103.
• SWANSON TJ, HAMMER CJ, LUTHER JS, CARLSON DB, TAYLOR JB, REDMER DA, NEVILLE TL, REED JJ, CATON JS & VONNAHME KA. 2008. Effects of gestational plane of nutrition and selenium supplementation on mammary development and colostrum quality in pregnant ewe lambs. J Anim Sci 86: 2415-2423.
• TONG JF, YAN X, ZHU MJ, FORD SP, NATHANIELSZ PW & DU M. 2009. Maternal obesity downregulates myogenesis and ß-catenin signaling in fetal skeletal muscle. Am J Physiol Endocrinol Metab 296: e917-E924.
• TORNBERG E. 2005. Effects of heat on meat proteins - Implications on structure and quality of meat products. Meat Sci 70: 493-508.
• UNDERWOOD KR, TONG JF, PRICE PL, ROBERTS AJ, GRINGS EE, HESS BW, MEANS WJ & DU M. 2010. Nutrition during mid to late gestation affects growth, adipose tissue deposition, and tenderness in cross-bred beef steers. Meat Sci 86: 588-593.
• VAN WYK JA & BATH GF. 2002. The FAMACHA system for managing haemonchosis in sheep and goats by clinically identifying individual animals for treatment. Vet Res 33: 509-529.
• VONNAHME KA. 2012. How the maternal environment impacts fetal and placental development: implications for livestock production. Anim Reprod 9: 789-797.
• WALLACE JM, BOURKE DA, AITKEN RP, LEITCH N & HAY JR WW. 2002. Blood flows and nutrient uptakes in growth-restricted pregnancies induced by overnourishing adolescent sheep. Am J Physiol Regul Integr Comp Physiol 282: R1027-R1036.
• WEISS WP. 1999. Energy prediction equations for ruminant feeds, In: CORNELL NUTRITION CONFERENCE FOR FEED MANUFACTURERS, 61., Ithaca. Proceedings ... , Rochester: Cornell University, p. 176-185.
• WILSON TB, FAULKNER DB & SHIKE DW. 2016. Influence of prepartum dietary on beef cow performance and calf growth and carcass characteristics. Livest Sci 184: 21-27.
• WHEELER TL & KOOHMARAIE M. 2002. The extent of proteolysis is independent of sarcomere length in lamb longissimus dorsi and psoas major. J Anim Sci 77: 2444-2451.
• ZUNDT M, MACEDO FAF, ASTOLPHI JLL, MEXIA AA & SAKAGUTI ES. 2006. Desempenho e características de carcaça de cordeiros Santa Inês confinados, filhos de ovelhas submetidas à suplementação alimentar durante a gestação. Rev Bras Zootec 35: 928-935.

Publication Dates

• Publication in this collection
  10 May 2024
• Date of issue
  2024

History

• Received
  24 Feb 2023
• Accepted
  04 Feb 2024