Advanced Onset of Puberty in Gilts of Thrifty Genotype (Iberian Pig)

Abstract

The Iberian pig is an autochthonous breed of the Mediterranean area, reared extensively in the central and southern areas of Spain and Portugal and that is known worldwide for the production of Iberian ham. The characteristics of the Iberian ham are related to its abundance of intramuscular fat, owing to the high capacity of the pig to accumulate fat under its skin and between the muscular fibres. This ability to store excess fat enables survival during periods of scarcity and it has been found in other antique animal breeds and even in humans, being named as the thrifty genotype. The reproductive management of the Iberian pig, in spite of a lack of accurate information unlike in other swine breeds, is based on the assumption of lower reproductive precocity and efficiency than the modern commercial breeds. The current study characterized and compared the onset of puberty in gilts of Iberian breed and meat commercial crosses (Large White × Landrace) reared in the same conditions by assessing weekly plasma progesterone profiles. At the end of the experimental period, when the gilts became 180 days old, the percentage of Iberian females that had reached puberty was 72.2%, with a mean age and weight of 160.5 ± 2.6 days and 92.9 ± 4.7 kg, respectively. The percentage of Large White × Landrace cross-breed females reaching puberty at 180 days was only 15% (p < 0.05). The mean age and weight were 165.0 ± 4.1 days and 107.8 ± 2.2 kg (p < 0.05), respectively. Thus, converse to the traditional assumption, onset of puberty was advanced in Iberian gilts. These results are important for the reproductive management of the Iberian pig but, at the same time, may set the basis for future studies on the metabolism-reproduction link and, specifically, on the possible relationship between earlier accumulation of fat and attainment of puberty.

Body composition and blood parameters of newborn piglets from Alentejano and conventional (Large White × Landrace) genotype

“…On these bases, piglets born from Alentejano sows are expected to be more mature at birth than those born from conventional sows. Further, similar to the Meishan female (Legault and Caritez, 1983), the onset of puberty occurs earlier in the IB female (González-Añover et al, 2009) than in modern commercial crosses (LW × LR) when fed similarly. This and the greater maturity at birth would indicate that the IB swine is more precocious than conventional swine.…”

Use of an anti-GnRF vaccine to suppress estrus in crossbred Iberian female pigs

“…However, there is no clear information about the real impact of this specific cross on the sexual maturation of these animals. For instance, Gonzalez-Añover et al [4] described that the onset of puberty was earlier in Iberian gilts compared to a Large White  Landrace commercial cross which differed from the traditional assumptions.…”

“…On the other hand, Gonzalez-Añover et al [4] concluded that Iberian females can reach puberty before 180 days of age. In our study, the Iberian females showed first estrus behavior at around 160 days of age.…”

“…It has been stated that the Iberian female pig begins puberty at an average age of 207 days (7 months) [1] or 180 days [4]. It is clear that males and females are reared for several months after becoming fertile.…”

Developmental Stage, Muscle and Genetic Type Modify Muscle Transcriptome in Pigs: Effects on Gene Expression and Regulatory Factors Involved in Growth and Metabolism

“…However, in the Mediterranean area these commercial breeds coexist with local breeds, used for the production of unique high-quality traditional pork products. These breeds, usually known as fatty-pigs, are smaller in size, have not undergone intense genetic selection and are less productive than modern breeds [2]. Moreover, due to the traditional rearing system, under extensive free-range conditions, they are exposed to harsh environments and seasonal variations in food availability (associated with the development of a thrifty genotype) [3].…”